Paroxetine (Paxil)

This article provides a comprehensive overview of paroxetine, including its uses and indications, side effects, precautions, and drug interactions.

Key Takeaways:

• Paroxetine is an SSRI antidepressant used for a variety of depression and anxiety disorders. It works by increasing the effects of serotonin in the brain, among other effects.

• Paroxetine has arguably the greatest severity and frequency of side effects among all SSRIs, some of which are severe or even life-threatening.

• Paroxetine has greater risks for several populations, including pregnant and breastfeeding women, older adults, and individuals with a variety of mental and physical conditions. Weighing the risks against the benefits is essential for the safest and most effective treatment.

Understanding Paroxetine

Paroxetine is an antidepressant in the class of prescription medications known as selective serotonin reuptake inhibitors (SSRIs). It was first approved for use in the United States in 1992. ^[1]

Due to certain actions in the brain, paroxetine may be beneficial not only for depression, but also for anxiety disorders and other mental health concerns. Compared to other SSRIs, paroxetine has a wide range of approved uses. ^[2]

Brand Names

The most common brand name of paroxetine is Paxil®. Other brand names of paroxetine include: ^[3]

• Paxil CR®

• Brisdelle®

• Pexeva®

How Does Paroxetine Work?

Paroxetine primarily works by inhibiting the reuptake of serotonin by nerve cells, which leaves more serotonin to be available in the brain. This is important since serotonin is a neurotransmitter involved in mood, sleep, appetite, sexual function, anxiety, and other important areas connected to mental health and general well-being. ^[2]

In addition, paroxetine affects other neurotransmitters, such as dopamine, adrenaline, acetylcholine, and histamine, although these aren’t its primary effects. ^[2]

When is it prescribed?

There are many different uses of paroxetine. Paroxetine is approved to treat several mental health conditions, including: ^{[2] [3]}

• Major depressive disorder (MDD)

• Social anxiety disorder (SAD)

• Panic disorder

• Obsessive-compulsive disorder (OCD)

• Post-traumatic stress disorder (PTSD)

• Generalized anxiety disorder (GAD)

• Pre-menstrual dysphoric disorder (PMDD)

It is also approved to treat vasomotor symptoms associated with menopause. ^[2]

Paroxetine is sometimes prescribed off-label for the following conditions: ^[2]

• OCD in children and adolescents

• SAD in children and adolescents

• Separation anxiety

• Dysthymia

• Body dysmorphic disorder

• Postpartum depression

• Premature ejaculation

• Malignancy-related pruritus

What to Know Before Taking Paroxetine

There are several important things to know before taking paroxetine. Firstly, paroxetine is primarily used for depression and anxiety conditions. It’s important to fully discuss your symptoms and all relevant information with your doctor to determine the most beneficial treatment plan. This is especially important given that mental health issues may increase the risk of suicidal behaviors and thoughts. ^[3]

Paroxetine may interact with other medications, including potentially dangerous interactions with other drugs that increase serotonin. You can’t take paroxetine within 14 days before or after using monoamine oxidase inhibitors (MAOIs), due to an increased risk of serotonin syndrome.

Paroxetine may increase the risk of suicidal thoughts or behaviors, especially in children and young adults under the age of 25. This risk is greatest when you first start taking paroxetine and when the dose is changed. Call your doctor right away if you notice any warning signs, such as new or worsening depression, thoughts of harming or killing yourself, extreme anxiety or worry, and severe agitation. ^{[2] [3]}

You should also know that paroxetine is available under several brand names and comes in different forms, such as regular tablets, controlled-release tablets, capsules, and liquid. Be sure to ask your doctor which form is best for you.

Dosage

The specific paroxetine dosage depends on the condition being treated and the specific drug form utilized. Listed below are commonly recommended dosages of paroxetine for its primary indications:

Note: All doses of paroxetine are taken orally. Always follow your doctor’s specific instructions when taking paroxetine.

• MDD

• Immediate-release formula:

• Adults: 20 to 50 mg per day

• Geriatric: 10 to 40 mg per day

• Controlled-release formula:

• Adults: 25 to 62.5 mg per day

• Geriatric: 12.5 to 25 mg per day

• GAD, OCD, and PTSD

• Immediate-release formula:

• Adults: 20 to 60 mg per day

• Geriatric: 10 to 40 mg per day

• SAD

• Immediate-release formula:

• Adults: 20 to 60 mg per day

• Geriatric: 10 to 40 mg per day

• Children and adolescents aged 8 and older: 10 to 50 mg per day (off label)

• Controlled-release formula:

• Adults: 12.5 to 37.5 mg per day

• Panic disorder:

• Immediate-release formula:

• Adults: 10 to 60 mg per day

• Geriatric: 10 to 40 mg per day

• Children and adolescents aged 7 and older: 10 to 40 mg per day (off-label)

• Controlled-release formula:

• Adults: 12.5 to 75 mg per day

• Geriatric: 12.5 to 50 mg per day

• PMDD

• Controlled-release tablet:

• Adult females: 12.5 to 25 mg per day

• Immediate-release formulation:

• Adult females: 5 to 30 mg per day

Precautions

Paroxetine may increase the risk of birth complications and other side effects, especially when taken in the last trimester. Paroxetine has also been shown to pass into breastmilk. Due to these issues, paroxetine is generally not recommended in these situations, but your doctor will determine if paroxetine is safe for you by weighing the benefits and risks. ^{[1] [3]}

You may require a lower dose of paroxetine (or may not be able to take it at all) if you have any of the following conditions or symptoms: ^{[1] [2] [4]}

• Liver or kidney impairments

• Heart attack

• Low sodium in blood

• Seizures

• Bipolar disorder

• Bleeding problems

• Glaucoma

• Osteoporosis

• Diabetes

Side Effects

There are numerous possible side effects of paroxetine, which can occur in many different areas of the body. It’s important to watch out for any side effects, especially after you first start taking paroxetine or when the dose is changed. If you notice any side effects, reach out to your doctor as soon as possible.

Common Side Effects

The most common side effects of paroxetine are: ^{[2] [3] [5]}

• Drowsiness

• Dry mouth

• Loss of appetite

• Sweating

• Sleep disturbance

• Feeling tired or weak

• Sexual problems

• In males: decreased sex drive, erectile dysfunction, delayed or absent ejaculation

• In females: decreased sex drive, delayed orgasm, or inability to have an orgasm

Other relatively common side effects of paroxetine include: ^{[3] [6]}

• Anxiety

• Shaking

• Vomiting

• Diarrhea

• Constipation

• Yawning

• Headache

• Confusion

• Muscle or joint pain

• Changes in ability to taste

• Weight changes

• Nervousness

• Trouble concentrating

Rare and Severe Side Effects

Some paroxetine side effects are rare but potentially severe and life-threatening. They include the following: ^{[1] [2] [3] [5] [6]}

• Changes in mental health, such as:

• New or worsening depression

• Aggression

• Irritability

• Extreme worry

• Agitation

• Impulsivity

• Abnormal excitement

• Painful, long-lasting erections

• Angle-closure glaucoma

• Cardiovascular complications, such as:

• Rapid heart rate

• Prolonged QT interval

• Palpitations

• Severe allergic reactions (anaphylaxis)

• Stool changes, such as:

• Black and tarry stools

• Blood in stool

• Bone pain or fractures

• Uncontrollable shaking

• Bleeding or bruising

• Fainting

• Seizures

• Difficulty breathing

• Infection

• Low sodium levels in blood

• Peeling or blistering of the skin

• Trouble with walking and balance

• Blood in your vomit

• Blurred vision

Serotonin Syndrome

Paroxetine may cause serotonin syndrome, especially if it is taken in higher doses or when combined with other medications or substances that increase serotonin.

Serotonin syndrome occurs when there is too much serotonin built up in the nervous system. It can cause a wide variety of symptoms, including dilated pupils, increased heart rate, muscle rigidity, sweating, vomiting, confusion, and tremors. Severe cases can lead to coma, seizures, or death. ^{[2] [6]}

Drug Interactions with Paroxetine

Paroxetine may have harmful interactions with several drugs and other substances. It is absolutely contraindicated with MAOIs (e.g. isocarboxazid, methylene blue, phenelzine) due to an increased risk of serotonin syndrome. Furthermore, it should never be taken with thioridazine or pimozide due to an increased risk of heart rhythm abnormalities. ^[2]

In addition, paroxetine can not be taken with tamoxifen (a drug used to prevent and treat breast cancer) due to an increased risk of death from breast cancer. ^[1]

Paroxetine may interact with other drugs and substances, including: ^{[3] [6] [7]}

• Other antidepressants, such as:

• Other SSRIs (e.g. fluoxetine, escitalopram)

• Serotonin-norepinephrine reuptake inhibitors (SNRIs) (e.g. desvenlafaxine)

• Tricyclic antidepressants (e.g. clomipramine)

• Antipsychotics (e.g. aripiprazole, risperidone)

• NSAIDs (e.g. ibuprofen, aspirin)

• St. John’s wort

• Tryptophan

• Dextromethorphan

• Alcohol

• Muscle relaxants

• Opioids (e.g. oxycodone, hydrocodone)

This list does not contain all possible interactions. Always tell your doctor everything you take or have taken, including prescription and over-the-counter medicines, herbs, and dietary supplements.

Cessation and Withdrawal

In general, paroxetine has a higher likelihood of discontinuation syndrome compared to other antidepressants. ^[2]

Cessation of paroxetine should only be done under careful medical supervision. Suddenly stopping paroxetine can increase the risk of withdrawal symptoms, including: ^{[2] [3]}

• Dizziness

• Lethargy

• Nausea

• Vomiting

• Electric shock-like sensations

• Anxiety

• Headache

• Fever

• Chills

• Irritability

• Depersonalization

• Numbness or tingling in limbs

• Trouble sleeping

These symptoms may occur even when stopping paroxetine in a gradual, controlled manner, although the risk is lower.

When to Stop Taking Paroxetine

You may be able to stop taking paroxetine if your symptoms have resolved and have a low risk of returning. However, this decision can only be made by consulting with your doctor and obtaining his or her approval.

Most individuals will take paroxetine for at least 3 to 6 months. Some individuals with chronic depression or anxiety may need to take paroxetine long-term, if not indefinitely.