Pristiq side effects and how to avoid them

Pristiq is a brand-name medication manufactured by Wyeth Pharmaceuticals Inc., a subsidiary of Pfizer Inc. It is classed as a serotonin and norepinephrine reuptake inhibitor (SNRI) used to treat major depressive disorder. While Pristiq is generally well tolerated, there are some potential side effects that people should be aware of. The most common side effects of Pristiq include nausea, dizziness, and trouble sleeping. Less common, but more serious side effects, can include allergic reactions and hypertension.

Learn more about the side effects of Pristiq and what you can do to avoid them.

What is Pristiq (desvenlafaxine)?

Pristiq is an antidepressant medication prescribed to adults to treat major depressive disorder, often just called depression, a common but serious mood disorder.

The active ingredient in Pristiq is called desvenlafaxine, a type of antidepressant called a serotonin and norepinephrine reuptake inhibitor (SNRI). When you swallow a Pristiq tablet, it dissolves in your digestive system and releases desvenlafaxine into your bloodstream. Desvenlafaxine is then carried in your blood to your brain, where it slows how quickly you break down two substances called serotonin and norepinephrine.

Serotonin and norepinephrine are natural substances produced in your brain. They’re called neurotransmitters. They help regulate your brain function by controlling how the nerve cells in your brain communicate with each other. By slowing how quickly serotonin and norepinephrine are broken down, desvenlafaxine causes their levels to increase.

Serotonin and norepinephrine regulate brain function in terms of thinking, emotion, mood, learning, reward, alertness, and many more. Research has shown that increasing levels of serotonin and norepinephrine can help reduce the symptoms of depression.

Pristiq is not approved to treat bipolar depression. Talk to your doctor about your mental health before taking any medication to make sure it is safe for you.

Pristiq dosage

Pristiq is available as extended-release tablets, each containing 76 mg or 152 mg of desvenlafaxine succinate equivalent to 50 mg or 100 mg of desvenlafaxine.

The recommended dose of Pristiq is 50 mg once daily with or without food. Gradual dose reduction is recommended whenever possible when stopping treatment. Tablets should be taken whole, do not break, crush, chew, or dissolve the tablets. Your recommended dose will need to be adjusted if you have moderate or severe renal impairment or hepatic impairment.

You are advised to read the medication guide provided with this medicine for the drug information and patient information, and always speak with your healthcare provider for medical advice about any changes to your dose so they can monitor and evaluate your condition.

Pristiq side effects

The most common possible side effects of Pristiq compared to placebo include:

  • Nausea
  • Dry mouth
  • Constipation
  • Dizziness
  • Sweating
  • Trouble sleeping
  • Drowsiness
  • Blurred vision, eye pain, eye swelling, or seeing halos around lights
  • Anxiety
  • Decreased appetite
  • Sexual dysfunction, like difficulties getting or keeping an erection, and problems with ejaculation

Pristiq can cause more serious side effects, including:

  • Severe allergic reactions to the medication
  • An increased risk of suicidal thoughts and suicide, particularly in young adults
  • Risk of serotonin syndrome – a potentially life-threatening condition caused by high levels of serotonin
  • Hyponatremia – low levels of sodium in your blood that can cause serious health problems and death
  • New or worsening hypertension (high blood pressure)
  • Lung problems that can cause discomfort and coughs, and cause trouble breathing
  • Seizures
  • An increased risk of developing an eye condition called angle-closure glaucoma
  • An increased risk of bleeding if taken with medications that can reduce blood clotting, like blood thinners, aspirin, or NSAIDs like ibuprofen

If you experience any of these serious side effects, stop taking Pristiq and seek medical attention immediately. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

Pristiq drug interactions

Pristiq can interact with other medications including:

  • Any other antidepressants, like tricyclic antidepressants, SSRIs, other SNRIs (serotonin-norepinephrine reuptake inhibitors), or lithium
  • Any other medications containing desvenlafaxine or venlafaxine
  • Any other medications that can affect your serotonin or norepinephrine levels
  • Any other medications taken to treat mental states and conditions, like mood and thought disorders, anxiety, or psychotic disorders
  • Any medications that can reduce blood clotting, like warfarin, aspirin, or nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Medications called triptans, used for migraines
  • Medications containing amphetamines often used to treat attention deficit hyperactivity disorder (ADHD)
  • Tryptophan
  • Opioid pain medications, like fentanyl or tramadol
  • An herbal supplement called St. John’s Wort

Before taking Pristiq, be sure to tell your doctor about all of the medications you are taking to ensure they are safe to take at the same time.

Pristiq warnings & precautions

Don’t take Pristiq if:

  • Are allergic to the active ingredient desvenlafaxine, or to venlafaxine
  • Are allergic to any of the other ingredients in Pristiq
  • Are taking an antibiotic called linezolid
  • Are being treated with an intravenous medication called methylene blue
  • Are under 18 years of age

Talk to your doctor before taking Pristiq if you:

  • Are taking any of the medications that could interact with Pristiq
  • Have, or have had, depression, suicidal thoughts, or have ever tried to commit suicide
  • Have, or have any family history, of mania, hypomania, or bipolar disorder
  • Have any heart problems
  • Have previously had a stroke
  • Have any kidney problems
  • Have any liver problems
  • Have hypertension (high blood pressure)
  • Have high cholesterol or high triglycerides (blood fats)
  • Have low blood sodium levels
  • Have, or have had, any bleeding problems
  • Have ever had a seizure
  • Are pregnant or are planning to become pregnant
  • Are breastfeeding or are planning to breastfeed – This drug passes into breast milk and may cause unwanted effects on a nursing infant. Consult your doctor before breast-feeding

You should always check with your doctor or pharmacist before taking any medication, including Pristiq, to make sure it is safe for you.

Other warnings you should know about

  • Increased risk of suicidal thoughts and behavior in children, adolescents, and young adults taking antidepressants for major depressive disorder (MDD) and other psychiatric disorders. See the full prescribing information for the complete boxed warning
  • Avoid taking monoamine oxidase inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine) during treatment with this medication. MAOIs should not be taken for two weeks before and at least 7 days after treatment with Pristiq
  • Pristiq can cause low blood sodium levels. Your risk of this side effect is increased if you are 65 years of age or older or take a diuretic. Taking Pristiq could worsen your condition if you already have low sodium levels
  • Antidepressant discontinuation syndrome can occur when stopping treatment with antidepressants, such as Pristiq. Withdrawal symptoms can include aggressive or hostile behavior, confusion, trouble sleeping, seizures, and suicidal thoughts

How to avoid Pristiq side effects

The best way to avoid side effects is to take Pristiq as directed by your doctor. Follow your doctor’s instructions carefully and do not take more or less than prescribed.

If you experience any side effects, talk to your doctor or pharmacist. They may be able to recommend ways to help reduce or prevent some of the side effects.

1. Stick to the recommended dosage

Take your prescribed dose of Pristiq that has been recommended by your healthcare professional. Do not take more or less than prescribed.

2. Avoid alcohol

Avoid drinking alcohol while taking Pristiq as it can increase your risk of side effects.

3. Know the signs and symptoms of Pristiq side effects

Signs and symptoms of side effects include insomnia, drowsiness, and sexual dysfunction. If you experience any of these symptoms speak to your doctor for medical advice.

4. Monitor your weight

Pristiq may cause weight gain. If you experience this side effect while taking Pristiq, get medical advice from your doctor.

5. Tell your doctor about all medications you’re taking

Be sure to tell your doctor about all other medications you’re taking, including over-the-counter drugs, vitamins, and herbal supplements, as they can interact with Pristiq.

6. Get regular medical checkups

If you have side effects it is important to get regular medical checkups. Your doctor will monitor your medical condition and may adjust your dose of Pristiq as needed.

Medically reviewed

A medical professional has reviewed this article.

Jamie Winn, PharmD
Jamie Winn, PharmD

Jamie Winn, PharmD

Medical Writer & Reviewer

Jamie Winn, PharmD

Medical Writer & Reviewer

Dr. Jamie Winn received his Doctor of Pharmacy in 2002 from the University of South Carolina College of Pharmacy, Columbia, SC. Jamie is a medical reviewer for NiceRx.

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The content on this website is intended for information purposes only. It does not constitute medical advice. The information on this website should not be relied upon and is not a substitute for professional medical advice. You should always speak to your doctor regarding the risks and benefits of any treatment.