Paroxetine

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) that has been used to treat depression, generalized anxiety disorder (GAD, excessive worrying that is difficult to control), social anxiety disorder (extreme fear of interacting with others or performing in front of others that interferes with normal life), obsessive compulsive disorder (OCD, bothersome thoughts that won’t go away and the need to perform certain actions over and over), premenstrual dysphoric disorder (PMDD, physical and psychological symptoms that occur before the onset of the menstrual period each month), post-traumatic stress disorder (PTSD, disturbing psychological symptoms that develop after a frightening experience), and panic disorder (sudden, unexpected attacks of extreme fear and worry about these attacks) ¹. Paroxetine is also used to treat chronic headaches, diabetic neuropathy (numbness in the hands and feet caused by diabetes), premature ejaculation and hot flashes (sudden feelings of warmth, especially in the face, neck, and chest) in women who are experiencing menopause (stage of life when menstrual periods become less frequent and stop and women may experience other symptoms and body changes) ². There is not enough information available at this time to know how paroxetine works to treat hot flashes in menopause. Paroxetine is also sometimes used with other medications to treat bipolar disorder (mood that changes from depressed to abnormally excited). Paroxetine may be prescribed for other uses; ask your doctor or pharmacist for more information.

Paroxetine was approved for use in the United States in 1992 and it remains in wide use, with more than 15 million prescriptions being filled yearly ³.

Paroxetine is available as tablets of 10, 20, 30 and 40 mg and an oral suspension (liquid) in generic forms and under the brand names of Paxil and Pexeva. The recommended dosage for depression in adults is 20 mg once daily, increasing the dosage by 10 mg increments weekly to a maximum of 50 mg. Controlled release or extended-release (long-acting) tablets are also available that have slightly different dosing recommendations.

The tablets, suspension, and controlled-release tablets are usually taken once daily in the morning or evening, with or without food. The capsules are usually taken once a day at bedtime with or without food. You may want to take paroxetine with food to prevent stomach upset. Take paroxetine at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take paroxetine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Shake the liquid well before each use to mix the medication evenly.

Swallow the extended-release and regular tablets whole; do not chew or crush them.

If you are taking paroxetine tablets, suspension, or controlled-release tablets, your doctor may start you on a low dose of paroxetine and gradually increase your dose, not more than once a week.

Paroxetine capsules contain a lower dose of paroxetine than is needed to treat depression and other forms of mental illness. Do not take paroxetine capsules to treat a mental illness. If you think you have depression or another mental illness, talk to your doctor about treatment.

Paroxetine may help control your symptoms but will not cure your condition. It may take several weeks or longer before you feel the full benefit of paroxetine. Continue to take paroxetine even if you feel well. Do not stop taking paroxetine without talking to your doctor. Your doctor may decrease your dose gradually. If you suddenly stop taking paroxetine tablets, suspension, or controlled-release tablets, you may experience withdrawal symptoms such as depression; mood changes; frenzied or abnormally excited mood; irritability; anxiety; confusion; dizziness; headache; tiredness; numbness or tingling in the arms, legs, hands, or feet; unusual dreams; difficulty falling asleep or staying asleep; nausea; or sweating. Tell your doctor if you experience any of these symptoms when your dose of paroxetine is decreased.

Common side effects of Paroxetine are drowsiness, dyspepsia, nausea, headache, increased sweating, increased appetite, weight gain and sexual dysfunction. Rare but potentially severe adverse events include suicidal ideation and behavior, activation of mania, serotonin syndrome, discontinuation syndrome, increased risk of bleeding, seizures, acute glaucoma, hypersensitivity reactions and embryo-fetal toxicity.

How does Paroxetine work?

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) that works by blocking the serotonin reuptake transporter (SERT) and thus increasing the concentration of synaptic serotonin. Current theory suggests that the diminished serotonin concentration in the depressed brain induces the upregulation of serotonergic receptors. By increasing the synaptic serotonin concentration, paroxetine thus induces the downregulation of the previously upregulated serotonin receptors, thus normalizing the receptor concentration ⁴. Furthermore, in a radioligand study, paroxetine showed some affinity for muscarinic, adrenergic (alpha and beta), dopaminergic (D2), serotonergic (5-HT2), and histaminergic (H1) receptors ⁵. These receptors have also appeared to contribute to Paroxetine’s antidepressant effects and its side effect profile ¹.

Paroxetine undergoes metabolism via liver CYPP450 2D6 and Paroxetine is 62% metabolized over a 10-day post-dosing period ¹. Paroxetine inhibits CYP2D6 and, thus, its own metabolism; plasma concentrations can potentially double following dosage increases of 50% ⁶. The urine excretes 2% Paroxetine and 36% excreted in the feces.

What is Paroxetine used for?

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) that is FDA approved to treat depression (major depressive disorder), generalized anxiety disorder (GAD, excessive worrying that is difficult to control), social anxiety disorder (extreme fear of interacting with others or performing in front of others that interferes with normal life), obsessive compulsive disorder (OCD, bothersome thoughts that won’t go away and the need to perform certain actions over and over), panic disorder (sudden, unexpected attacks of extreme fear and worry about these attacks), premenstrual dysphoric disorder (PMDD, physical and psychological symptoms that occur before the onset of the menstrual period each month) and post-traumatic stress disorder (PTSD, disturbing psychological symptoms that develop after a frightening experience) ¹. Paroxetine is not FDA approved for use in children and adolescents less than 18 years of age; however, clinicians use it off-label in this group.

Paroxetine is also used to treat chronic headaches, diabetic neuropathy (numbness in the hands and feet caused by diabetes), premature ejaculation and hot flashes (sudden feelings of warmth, especially in the face, neck, and chest) in women who are experiencing menopause (stage of life when menstrual periods become less frequent and stop and women may experience other symptoms and body changes) ². There is not enough information available at this time to know how paroxetine works to treat hot flashes in menopause. Paroxetine is also sometimes used with other medications to treat bipolar disorder (mood that changes from depressed to abnormally excited). Paroxetine may be prescribed for other uses; ask your doctor or pharmacist for more information.

Paroxetine Off-Label Use

• Obsessive-compulsive disorder (in children and adolescents)
• Social anxiety disorder (in children and adolescents)
• Separation anxiety
• Dysthymia also known as persistent depressive disorder, which is a chronic, low-grade form of depression characterized by persistent feelings of sadness and hopelessness, lasting for at least two years
• Body dysmorphic disorder
• Postpartum depression
• Premature ejaculation
• Cancer causing itch that is unresponsive to standard treatment.

Paroxetine Contraindications

There are only a few absolute contraindications for the use of paroxetine. Absolute contraindications include concurrent use of monoamine oxidase inhibitors (MAOIs), thioridazine, and pimozide. Concomitant use of monoamine oxidase (MAO) inhibitors and paroxetine can precipitate serotonin syndrome. Concurrent use of thioridazine and paroxetine can induce cardiac arrhythmias; similar effects can occur with pimozide and paroxetine ⁷.

Precautions that should be acknowledged when prescribing paroxetine include concurrent tricyclic antidepressant (TCA) use, concomitant tamoxifen use, and drugs affecting liver metabolism. Paroxetine inhibits tricyclic antidepressant (TCA) metabolism, leading to possible tricyclic antidepressant (TCA) toxicity. Tamoxifen is active once metabolized by CYP4502D6; thus, paroxetine essentially inactivates tamoxifen.

Paroxetine is not recommended for use during pregnancy or if breastfeeding. Based on epidemiological studies, infants exposed to paroxetine during the first trimester had an increased risk for cardiovascular malformations ⁷.

Before taking Paroxetine

You should not use Paroxetine if you are allergic to paroxetine, or if you are also taking pimozide or thioridazine.

Do not use Paroxetine if you have used an monoamine oxidase (MAO) inhibitor in the past 14 days. A dangerous drug interaction could occur. Monoamine oxidase (MAO) inhibitors include isocarboxazid (Marplan), linezolid (Zyvox), methylene blue, rasagiline, phenelzine (Nardil), selegiline (Emsam, Zelapar), and tranylcypromine (Parnate). You must wait at least 14 days after stopping an monoamine oxidase (MAO) inhibitor before you take Paroxetine.

To make sure paroxetine is safe for you, tell your doctor if you have:

• Bipolar disorder (mood disorder with mania and depression)
• Bleeding problems
• Bone problems
• Angle-closure glaucoma. You should know that Paroxetine may cause angle-closure glaucoma, a condition where the fluid is suddenly blocked and unable to flow out of the eye causing a quick, severe increase in eye pressure which may lead to a loss of vision. Talk to your doctor about having an eye examination before you start taking Paroxetine. If you have nausea, eye pain, changes in vision, such as seeing colored rings around lights, and swelling or redness in or around the eye, see your doctor or get emergency medical treatment right away.
• Drug addiction
• Hyponatremia (low sodium in the blood)
• Hyponatremia (low sodium in the blood)
• Mania, history of or
• Seizures, history of or
• Sexual problems: Use with caution. May make these conditions worse.
• Kidney disease, severe or
• Liver disease, severe: Use with caution. The effects may be increased because of slower removal of the medicine from the body.
• Suicidal thoughts.

Be sure your doctor knows if you also take stimulant medicine, opioid medicine, herbal products, or medicine for depression, mental illness, Parkinson’s disease, migraine headaches, serious infections, or prevention of nausea and vomiting. These medicines may interact with paroxetine and cause a serious condition called serotonin syndrome.

Some young people have thoughts about suicide when first taking an antidepressant. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Taking an SSRI antidepressant during pregnancy may cause serious lung problems or other complications in the baby. However, you may have a relapse of depression if you stop taking your antidepressant. Tell your doctor right away if you become pregnant. Do not start or stop taking Paroxetine without your doctor’s advice.

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to Paroxetine or any other medicines. Also tell your doctor if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children

Appropriate studies have not been performed on the relationship of age to the effects of paroxetine in the pediatric population. Safety and efficacy have not been established.

Use of Brisdelle® or paroxetine capsules is not indicated in the pediatric population.

Elderly

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of paroxetine in the elderly. However, elderly patients may be more sensitive to the effects of Paroxetine than younger adults, and are more likely to have hyponatremia (low sodium in the blood), which may require caution and an adjustment in the dose for patients receiving paroxetine.

Pregnancy

Paroxetine is contraindicated in pregnancy and is classified as category D/X due to its teratogenic effects in causing cardiovascular defects, specifically heart malformations if prescribed in the first trimester ⁸.

In some women, paroxetine may raise the levels of a hormone called prolactin ⁹. High levels of prolactin can stop ovulation (part of the menstrual cycle when an ovary releases an egg). This can make it harder to get pregnant. Paroxetine has also been associated with changes in sexual function such as less desire to have sex ⁹.

Miscarriage is common and can occur in any pregnancy for many different reasons. Some studies suggest that taking paroxetine may slightly increase the chance of miscarriage. However, research also shows that depression itself may increase the chance of miscarriage. This makes it hard to know if an increased chance of miscarriage is due to medication, the underlying condition, or other factors.

Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Some studies suggest that exposure to paroxetine in the first trimester might be associated with a small increased chance for heart defects. Other studies did not find a possible increased risk. The background rate of heart defects for any pregnancy is about 1 in 100 (1%). If there is an increased chance of birth defects with paroxetine use in the first trimester, it is expected to be small. Paroxetine exposure in pregnancy has not been shown to increase the chance of other birth defects.

Some studies suggest a higher chance for preterm delivery (birth before week 37) with the use of an SSRI such as paroxetine, while others do not. Conditions such as depression may increase the chance of pregnancy-related problems, such as preterm delivery. This makes it hard to know if it is the medication, the condition being treating, or other factors that are increasing the chance of pregnancy-related problems.

Some, but not all, studies have suggested that when women who are pregnant take SSRIs during the second half of the pregnancy, their babies might have a higher chance for a serious lung condition called persistent pulmonary hypertension ⁹. Persistent pulmonary hypertension happens in 1 or 2 out of 1,000 births. Among the studies looking at this, the overall chance for pulmonary hypertension when an SSRI was used in pregnancy was less than 1/100 (less than 1%).

The use of paroxetine during pregnancy can cause temporary symptoms in newborns soon after birth. These symptoms are sometimes referred to as withdrawal. Symptoms may include jitteriness, increased muscle tone, irritability, changes in sleep patterns, tremors, trouble eating, and trouble breathing. These symptoms are usually mild and go away on their own. Some babies may need to stay in a special care nursery for several days. Not all babies exposed to paroxetine will have these symptoms. It is important that your doctor know you are taking paroxetine so that if symptoms occur your baby can get the care that’s best for them.

It is not known if paroxetine can increase the chance for behavior or learning issues. One study looking at prescriptions for SSRIs including paroxetine suggested an increased chance of autism spectrum disorder. Studies based on filled prescriptions/prescription records cannot tell if a person took the medication, so it is hard to know if the outcomes are related to the medication or other factors. Also, this study did not look at factors such as other exposures, paternal mental illness, or other family history of autism. Another prescription study did not report an increased chance for autism spectrum disorder.

One study looking at pregnancies exposed at least during the third trimester to SSRIs including paroxetine reported no differences in developmental outcomes between the exposed 46 infants or the unexposed 23 infants at 2 and 8 months of age. A follow-up study on some of these children found no difference in behaviors such as emotional reactivity, withdrawal, irritability, depression, or anxiety in the exposed group (22 children) when compared to the group that was not exposed to paroxetine (14 children).

Breastfeeding

Paroxetine passes into breastmilk in small amounts. In some cases, mild side effects have been reported. If you suspect the baby has any symptoms (trouble sleeping, restlessness, or increased crying), contact the child’s doctor. Be sure to talk to your doctor about all your breastfeeding questions. An alternative to Paroxetine should be prescribed or you should stop breastfeeding while using Paroxetine.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking Paroxetine, it is especially important that your doctor know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using Paroxetine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Bepridil
• Bromopride
• Cisapride
• Colchicine
• Dronedarone
• Isocarboxazid
• Levoketoconazole
• Linezolid
• Mavorixafor
• Mesoridazine
• Methylene Blue
• Ozanimod
• Phenelzine
• Pimozide
• Piperaquine
• Potassium Chloride
• Potassium Citrate
• Procarbazine
• Rasagiline
• Safinamide
• Saquinavir
• Selegiline
• Sparfloxacin
• Terfenadine
• Thioridazine
• Tranylcypromine
• Ziprasidone

Using Paroxetine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Abciximab
• Abiraterone Acetate
• Abiraterone Acetate, Micronized
• Aceclofenac
• Acemetacin
• Acenocoumarol
• Adagrasib
• Alfentanil
• Alfuzosin
• Almotriptan
• Amantadine
• Amineptine
• Amiodarone
• Amisulpride
• Amitriptyline
• Amitriptylinoxide
• Amoxapine
• Amphetamine
• Amtolmetin Guacil
• Anagrelide
• Anileridine
• Apixaban
• Apomorphine
• Ardeparin
• Argatroban
• Aripiprazole
• Aripiprazole Lauroxil
• Arsenic Trioxide
• Asenapine
• Aspirin
• Astemizole
• Atazanavir
• Atomoxetine
• Azathioprine
• Azithromycin
• Bedaquiline
• Bemiparin
• Benzhydrocodone
• Benzphetamine
• Betrixaban
• Plus many more not on this list.

Using Paroxetine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Amprenavir
• Cimetidine
• Cyproheptadine
• Fluphenazine
• Fosamprenavir
• Ginkgo
• Metoprolol
• Phenytoin

Paroxetine dosage

The dose of Paroxetine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of Paroxetine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Oral dosage form (capsules)

• For moderate to severe hot flashes caused by menopause
  • Adults: 7.5 milligrams (mg) once a day, at bedtime.
  • Children: Use is not recommended.

Oral dosage form (suspension)

Depression

• Adults: At first, 20 milligrams (mg) (10 milliliters [mL]) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg (25 mL) per day.
• Older adults: At first, 10 mg (5 mL) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg (20 mL) per day.
• Children: Use and dose must be determined by your doctor.

Generalized anxiety disorder (GAD)

• Adults: At first, 20 milligrams (mg) (10 milliliters [mL]) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg (25 mL) per day.
• Older adults: At first, 10 mg (5 mL) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg (20 mL) per day.
• Children: Use and dose must be determined by your doctor.

Obsessive-compulsive disorder (OCD)

• Adults: At first, 20 milligrams (mg) (10 milliliters [mL]) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 60 mg (30 mL) per day.
• Older adults: At first, 10 mg (5 mL) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg (20 mL) per day.
• Children: Use and dose must be determined by your doctor.

Panic disorder

• Adults: At first, 10 milligrams (mg) (5 milliliters [mL]) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 60 mg (30 mL) per day.
• Older adults: At first, 10 mg (5 mL) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg (20 mL) per day.
• Children: Use and dose must be determined by your doctor.

Post traumatic stress disorder (PTSD)

• Adults: At first, 20 milligrams (mg) (10 milliliters [mL]) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg (25 mL) per day.
• Older adults: At first, 10 mg (5 mL) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 40 mg (20 mL) per day.
• Children: Use and dose must be determined by your doctor.

Social anxiety disorder

• Adults: At first, 20 milligrams (mg) (10 milliliters [mL]) once a day, usually taken in the morning.
• Older adults: At first, 10 mg (5 mL) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 20 mg (10 mL) per day.
• Children: Use and dose must be determined by your doctor.

Oral dosage form (tablets)

Depression

• Adults: At first, 20 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg per day.
• Older adults: At first, 10 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg per day.
• Children: Use and dose must be determined by your doctor.

Generalized anxiety disorder (GAD)

• Adults: At first, 20 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg per day.
• Older adults: At first, 10 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 40 mg per day.
• Children: Use and dose must be determined by your doctor.

Obsessive-compulsive disorder (OCD)

• Adults: At first, 20 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 60 mg per day.
• Older adults: At first, 10 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg per day.
• Children: Use and dose must be determined by your doctor.

Panic disorder

• Adults: At first, 10 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 60 mg per day.
• Older adults: At first, 10 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg per day.
• Children: Use and dose must be determined by your doctor.

Post traumatic stress disorder (PTSD)

• Adults: At first, 20 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 50 mg per day.
• Older adults: At first, 10 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 40 mg per day.
• Children: Use and dose must be determined by your doctor.

Social anxiety disorder

• Adults: At first, 20 milligrams (mg) once a day, usually taken in the morning.
• Older adults: At first, 10 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 20 mg per day.
• Children: Use and dose must be determined by your doctor.

Oral dosage form (extended-release tablets)

Depression

• Adults: At first, 25 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 62.5 mg per day.
• Older adults: At first, 12.5 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg per day.
• Children: Use and dose must be determined by your doctor.

Panic disorder

• Adults: At first, 12.5 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose usually is not more than 75 mg per day.
• Older adults: At first, 12.5 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg per day.
• Children: Use and dose must be determined by your doctor.

Premenstrual dysphoric disorder (PMDD)

• Adults: At first, 12.5 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 25 mg per day.
• Older adults and children: Use and dose must be determined by your doctor.

Social anxiety disorder

• Adults: At first, 12.5 milligrams (mg) once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 37.5 mg per day.
• Older adults: At first, 12.5 mg once a day, usually taken in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 37.5 mg per day.
• Children: Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of Paroxetine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Kidney impairment

For patients with kidney impairment, Paroxetine dosage is based on Creatinine clearance (CrCl), as shown below.

• If the Creatinine clearance (CrCl) is 30 to 60 ml per minute: No need to change the dosing.
• If Creatinine clearance (CrCl) is less than 30 ml per minute:
  • Immediate release formulation: 10 mg per day; increase if needed by 10 mg per day increments at an interval of at least a week; maximum dose: 40 mg per day.
  • Controlled release formulation: 12.5 mg per day; increase if needed by 12.5 mg per day increments at interval one week; maximum dose: 50 mg per day.

Liver impairment

In liver impairment, Paroxetine plasma concertation of two times normal can occur.

• If mild to moderate liver impairment: no change in dosage.
• If severe liver impairment:
  • Immediate-release formulations: 10 mg per day and, if needed, increase by 10 mg per day at intervals of 1 week; maximum dose of 40 mg per day.
  • Controlled release formulation: 12.5 mg per day; increase if needed by 12.5 mg per day increments at intervals of 1 week; maximum dose is 50 mg per day.

Monitoring

Patients initiated on paroxetine should initially receive close observation and be monitored for worsening clinical symptoms, behavior changes (mania, social function, anxiety), or suicidal ideations. Labs should include serum sodium concentration to rule out syndrome of inappropriate antidiuretic hormone secretion (SIADH) ¹⁰. Vital signs should be monitored for signs of serotonin syndrome (serotonergic toxicity). Serotonin syndrome precipitates via the manifestation of changes in mental status, autonomic instability, gastrointestinal symptoms, hyperreflexia, and myoclonus. Serotonin syndrome is treated by discontinuing any of the offending agents. If symptoms continue to escalate, the clinician can administer cyproheptadine ¹¹.

Paroxetine side effects

Paroxetine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• headache
• dizziness
• weakness
• difficulty concentrating
• nervousness
• forgetfulness
• confusion
• sleepiness
• nausea
• vomiting
• diarrhea
• constipation
• gas
• stomach pain
• heartburn
• changes in ability to taste food
• decreased appetite
• weight loss or gain
• sexual problems in males; decreased sex drive, inability to get or keep an erection, or delayed or absent ejaculation
• sexual problems in females; decreased sex drive, or delayed orgasm or unable to have an orgasm
• dry mouth
• sweating
• yawning
• pain in the back, muscles, bones, or anywhere in the body
• tenderness or swelling of joints

Some side effects can be serious. If you experience any of the following symptoms or those listed in the IMPORTANT WARNING or SPECIAL PRECAUTIONS sections, call your doctor immediately or get emergency medical treatment:

• seeing things or hearing voices that do not exist (hallucinating)
• fainting
• rapid, pounding, or irregular heartbeat
• chest pain
• difficulty breathing
• seizures
• agitation, fever, sweating, confusion, fast or irregular heartbeat, and severe muscle stiffness or twitching, hallucinations, loss of coordination, nausea, vomiting, or diarrhea
• abnormal bleeding or bruising
• tiny red spots directly under the skin
• peeling or blistering of skin
• sore throat, fever, chills, cough, and other signs of infection
• uncontrollable shaking of a part of the body
• unsteady walking that may cause falling
• numbness or tingling in your hands, feet, arms, or legs
• painful erection that lasts for hours
• sudden nausea, vomiting, weakness, cramping, bloating, swelling, tightness in hands and feet, dizziness, headache and/or confusion
• hives
• rash
• itching
• swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
• hoarseness
• black and tarry stools
• red blood in stools
• bloody vomit
• vomit that looks like coffee grounds
• bone pain or fracture
• tenderness, swelling, or bruising of one part of your body

Paroxetine may decrease appetite and cause weight loss in children. Your child’s doctor will watch his or her growth carefully. Talk to your child’s doctor if you have concerns about your child’s growth or weight while he or she is taking this medication. Talk to your child’s doctor about the risks of giving paroxetine to your child.

Paroxetine may cause other side effects. See your doctor if you have any unusual problems while taking Paroxetine.

Paroxetine discontinuation syndrome

Discontinuation syndrome is more common and more severe with paroxetine than with other SSRIs; this may be due in part to the fact that it inhibits its own metabolism ¹. Withdrawal symptoms from Paroxetine discontinuation include dizziness, lethargy, nausea, vomiting, headache, fever, chills, vivid dreams, electric shock-like-sensation, dyskinesia, anxiety, crying, irritability, and depersonalization ¹².

Paroxetine Toxicity

Paroxetine is rarely lethal in overdose. In Paroxetine overdose, patients can develop somnolence, nausea, tremor, heart rhythm disturbances, confusion, vomiting, dizziness, and mydriasis. During Paroxetine overdose, a patient’s airway, oxygenation, and ventilation require evaluation first. The treatment for Paroxetine overdose includes symptomatic supportive treatment. There is no specific treatment for paroxetine toxicity ¹.

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