Pristiq (desvenlafaxine) is a prescription brand-name medication. It’s approved by the Food and Drug Administration (FDA) to treat major depressive disorder in adults. This is a serious mental health condition often referred to as clinical depression or depression.

If you and your doctor agree that Pristiq is working to treat your depression, you’ll likely take the medication long term.

Here are some fast facts about Pristiq:

Like other drugs, Pristiq can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Pristiq, see this article.

Pristiq can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Pristiq in clinical trials:

Mild side effects can occur with Pristiq use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Pristiq’s prescribing information.

Mild side effects that have been reported with Pristiq include:

These side effects may be temporary, lasting a few days to weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Pristiq and want to tell the FDA about it, visit MedWatch.

* For more information, see the “Side effect specifics” section below.

Pristiq may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Pristiq’s prescribing information.

If you develop serious side effects while taking Pristiq, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported with Pristiq and their symptoms include:

* Pristiq has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA).
† For more information, see the “Side effect specifics” section below.

Long-term side effects

Although Pristiq can cause some serious side effects, these were rarely reported in clinical studies. Most of them aren’t long term and should go away if treatment with Pristiq is stopped.

But in rare cases, Pristiq may cause long-term side effects. For example, interstitial lung disease (scarring in your lungs) may not go away, even if you stop taking Pristiq. And if you develop high blood pressure from Pristiq, you may need to take medication long term for this condition.

Pristiq may also cause long-term side effects in people who already have certain medical conditions. For more information, see the “Precautions for Pristiq” section below.

Pristiq may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Do Pristiq side effects go away?

If your doctor prescribes Pristiq for you, you may wonder how long Pristiq side effects last.

Most mild side effects caused by Pristiq usually go away on their own after a few days to weeks. Although the medication can also cause serious side effects, most of these can be treated and go away if you stop taking Pristiq.

But in rare cases, Pristiq may cause long-term side effects that don’t go away. For more information, see “Long-term side effects” in the “Serious side effects” section above.

Are weight gain and weight loss side effects of Pristiq?

A very small number of people reported weight gain from taking Pristiq in clinical studies. In addition, decreased appetite was a common side effect in people who took Pristiq. Having less of an appetite may cause you to lose weight.

Keep in mind that depression, which Pristiq is prescribed to treat, can also affect your appetite and your weight. It can be difficult to know whether weight changes are due to depression symptoms easing, medications (such as Pristiq), or a combination of factors.

If you’re concerned about your weight, talk with your doctor. They can advise you on how to maintain a moderate weight with your depression treatment plan.

Could stopping Pristiq treatment cause side effects of withdrawal?

Yes, stopping treatment with antidepressants, such as Pristiq, can cause side effects of withdrawal. This is also known as antidepressant discontinuation syndrome.

For more information about this syndrome and Pristiq, see the “Side effects specific” section below.

Do Pristiq’s side effects vary depending on the strength (25 mg, 50 mg, 100 mg)?

Yes, Pristiq’s side effects can vary depending on the strength. In general, side effects are more likely to happen with higher doses.

To see more information about how side effects varied depending on strength in clinical trials, you can refer to the Pristiq’s prescribing information.

Does Pristiq cause side effects when you first start treatment?

It’s possible for Pristiq to cause side effects when you first start treatment. Some of the more common ones when you begin taking the drug can include:

  • nausea
  • dizziness
  • decreased appetite
  • feeling anxious

For most people, these side effects are usually mild and ease within a few days to weeks.

Keep in mind that side effects can occur at any time while you take Pristiq. If your doctor increases your dose of the drug, side effects may become more bothersome.

If you have side effects that don’t go away or become severe during your Pristiq treatment, be sure to talk with your doctor.

Learn more about some of the side effects that Pristiq may cause.

Headache

It’s possible to have headache as a side effect from Pristiq. But this wasn’t commonly reported by people taking the medication in clinical studies.

Headache can also be a symptom of serious side effects of Pristiq. These side effects rarely occurred with the drug but can include:

* To learn more, see the “Precautions for Pristiq” section below.

What you can do

If you have a sudden, severe headache while taking Pristiq, talk with your doctor right away. This could be a symptom of the serious side effects mentioned above.

If you have a mild headache while during Pristiq treatment, talk with your doctor or pharmacist. Certain over-the-counter pain relievers may increase your risk of bleeding if you take them with Pristiq. This is why it’s important to not take any medication for headache unless you first speak with your doctor or pharmacist.

Sexual side effects

Pristiq can rarely cause sexual side effects. Such side effects can occur with antidepressant medications, including Pristiq.

Sexual side effects were more likely to happen in males* taking Pristiq in clinical trials and included:

A small number of females* taking Pristiq in these studies reported reduced sex drive and not being able to have an orgasm.

The risk of sexual side effects increases with higher doses of Pristiq.

* Sex and gender exist on spectrums. Use of the terms “male” and “female” in this article refers to sex assigned at birth.

What you can do

If you have sexual side effects while taking Pristiq, talk with your doctor. These side effects may ease over time. But if they don’t go away, your doctor may recommend that you switch to a different antidepressant. They can recommend the best treatment plan for your depression.

Discontinuation syndrome

Stopping treatment with antidepressants, such as Pristiq, can cause side effects of withdrawal. This is also known as antidepressant discontinuation syndrome. It’s not known how often people taking Pristiq in clinical studies had withdrawal symptoms.

Withdrawal symptoms can be severe, especially if you suddenly stop taking a high dose of Pristiq. Withdrawal symptoms can include:

Keep in mind that missing a dose of Pristiq may also cause mild withdrawal symptoms. They can include dizziness, headache, changes in mood, and feeling anxious. These symptoms should ease shortly after you take a dose. To help make sure that you don’t miss a dose, try using a medication reminder.

* Pristiq has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see “Suicidal thoughts and actions” below.

What you can do

You should not stop taking Pristiq unless your doctor specifically advises you to.

If you’re interested in stopping Pristiq treatment, talk with your doctor. They can suggest a drug taper for you. A drug taper is when your doctor slowly decreases your dosage over time until it’s safe for you to stop taking the medication. Tapering drugs such as Pristiq can help avoid or minimize withdrawal symptoms. Keep in mind that if you’re taking a high dose of Pristiq, your drug taper may take several months.

High blood pressure

Treatment with Pristiq can cause hypertension (high blood pressure), but this wasn’t common in clinical studies.

High blood pressure doesn’t cause symptoms in most people.

If you have certain medical conditions, they may worsen if you take Pristiq and have high blood pressure as a side effect. These conditions include:

To learn more, see the “Precautions for Pristiq” section below.

What you can do

Before you start taking Pristiq, your doctor will typically check your blood pressure. They’ll also monitor your blood pressure during your treatment.

If you have high blood pressure, it will need to be treated before you start taking Pristiq.

If you develop high blood pressure, your doctor will typically decrease your Pristiq dose. But if your blood pressure remains high, they may recommend a different treatment for your depression.

Allergic reaction

As with most drugs, Pristiq can cause an allergic reaction in some people. This side effect was rare in clinical studies of the drug.

Symptoms of allergic reaction can be mild or serious and can include:

  • rash
  • itching
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Pristiq. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Suicidal thoughts and actions

Pristiq has a boxed warning about suicidal thoughts and actions. This is the most serious warning from the FDA. A boxed warning alerts doctors and patients about drug effects that may be dangerous.

Antidepressant drugs, including Pristiq, can increase the risk of suicidal thoughts and actions in children and young adults younger than age 25 years. This risk is highest during your first few months of taking an antidepressant and any time your dose is changed.

Pristiq is not approved for use in people younger than age 18.

It’s important to note that depression and other mental health conditions are often linked to suicidal thoughts or actions.

What you can do

While taking Pristiq, call your doctor right away if you:

  • have aggressive or hostile behavior
  • feel that your depression is getting worse
  • have sudden changes in your behavior, feelings, mood, or thoughts
  • have thoughts about harming yourself or dying
  • have new or worsening anxiety
  • have panic attacks
  • try to harm yourself or attempt to take your own life

During your Pristiq treatment, it’s important to keep all follow-up appointments with your doctor. You can also talk with your doctor in between visits if you have concerns about any symptoms.

Keep reading for important information about precautions to consider before you start taking Pristiq.

Boxed warning: Suicidal thoughts and actions

Pristiq has a boxed warning for suicidal thoughts and actions. This is a serious warning from the Food and Drug Administration (FDA). For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take Pristiq. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Bipolar disorder, mania, or hypomania. Pristiq may not be safe for you to take if you or a close relative has ever had bipolar disorder, mania, or hypomania. Antidepressants such as Pristiq may worsen these problems or increase your risk of a manic episode. In addition, Pristiq is not approved to treat bipolar depression. Be sure to talk with your doctor about your mental health before you start taking Pristiq.

High bleeding risk. Treatment with Pristiq can increase your risk of bleeding. Your risk may be higher than usual if you already have a bleeding problem, such as hemophilia, or take certain drugs. These medications include blood thinners and nonsteroidal anti-inflammatory drugs (NSAIDs). Your doctor can determine if Pristiq is safe for you to take with your condition and current treatments.

Heart problems. Taking Pristiq can cause increases in your blood pressure. This could worsen any existing heart problem, including heart disease, you already have. Your doctor can advise you on whether Pristiq is safe for you to take if you have a heart problem.

High blood pressure. Taking Pristiq can cause increases in your blood pressure. People who already have high blood pressure may need to be monitored more closely if they take Pristiq. Your blood pressure needs to be treated before you can consider treatment with Pristiq. Your doctor can help determine if Pristiq is safe for you to take with your high blood pressure.

High cholesterol or triglycerides. Pristiq may raise cholesterol or triglyceride levels in some people, but this isn’t common. If your levels are already high, taking Pristiq could worsen them. Your doctor can advise you on whether Pristiq is safe for you to take if you have high cholesterol or triglyceride levels. If they prescribe Pristiq, they may monitor your levels more often than usual.

History of stroke or ministroke. Taking Pristiq can cause increases in your blood pressure. This can raise your risk of stroke or ministroke if you’ve had one in the past. Your doctor can determine if Pristiq is safe for you to take if you have history of stroke or ministroke.

Kidney or liver problems. After you take a dose of Pristiq, your kidneys and liver help remove the drug from your system. If you have kidney or liver problems, this may be harder for your body to do. So your doctor may prescribe a lower dose of Pristiq than usual. If your kidney or liver problems worsen during treatment, they may have you stop taking the drug. Your doctor may also recommend a different medication.

Low blood sodium levels. Treatment with Pristiq can cause low blood sodium levels in some people. You may have an increased risk of this side effect if you’re age 65 years or older or take a diuretic. If you already have low sodium levels, taking Pristiq could worsen your condition. Your doctor can help determine if Pristiq is safe for you to take.

Seizures and epilepsy. Some people reported seizures after taking Pristiq in clinical trials. The drug wasn’t studied in people who previously had seizures. So it’s not known whether Pristiq is safe for people with epilepsy or another condition that causes seizures. Your doctor can advise you on whether Pristiq is safe for you.

Allergic reaction. You should not take Pristiq If you’ve ever had an allergic reaction to Pristiq or any of its ingredients. Talk with your doctor about which other treatments are better choices for you.

Alcohol use with Pristiq

The manufacturer of Pristiq advises that you avoid drinking alcohol while taking the medication. Drinking alcohol may increase your risk of certain side effects of Pristiq, including:

Drinking alcohol can also make depression worse. (Pristiq is approved to treat depression.)

Before you start treatment with Pristiq, tell your doctor if you drink alcohol. They can help develop the best treatment plan for your depression.

* For details, see the “Side effect specifics” section above.

Pregnancy and breastfeeding while taking Pristiq

Here’s some information about pregnancy, breastfeeding, and Pristiq.

Pregnancy. Pristiq has not been studied in pregnant people. Before you start taking Pristiq, tell your doctor if you’re pregnant or plan to become pregnant. They can advise you on the risks and benefits of Pristiq treatment.

Be sure to talk with your doctor if you become pregnant during your Pristiq treatment.

If you decide to take Pristiq while pregnant, talk with your doctor about joining the National Pregnancy Registry for Antidepressants. This registry helps identify effects that may occur when antidepressants are used during pregnancy. You can learn more by visiting the registry website.

Breastfeeding. Pristiq passes into human breast milk in low levels. But the drug has not been shown to cause side effects in a breastfed child.

If you’re breastfeeding or considering it, talk with your doctor. They can discuss the risks and benefits of taking Pristiq and recommend healthy ways to feed your child.

Like most medications, Pristiq can cause side effects. Most are mild and usually go away on their own after a few days to weeks. Pristiq can also cause some serious side effects. You should talk with your doctor if you have any side effects that last, are bothersome, or are serious.

You should also talk with your doctor if you become pregnant while taking Pristiq.

If you’d like to learn more about Pristiq, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

You can also do some research on your own. These articles might help:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.