What is ranitidine

Ranitidine is a class of medications called histamine-2 blockers (H2 blockers) and ranitidine works by reducing the amount of acid your stomach produces. Ranitidine is used to treat and prevent ulcers in the stomach and intestines. Ranitidine also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Ranitidine also treats gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn and injury of the food pipe (esophagus).

Over-the-counter ranitidine is used to prevent and treat symptoms of heartburn associated with acid indigestion and sour stomach.

Ranitidine comes as tablets, soluble (dispersible) tablets that dissolve in water to make a drink, or as a liquid that you drink.

All types of ranitidine are available on prescription. You can also buy the lowest strength 75mg tablets from pharmacies and supermarkets.

Key facts

• It’s usual to take ranitidine once or twice a day.
• Some people only need to take ranitidine for a short time, when they have symptoms. Others need to take it for longer.
• You can take ranitidine with or without food.
• It’s unusual to get any side effects. However, some people may get stomach pain or constipation, or feel sick (nausea). This tends to get better as you carry on taking ranitidine.
• Ranitidine is called by the brand names Zantac, Zantac 75, Zantac EFFERdose, Zantac Syrup and Taladine

Ranitidine mechanism of action

Ranitidine is a histamine-2 antagonist or H2 blocker. Ranitidine works by reducing the amount of acid your stomach produces. Histamine is a chemical that occurs naturally in your body. Histamine encourages your stomach to produce acid which it needs to digest your food. By blocking the histamine, ranitidine reduces the amount of acid your stomach produces. Having less acid in your stomach allows ulcers and inflammation to heal. If your foodpipe (esophagus) has been damaged by stomach acid, this will also have a chance to heal.

Before taking ranitidine – Precautions

• tell your doctor and pharmacist if you are allergic to ranitidine or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention either of the following: anticoagulants (‘blood thinners’) such as warfarin (Coumadin); and triazolam (Halcion). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had porphyria, phenylketonuria, or kidney or liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking ranitidine, call your doctor.
• Using ranitidine may increase your risk of developing pneumonia. Symptoms of pneumonia include chest pain, fever, feeling short of breath, and coughing up green or yellow mucus. Talk with your doctor about your specific risk of developing pneumonia.

How much ranitidine is safe to take?

Ranitidine comes as a tablet, an effervescent tablet, effervescent granules, and a syrup to take by mouth. Each tablet contains 75mg, 150mg or 300mg of ranitidine. You can buy 75mg tablets in pharmacies and supermarkets. Soluble tablets, and 150mg and 300mg tablets are only available on prescription.

Ranitidine is usually taken once a day at bedtime or two to four times a day. Over-the-counter ranitidine comes as a tablet to take by mouth. It is usually taken once or twice a day. To prevent symptoms, it is taken 30 to 60 minutes before eating or drinking foods that cause heartburn. Follow the directions on your prescription or the package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take ranitidine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Dissolve ranitidine effervescent tablets and granules in a full glass (6 to 8 ounces [180 to 240 milliliters]) of water before drinking.

Do not take over-the-counter ranitidine for longer than 2 weeks unless your doctor tells you to. If symptoms of heartburn, acid indigestion, or sour stomach last longer than 2 weeks, stop taking ranitidine and call your doctor.

The usual dose to treat:

• indigestion or heartburn is 75mg to 300mg ranitidine a day
• stomach ulcers and inflammation of the food pipe is 300mg to 600mg ranitidine a day
• Zollinger-Ellison syndrome is 450mg to 6 grams ranitidine a day

Ranitidine liquid comes in 2 different strengths – your daily dose will depend on what your doctor prescribes. Follow your doctor’s advice about how much ranitidine to take and when.

• Doses are usually lower for children and people with kidney problems.

If a doctor prescribes ranitidine for your child, they will use your child’s weight or age to work out the right dose.

How long does ranitidine take to work

Your indigestion and heartburn should start to feel better within 1 or 2 hours. The effects will usually last for around 12 hours.

It may take a few weeks for ranitidine to work properly. Depending on your problems, you may still have some acid symptoms during this time.

If you’re taking ranitidine to prevent stomach ulcers, however, you may not feel any different. Carry on taking your medicine. It will still be working.

How long will I take ranitidine for?

If you’re taking lower strength ranitidine (75mg) that you bought from a pharmacy or supermarket, speak to a pharmacist or doctor before starting on a second packet. They may recommend tests to find out what’s causing your symptoms, if taking ranitidine hasn’t cleared them up.

If your doctor prescribes ranitidine for you, you may only need to take it for a few weeks or months, depending on your health problem. Sometimes you might need to take it for longer.

Your doctor may suggest taking ranitidine only when you have symptoms. This means you won’t have to take it every day. Once you feel better, you can stop taking it – often after a few days or weeks.

Taking ranitidine this way isn’t suitable for everyone. Speak to your doctor about what’s best for you.

Although ranitidine appears to only minimally affect the secretion of gastric intrinsic factor, malabsorption of, and resultant deficiency in vitamin B12 may occur during long-term ranitidine therapy ¹.

Is it safe to take ranitidine every day?

It’s usually best to take ranitidine for a short time. You might take it for a month or two, for example, until your stomach heals. Some people may take it every now and again when they have symptoms. You may find that ranitidine stops working and your symptoms come back if you take it for longer than this.

If you’re taking ranitidine to treat Zollinger Ellison syndrome or another long term problem, however, you may need to take it for longer. In this case, follow your doctor’s instructions about the best way to take it.

Are there similar medicines to ranitidine?

There are 3 other medicines that are similar to ranitidine. They are cimetidine, famotidine and nizatidine.

Like ranitidine, these medicines are H2 blockers. They work in the same way as ranitidine to reduce the amount of acid in your stomach.

Famotidine and nizatidine generally work as well as ranitidine and have similar side effects. However they may suit some people better.

Cimetidine can interfere with lots of medicines and has more side effects than other H2 blockers.

Are there other indigestion medicines?

Yes there are other pharmacy and prescription medicines for indigestion and heartburn.

Antacids, like calcium carbonate (Tums or Mylanta), sodium bicarbonate (Neut), Maalox and Milk of Magnesia, relieve indigestion and heartburn by neutralizing the acid in your stomach. They give quick relief that lasts for a few hours. They’re ideal for occasional stomach acid symptoms.

Some antacids, such as Gaviscon, have an extra ingredient called alginic acid. They work by lining your stomach so that juices from it don’t splash up into your foodpipe. They’re especially good for relieving acid reflux.

Antacids are available from pharmacies and supermarkets.

Proton pump inhibitors (PPIs) reduce the amount of acid made in your stomach, but they do this in a different way to H2 blockers.

They include esomeprazole (Nexium), lansoprazole (Zoton FasTabs), omeprazole (Losec), pantoprazole (Pantoloc Control) and rabeprazole (Pariet).

In general, proton pump inhibitors (PPIs) are used first because they are better than H2 blockers at reducing stomach acid. Your doctor may prescribe an H2 blocker if you don’t get on with a proton pump inhibitor (PPI) – for example because of the side effects.

Lansoprazole and rabeprazole are only available on prescription but you can buy omeprazole, esomeprazole and pantoprazole directly from pharmacies. You can also buy esomeprazole from supermarkets.

Can I take ranitidine with other indigestion medicines?

Some antacids are okay to take at the same time as ranitidine. Other antacids, such as Gaviscon, need to be taken a certain amount of time before or after you take the ranitidine. Check the instructions on the packet to see how long you need to wait between medicines.

Sometimes, depending on your symptoms, your doctor may prescribe an H2 blocker as well as a proton pump inhibitor. This will often be for a short time and you’ll usually take the H2 blocker at night.

If you’re prescribed sucralfate (a medicine to treat ulcers), take it at least 2 hours after ranitidine. This is because sucralfate can stop your body from properly absorbing the ranitidine.

Can I drive or ride a bike after taking ranitidine?

Occasionally, ranitidine can make you feel dizzy or sleepy, or give you blurred vision. If this happens to you, don’t drive, cycle or use machinery or tools until you feel better.

Furthermore, the amount of alcohol contained in a large dose of ranitidine liquid may affect your ability to drive or operate machines. In this case, do not attempt to drive or use any machinery.

Can I drink alcohol with ranitidine?

Yes, you can drink alcohol with ranitidine but be aware that ranitidine liquid also contains a small amount of alcohol.

Also, drinking alcohol makes your stomach produce more acid than normal. This can irritate your stomach lining and make your symptoms worse.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking ranitidine.

However, it’s best to avoid foods that seem to make your indigestion worse, such as rich, spicy and fatty foods. You may also want to cut down on caffeinated drinks, such as tea, coffee and cola, as well as alcohol.

Can lifestyle changes help?

It may be possible to ease symptoms caused by too much stomach acid by making a few changes to your diet and lifestyle:

• lose excess weight
• don’t eat foods that can make your symptoms worse, such as rich, spicy and fatty foods, and acidic foods like tomatoes, citrus fruits, salad dressings and fizzy drinks
• cut down on caffeinated drinks, such as tea, coffee and cola, as well as alcohol and smoking
• if you have symptoms at night, try not to eat for at least 3 hours before you go to bed
• raise the head of your bed by 10 to 20cm, so your head and chest are higher than your waist

Who can and can’t take ranitidine

Ranitidine can be taken by adults. It can also be given to children under 16 years of age on prescription.

Ranitidine isn’t suitable for some people. To make sure that it is safe for you, tell your doctor if you:

• have had an allergic reaction to ranitidine or any other medicines in the past
• have kidney problems
• have an intolerance to, or cannot absorb, some sugars such as fructose
• have been advised to eat a low calcium or low salt diet
• cannot have alcohol – ranitidine liquid contains a small amount of alcohol
• have phenylketonuria (PKU), a rare inherited illness

If you’re due to have an endoscopy to find out what’s causing your symptoms, stop taking ranitidine at least 2 weeks before your procedure. This is because ranitidine may hide some of the problems that would usually be spotted during an endoscopy.

Pediatric Use

The safety and effectiveness of ranitidine have been established in the age-group of 1 month to 16 years for the treatment of duodenal and gastric ulcers, gastroesophageal reflux disease and erosive esophagitis, and the maintenance of healed duodenal and gastric ulcer. Use of ranitidine in this age-group is supported by adequate and well-controlled trials in adults, as well as additional pharmacokinetic data in pediatric patients and an analysis of the published literature.

Safety and effectiveness in pediatric patients for the treatment of pathological hypersecretory conditions or the maintenance of healing of erosive esophagitis have not been established.

Safety and effectiveness in neonates (aged younger than 1 month) have not been established.

Geriatric Use

Of the total number of subjects enrolled in US and foreign controlled clinical trials of oral formulations of ranitidine, for which there were subgroup analyses, 4,197 were aged 65 and older, while 899 were aged 75 and older. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

This drug is known to be substantially excreted by the kidney and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, caution should be exercised in dose selection, and it may be useful to monitor renal function.

Pregnancy and breastfeeding

Tell your pharmacist or doctor if you’re trying to get pregnant, are already pregnant or if you’re breastfeeding.

Usually, ranitidine is safe to take during pregnancy and while breastfeeding. Animal models have failed to reveal evidence of impaired fertility or fetal harm. It is unknown whether use of gastric-suppressing drugs are associated with childhood allergy and asthma. There are no controlled data in human pregnancy.

If you’re pregnant, it’s always better to try to treat indigestion without taking a medicine.

Your doctor or midwife will first advise you to try to ease your symptoms by eating smaller meals more often, and not eating fatty and spicy foods. They may also suggest raising the head of your bed by 10 to 20cm, so your head and chest are higher than your waist. This will help stop stomach acid travelling up towards your throat.

If these lifestyle changes don’t work, you may be recommended a medicine like ranitidine.

Teratogenic Effects

Pregnancy Category B. Reproduction studies have been performed in rats and rabbits at doses up to 160 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to ranitidine. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Carcinogenesis, Mutagenesis, Impairment of Fertility

There was no indication of tumorigenic or carcinogenic effects in life-span studies in mice and rats at dosages up to 2,000 mg/kg/day.

Ranitidine was not mutagenic in standard bacterial tests (Salmonella, Escherichia coli) for mutagenicity at concentrations up to the maximum recommended for these assays.

In a dominant lethal assay, a single oral dose of 1,000 mg/kg to male rats was without effect on the outcome of 2 matings per week for the next 9 weeks.

Ranitidine and breastfeeding

Ranitidine is safe to take while you’re breastfeeding. It passes into breast milk, but only in small amounts which aren’t harmful to the baby.

However, if your baby is premature or has health problems check with your doctor first.

Cautions with other medicines

For safety, tell your pharmacist or doctor if you’re taking other medicines including herbal remedies, vitamins or supplements.

Some medicines can interfere with ranitidine and make you more likely to have side effects.

Tell your doctor if you’re taking these medicines before you start taking ranitidine:

• anti-fungal medicines such as itraconazole, ketoconazole or posaconazole
• any medicine used to treat cancer
• HIV medicines

Ranitidine has been reported to affect the bioavailability of other drugs through several different mechanisms such as competition for renal tubular secretion, alteration of gastric pH, and inhibition of cytochrome P450 enzymes.

Procainamide: Ranitidine, a substrate of the renal organic cation transport system, may affect the clearance of other drugs eliminated by this route. High doses of ranitidine (e.g., such as those used in the treatment of Zollinger-Ellison syndrome) have been shown to reduce the renal excretion of procainamide and N-acetylprocainamide resulting in increased plasma levels of these drugs. Although this interaction is unlikely to be clinically relevant at usual ranitidine doses, it may be prudent to monitor for procainamide toxicity when administered with oral ranitidine at a dose exceeding 300 mg per day.

Warfarin: There have been reports of altered prothrombin time among patients on concomitant warfarin and ranitidine therapy. Due to the narrow therapeutic index, close monitoring of increased or decreased prothrombin time is recommended during concurrent treatment with ranitidine.

Ranitidine may alter the absorption of drugs in which gastric pH is an important determinant of bioavailability. This can result in either an increase in absorption (e.g., triazolam, midazolam, glipizide) or a decrease in absorption (e.g., ketoconazole, atazanavir, delavirdine, gefitinib). Appropriate clinical monitoring is recommended.

Atazanavir: Atazanavir absorption may be impaired based on known interactions with other agents that increase gastric pH. Use with caution. See atazanavir label for specific recommendations.

Delavirdine: Delavirdine absorption may be impaired based on known interactions with other agents that increase gastric pH. Chronic use of H2-receptor antagonists with delavirdine is not recommended.

Gefitinib: Gefitinib exposure was reduced by 44% with the coadministration of ranitidine and sodium bicarbonate (dosed to maintain gastric pH above 5.0). Use with caution.

Glipizide: In diabetic patients, glipizide exposure was increased by 34% following a single 150-mg dose of oral ranitidine. Use appropriate clinical monitoring when initiating or discontinuing ranitidine.

Ketoconazole: Oral ketoconazole exposure was reduced by up to 95% when oral ranitidine was coadministered in a regimen to maintain a gastric pH of 6 or above. The degree of interaction with usual dose of ranitidine (150 mg twice daily) is unknown.

Midazolam: Oral midazolam exposure in 5 healthy volunteers was increased by up to 65% when administered with oral ranitidine at a dose of 150 mg twice daily. However, in another interaction trial in 8 volunteers receiving IV midazolam, a 300-mg oral dose of ranitidine increased midazolam exposure by about 9%. Monitor patients for excessive or prolonged sedation when ranitidine is coadministered with oral midazolam.

Triazolam: Triazolam exposure in healthy volunteers was increased by approximately 30% when administered with oral ranitidine at a dose of 150 mg twice daily. Monitor patients for excessive or prolonged sedation.

These are not all the medicines that may not mix well with ranitidine. For a full list see the leaflet inside your medicines packet.

Mixing ranitidine with herbal remedies and supplements

There isn’t enough research to know if complementary medicines and herbal remedies are safe to take with ranitidine.

What is ranitidine used for

Ranitidine is used to treat and prevent ulcers in the stomach and intestines. Ranitidine also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Ranitidine also treats gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn and injury of the food pipe (esophagus).

Ranitidine is also used sometimes to treat upper gastrointestinal bleeding and to prevent stress ulcers, stomach damage from use of nonsteroidal anti-inflammatory drugs (NSAIDs), and aspiration of stomach acid during anesthesia. Talk to your doctor about the risks of using this medication for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Ranitidine reduces the amount of acid your stomach makes.

• Short-term treatment of active duodenal ulcer. Most patients heal within 4 weeks. Trials available to date have not assessed the safety of ranitidine in uncomplicated duodenal ulcer for periods of more than 8 weeks.
• Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of acute ulcers. No placebo-controlled comparative trials have been carried out for periods of longer than 1 year.
• The treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome and systemic mastocytosis).
• Short-term treatment of active, benign gastric ulcer. Most patients heal within 6 weeks and the usefulness of further treatment has not been demonstrated. Trials available to date have not assessed the safety of ranitidine in uncomplicated, benign gastric ulcer for periods of more than 6 weeks.
• Maintenance therapy for gastric ulcer patients at reduced dosage after healing of acute ulcers. Placebo-controlled trials have been carried out for 1 year.
• Treatment of gastro-esophageal reflux disease (GERD). Symptomatic relief commonly occurs within 24 hours after starting therapy with Zantac 150 mg twice daily.
• Treatment of endoscopically diagnosed erosive esophagitis. Symptomatic relief of heartburn commonly occurs within 24 hours of therapy initiation with ranitidine 150 mg 4 times daily.
• Maintenance of healing of erosive esophagitis. Placebo-controlled trials have been carried out for 48 weeks.

Concomitant antacids should be given as needed for pain relief to patients with active duodenal ulcer; active, benign gastric ulcer; hypersecretory states; GERD; and erosive esophagitis.

Ranitidine is also taken to prevent and treat stomach ulcers.

Sometimes, ranitidine is taken for a rare illness caused by a tumor in the pancreas or gut called Zollinger-Ellison syndrome.

Ranitidine dose

Usual Adult Dose for Duodenal Ulcer

Oral

• Treatment dose: 150 mg orally 2 times a day OR 300 mg orally once a day after the evening meal or at bedtime
• Maintenance dose: 150 mg orally once a day at bedtime
• Duration of therapy: 8 weeks (treatment); up to 1 year (maintenance)

Parenteral:

IM or IV (bolus or intermittent infusion) Injection:

-Usual dose: 50 mg IM or IV every 6 to 8 hours
-Maximum dose: 400 mg/day

Continuous IV Infusion:

-Usual rate: 6.25 mg/hour

Comments:

• Patients may use antacids to treat pain.
• Both once or 2 times a day oral dosing regimens were shown to be effective in inhibiting gastric acid secretion.
• Injectable formulations do not require dilution when given as an IM injection.
• Intermittent IV bolus injections should be diluted up to 2.5 mg/mL and injected at a rate of up to 4 mL/min.
• Intermittent IV infusions should be diluted up to a concentration of 0.5 mg/mL and infused at a rate of up to 5 to 7 mL/min (approximately 15 to 20 minutes).
• Most patients receiving oral formulations heal within 4 weeks; there are no safety data for the treatment of uncomplicated duodenal ulcer beyond 8 weeks. Studies have not been conducted to assess safety in oral maintenance therapy longer than 1 year.
  

Uses:

• Short-term treatment of active duodenal ulcer
• Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of acute ulcers
• Some hospitalized patients with intractable duodenal ulcers

Usual Adult Dose for Dyspepsia

ORAL (OVER-THE-COUNTER FORMULATIONS):

• Symptom relief: 75 to 150 mg orally with a glass of water
• Symptom prevention: 75 to 150 mg orally with a glass of water 30 to 60 minutes before a meal
• Maximum dose: 2 tablets/day
• Duration of therapy: Up to 14 days (self-treatment)

Uses:

• Relief of heartburn associated with acid indigestion and sour stomach
• Relief of heartburn associated with acid indigestion and sour stomach brought on by eating/drinking certain foods and beverages

Usual Adult Dose for Erosive Esophagitis

ORAL:

• Treatment dose: 150 mg orally 4 times a day
• Maintenance dose: 150 mg orally 2 times a day
• Duration of therapy: Up to 48 weeks (maintenance)

Comments:

• Symptomatic relief usually starts within 24 hours of starting oral treatment.
• Placebo-controlled studies included use of maintenance doses for up to 48 weeks.

Use:

• Treatment of endoscopically diagnosed erosive esophagitis

Usual Adult Dose for Zollinger-Ellison Syndrome

ORAL:

• Initial dose: 150 mg orally 2 times a day
• Maximum dose: Up to 6 g/day

PARENTERAL:
Continuous IV Infusion:

-Initial rate: 1 mg/kg/hr
-Titration: After 4 hours, if gastric acid output is greater than 10 mEq/hr or the patient is symptomatic, the dose should be increased in 0.5 mg/kg/hr increments and acid levels should be re-measured
-Maximum dose: 2.5 mg/kg/hr
-Maximum rate: 220 mg/hr

Comment:
-Continuous IV infusions should be diluted to a concentration of 2.5 mg/mL or less.

Uses:

• Treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome, systemic mastocytosis)
• Alternative to oral formulations for short-term use in some hospitalized patients who are unable to take oral medications

Usual Adult Dose for Pathological Hypersecretory Conditions

ORAL:

• Initial dose: 150 mg orally 2 times a day
• Maximum dose: Up to 6 g/day

PARENTERAL:
Continuous IV Infusion:

-Initial rate: 1 mg/kg/hr
-Titration: After 4 hours, if gastric acid output is greater than 10 mEq/hr or the patient is symptomatic, the dose should be increased in 0.5 mg/kg/hr increments and acid levels should be re-measured
-Maximum dose: 2.5 mg/kg/hr
-Maximum rate: 220 mg/hr

Comment:
-Continuous IV infusions should be diluted to a concentration of 2.5 mg/mL or less.

Uses:

• Treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome, systemic mastocytosis)
• Alternative to oral formulations for short-term use in some hospitalized patients who are unable to take oral medications

Usual Adult Dose for Gastroesophageal Reflux Disease (GERD)

ORAL:

• Usual dose: 150 mg orally 2 times a day

Comment:

Symptomatic relief usually starts within 24 hours of starting oral treatment.

Use:

Treatment of gastroesophageal reflux disease

Usual Adult Dose for Gastric Ulcer

ORAL:

• Treatment dose: 150 mg orally 2 times a day
• Maintenance dose: 150 mg orally once a day at bedtime

Comments:

Most patients heal within 6 weeks; there are no safety data for the treatment of uncomplicated, benign gastric ulcer beyond 6 weeks.

Uses:

Short-term treatment of active, benign gastric ulcer
Maintenance therapy for gastric ulcer patients at reduced dosage after healing of acute ulcers

Usual Pediatric Dose for Duodenal Ulcer

Less than 1 month AND with Extracorporeal membrane oxygenation:

PARENTERAL:
-2 mg/kg IV every 12 to 24 hours OR as a continuous infusion

1 month to 16 years:

ORAL:

• Treatment dose: 2 to 4 mg/kg orally 2 times a day
• Maximum treatment dose: 300 mg/day
• Maintenance dose: 2 to 4 mg/kg orally once a day
• Maximum maintenance dose: 150 mg/day

PARENTERAL:
-Usual dose: 2 to 4 mg/kg IV, divided and given every 6 to 8 hours OR as a continuous infusion
-Maximum dose: 50 mg/dose

16 years and older:

ORAL:

• Treatment dose: 150 mg orally 2 times a day OR 300 mg orally once a day after the evening meal or at bedtime
• Maintenance dose: 150 mg orally once a day at bedtime
• Duration of therapy: 8 weeks (treatment); up to 1 year (maintenance)

PARENTERAL:

IM or IV (bolus or intermittent infusion) Injection:
-Usual dose: 50 mg IM or IV every 6 to 8 hours
-Maximum dose: 400 mg/day

Continuous IV Infusion:
-Usual rate: 6.25 mg/hour

Comments:
-Patients younger than 1 month with ECMO who were given doses of 2 mg/kg had a gastric pH of greater than 4 for at least 15 hours.
-Placebo-controlled studies included use of maintenance doses for up to 48 weeks.
-Injectable formulations do not require dilution when given as an IM injection.
-Intermittent IV bolus injections should be diluted up to 2.5 mg/mL and injected at a rate of up to 4 mL/min.
-Intermittent IV infusions should be diluted up to a concentration of 0.5 mg/mL and infused at a rate of up to 5 to 7 mL/min (approximately 15 to 20 minutes).

Uses:

• Alternative to oral formulations for short-term use in some hospitalized patients who are unable to take oral medications
• Short-term treatment of active duodenal ulcer
• Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of acute ulcers
• Some hospitalized patients with intractable duodenal ulcers

Usual Pediatric Dose for Gastric Ulcer

Less than 1 month AND with Extracorporeal membrane oxygenation (ECMO):

PARENTERAL:

-2 mg/kg IV every 12 to 24 hours OR as a continuous infusion

1 month to 16 years:

ORAL:

• Treatment dose: 2 to 4 mg/kg orally 2 times a day
• Maximum treatment dose: 300 mg/day
• Maintenance dose: 2 to 4 mg/kg orally once a day
• Maximum maintenance dose: 150 mg/day

PARENTERAL:

-Usual dose: 2 to 4 mg/kg IV, divided and given every 6 to 8 hours OR as a continuous infusion
-Maximum dose: 50 mg/dose

16 years and older:

ORAL:

• Treatment dose: 150 mg orally 2 times a day OR 300 mg orally once a day after the evening meal or at bedtime
• Maintenance dose: 150 mg orally once a day at bedtime
• Duration of therapy: 8 weeks (treatment); up to 1 year (maintenance)

PARENTERAL:

IM or IV (bolus or intermittent infusion) Injection:

-Usual dose: 50 mg IM or IV every 6 to 8 hours
-Maximum dose: 400 mg/day

Continuous IV Infusion:

-Usual rate: 6.25 mg/hour

Comments:

• Patients younger than 1 month with extracorporeal membrane oxygenation who were given doses of 2 mg/kg had a gastric pH of greater than 4 for at least 15 hours.
• Placebo-controlled studies included use of maintenance doses for up to 48 weeks.
• Injectable formulations do not require dilution when given as an IM injection.
• Intermittent IV bolus injections should be diluted up to 2.5 mg/mL and injected at a rate of up to 4 mL/min.
• Intermittent IV infusions should be diluted up to a concentration of 0.5 mg/mL and infused at a rate of up to 5 to 7 mL/min (approximately 15 to 20 minutes).

Uses:

• Alternative to oral formulations for short-term use in some hospitalized patients who are unable to take oral medications
• Short-term treatment of active duodenal ulcer
• Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of acute ulcers
• Some hospitalized patients with intractable duodenal ulcers

Usual Pediatric Dose for Gastroesophageal Reflux Disease

1 month to 16 years:

ORAL:

Usual dose: 5 to 10 mg/kg/day orally, given in 2 divided doses

16 years and older:

ORAL:

Usual dose: 150 mg orally 2 times a day

Comments:

Symptomatic relief usually starts within 24 hours of starting oral treatment.
Placebo-controlled studies included use of maintenance doses for up to 48 weeks.

Use:

Treatment of gastroesophageal reflux disease

Usual Pediatric Dose for Erosive Esophagitis

1 month to 16 years:

ORAL:

Usual dose: 5 to 10 mg/kg/day, given in 2 divided doses

16 years and older:

ORAL:

• Treatment dose: 150 mg orally 4 times a day
• Maintenance dose: 150 mg orally 2 times a day
• Duration of therapy: Up to 48 weeks (maintenance)

Comments:

• Symptomatic relief usually starts within 24 hours of starting oral treatment.
• Placebo-controlled studies included use of maintenance doses for up to 48 weeks.

Use:

Treatment of endoscopically diagnosed erosive esophagitis

Usual Pediatric Dose for Dyspepsia

12 years and older:

ORAL (OVER-THE-COUNTER FORMULATIONS):

• Symptom relief: 75 mg orally with a glass of water
• Symptom prevention: 75 mg orally with a glass of water 30 to 60 minutes before a meal
• Maximum dose: 150 mg/day
• Duration of therapy: Up to 14 days (self-treatment)

Uses:

• Relieve heartburn associated with acid indigestion and sour stomach
• Relieve heartburn associated with acid indigestion and sour stomach brought on by eating/drinking certain foods and beverages

Renal Dose Adjustments

Creatinine Clearance less than 50 mL/min:

Oral: 150 mg orally every 24 hours. The frequency of dosing may be increased with caution.

Parenteral:

• IM/IV: 50 mg IM/IV every 18 to 24 hours. The frequency of dosing may be increased to every 12 hours (or further) with caution.
• Continuous infusion: Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

Elderly patients: Since elderly patients are more likely to have decreased renal function, dose selection should be made cautiously, and an increased frequency of renal function monitoring should be considered.

How and when to take ranitidine

It’s usual to take ranitidine twice a day – 1 dose in the morning and 1 dose in the evening. Some people only need to take ranitidine once a day, at bedtime.

Very young babies, and people with Zollinger-Ellison syndrome, usually take ranitidine 3 times a day. People with severe inflammation of the food pipe (esophagitis) may need to take it 4 times a day.

How to take ranitidine

Take ranitidine exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Your doctor may recommend an antacid to help relieve pain. Carefully follow your doctor’s directions about the type of antacid to use, and when to use it.

You can take ranitidine with or without food. However, if you get symptoms whenever you eat or drink, take your medicine 30 minutes to 60 minutes before having a drink, snack or meal.

• Tablets – swallow tablets whole with a glass of water, milk or juice.
• Soluble tablets – dissolve tablets in half a glass of water. Do not use milk, fizzy water or other fizzy drinks. Wait until the medicine has completely dissolved and then drink it straight away.
• Liquid – this comes with a syringe or spoon to help you measure it. If you don’t have a syringe or spoon, ask your pharmacist for one. Do not use a kitchen teaspoon as it won’t give you the right amount.

Liquid ranitidine is suitable for children and people who find it difficult to swallow tablets.

Do not crush, chew, or break the ranitidine effervescent tablet, and do not allow it to dissolve on your tongue. The 25-milligram effervescent tablet must be dissolved in at least 1 teaspoon of water before swallowing. The150-milligram effervescent tablet should be dissolved in 6 to 8 ounces of water.

Allow the ranitidine effervescent tablet to dissolve completely in the water, and then drink the entire mixture. If you are giving this medicine to a child, you may draw the liquid mixture into a medicine dropper and empty the dropper into the child’s mouth.

Ranitidine granules should be mixed with 6 to 8 ounces of water before drinking.

Measure ranitidine liquid with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

It may take up to 8 weeks before your ulcer heals. Keep using the medication as directed and tell your doctor if your symptoms do not improve after 6 weeks of treatment.

This medication can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using ranitidine.

Store ranitidine at room temperature away from moisture, heat, and light.

Active Duodenal Ulcer:

The current recommended adult oral dosage of ranitidine for duodenal ulcer is 150 mg twice daily. An alternative dosage of 300 mg once daily after the evening meal or at bedtime can be used for patients in whom dosing convenience is important. The advantages of one treatment regimen compared with the other in a particular patient population have yet to be demonstrated. Smaller doses have been shown to be equally effective in inhibiting gastric acid secretion in US trials, and several foreign trials have shown that 100 mg twice daily is as effective as the 150-mg dose.

Antacid should be given as needed for relief of pain.

Maintenance of Healing of Duodenal Ulcers:

The current recommended adult oral dosage is 150 mg at bedtime.

Pathological Hypersecretory Conditions (such as Zollinger-Ellison syndrome):

The current recommended adult oral dosage is 150 mg twice daily. In some patients it may be necessary to administer ranitidine 150-mg doses more frequently. Dosages should be adjusted to individual patient needs, and should continue as long as clinically indicated. Dosages up to 6 g/day have been employed in patients with severe disease.

Benign Gastric Ulcer:

The current recommended adult oral dosage is 150 mg twice daily.

Maintenance of Healing of Gastric Ulcers:

The current recommended adult oral dosage is 150 mg at bedtime.

Gastro-esophageal reflux disease (GERD):

The current recommended adult oral dosage is 150 mg twice daily.

Erosive Esophagitis:

The current recommended adult oral dosage is 150 mg 4 times daily.

Maintenance of Healing of Erosive Esophagitis:

The current recommended adult oral dosage is 150 mg twice daily.

Pediatric Use:

The safety and effectiveness of ranitidine have been established in the age-group of 1 month to 16 years. There is insufficient information about the pharmacokinetics of ranitidine in neonatal patients (aged younger than 1 month) to make dosing recommendations.

The following 3 subsections provide dosing information for each of the pediatric indications.

• Treatment of Duodenal and Gastric Ulcers: The recommended oral dose for the treatment of active duodenal and gastric ulcers is 2 to 4 mg/kg twice daily to a maximum of 300 mg/day. This recommendation is derived from adult clinical trials and pharmacokinetic data in pediatric patients.
• Maintenance of Healing of Duodenal and Gastric Ulcers: The recommended oral dose for the maintenance of healing of duodenal and gastric ulcers is 2 to 4 mg/kg once daily to a maximum of 150 mg/day. This recommendation is derived from adult clinical trials and pharmacokinetic data in pediatric patients.
• Treatment of GERD and Erosive Esophagitis: Although limited data exist for these conditions in pediatric patients, published literature supports a dosage of 5 to 10 mg/kg/day, usually given as 2 divided doses.

Dosage Adjustment for Patients with Impaired Renal Function:

On the basis of experience with a group of subjects with severely impaired renal function treated with ranitidine, the recommended dosage in patients with a creatinine clearance <50 mL/min is 150 mg every 24 hours. Should the patient’s condition require, the frequency of dosing may be increased to every 12 hours or even further with caution. Hemodialysis reduces the level of circulating ranitidine. Ideally, the dosing schedule should be adjusted so that the timing of a scheduled dose coincides with the end of hemodialysis.

Elderly patients are more likely to have decreased renal function, therefore caution should be exercised in dose selection, and it may be useful to monitor renal function.

Will my dose go up or down?

Sometimes your doctor will increase your dose of ranitidine if it isn’t working well enough.

Depending on the reason you take ranitidine, you may take a higher dose to start with – usually for at least 1 month. After this, your doctor may recommend a lower dose.

What if I forget to take ranitidine?

If you usually take it:

• once a day, take the missed dose as soon as you remember, unless it’s less than 12 hours until your next dose – in which case skip the missed dose
• twice a day, take the missed dose as soon as you remember, unless it’s nearly time for your next dose – in which case skip the missed dose
• 3 or 4 times a day, skip the missed dose and take your next dose as normal

Do NOT take a double dose to make up for a forgotten dose.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to remember your medicine.

What if I take too much ranitidine?

Ranitidine is generally very safe. Taking too much is unlikely to harm you or your child.

If you take an extra dose by mistake, you might get some side effects, such as feeling sick. Call your doctor if you’re worried, or you’re bothered by side effects.

Ranitidine side effects

Most people who take ranitidine do not have any side effects. If you do get a side effect, it is usually mild and will go away when you stop taking ranitidine.

The following side effects aren’t common and may happen in more than 1 in 1,000 people. Talk to your doctor or pharmacist if these side effects bother you or don’t go away:

• stomach pains
• constipation
• feeling sick (nausea)
• headache
• diarrhea
• vomiting

Ranitidine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

These are not all the side effects of ranitidine. For a full list see the leaflet inside your medicines packet.

The following have been reported as events in clinical trials or in the routine management of patients treated with ranitidine. The relationship to therapy with ranitidine has been unclear in many cases. Headache, sometimes severe, seems to be related to administration of ranitidine.

Central Nervous System

Rarely, malaise, dizziness, somnolence, insomnia, and vertigo. Rare cases of reversible mental confusion, agitation, depression, and hallucinations have been reported, predominantly in severely ill elderly patients. Rare cases of reversible blurred vision suggestive of a change in accommodation have been reported. Rare reports of reversible involuntary motor disturbances have been received.

Cardiovascular

As with other H2-blockers, rare reports of arrhythmias such as tachycardia, bradycardia, atrioventricular block, and premature ventricular beats.

Gastrointestinal

Constipation, diarrhea, nausea/vomiting, abdominal discomfort/pain, and rare reports of pancreatitis.

Hepatic

There have been occasional reports of hepatocellular, cholestatic, or mixed hepatitis, with or without jaundice. In such circumstances, ranitidine should be immediately discontinued. These events are usually reversible, but in rare circumstances death has occurred. Rare cases of hepatic failure have also been reported. In normal volunteers, SGPT values were increased to at least twice the pretreatment levels in 6 of 12 subjects receiving 100 mg intravenously 4 times daily for 7 days, and in 4 of 24 subjects receiving 50 mg intravenously 4 times daily for 5 days.

Musculoskeletal

Rare reports of arthralgias and myalgias.

Hematologic

Blood count changes (leukopenia, granulocytopenia, and thrombocytopenia) have occurred in a few patients. These were usually reversible. Rare cases of agranulocytosis, pancytopenia, sometimes with marrow hypoplasia, and aplastic anemia and exceedingly rare cases of acquired immune hemolytic anemia have been reported.

Endocrine

Controlled studies in animals and man have shown no stimulation of any pituitary hormone by ranitidine and no antiandrogenic activity, and cimetidine-induced gynecomastia and impotence in hypersecretory patients have resolved when ranitidine has been substituted. However, occasional cases of impotence and loss of libido have been reported in male patients receiving ranitidine, but the incidence did not differ from that in the general population. Rare cases of breast symptoms and conditions, including galactorrhea and gynecomastia, have been reported in both males and females.

Integumentary

Rash, including rare cases of erythema multiforme. Rare cases of alopecia and vasculitis.

Respiratory

A large epidemiological study suggested an increased risk of developing pneumonia in current users of histamine-2-receptor antagonists (H2RAs) compared with patients who had stopped H2RA treatment, with an observed adjusted relative risk of 1.63. However, a causal relationship between use of H2RAs and pneumonia has not been established.

Other

Rare cases of hypersensitivity reactions (e.g., bronchospasm, fever, rash, eosinophilia), anaphylaxis, angioneurotic edema, acute interstitial nephritis, and small increases in serum creatinine.

Serious side effects

Serious side effects are very rare and happen in less than 1 in 10,000 people. Call a doctor straight away if you have:

• stomach pain that seems to be getting worse – this can be a sign of an inflamed liver or pancreas
• back pain, fever, pain when peeing or blood in your pee – these can be signs of kidney problems
• a rash, swollen joints or kidney problems – these can be signs that your small blood vessels are swollen (vasculitis)
• a slow or irregular heartbeat

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to ranitidine.

• A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.

The warning signs of a serious allergic reaction are:

• getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
• wheezing
• tightness in the chest or throat
• having trouble breathing or talking
• swelling of the mouth, face, lips, tongue or throat

How to cope with side effects

What to do about:

• stomach pains – try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your tummy may also help. If you are in a lot of pain, speak to your pharmacist or doctor.
• constipation – eat more high-fiber foods such as fresh fruit and vegetables and cereals, and drink plenty of water. Try to exercise more regularly, for example, by going for a daily walk or run. If this doesn’t help, talk to your pharmacist or doctor.
• feeling sick – it may help if you don’t eat rich or spicy food while you’re taking ranitidine.

Human Toxicity Reports

Headache (sometimes severe) occurs in approx 3% of patients receiving the drug ². Malaise, dizziness, somnolence, insomnia, and vertigo have been reported less frequently. Reversible mental confusion, agitation, mental depression, and hallucinations have occurred, mainly in debilitated geriatric patients. A child who was receiving prolonged, high-dose oral ranitidine therapy (8 mg/kg once daily for 10 months) developed altered consciousness, drowsiness, dysarthria, hyporeflexia, positive Babinski’s sign, diaphoresis, and bradycardia, which resolved within 24 hr after discontinuance of the drug.

Constipation, nausea, vomiting, and abdominal discomfort or pain have occurred in patients receiving ranitidine. Pancreatitis has been reported rarely ².

Rash, which may be urticarial, maculopapular, and/or pruritic, has been reported during ranitidine therapy ². Rash suggestive of mild erythema multiforme has occurred rarely. Urticaria at the site of injection has occurred following IV admin of ranitidine. Alopecia has occurred rarely ².

Leukopenia, granulocytopenia, agranulocytosis, thrombocytopenia, aplastic anemia, acquired immune hemolytic anemia, and pancytopenia, which may be accompanied by bone marrow hypoplasia, have been reported rarely in patients receiving ranitidine ². Alterations in blood cell counts usually were reversible. At least one case of leukocytosis has been reported 6-8 days after initiating ranitidine therapy, which resolved following discontinuance ². Aplastic anemia has occurred in at least one patient receiving ranitidine ².

Small increases in serum creatinine, without concomitant increases in BUN, have been reported during ranitidine therapy ². Increases in serum aminotransferase, alkaline phosphatase, LDH, total bilirubin, and gamma-glutamyl transferase concentration have been reported and reversible hepatitis, which may be hepatocellular, hepatocanalicular, or both and may or may not be accompanied by jaundice, has occurred occasionally in individuals receiving ranitidine and usually was reversible; however, death has been reported rarely ².

A 63 yr old woman developed anicteric hepatitis after two wk of therapy with ranitidine ³. Despite continuation of therapy, her symptoms resolved within 5 days and transaminase levels returned to normal in the next 4 weeks, at which time use of the drug ceased. No other cause for the reaction could be found ³.

Cardiac arrhythmias have occurred rarely in patients receiving ranitidine ². Bradycardia, sometimes assoc with dyspnea, has occurred ². Tachycardia, AV block, asystole, and ventricular premature complexes have also been reported rarely ².

Arthralgias, myalgias, and hypersensitivity reactions such as bronchospasm, fever, rash, and eosinophilia have occurred rarely in patients receiving ranitidine ². Anaphylaxis, characterized by severe urticaria and a decrease in blood pressure in one patient following administration of a single dose of ranitidine, has occurred rarely; exacerbation of asthma and angioedema also has occurred ². Mild erythema multiforme-like rash and alopecia also have occurred rarely. Rare reports suggest that ranitidine may precipitate acute attacks of porphyria in patients with acute porphyria; therefore, the drug should be avoided in patients with a history of acute porphyria ².

In a study of 51 male patients with duodenal ulcer, treatment with ranitidine, produced no decrease in basal levels of serum testosterone, as did cimetidine ⁴.

Ranitidine inhibited in a dose-dependent manner acetylcholinesterases from human erythrocytes and gastric mucosa ⁵. Pseudocholinesterase in serum was also inhibited, the levels required were about 25 times higher. A stimulation of cholinergic mechanisms in ranitidine treatment should occur, e.g, stimulation of glandular secretion or increase of gastrointestinal motility ⁵.

Symptoms of acute intoxication with both cimetidine and ranitidine are bradycardia and tachycardia ⁶; CNS disturbances, including confusion, delirium, drowsiness, slurred speech, flushing, and sweating; dermatologic lesions; endocrine abnormalities; GI disorders; and liver dysfunction ⁶.

Most controlled studies in humans indicate that ranitidine does not alter theophylline metabolism, even at high doses ⁷. However, there have been several case reports published recently which demonstrate the development of theophylline toxicity mostly in older patients receiving stable oral doses of this drug when ranitidine was administered simultaneously ⁷. A study involving eleven elderly (mean age, 69.0 + or – 6.2 years) patients with chronic obstructive pulmonary disease (COPD). During one week the patients took slow-release theophylline, 200 mg every 12 hr, followed by one week intake of the same dose of theophylline plus ranitidine tablets, 150 mg every 12 hr. At the end of each period, blood samples were obtained 0, 1, 2, 3, 4, 5, 6, 7, 8 and 12 hr after the morning dose for the determination of serum theophylline levels. The peak theophylline concentration (Tmax) was achieved after 4.1 + or – 0.9 hr while the patients were taking theophylline, and after 2.9 + or – 1.4 hr with the combined regimen. This difference was statistically significant. In only 3/11 subjects did Tmax remain unchanged during both phases of the study. The mean theophylline clearance rates while the patients were receiving theophylline alone (39.58 + or – 19.89 ml/min) and when they were receiving both medications 134.42 + or – 10.55 ml/min) were similar. The mean serum levels while the patients were receiving theophylline alone were slightly higher but not statistically different. These results suggest that the reported increases in serum theophylline levels in older patients receiving theophylline and ranitidine cannot be ascribed to slower theophylline metabolism in the geriatric patients with chronic obstructive pulmonary disease who is also given ranitidine ⁷.

A case report of acute cholestatic hepatitis associated with rash and hypereosinophilia, in which the absence of transfusion, intercurrent viral infection, alcohol consumption or other hepatotoxic drugs are suggestive of ranitidine-induced hepatotoxicity ⁸. The pathogenesis of the disorder is unknown, but the lack of a dose-effect relationship, the rarity and unpredictability of the reaction, as well as the clinical signs suggest that hypersensitivity is involved. Physicians should be aware of this rare and idiosyncratic side-effect of ranitidine ⁸.

Although acute interstitial nephritis has been well described with the histamine H2-receptor antagonist cimetidine, a study authors found only one previous case report of ranitidine-induced interstitial nephritis in the literature ⁹. They describe an additional patient who developed acute interstitial nephritis after taking ranitidine ⁹. Electron microscopy showed focal fusion of the epithelial cell foot processes that was not described in the previous report of ranitidine-induced interstitial nephritis.

Reversible hematologic abnormalities including hemolytic anemia ¹⁰ with a positive direct Coombs’ test have been associated with ranitidine. In addition to the case report cited above, the US Food and Drug Administration had received five other cases of hemolysis associated with recent intake of ranitidine as of February 1991 ¹⁰. To investigate the possible association of ranitidine with autoimmune hemolytic anemia, a study was conducted to determine how often diagnoses of hemolytic anemia or abnormal Coombs’ test results followed dispensing of ranitidine using the automated medical and pharmacy records of a large health maintenance organization. No occurrences of hemolytic anemia were identified among 12,054 individuals following 38,686 prescriptions for this medication. The 95% upper confidence bound was 3.1 cases/10,000 exposed persons. One abnormal direct Coombs test with mild anemia was discovered during routine prenatal testing of an asymptomatic patient who was dispensed ranitidine two and a half months previously. Hemolysis, however, was not demonstrated and an association with prior ranitidine use could not be confirmed. Additional analyses indicate that in only 30% of ranitidine courses was a blood count obtained. In those courses with hematocrits below 40%, less than 1% had a Coombs’ test performed. Chart review suggests that the majority of individuals with severe anemia have alternative explanations other than autoimmune hemolysis for their anemia ¹⁰. This analysis indicates that ranitidine is unlikely to be a common cause of clinically recognized autoimmune hemolytic anemia and demonstrates the utility of large automated medical and pharmacy data bases to conduct post-marketing studies of spontaneously reported drug effects.

Ranitidine overdose

Ranitidine overdose occurs when someone takes more than the normal or recommended amount of this medicine. This can be by accident or on purpose.

There has been limited experience with overdosage. Reported acute ingestions of up to 18 g orally have been associated with transient adverse effects similar to those encountered in normal clinical experience. In addition, abnormalities of gait and hypotension have been reported.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Symptoms of an ranitidine overdose are:

• Abnormal heartbeat, including rapid or slow heartbeat
• Drowsiness, confusion
• Diarrhea
• Difficulty breathing
• Dilated pupils
• Flushing
• Low blood pressure
• Nausea, vomiting
• Slurred speech
• Sweating

Seek medical help right away. DO NOT make the person throw up unless poison control or a health care provider tells you to.

When overdosage occurs, the usual measures to remove unabsorbed material from the gastrointestinal tract, clinical monitoring, and supportive therapy should be employed.

Studies in dogs receiving dosages of ranitidine in excess of 225 mg/kg/day have shown muscular tremors, vomiting, and rapid respiration. Single oral doses of 1,000 mg/kg in mice and rats were not lethal. Intravenous LD50 values in mice and rats were 77 and 83 mg/kg, respectively.

What to Expect at the Emergency Room

Take the container with you to the hospital, if possible.

The provider will measure and monitor the person’s vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated. The person may receive:

• Activated charcoal
• Blood and urine tests
• Breathing support, including oxygen
• Chest x-ray
• ECG (electrocardiogram, or heart tracing)
• Intravenous fluids (through a vein)
• A laxative
• Medicine to treat symptoms
• Tube through the mouth into the stomach to empty the stomach (gastric lavage)

Outlook (Prognosis)

Serious complications are rare. These are generally safe medicines, even when taken in large doses.

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