Paxil Side Effects: What the Paroxetine Label Says to Watch For

What should you expect when you start Paxil?

Paxil (paroxetine) is an SSRI with the side effects common to its class and a few warnings that are more specific to it: sexual dysfunction, a discontinuation syndrome when it is stopped abruptly, and a caution about use in early pregnancy. The FDA prescribing information for Paxil approves paroxetine for major depressive disorder, obsessive-compulsive disorder, panic disorder, social anxiety disorder, generalized anxiety disorder, and posttraumatic stress disorder in adults, and directs that it be taken once daily in the morning, with or without food. This article explains what the label lists as the most common side effects, which ones mean an immediate call, why stopping it needs a plan, and what to tell a prescriber before the first dose.

What are the most common side effects?

The label's list of reactions seen most often includes nausea, dry mouth, constipation, diarrhea, decreased appetite, dizziness, somnolence, insomnia, sweating, tremor, weakness, yawning, and abnormal ejaculation. The MedlinePlus patient information for paroxetine describes the same ground in plainer words: dizziness, weakness, uncontrollable shaking, trouble sleeping, nervousness, yawning, nausea, diarrhea, constipation, decreased appetite, dry mouth, sweating, and sexual problems such as lower sex drive and trouble with erection, ejaculation, or orgasm.

Several of these are most noticeable in the first weeks and settle. Others do not, and those are the ones to report rather than endure. MedlinePlus says it may take several weeks or longer to feel the full effect, and the National Institute of Mental Health's depression booklet puts antidepressants in general at four to eight weeks, so the early side effects usually arrive before the benefit does. Our article on how long antidepressants take to work explains how to judge that stretch.

Why does the label single out sexual side effects?

Because they are frequent, and because they are the side effect patients most often stop mentioning. The label lists sexual dysfunction as its own warning, and MedlinePlus names lower sex drive and problems with erection, ejaculation, or orgasm among the side effects. There is nothing shameful about raising it; it is a labeled effect of the medicine, and a prescriber who knows about it has options to consider with you. Our article on how to bring up antidepressant sexual side effects gives you the words.

Which side effects mean you should call right away?

MedlinePlus says to call your doctor immediately for chest pain, shortness of breath, dizziness, or fainting; seizures; agitation, fever, confusion, a fast or irregular heartbeat, severe muscle stiffness, hallucinations, or loss of coordination; abnormal bleeding or bruising; peeling or blistering skin; a severe headache, unsteadiness, or problems with thinking or memory; and for signs of an allergic reaction such as rash, hives, hoarseness, or swelling of the face, throat, or lips.

The reasons are in the label's warnings. Fever, stiffness, confusion, and agitation can be signs of serotonin syndrome, which the label says is more likely when paroxetine is combined with other medicines that affect serotonin and which is the reason it must never be taken with a monoamine oxidase inhibitor. Bruising and bleeding track the bleeding warning, especially with aspirin, anti-inflammatories, or blood thinners. The label also warns of activation of mania or hypomania, so any history of bipolar disorder should be on the table before you start, and of angle-closure glaucoma, low sodium, seizures, and an increased risk of bone fracture. You do not need to memorize that list; you do need to tell your prescriber your history so that the warnings that apply to you get discussed.

What about the suicide warning?

Paroxetine carries the antidepressant class boxed warning. The label states that antidepressants increased the risk of suicidal thoughts and behaviors in pediatric and young adult patients, asks that all patients be monitored for clinical worsening and the emergence of suicidal thoughts, and states that Paxil is not approved for pediatric use. The label puts the young-adult group at ages 18 to 24, and MedlinePlus says the risk may be higher in the first few months of treatment and after dose increases. MindVibe sees patients aged 13 and up, in person at offices in Texas and California and by telehealth, so a prescriber who considers paroxetine for a teen is prescribing off-label and should be able to explain why.

If you or someone you know is thinking about suicide or is in crisis, call or text 988 to reach the 988 Suicide & Crisis Lifeline. It is free, confidential, and available around the clock. If someone is in immediate danger, call 911.

Why is stopping Paxil different from stopping other medicines?

The label describes a discontinuation syndrome, with symptoms that include nausea, dizziness, and irritability, and says the dose should be reduced gradually when possible rather than stopped abruptly. MedlinePlus lists mood changes, dizziness, irritability, and trouble sleeping among the withdrawal symptoms and says not to stop without talking to your doctor. In practice that means two things: a missed dose can be felt sooner on paroxetine than people expect, and coming off it is a planned conversation with a schedule, not a decision made when the bottle runs out. Our article on why tapering off an antidepressant matters explains what that plan looks like.

What should you tell a prescriber before you start?

Pregnancy plans come first. The label warns of embryofetal toxicity and says paroxetine should be used in the first trimester only after other options have been considered, because some studies found an increased rate of cardiovascular malformations. MedlinePlus says to tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding, and to call immediately if you become pregnant while taking it. Then the rest of the history: every other medicine and supplement, including tamoxifen, which the label says paroxetine can make less effective; any monoamine oxidase inhibitor in the last two weeks; bleeding problems, seizures, glaucoma, bipolar disorder, and bone fractures; and how much you drink, because MedlinePlus says alcohol can make the side effects worse.

Never stop, start, or switch an antidepressant on your own; talk with your prescriber. If you are starting from scratch, you can read about how depression is evaluated and treated or book a visit with a psychiatric provider to talk through whether paroxetine, or something else, fits your situation.

This article is for educational purposes only and is not medical advice, a diagnosis, or a substitute for care from a licensed clinician. Never stop, start, or switch a medication on your own; talk with your prescriber. In a crisis, or if you are having thoughts of suicide, call or text 988 to reach the 988 Suicide & Crisis Lifeline, or go to the nearest emergency room.

Frequently asked questions

What are the most common Paxil side effects?

The FDA prescribing information lists, among the reactions seen most often, nausea, dry mouth, constipation, diarrhea, decreased appetite, dizziness, drowsiness, insomnia, sweating, tremor, weakness, yawning, and abnormal ejaculation. MedlinePlus adds nervousness, uncontrollable shaking, and sexual problems in both men and women. Many are most noticeable early; report the ones that do not settle.

Does Paxil cause sexual side effects?

Yes, and the label treats sexual dysfunction as its own warning rather than a footnote. MedlinePlus lists lower sex drive and trouble with erection, ejaculation, or orgasm among the side effects. These are among the side effects patients most often stop mentioning, which is why it helps to raise them at the first follow-up rather than the fourth.

Why does the label warn about stopping Paxil?

The label describes a discontinuation syndrome, with symptoms such as nausea, dizziness, and irritability, and says the dose should be reduced gradually when possible rather than stopped abruptly. MedlinePlus lists mood changes, dizziness, irritability, and trouble sleeping among the withdrawal symptoms. That is why a missed dose can feel different on paroxetine, and why stopping is a planned conversation.

Is Paxil safe in pregnancy?

The label carries a warning about embryofetal toxicity: it says paroxetine should be used in the first trimester only after other options have been considered, because of an increased rate of cardiovascular malformations in some studies. MedlinePlus says to tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding, and to call immediately if you become pregnant while taking it. Pregnancy plans belong in the first conversation.

Can a teenager take Paxil?

The label approves paroxetine for adults only and states that it is not approved for pediatric use; its studies in children and teens with depression did not show it worked. It also carries the boxed warning about suicidal thoughts in children, adolescents, and young adults. A prescriber who considers it for a teen is prescribing off-label and should be able to explain why.

What should I tell my prescriber before starting Paxil?

Any plan to become pregnant, every other medicine and supplement you take, especially blood thinners, aspirin, anti-inflammatories, tamoxifen, and any monoamine oxidase inhibitor in the last two weeks, any history of bipolar disorder, seizures, bleeding problems, glaucoma, or bone fractures, and how much alcohol you drink. Each of those maps to a warning on the label.