Pristiq (Desvenlafaxine)

By Andrew Yocum, MD
Medically reviewed checkmarkMedically reviewed
May 16, 2022

An estimated 21 million Americans suffer from major depressive disorder, or MDD, each year.

Also sometimes called clinical depression, MDD is more than just feeling down: People suffering from depression experience a loss of interest in daily activities, can have trouble sleeping and eating, and feel a diminished sense of self-worth for weeks.

These symptoms can affect daily function, as well as work and relationships.

For many patients, antidepressants can help.

If you’re suffering from MDD, your doctor may suggest Pristiq, a brand name version of an antidepressant called desvenlafaxine.

It’s a serotonin-norepinephrine reuptake inhibitor, or SNRI, and it works by changing how your brain uses and recycles certain chemicals that can affect mood.

In this article, I’ll talk more about how Pristiq is used, how it works, its dosage, and side effects.

I’ll list some precautions you should know about before taking Pristiq, and I’ll tell you when to talk to your doctor.

Pristiq Uses

Pristiq is most commonly prescribed for major depressive disorder (MDD)—which we will be referring to as simply “depression” in this article—in adults.

However, your doctor may also prescribe it off-label for a few other health issues. 

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Treatment of depression

Currently, Pristiq is only approved by the U.S. Food and Drug Administration (FDA) for the treatment of depression in adults.

In clinical studies, Pristiq helped relieve both emotional and physical symptoms of depression in adults.

It also was shown to improve users’ ability to function in social, work, and family situations. 

Studies also show that Pristiq is effective long-term, as users are less likely to experience depression relapse after improving, compared to those who took a placebo. 

Off-label uses

While Pristiq is only FDA approved for the treatment of depression, some doctors may prescribe it “off-label” for a few other conditions.

When a doctor prescribes something “off label,” it means the medication isn’t FDA approved for that use, but has been shown to be effective. These include:

  • Anxiety: More research is needed to determine whether Pristiq is effective for treating anxiety. However, one 2014 review found that it was effective in treating anxiety in people with depression much more than placebo.
  • Menopausal hot flashes: In a 2014 review of studies, Pristiq was found to be effective at reducing the severity and amount of hot flashes experienced by those undergoing menopause. 
  • Diabetic neuropathy: A 2013 study found that Pristiq was more effective than placebo at treating pain related to diabetic neuropathy, a condition experienced by those who have nerve damage as a result of diabetes. 

Pristiq has also been prescribed for bipolar disorder, fibromyalgia, and obsessive-compulsive disorder (OCD), but there have been no definitive studies. 

How Pristiq Works

Pristiq is a type of antidepressant called a serotonin-norepinephrine reuptake inhibitor (SNRI).

SNRI antidepressants help ease depression by increasing the levels of serotonin and norepinephrine in the brain.

These two chemicals are called neurotransmitters, and they help regulate mood.

SNRIs increase the amounts of these chemicals in the brain by blocking the reabsorption of serotonin and norepinephrine, meaning there is more of each in the brain at one time.

This can help to relieve depression symptoms like irritability and sadness. 

When taking Pristiq, it can take a few weeks before the positive effects of the drug are felt.

Some people, however, quickly feel their depression symptoms decreasing.   

How to Use Pristiq

Pristiq is an extended-release tablet taken orally once per day, with or without food.

You should try to take it at the same time each day, and it should be swallowed whole—not crushed, chewed, or dissolved. 

Because it’s an extended-release tablet, the contents of the tablet are slowly released into the body throughout the day.

The tablets are available in 25 mg, 50 mg, and 100 mg strengths.

Your doctor will prescribe what dose is best for you. Never take more than you have been prescribed. 

Standard dosage

Dosage can range from 50-400 mg per day, though 50 mg is most common.

Your doctor will prescribe you a dose based on the severity of your depression, your overall health, and any other medications you may take.

Your doctor may prescribe a lower dose of Pristiq to start, and then increase the dosage over a few weeks as your body adjusts. 

What happens if I miss a dose?

If you miss a dose of Pristiq, take it as soon as you remember.

If it is close to when you are supposed to take your next dose, take your next dose as planned and do not double up.

If you’re unsure about what to do after missing a dose, check in with your healthcare provider. 

What happens if I overdose?

If you take more than your prescribed dose of Pristiq, contact your doctor or a healthcare professional immediately.

If you overdose, you may need emergency medical care.

Call your doctor, 9-1-1, or poison control at 1-800-222-1222. 

There is currently no specific treatment that can reverse the effects of Pristiq. 

Pristiq Side Effects

There are a variety of side effects that can occur as a result of taking Pristiq—some common and unproblematic, and some more serious and concerning.

Your doctor will determine whether the benefits of the drug outweigh the risks of side effects in your situation.

Common side effects

Most common side effects will improve in a week or two as your body adjusts to the drug.

These common side effects include:

  • Nausea
  • Constipation
  • Dizziness
  • Decreased appetite
  • Sweating
  • Fatigue
  • Headache
  • Tremors
  • Feeling nervous or restless
  • Insomnia or trouble sleeping
  • Low sodium levels
  • Increased blood pressure (this generally does not improve over time)
  • Sexual disfunction, such as ejaculatory delay or difficulty orgasming (this generally does not improve over time)

Serious side effects

Rare and serious side effects include, but are not limited to, the following:

  • Heart attack and heart problems
  • Stevens-Johnson syndrome (a life-threatening skin condition)
  • Increased liver enzymes
  • Low sodium
  • Increased heart rate
  • Changes in taste
  • Irregular menstrual cycle
  • Difficulty urinating

Pristiq Precautions

Pristiq is effective and unproblematic for most users.

But there are several warnings and precautions that the manufacturer has listed in association with the drug.

These precautions include:

  • Suicidal thoughts and behaviors: There is a risk of suicidal thoughts increasing when people begin taking antidepressant medications, especially when they first start. This is especially true in children, adolescents, and young adults. All users should be monitored for increasing or newly emerging suicidal thoughts and behaviors.
  • Increased blood pressure: Pristiq can elevate blood pressure, so your doctor should make sure high blood pressure is treated ahead of taking the medication, and monitored while taking Pristiq. 
  • Serotonin syndrome: Serotonin syndrome is a potentially life-threatening condition that can be brought on by Pristiq and other SNRIs. The risk of serotonin syndrome is greater in those who are also taking serotonergic drugs and other drugs that impact the metabolism of serotonin. 
  • Sexual disfunction: In people with penises, SNRIs, including Pristiq, can cause ejaculatory delay or failure, decreased libido, and erectile dysfunction. In people with vaginas, decreased libido and trouble orgasming are possible. 
  • Mania/hypomania: Mania and hypomania can be activated by Pristiq, so caution should be taken when prescribing to those with bipolar disorder. 
  • Increased risk of bleeding: Pristiq may increase the risk of bleeding events (especially gastrointestinal bleeding), so users should use caution before taking aspirin, NSAIDs, antiplatelet drugs, warfarin, and anticoagulants.
  • Seizure: Seizure may be more likely as a result of taking the medication.
  • Discontinuation syndrome: A number of adverse reactions can occur when Pristiq is discontinued, especially if abruptly. Discontinuation symptoms, also called withdrawal, include nausea, dysphoric mood, irritability, agitation, etc. If you want to stop taking Pristiq, your doctor will help build a plan for you to wean off the drug over time. 
  • Lung problems: Interstitial lung disease and eosinophilic pneumonia have been associated with venlafaxine, the parent drug of Pristiq. Progressive dyspnea, cough, and/or chest discomfort should be monitored.
  • Angle-closure glaucoma: This is a change in vision. If you experience changes in vision while taking Pristiq, tell your doctor.

Symptoms of Depression

According to the National Alliance on Mental Illness, those who experience depression commonly experience the following symptoms:

  • Feeling sad, empty, or tearful (depressed mood)
  • Feeling hopeless, worthless, or helpless
  • Low energy
  • Trouble concentrating
  • Thoughts of death, suicidal ideation, or suicidal behaviors
  • Loss of interest or pleasure in everyday activities
  • Eating and/or sleeping more or less than usual
  • Nervous energy
  • Psychomotor retardation (feeling like you are moving and thinking less efficiently)
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When to See a Doctor for Depression

According to the World Health Organization, approximately 2​​80 million people in the world have depression.

So if you believe you have MDD, you are not alone.

Whether you have mild, moderate, or severe depression, effective treatment is available—whether in the form of medication, therapy, or lifestyle changes—and a medical professional can get you started on a treatment plan that can change your life. 

If you are experiencing suicidal thoughts and/or behaviors, seek medical attention immediately. The National Suicide Prevention Lifeline is free, confidential, and available 24 hours a day at 800-273-8255.

How K Health Can Help

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Download K to check your symptoms, explore conditions and treatments, and if needed text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Frequently Asked Questions

Is Pristiq good for anxiety?
Pristiq is not currently FDA approved for the treatment of anxiety. However, that doesn’t mean it isn’t effective: Your doctor may prescribe it off-label for anxiety if they think it will be beneficial for you.
What are the most common side effects of Pristiq?
In clinical studies, the most common side effects of Pristiq were nausea, dizziness, sweating, decreased appetite, and constipation.
Is Pristiq a good antidepressant?
Yes, studies show that Pristiq is an effective drug when it comes to lessening depression-related symptoms and preventing symptom relapse after improving.
How does Pristiq make you feel?
If Pristiq is right for you, it can help make you feel happier by lessening your depression-related symptoms. There are also a variety of side effects that can occur when taking the drug—for example, it can make you feel fatigued, nauseous, dizzy, nervous, etc. An overview of all the side effects you may feel are included in the section “Pristiq Side Effects,” above.

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.

K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

Andrew Yocum, MD

Dr Andrew Yocum is a board certified emergency physician. He graduated Summa Cum Laude from Kent State University with a Bachelor of Science in Molecular Biology before attending Northeast Ohio Medical University where he would earn his Medical Doctorate (MD).