Paroxetine

(par-ox-uh-teen)

Trade/other name(s): paroxetine hydrochloride (Paxil, Paxil CR), paroxetine mesylate (Pexeva)

Why would this drug be used?

Paroxetine is a type of antidepressant known as a selective serotonin reuptake inhibitor (SSRI). It is used to help treat depression, anxiety, obsessive compulsive disorder, post-traumatic stress disorder, and social phobia. Doctors may prescribe it for other reasons as well.

How does this drug work?

Paroxetine works by raising levels of serotonin, a key chemical in the brain.

Before taking this medicine

Tell your doctor…

• If you are allergic to any medicines, dyes, additives, or foods.
• If you have ever thought of or attempted suicide. Treatment with an antidepressant may raise the risk of suicidal thoughts, especially during the first few months of treatment.
• If you drink alcohol or are taking any type of sedative. This drug may increase their effects on the nervous system, which in some cases could be dangerous.
• If you have ever had kidney or liver disease (including hepatitis or cirrhosis). This drug is cleared from the body by these organs. Reduced kidney or liver function may result in more drug than expected staying in the body. This could lead to unwanted side effects. Your doctor will want to monitor you closely and may need to adjust your dose accordingly.
• If you have ever had bleeding problems or are taking medicines that might raise your risk of bleeding (aspirin or aspirin-containing medicines, other non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen, warfarin (Coumadin), vitamin E, etc.). This drug may raise your risk of abnormal bleeding.
• If you have taken monoamine oxidase inhibitors (such as isocarboxazid, phenelzine, selegiline, and tranylcypromine) within the past 2 weeks. Carbamazepine may raise the blood pressure and body temperature, and cause seizures, coma, and even death.
• If you have or have ever had glaucoma, seizures or bipolar disorder (manic depression). This drug could make these conditions worse.
• If you have any other medical conditions such as congestive heart failure, lung disease, heart disease, high blood pressure, diabetes, gout, or infections. You may need closer monitoring of these conditions while being treated.
• If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug might cause problems if it is taken at the time of conception or during pregnancy. It is important to check with your doctor about whether birth control should be used with this medicine. In some women who have taken this drug in the weeks before delivery, babies have required longer hospital stays due to problems that may have been related to the drug. Women who are pregnant should discuss this with their doctor before starting paroxetine.
• If you are breast-feeding. This drug passes into breast milk and affect the baby. Talk with your doctor about the possible risks of breast-feeding while taking this drug.

About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Paroxetine may interact with several other drugs and dietary supplements.

Antidepressants known as monoamine oxidase inhibitors (MAOIs) such as phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), or selegiline (Emsam) may raise the risk of serious side effects. Paroxetine should not be taken within 2 weeks of taking an MAOI.

Pimozide (Orap) and thioridazine (Mellaril) should not be taken with paroxetine or within 2 weeks after paroxetine has been stopped. Interactions with these drugs could affect the heart rhythm.

Linezolid (Zyvox) should not be taken with paroxetine.

Paroxetine may raise the risk of abnormal bleeding. This risk may be increased further if you are taking aspirin or aspirin-containing medicines, other non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen, warfarin (Coumadin), or vitamin E.

Tryptophan supplements and St. John's wort are not recommended while taking paroxetine.

Drugs that are used to treat migraine or cluster headaches (triptans, such as those listed below) can increase risk of serious side effects (see serotonin syndrome information in "Precautions" section) if taken with paroxetine:

• sumatriptan (Imitrex)
• rizatripan (Maxalt)
• Naratripan (Amerge)
• eletripan (Relpax)
• frovatripan (Frova)
• almotriptan (Axert)
• zolmitriptan (Zomig)

Other drugs that could interact with paroxetine include:

• sedatives, anxiety medicines, antihistamines, or alcohol
• fentanyl (Duragesic), an opioid pain medicine
• other antidepressants (amitriptyline, desipramine, doxepin, imipramine, nortriptyline, fluoxetine)
• antiseizure drugs such as carbamazepine (Tegretol), phenytoin (Dilantin), and phenobarbital
• antipsychotics such as haloperidol (Haldol), risperidone (Risperdal), and clozapine (Clozaril)
• heart rhythm drugs (propafenone, flecainide, encainide, quinidine)
• HIV/AIDS drugs such as fosamprenavir (Lexiva) and ritonavir (Norvir)
• atomoxetine (Strattera)
• lithium (Eskalith, Lithobid)
• tramadol (Ultram)
• cimetidine (Tagamet)
• digoxin (Lanoxin)
• metoprolol (Lopressor, Toprol XL)
• procyclidine
• theophylline

Paroxetine may cause tamoxifen to be less effective.

There may be other interactions not listed above. Check with your doctor, nurse, or pharmacist about all of your medicines, herbs, and supplements.

Interactions with foods

Alcohol may have more potent effects on the nervous system while taking paroxetine. Its use should be minimized or avoided while taking this drug. No other serious interactions with foods are known at this time. Check with your doctor, nurse, or pharmacist about whether some foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Paroxetine is taken by mouth as a tablet or liquid. It is usually taken once a day (in the morning), with or without food.

The dose depends on a number of factors, including the reason the drug is being taken, the patient’s age, and kidney and liver function. If needed, the dose may be increased after waiting at least a week. Lower doses may be recommended in elderly patients and in those with kidney or liver problems.

This medicine may take several weeks to start to work. Do not change the dose or stop taking this drug without first speaking to your doctor or nurse. Talk to your doctor before starting any new medicines.

Store the medicine in a tightly closed container and out of the reach of children or pets.

Precautions

This drug should be used with caution if you have ever had kidney or liver disease (including hepatitis or cirrhosis). This drug is cleared from the body by these organs. Reduced kidney or liver function may result in more drug than expected staying in the body, which could lead to unwanted side effects. Your doctor will want to monitor you closely and may need to adjust your dose accordingly.

This drug may make you feel drowsy when you first start taking it or if the dose is increased. Do not drive or operate heavy machinery until you know how the drug affects you. Use caution if taking cold or allergy medicines, sedatives, anxiety medicines, or sleeping pills or if consuming alcohol while taking this medicine. Talk to your doctor or nurse if you feel too drowsy or it does not go away.

As with other antidepressants, this drug may raise the risk of suicidal thoughts and actions, mostly in people up to age 24, especially during the first few months of treatment. If you notice any strange or unusual thoughts or behavior, such as irritability, sleep problems, aggressiveness, restlessness, panic attacks, or thoughts of suicide while on this medicine, call your doctor. Tell family members, loved ones, and caregivers that you are taking this drug, so that they can help you if they notice behavior changes.

This medicine may take 2 weeks or longer to take effect. Do not stop taking this drug without first speaking to your doctor or nurse. If you are going to stop taking this drug, it should usually be tapered down over the course of several weeks, as directed by your doctor. Suddenly stopping the drug can cause anxiety, dizziness, irritability, headache, insomnia, and confusion in some people.

Paroxetine should be used with caution if you have ever had glaucoma, seizures, bipolar disorder (manic depressive illness), or have ever had bleeding problems. This drug could make these conditions worse.

This drug may lessen saliva production, which can lead to dry mouth and an increased risk of dental cavities or gum disease, especially in older people. Your doctor or nurse should be able to offer suggestions on how to deal with this if needed.

This drug can rarely cause a problem called serotonin syndrome, with symptoms such as nausea, vomiting, diarrhea, headache, restlessness, and confusion. It can also cause bleeding, easy bruising, and trouble walking. This syndrome can become life-threatening if not treated quickly. If you have symptoms like these, get help and call your doctor right away.

Older people may have low levels of sodium in the blood while on this drug. This is usually found only on blood tests, but if severe, may cause sluggishness, unsteadiness, confusion, muscle twitching, seizures, and coma.

Possible side effects

Should you have any of the following side effects, tell your doctor or nurse. They can help you understand these side effects and help you deal with them.

Common

• nausea
• trouble sleeping
• headache
• problems with ejaculation (men)

Less common

• feeling drowsy*
• dry mouth*
• feeling tired or weak
• sweating
• diarrhea
• constipation
• upset stomach
• feeling restless or nervous
• feeling dizzy
• trembling
• loss of appetite
• less interest in sex
• impotence (men)
• decreased ability to reach orgasm (women)

Rare

• increased sensitivity to sunlight
• blurred vision
• change in how things taste
• reduced fertility in men due to changes in sperm quality
• bones may break more easily, especially if you have osteoporosis (thinning bones)
• low blood sodium levels*
• suicidal thoughts or actions*

*See the "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 1992.

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.