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Rx pill bottle and prescription pad: Paroxetine side effects and how to avoid them
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Paroxetine side effects and how to avoid them

Paroxetine side effects include depression, weight gain, and headaches
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By | Oct. 17, 2022 Medically reviewed by Irene Xue, Pharm.D.

Common paroxetine side effects | Serious side effects | Depression | Insomnia | Sexual side effects | Weight Gain | Headaches | Side effects timeline | Contraindications | Warnings | Interactions | How to avoid side effects | How to treat side effects

Paroxetine, better known to most people as brand-name Paxil, is a generic prescription drug used to treat major depressive disorder (MDD), obsessive-compulsive disorder (OCD), generalized anxiety disorder, panic disorder, social anxiety disorder, post-traumatic stress disorder, and premenstrual dysphoric disorder (PDD). Healthcare providers also prescribe paroxetine as brand-name Brisdelle, a low-dose paroxetine mesylate capsule used to treat severe hot flashes or night sweats in menopausal women, or Pexeva, another chemical variant of paroxetine. Paroxetine is a well-known member of a class of drugs called selective serotonin reuptake inhibitors (SSRIs). These drugs increase a chemical in the brain called serotonin which is responsible for passing signals between nerves. In this way, it increases activity in the parts of the brain responsible for mood. Although paroxetine is a highly effective drug, it does have side effects very similar to other SSRIs. 

Common side effects of paroxetine

One of the most common side effects of paroxetine in clinical trials is headache. Certain side effects such as nausea are more commonly experienced in people taking immediate-release paroxetine than in people taking extended-release paroxetine (Paxil CR) or low-dose Brisdelle.

The most common side effects of paroxetine are:

  • Headache
  • Ejaculation problems
  • Drowsiness
  • Nausea
  • Diarrhea
  • Trouble sleeping
  • Dry mouth
  • Dizziness
  • Weakness
  • Constipation
  • Orgasm problems (in women)
  • Stomach pain
  • Decreased libido
  • Tremor
  • Flatulence
  • Sweating
  • Back pain
  • Blurred vision
  • Impotence
  • Decreased appetite
  • Indigestion
  • Muscle pain
  • Nervousness
  • Anxiety 
  • Sinusitis
  • Yawning

Serious side effects of paroxetine

The most serious side effects of paroxetine include:

  • Suicidal thoughts and behaviors
  • Worsening of depression
  • Hypomania or mania
  • Bleeding
  • Angle-closure glaucoma
  • Seizures
  • Low sodium (hyponatremia)
  • Painful or persistent erections (priapism)
  • Restlessness (akathisia)
  • Heart rate or rhythm problems
  • Serotonin syndrome
  • Severe allergic reactions
  • Bone fracture

Depression

Paroxetine drug information includes a black-box warning about the risk of suicide among children, teens, and young adults taking paroxetine. Short-term studies have not shown an increased suicide risk in adults beyond the age of 24. Depression is not considered a side effect of paroxetine, but the onset or worsening of depression, especially at the beginning of treatment, is a sign that suicide may be a risk. If anyone taking paroxetine gets depressed or their depression worsens, immediately talk to the prescribing healthcare provider. 

Insomnia

While insomnia is a common side effect, its likelihood depends on the type of paroxetine being taken. In clinical trials for immediate-release paroxetine, up to 24% of participants reported problems sleeping. This was about twice the rate for participants who were not taking paroxetine. Only up to 20% of participants in the clinical trials for extended-release paroxetine, however, reported sleep problems. Insomnia was not a common side effect in women taking Brisdelle for menopause symptoms. Insomnia is usually not a medical emergency, but it isn’t good, either. If falling asleep or staying asleep is a problem for any reason, get medical advice from a healthcare professional.

Sexual side effects

All SSRIs can decrease sexual interest, affect sexual functioning, or both. In clinical trials, at least 7% of participants with MDD taking extended-release paroxetine reported a decrease in libido. Twenty-six of men had ejaculation problems and 5% reported impotence as a side effect. Among women, one out of 10 had problems reaching orgasm. However, women taking low-dose paroxetine for menopause symptoms did not report significant changes in sexual function. It helps to know that the majority of people who take an SSRI like paroxetine will experience sexual side effects such as a decrease in genital sensitivity. Because of its genital numbing effects, paroxetine is one of the most effective SSRIs for treating premature ejaculation. Sexual problems, though, will only last as long as paroxetine is being taken. Genital sensitivity and normal sexual function will return when paroxetine is discontinued.

RELATED: Sex on antidepressants: Exploring the sexual side effects of SSRIs

Weight gain

Weight gain is a common side effect of SSRI treatment, but it only occurred in 1% to 5% of people taking paroxetine in clinical trials. Women on low-dose paroxetine for menopausal symptoms do not experience weight changes. If weight goes up or down involuntarily when taking paroxetine, report this problem to the prescribing healthcare provider. There are lifestyle and diet changes that can help.

Headaches

Headaches are one of the most common problems people have with paroxetine. In clinical trials, 17% to 18% of people taking immediate-release paroxetine reported headaches as a side effect. In clinical trials, 15% to 27% of people taking extended-release paroxetine reported headaches. About 6% had problems with headaches in low-dose paroxetine trials. In all cases, though, headache was one of the most common side effects. Headaches, however, were not a common reason in these trials for people to quit paroxetine. If headaches become a serious problem when taking paroxetine, talk to the prescribing healthcare provider. There may be simple remedies including over-the-counter pain relievers that can help.

How soon do paroxetine side effects start?

Paroxetine side effects that can occur early in treatment include headaches, drowsiness, weakness, dizziness, sleeping problems, diarrhea, nausea, and dry mouth. Suicidal thoughts or worsening of depression in young patients is more likely to occur when starting paroxetine. Allergic reactions and effects involving heart rhythm or heart rate could happen after the first dose or could be delayed. Some other side effects could also be delayed, requiring weeks or months to become problems. These include sexual dysfunction, weight changes, and many of the most serious side effects.

How long do paroxetine side effects last?

Many of the most common side effects may improve over time. Both common side effects and most serious side effects typically improve when paroxetine is discontinued. Some of the most concerning side effects, such as decreased libido and sexual dysfunction, are usually reversible if the drug is stopped. It may take a few days, though. It takes the body almost a day to clear half a dose of paroxetine.

What are the long-term side effects of paroxetine?

Paroxetine is usually taken for several months or even years. There are no side effects that are specifically due to long-term use. Most of paroxetine’s side effects typically improve after the medicine has been stopped, but a few of the most serious side effects, like hyponatremia, may have long-term consequences.

Paroxetine contraindications

Paroxetine is never prescribed to anyone with allergies to paroxetine. It should also not be used in anyone that is taking a monoamine oxidase inhibitor (MAOI) or the medications Mellaril (thioridazine) and Orap (pimozide).

Pregnancy

The use of paroxetine should be avoided in pregnant women because of the risk of heart defects, spontaneous abortions, premature birth, and other problems. Women will usually not be started on paroxetine if pregnant. Women who become pregnant while on paroxetine should talk to a healthcare provider about these risks and the possibility of switching to a different drug. Brisdelle is contraindicated for use during pregnancy.

RELATED: Can you take antidepressants when pregnant?

Breastfeeding

Paroxetine can be given to women who are breastfeeding under a doctor’s guidance. Paroxetine is present in human breast milk but is not known to cause problems in a nursing infant. Other SSRIs do, however, so the Food and Drug Administration (FDA) advises healthcare providers to be cautious when prescribing paroxetine to women who are nursing. 

RELATED: What nursing moms need to know about antidepressants and breastfeeding

Children

Paroxetine is not approved for use in children or adolescents. When used off-label, both the prescriber and caregiver should monitor the child for signs of suicidality.

Seniors

Paroxetine is safe but a bit riskier in people older than 65. People of advanced age eliminate the drug more slowly than young adults and have an increased risk for low sodium. Healthcare providers are urged to start at lower doses and increase the dose at a slower rate in seniors than they would in younger patients.

Paroxetine warnings

Black box warning

Paroxetine comes with a black box warning about the risk of suicidal thoughts and behaviors in children, adolescents, and young adults taking the drug.

Cautions

Some pre-existing health conditions may increase the risk or severity of paroxetine side effects:

  • Bipolar disorder, mania, or hypomania
  • Narrow angles in the eyes or previous bouts with angle-closure glaucoma
  • Dehydration
  • Bleeding problems
  • Kidney dysfunction
  • Liver dysfunction
  • Seizures
  • Heart problems

Abuse and dependence

Paroxetine is not associated with drug addiction, drug abuse, or physical dependence. However, it’s best not to stop taking paroxetine suddenly because of possible withdrawal symptoms. When it’s time to quit, a healthcare provider will most likely prescribe a steadily decreasing dose. 

Overdose

Get medical help or call a poison control center if too much paroxetine is taken. A severe overdose could cause heart problems, seizures, or serotonin syndrome.

Paroxetine interactions

Quite a few drugs cause problems when taken with paroxetine. In some cases, these drug interactions are so hazardous that these drugs are contraindicated for use with paroxetine. These include MAOIs and the antipsychotic medications pimozide and thioridazine.

Drugs that increase the risk of serotonin syndrome, a medical condition caused by taking too many drugs that raise serotonin levels, include:

Paroxetine affects the body’s ability to form blood clots, so bleeding episodes are more likely to occur when paroxetine is combined with blood thinners such as warfarin or nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, or naproxen.

Finally, paroxetine can block the ability of the body to break down other drugs and supplements. This results in higher concentrations of coadministered drugs and increases the risk of their side effects. Both the prescribing healthcare provider and the pharmacist are familiar with all these drugs, so make sure they have a complete list of all the prescription drugs, over-the-counter medications, and even dietary supplements that you take regularly to prevent possible problems.

How to avoid paroxetine side effects

Paroxetine is intended for long-term use, so efforts to prevent possible side effects will pay off in the long run.

1. Give the prescriber a complete medical history

Paroxetine taken on top of pre-existing medical conditions is a principal source of side effects. Don’t assume the prescriber has a complete medical history. That prescriber will particularly need to know about:

  • Suicidal thoughts or behaviors
  • Bipolar disorder or a history of mania or hypomania
  • Drug abuse
  • Heart problems
  • High blood pressure
  • Stroke
  • History of seizures
  • Bleeding problems
  • Uncorrected narrow angles or a history of narrow-angle glaucoma
  • Liver problems
  • Kidney problems
  • Bone problems
  • Pregnancy or pregnancy plans
  • Breastfeeding or breastfeeding plans

2. Give the prescriber a complete list of drugs being taken

Combining paroxetine with certain prescription drugs, over-the-counter medications, and dietary supplements is another significant source of paroxetine adverse effects. Give the prescriber a complete list of the drugs being taken, especially:

3. Take paroxetine as instructed

Follow the directions for taking paroxetine given by the prescriber or written on the prescription label. If a dose is missed, take it when remembered. If it’s almost time for the next dose, then just forget about the missed dose and take the next dose as scheduled. 

4. Take the dose in the morning

To avoid trouble sleeping, take each day’s dose in the morning.

5. Avoid alcohol

Drinking alcohol will worsen drowsiness and sedation caused by paroxetine.

6. Avoid NSAIDs

Taking common over-the-counter NSAIDs with paroxetine increases the risk of stomach pain and bleeding. Use acetaminophen instead for pain or fever.

How to treat side effects of paroxetine

Side effects aren’t always avoidable, but some can be managed. More troublesome or serious side effects, though, may require the help of a healthcare professional. 

Headaches

Try drinking more fluids and resting. You can safely use acetaminophen as a pain reliever, but you might want to avoid aspirin or ibuprofen. If headaches become too severe, talk to the prescribing healthcare provider. 

Drowsiness and dizziness

Drowsiness and dizziness tend to go away after a few weeks. In the meantime, the goal is to prevent falls, accidents, or injuries. Stand up slowly, move carefully, and remove any obstacles that can be tripped over. 

Low sodium

Normally, low sodium is unpleasant and can be fixed by increasing salt intake. However, it can quickly develop into a serious or life-threatening medical condition. Call the prescribing healthcare provider when there are signs of low sodium including:

  • Headache
  • Weakness
  • Problems with coordination
  • Confusion
  • Seizures

Suicide

Immediate medical help is required when anyone shows signs of suicidal thoughts or behaviors including:

  • Suicide attempts
  • Talking or thinking about suicide or death
  • Worsening of depression
  • Anxiety
  • Panic attacks
  • Sudden mood or behavior changes
  • Reckless or risk-taking behaviors
  • Hostile or violent behavior
  • Unusual behaviors
  • Agitation, restlessness, irritability, or anger
  • A marked increase in activity or talking
  • Sleeplessness

Serotonin syndrome

Serotonin syndrome is a neurological problem caused by high levels of serotonin in the brain. In most cases, it’s due to people taking too many drugs like paroxetine that raise serotonin levels. All these drugs, including paroxetine, should be stopped and medical help sought out when a person experiences symptoms of serotonin syndrome including:

  • Racing heartbeats
  • High or low blood pressure
  • Muscle tightness
  • Sweating
  • Dizziness
  • Fever
  • Flushing
  • Agitation
  • Hallucinations
  • Tremor
  • Seizures

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