Paxil (Paroxetine HCl): Facts, Dosage & Side Effects

By Jenell Decker, MD
Medically reviewed checkmarkMedically reviewed
April 16, 2020

Paxil (paroxetine HCl) is a commonly prescribed medicine that nearly twelve million Americans take to treat depression, anxiety, and other mood disorders. It can help improve your day-to-day mood, energy, and interest in life, while reducing any fear, anxiety, unwanted thoughts, and panic attacks. It may also help to dampen down the urge to perform repetitive compulsive tasks that can interfere with your daily living.

What Is Paxil?

Paxil is a prescription-only psychotropic drug that is used to help you with conditions that are negatively affecting your mind, emotions, or behavior. It comes in tablet or liquid suspension form. Paxil has helped millions of Americans feel better when suffering from depression, anxiety, panic attacks, obsessive compulsive disorder, post-traumatic stress disorder, social anxiety disorder, and premenstrual dysphoric disorder.

Paxil belongs to the class of drugs called selective serotonin reuptake inhibitors (SSRIs) and affects chemicals in the brain that may be unbalanced in people with depression, anxiety, or other mood disorders.

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Paxil Generic Name

Paxil is a brand name for the generic drug called paroxetine hydrochloride (HCl) or paroxetine for short. Paroxetine is also sold under another brand name called Brisdelle.

The well-known international biopharmaceutical company, GlaxoSmithKline developed Paxil and obtained approval from the U.S. Food and Drug Administration (FDA) in 1992 for its use in the treatment of depression, anxiety, and other mood disorders. Since 2003, Paxil has been available as a cheaper generic drug, paroxetine, in the United States.

Paroxetine Uses

Paroxetine HCl is a prescribed medication used to treat the following conditions:

Major depressive disorder

Major depressive disorder (MDD), also called clinical depression, is a common and serious mood disorder where you have a persistent feeling of sadness and loss of interest, and you may feel as if life isn’t worth living. You lose interest in activities you once enjoyed and you are unable or find it hard to carry out your day-to-day tasks. Apart from these emotional problems, you may also have physical symptoms such as chronic pain or digestive issues.

According to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), to be diagnosed with major depressive disorder, you will have at least five of the following symptoms where one of the symptoms must be either a depressed mood or a loss of interest/pleasure. If you have MDD you will have had these symptoms persistently almost every day for a minimum of two weeks:

  • Depressed mood
  • Noticeable loss of interest or pleasure in your usual activities
  • Significant/noticeable change in weight and/or appetite
  • Slower thoughts and movements, and physical and emotional reactions (psychomotor retardation)
  • Fatigue or lack of energy
  • Feelings of excessive or inappropriate guilt or worthlessness
  • Difficulty thinking and concentrating, or indecisiveness
  • Suicidal thoughts, recurrent suicidal ideation, or a suicide plan or attempt

Depression most often occurs in young adults between the ages of 18-25. Over 7% of American adults have at least one major depressive episode a year, with more women suffering from this disorder than men.

Generalized anxiety disorder

Paxil was approved for the treatment of generalized anxiety disorder (GAD) in 2001. GAD is a condition in which you have excessive anxiety and worry that is difficult to control. This anxiety and worry can be about various activities in your life, reducing your ability to cope with everyday tasks and causing you a lot of distress. GAD occurs on more days than not for at least six months.

According to the DSM-5, GAD is associated with at least three of the following symptoms:

  • Restlessness or feeling keyed up or on edge
  • Being easily fatigued
  • Difficulty concentrating or your mind going blank
  • Irritability
  • Muscle aches or soreness
  • Difficulty sleeping

Almost 6% of American adults have suffered from GAD at some point in their lifetime. What’s more, nearly one in three people with GAD struggle with severe anxiety and mental illness.

Social anxiety disorder

Paxil was approved for the treatment of social anxiety disorder in 1999. Social anxiety disorder, also known as social phobia, is the feeling of intense anxiety or fear of being judged, negatively evaluated or rejected in a social or performance situation. You may be worried about acting or appearing visibly anxious, or being viewed as stupid, awkward, or boring. This may lead you to avoid such situations whenever possible. In such social situations, as well as suffering from extreme anxiety and distress, you may also feel physical symptoms, such as a rapid heart rate, nausea, sweating, and even full-blown anxiety attacks. Although you know rationally that your anxiety and fear is excessive, you may feel powerless to prevent it and it can negatively affect your life and prevent you from forming social and romantic relationships, finishing your studies, and getting a job.

It is important you seek professional medical help if you think you may have social anxiety disorder since there are effective treatments, such as paroxetine, that can help you live a less anxious life. Unfortunately, of the approximately 15 million American adults who suffer from social anxiety disorder, fewer than 5% seek treatment and those who don’t are at increased risk of becoming depressed or alcoholic.

Panic disorder

Panic disorder is classified as an anxiety disorder in the DSM-5. To be diagnosed with panic disorder, you need to:

  • Experience unexpected panic attacks on a regular basis
  • At least one attack is followed by at least one month or feeling fearful of further attacks and accordingly trying to avoid situations that might induce an attack
  • The attacks are not due to the direct physiological effects of a drug, medication, or medical condition
  • The attacks are not better accounted for by another mental disorder

According to the DSM-5, there are two categories of panic attacks: expected and unexpected. Expected panic attacks are typically linked to a specific fear such as being afraid of heights, whereas unexpected panic attacks have no known triggers and appear to occur out of the blue.

According to DSM-5, a panic attack is characterized by four or more of the following symptoms :

  • Numbness or tingling sensations
  • Body chills or hot flashes
  • Shortness of breath
  • A feeling of choking
  • Palpitations, pounding heart, or accelerated heart rate
  • Sweating
  • Trembling or shaking
  • Chest pain
  • Nausea or abdominal pain
  • Feelings of unreality or being detached from oneself
  • Fear of losing control or going crazy
  • Feeling dizzy, unsteady, lightheaded, or faint
  • Fear of dying

If you have fewer than four of the above symptoms, it is considered a limited-symptom panic attack.

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Obsessive compulsive disorder

Obsessive compulsive disorder (OCD) is when you get caught up in a cycle of obsessions and compulsions.

Obsessions are defined as repetitive, unwanted, and uncontrollable intrusive thoughts, images, or urges that trigger intensely distressing feelings, including the feeling that things need to be done in the ‘right’ way. Obsessions seen with OCD include obsessions related to contamination, losing control, fear of harm, perfectionism, religion, unwanted sexual thoughts, and more.

Compulsions are defined as behaviors you engage in to attempt to get rid of or escape the obsessions and reduce your distress. Common compulsions include excessive washing and cleaning, checking, and repeating, as well as mental compulsions including mental reviewing, counting, praying, and others.

To be diagnosed with OCD, this cycle of obsessions and compulsions becomes so extreme that it takes up much of your time and prevents you from carrying out other activities you value and would like to do.

Post-traumatic stress disorder

Post-traumatic stress disorder or PTSD is the brain’s natural reaction following the experience of a traumatic situation or event. Such an event may have been an accident, you being a victim or witness to a violent crime, war or terrorism, serious disease or natural disaster, or if you’ve suffered physical or sexual abuse. Such a trauma may have led you to feel intense fear, pain, or sorrow to the extent that you are fearful of serious harm or death. You continue to feel helpless after the event and altogether these feelings affect your daily activities and relationships.

Signs and symptoms of PTSD include:

  • Nightmares, flashbacks, bad memories, hallucinations
  • Feeling anxious, restless, or on edge
  • Trouble sleeping, feeling depressed
  • Feeling afraid, helpless, numb, or detached from others
  • Angry or violent outbursts
  • Avoiding things or people that remind you of the trauma
  • Negative feelings about yourself, feeling guilty

According to the DSM-5 criteria, you can be diagnosed with PTSD if you have had all of the following for at least one month that cause you distress and the inability to function normally at work and socially (and are not due to a medication side-effect or other illness):

  • You have seen, faced, or experienced an event that involved or threatened serious injury, sexual violence, near death, or death
  • You have at least one constant symptom of re-experiencing the traumatic event
  • You have at least one symptom of avoidance of trauma-related stimuli
  • You have at least two negative changes to the way you think and your mood following the trauma
  • You have at least two hyper-arousal symptoms such as irritability, aggression, risky behavior, hyper-vigilance, trouble concentrating and sleeping
  • Your symptoms cause distress and affect your daily activities, work, and relationships

It is estimated that nearly 3% of U.S. adults had panic disorder in the past year.

Premenstrual dysphoric disorder

Premenstrual dysphoric disorder (PMDD) is a condition in which a woman has serious depression, irritability, and tension before menstruation. Unlike premenstrual syndrome (PMS), PMDD is much more severe to the extent that it can affect a woman from carrying out her normal daily activities and relationships. In both conditions, about 5-11 days before menstruation, a woman will have a wide range of physical or emotional symptoms that will then usually stop once her period starts.

To be diagnosed with PMDD, according to the DSM-5, you will need to have at least five of the following 11 symptoms, including at least one of the first four listed:

  • Marked lability (e.g., mood swings)
  • Marked irritability or anger
  • Markedly depressed mood
  • Marked anxiety and tension
  • Decreased interest in usual activities
  • Hypersomnia or insomnia
  • Difficulty in concentration
  • Physical symptoms (e.g., breast tenderness or swelling, joint or muscle pain, a sensation of bloating and weight gain)
  • Lethargy and marked lack of energy
  • Marked change in appetite (e.g., overeating or specific food cravings)
  • Feeling overwhelmed or out of control

Hormonal changes play a role in both PMDD and PMS but the actual causes are unknown.

How Does Paroxetine Work?

Paroxetine is a medication that belongs to the drug class of selective serotonin reuptake inhibitors (SSRIs). This drug group also contains fluoxetine (Prozac), citalopram (Celexa), and sertraline (Zoloft). Depression and other mood disorders are thought to occur due to an imbalance among chemicals called neurotransmitters that are sent between the nerve cells or neurons of your brain. Paroxetine works by preventing the reuptake or absorption of one neurotransmitter, serotonin, by neurons after it has been released from other neurons. This increases the level of free serotonin that can stimulate your brain’s neurons. Therefore, by balancing the levels of serotonin in the brain, paroxetine can help enhance your mood, reduce anxiety, and alleviate the symptoms of other mood disorders.

Before You Take Paroxetine

Paroxetine is not a medication that is ideal for everyone with clinical depression, GAD, or other mood disorders. You should not take it if you are aware of an allergy or hypersensitivity to paroxetine or if you also take pimozide (Orap). Before you take paroxetine, your doctor will go through your medical history and check that you do not have any other health issues which would affect how well this medicine will work. Let you doctor know if you have any of the following:

  • Low levels of sodium in your blood
  • Heart disease, high blood pressure, or a stroke
  • Bipolar disorder (manic depression), drug addiction, or suicidal thoughts
  • Narrow-angle glaucoma
  • Liver or kidney disease
  • A bleeding or blood clotting disorder
  • Seizures or epilepsy

Moreover, if you’re pregnant or nursing a baby, paroxetine should be avoided since there is a risk it could harm the fetus and it can be passed through breast milk to a newborn baby.

Paroxetine can potentially interact with numerous medications, increasing or decreasing its concentration in the blood or how well it works. Such paroxetine interactions can also cause preventable side-effects so it’s important that your doctor knows what other medications you are currently taking before prescribing paroxetine. You also need to make sure you notify your doctor if you start or stop taking over-the-counter medications or off-the-counter supplements while on paroxetine.

Do not use paroxetine if you have taken a monoamine oxidase inhibitor (MAOI) in the last 14 days or are about to take an MAOI within the next 14 days because this can result in dangerously increased blood pressure and serotonin syndrome.

Other medications that can interact with paroxetine include but are not limited to:

  • Blood thinners
  • Medications for an irregular heartbeat
  • Drugs used to treat nausea
  • Medications for migraine headaches
  • Anti-seizure drugs
  • Antidepressants
  • Antihistamines
  • Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs)
  • Diuretics (“water pills”)
  • Codeine, which is found in many cough and pain medications
  • Other SSRIs
  • Gastrointestinal drugs
  • Certain antibiotics
  • ADHD drug atomoxetine (Strattera)
  • HIV drugs
  • Certain heart medications
  • Anti-anxiety drugs, including buspirone (Buspar) and diazepam (Valium)
  • Drugs prescribed for other mental illnesses other than depression, including chlorpromazine (Thorazine), risperidone (Risperdal), and haloperidol (Haldol)
  • Antifungal medications
  • Certain pain medications
  • The breast cancer drug tamoxifen (Nolvadex)

Drinking alcohol with paroxetine should be avoided since this can cause unpleasant but preventable side effects. Be aware that paroxetine can impair your thinking and reactions so make sure while you are taking this medicine that you are especially careful while driving or carrying out other activities where you need to be alert.

Paroxetine is not approved for use in children and adolescents under 18 years old.

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Paroxetine Dosage

Paroxetine is available as a liquid suspension, as immediate-release tablets, and as extended-release (long-acting) tablets. Normally, you take paroxetine once a day, either in the morning or in the evening. Swallow the medication whole without crushing or chewing. You can take paroxetine with or without food but it is recommended to take it with food to help prevent an upset stomach.

The following are the recommended dosages for immediate-release tablets and suspension for the different conditions that are treated with paroxetine. After the initial dose, your doctor can increase your dose, if needed, by 10 mg each day until you reach the optimal dose for you.

  • Major depressive disorder: recommended daily dose = 20-50 mg; initial daily dose = 20 mg; maximum daily dose = 50 mg
  • Generalized anxiety disorder: recommended daily dose = 20 mg; initial daily dose = 20 mg; maximum daily dose = 20 mg
  • Obsessive compulsive disorder: recommended daily dose = 40 mg; initial daily dose = 20 mg; maximum daily dose = 60 mg
  • Panic disorder: recommended daily dose = 10-40 mg; initial daily dose = 10 mg; maximum daily dose = 60 mg
  • Social anxiety disorder: recommended daily dose = 20-60 mg; initial daily dose = 20 mg; maximum daily dose = 60 mg
  • Post-traumatic stress disorder: recommended daily dose = 20-50 mg; initial daily dose = 20 mg; maximum daily dose = 50 mg
  • Premenstrual dysphoric disorder*: recommended daily dose = 12.5-25 mg; initial daily dose = 12.5 mg; maximum daily dose = 25 mg

*for controlled-release tablets starting 14 days before your anticipated date of your period through to the first day of your period.

What happens if I miss a dose?

Always take your medication according to your doctor’s instructions and what it says on the information sheet that comes with your tablets. If you miss a dose, take it as soon as possible. However, if it is nearly time for your next dose, skip the missed dose and continue with your regular dosing schedule. Never double your dose to compensate for your missed dose.

How long does it take for paroxetine to take effect?

You will need to be patient when you first start taking paroxetine since it is slow acting and it can take up to 6-8 weeks before you feel real improvements. However, it’ll only take 1-2 weeks to see improvement in physical symptoms such as better sleep, energy, and appetite; this will give you an early signal that the medication is working. You will need to make regular follow-up appointments with your doctor to make sure you are continuing on the best dosage for you.

Can you stop paroxetine cold turkey? Does paroxetine cause withdrawal symptoms?

Do not stop taking paroxetine, even if you feel better, without discussing it first with your doctor. If you and your doctor find that it is time to stop taking paroxetine, it is not a good idea to cease the medication suddenly. This is because you can end up with some unpleasant paroxetine withdrawal symptoms. These can include irritability, nausea, dizziness, vomiting, nightmares, headaches, and/or tingling prickly skin. Instead, discuss with your doctor how you can slowly reduce your dose to avoid any unwanted withdrawal effects.

Common Side Effects

Common Paxil or paroxetine side effects include but are not limited to:

  • Vision changes
  • Weakness, drowsiness, dizziness, tiredness
  • Sweating, anxiety, shaking
  • Sleep problems (insomnia)
  • Loss of appetite, nausea, vomiting, diarrhea, constipation
  • Dry mouth, yawning
  • Infection
  • Headache
  • Decreased sex drive, impotence, abnormal ejaculation, or difficulty having an orgasm

Paroxetine and weight gain

You may experience weight gain when taking paroxetine. Experts are not sure why this happens but it may be that SSRIs cause changes in your body’s metabolism so that you are not as efficiently using up the calories you take in through your food, or because the drug increases your appetite.

Paroxetine Alternatives

Paroxetine is not for everyone. If for whatever reason paroxetine is not alleviating your symptoms, or you cannot take paroxetine due to a pre-existing medical condition or medication that would interact with paroxetine, there are other treatments that may help you. Talk with your doctor to see whether you can try other medications or various therapies such as cognitive-behavioral therapy, psychotherapy, acceptance and commitment therapy (ACT), or other ‘talk therapies’. Many people suffering from depression, GAD, and other mood disorders find such therapies to be of great benefit.

Paxil vs. Xanax

Paxil and Xanax (alprazolam) are similar medications in that they are both used to treat panic attacks and anxiety disorders. However, Paxil is also used to treat depression, obsessive-compulsive disorder, post-traumatic stress disorder, and premenstrual dysphoric disorder.

The reason Paxil can treat more conditions than Xanax is because it belongs to a different drug class; Paxil is a selective serotonin reuptake inhibitor while Xanax is a benzodiazepine. This means the two drugs are chemically and pharmacologically different. Xanax can have many unpleasant side effects but unlike Paxil, it can also have sedative and muscle relaxant effects and can be extremely habit-forming or addictive and therefore be abused.

Paxil vs. Prozac

Prozac (fluoxetine) and Paxil (paroxetine) are different medications but they do have some things in common. Firstly, they are both prescription medications used to treat depression and other psychiatric disorders, and secondly, they both belong to the same drug class called selective serotonin reuptake inhibitors. This means that Paxil and Prozac work in a similar way to increase the amount of serotonin in the brain and reduce depression.

Prozac and Paxil work in the brain in a similar way. However, they are not identical medications and have different FDA approval for how they are used. Both drugs are used to treat major depressive disorder, panic disorder, obsessive compulsive disorder, and premenstrual dysphoric disorder. However, Prozac can also be used to treat bulimia nervosa and Paxil can also treat generalized anxiety disorder, social anxiety disorder and post-traumatic stress disorder. Usually, antidepressants are not designed for children but in the case of Prozac it can also be used to treat depression (in children at least eight years old) and obsessive compulsive disorder (in children at least seven years old).

Since Paxil and Prozac work in a similar way in your brain, they do cause similar side effects and have shared drug interactions. Nevertheless, Prozac is more stimulating than Paxil. Therefore doctors recommend you take Prozac in the morning rather than the evening so that it doesn’t cause you to lose sleep at night.

Finally, it is important to know that if you stop either Paxil or Prozac abruptly, you can suffer from unpleasant withdrawal symptoms. Make sure you work with your doctor to slowly reduce your dose before coming off your medicine.

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When to See a Doctor

These conditions do not need to take over your life. Seeking professional help can guide you to a treatment that works best for you. Once suitable treatment is found, you will feel much more in control and find life more enjoyable.

It’s time to see your primary-care doctor or a mental-health specialist for an evaluation if you are suffering from any of the mental and/or physical symptoms discussed above of the conditions treated by paroxetine hydrochloride. This is especially true if they are severely affecting your ability to function in your daily tasks and interact with other people. Don’t wait for things to become unbearable; there is no shame in getting help and there are many medications and therapies available that can significantly alleviate symptoms.

At your first visit to the doctor or mental-health specialist, he or she will ask you about your feelings and symptoms, how long you’ve had them, and whether you’re changing or limiting your activities as a result. You may also be asked to answer a short questionnaire which will further help your doctor diagnose your condition and determine how severely you’re suffering from this condition.

Your doctor or mental health practitioner is there to discuss your concerns, help you find ways of coping you may have not considered before, recommend a form of psychotherapy, and if needed, see if you can benefit from medication. Normally you will be on paroxetine for at least half a year but make sure you don’t stop suddenly and suffer unpleasant withdrawal symptoms. You will need regular monthly appointments with your doctor to check all is going as it should. If you feel that your symptoms are getting worse or you are noticing new symptoms, make an appointment with your doctor as soon as possible.

Your family and close friends should also be aware you’re on medication so they can support you and also because some young people can have thoughts of suicide when first taking an antidepressant. Seek help from a mental health profession or organization and talk to a friend as soon as possible if you have thoughts about suicide or hurting yourself.

An allergic reaction to paroxetine is rare but do make sure you seek immediate medical assistance if you have any of the following signs:

  • Rashes or hives
  • Trouble breathing
  • Swelling of your face, lips, tongue, or throat

Also call your doctor straight away if you have any of the following serious side effects when taking paroxetine:

  • Vision or eye problems: blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights
  • Mental symptoms: racing thoughts, unusual risk-taking behavior, feelings of extreme happiness or sadness
  • Unusual bone pain: including bone tenderness, swelling or bruising
  • Unusual bleeding: from your nose, mouth, vagina, or rectum
  • Signs of low salt levels: headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady
  • Severe nervous system reactions: very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out
  • Signs of serotonin syndrome: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea

If you think you may have taken an overdose of paroxetine, seek emergency medical attention (by calling 911), or call the poison help line at 1-800-222-1222. Symptoms of overdose can include:

  • Extreme fatigue
  • Coma
  • Involuntary shaking or twitching
  • Fast, pounding, irregular, or slow heartbeat
  • Confusion
  • Nausea
  • Vomiting
  • Dizziness

How K Health Can Help

Anxiety and depression are among the most under-reported and under-treated diseases in America. Nearly 20% of adults in the US suffer from mental health illness and fewer than half receive treatment. Our mission is to increase access to treatment for those suffering in silence.

You can start controlling your anxiety and depression and get access to the treatment you need with K Health. Starting at $49/month get prescriptions for mental health medications plus unlimited doctor visits through the K Health app. Start your free assessment to see if you’re eligible.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Jenell Decker, MD

Dr. Decker is a family medicine physician who completed her residency at East Carolina University School of Medicine. She graduated medical school from Marshall University School of Medicine.