Pristiq (Desvenlafaxine) – Oral

Warning:

Serotonin-norepinephrine reuptake inhibitors (SNRIs), like Pristiq, have increased suicidal thoughts and actions in children and young adults. People who have previously experienced suicidal thoughts or behaviors may be at a higher risk. All people who use this medication must be closely monitored.

Call your healthcare provider if you notice any new or worsening symptoms such as anxiety, panic attack, depression, grouchiness, or mood swings. If you have suicidal thoughts or behaviors, contact your healthcare provider right away.

What Is Pristiq?

Pristiq (desvenlafaxine) is an antidepressant used to treat low mood (depression) in adults. It belongs to the serotonin/norepinephrine reuptake inhibitor (SNRI) drug class. Desvenlafaxine is only available with a prescription and as an extended-release tablet.

Drug Facts

Generic Name: Desvenlafaxine

Brand Name(s): Pristiq

Drug Availability: Prescription

Therapeutic Classification: Serotonin-norepinephrine reuptake inhibitor (SNRI)

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Desvenlafaxine

Dosage Form(s): Extended-release tablets

What Is Pristiq Used For?

Pristiq (Desvenlafaxine) is a prescription drug used to treat major depressive disorder (MDD), a widespread and serious problem in the United States. MDD is usually linked with other mental health conditions. It is commonly seen among younger adults, White adults, and Native American adults, although anyone can experience it. Symptoms of MDD include constant sadness and loss of interest that interferes with everyday living.

How to Take Pristiq

Take Pristiq with water at about the same time every day. You may take it with or without meals. Swallow the tablet whole. Do not dissolve, divide, crush or chew the tablet.

Keep taking this drug even if you feel well. Do not stop taking your medication all of a sudden. If you need to stop taking Pristiq, your healthcare provider will slowly taper (lower) your dose.

Pristiq may show up on a drug test. Let your health professional know that you are on this medicine. 

Note: You may notice something resembling a tablet in your stool. This is the outer shell of the pill and is a typical occurrence for extended-release tablets and caplets. It should not be a source of concern. Consult your healthcare provider if you have any questions.

Storage

Store Pristiq at room temperature (68 to 77 degrees Fahrenheit (F)) in a dry place. Do not store it in your bathroom. When traveling, you may keep it between 59 and 86 degrees F for short periods of time.

Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet.

Discard your unused and expired drugs properly. Do not toss them into the sink, toilet, or drain. Ask your healthcare provider the best ways to dispose of your medicine. There may be drug take-back programs near you.

Off-Label Uses

Pristiq may be used off-label to treat vasomotor symptoms associated with menopause (marking the time when menstrual periods have stopped for 12 straight months). Although it reduces hot flashes and flushes, Pristiq also comes with side effects, which should be considered when taking this drug for menopause.

How Long Does Pristiq Take to Work?

Pristiq takes about one to two weeks to work in your system. Its full effects may be seen in four to six weeks of treatment.

What Are the Side Effects of Pristiq?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects of Pristiq include but are not limited to:

  • Headache
  • Excessive sweating
  • Feeling dizzy, sleepy, tired, or weak
  • Trouble sleeping
  • Upset stomach or vomiting
  • Diarrhea
  • Constipation
  • Dry mouth
  • Lack of appetite
  • Shakiness, nervousness, or restlessness
  • Specific male sexual function disorders

Severe Side Effects

Pristiq can cause many side effects. Some may be life-threatening. Call your medical provider right away if you have serious side effects. Call 911 if you think you have a medical emergency.

Rare but severe side effects include:

  • Increased heart rate
  • High blood pressure
  • Heart attack
  • Irregular menstrual cycle
  • Frequent urination
  • Change in vision, as well as eye pain and swelling or redness in or around the eye
  • Mood swings
  • Lung problems
  • Bleeding
  • Panic attacks
  • Anxiety
  • Thoughts or actions of suicide
  • Hallucinations 
  • Serotonin syndrome, including shivering, diarrhea, confusion, muscle tightness, fever, seizures, and abnormal heartbeat
  • Signs of an allergic reaction, like wheezing, trouble breathing, swallowing, or talking

The risk of serotonin syndrome, a potentially life-threatening condition, increases when taking Pristiq with other serotonergic agents, including fentanyl, lithium, tramadol, and Saint-John's-wort.

Discontinuation syndrome, which occurs when you stop your medicine suddenly, may have severe consequences, including panic attacks and seizures. Discontinuation syndrome may occur within two to five days of stopping the drug and may last for seven to 14 days.

These are not all the side effects of Pristiq. Call your healthcare provider if you have questions.

Long-Term Side Effects

Bone fragility and fractures may be associated with antidepressant treatment. If you experience unexplained bone pain, speak to your healthcare professional.

Report Side Effects

Pristiq may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Pristiq Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (extended-release tablets):
    • For depression:
      • Adults—50 milligrams (mg) once a day. Your doctor may adjust your dose as needed.
      • Children—Use and dose must be determined by your doctor.

Modifications

The following modifications (changes) should be kept in mind when taking Pristiq:

Pregnancy: Pristiq has been used in pregnant people, but its use varies based on each individual's health history. Pristiq may affect your newborn if used in the third trimester, causing seizures, breathing problems, constant crying, cyanosis (lack of oxygen that causes bluish skin and nail beds), and tremors. The long-term effects of exposure to this drug on newborn development and behavior remain unknown.

Pregnant people exposed to Pristiq are recommended to join the National Pregnancy Registry for Antidepressants (NPRAD) by calling 844-405-6185. Enroll as soon as possible during your pregnancy.

Breastfeeding: Desvenlafaxine is present in breast milk. If you plan to breastfeed, speak to your healthcare provider to ensure that the benefit of using this drug outweighs the possible harm to your infant. Monitor your infant's feeding, sleep, growing, development, and behavior patterns.

Adults over 65 years:  Compared to younger people, this population may be at higher risk of orthostatic hypotension during therapy. Dose adjustment in people over the age of 65 may be based on age and kidney function.

Children: Pristiq is not approved for use in children.

Switching from or to a monoamine oxidase inhibitor (MAOI). MAOIs are used to treat depression. MAOIs include:

  • Azilect (rasagiline)
  • Marplan (isocarboxazid)
  • Nardil (phenelzine)
  • Parnate (tranylcypromine)
  • Zelapar (selegiline)

Allow 14 days between stopping an MAOI and starting desvenlafaxine. The manufacturer suggests that you allow seven days between discontinuing desvenlafaxine and starting an MAOI. However, a 14-day washout period is usually recommended to reduce the risk of developing serotonin syndrome.

Missed Dose

If you mistakenly miss a dose, take the missed dose once you think of it. If it is very close to your next dose, skip the missed dose and go back to your regular time. Do not take or extra doses or take two doses at the same

Try to find ways to help yourself remember to routinely take your medicine. If you miss too many doses, Pristiq might be less effective in treating your depression

Overdose: What Happens If I Take Too Much Pristiq?

There is limited information about the overdose of Pristiq in humans. If you think that you're experiencing an overdose or life-threatening symptoms, however, seek immediate medical attention.

What Happens If I Overdose on Pristiq?

If you think you or someone else may have overdosed on Pristiq, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Pristiq, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

It is important that your doctor check your progress at regular visits, to allow for changes in your dose and to help reduce any side effects. Blood and urine tests may be needed to check for any unwanted effects.

Do not take desvenlafaxine with a monoamine oxidase (MAO) inhibitor (eg, isocarboxazid [Marplan®], phenelzine [Nardil®], selegiline [Eldepryl®], tranylcypromine [Parnate®]). Do not start taking desvenlafaxine within 14 days after you stop using an MAO inhibitor. Wait 7 days after stopping desvenlafaxine before you start taking an MAO inhibitor. If you take them together or do not wait the proper amount of time, you may develop confusion, agitation, restlessness, stomach or bowel symptoms, a sudden high body temperature, an extremely high blood pressure, or severe seizures.

Do not take any medicine that contains venlafaxine (Effexor®) while you are using Khedezla® or Pristiq®.

Desvenlafaxine may cause some teenagers and young adults to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Some people may have trouble sleeping, get upset easily, have a big increase in energy, or start to act reckless. If you or your caregiver notice any of these unwanted effects, tell your doctor right away. Let the doctor know if you or anyone in your family has bipolar disorder (manic-depressive) or has tried to commit suicide.

Do not stop using this medicine without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely to decrease the chance of side effects, such as agitation, breathing problems, chest pain, confusion, diarrhea, dizziness or lightheadedness, fast or irregular heartbeat, feeling more excited or energetic than usual, headache, increased sweating, irritability, muscle pain, nausea, numbness or tingling feeling, restlessness, ringing in your ears, runny nose, seizures, thoughts of hurting yourself or others, trouble sleeping, trembling or shaking, unusual dreams, unusual mood or behavior, unusual tiredness or weakness, vision changes, or vomiting.

Desvenlafaxine may cause a serious condition called serotonin syndrome if taken together with some medicines. Do not use desvenlafaxine with buspirone (Buspar®), fentanyl (Abstral®, Duragesic®), lithium (Eskalith®, Lithobid®), tryptophan, St. John's wort, amphetamines, or some pain or migraine medicines (eg, rizatriptan, sumatriptan, tramadol, Frova®, Imitrex®, Maxalt®, Relpax®, Ultram®, Zomig®). Check with your doctor first before using any other medicines with desvenlafaxine.

Tell your doctor right away if you have chest discomfort, cough, or trouble breathing while using this medicine. These might be symptoms of a serious lung problem.

This medicine may increase your risk for bleeding problems. Make sure your doctor knows if you are also taking other medicines that thin the blood, including aspirin, NSAIDs (eg, diclofenac, ibuprofen, naproxen, Advil®, Aleve®, Celebrex®, Voltaren®), or warfarin (Coumadin®, Jantoven®).

This medicine may cause hyponatremia (low sodium in the blood). This is more common in elderly patients, those who are taking diuretic medicines for high blood pressure, or those who have decreased amounts of fluid in the body due to severe diarrhea or vomiting. Check with your doctor right away if you have confusion, headache, memory problems, trouble concentrating, weakness, or feel unsteady when standing.

This medicine may cause some people to become dizzy, drowsy, or less alert than they are normally. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Check with your doctor right away if you have decreased interest in sexual intercourse, delayed or inability to have an orgasm in women, inability to have or keep an erection in men, or loss in sexual ability, desire, drive, or performance. These could be symptoms of sexual dysfunction.

The use of alcohol is not recommended in patients who are using this medicine.

Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests may be affected by this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

What Are Reasons I Shouldn’t Take Pristiq?

Avoid taking Pristiq if you are:

  • Hypersensitive to desvenlafaxine, venlafaxine, or any part of the formulation
  • Using MAOIs (concurrently or within 14 days of discontinuing the MAOI)
  • Starting an MAOI within seven days of stopping Pristiq
  • Taking Zyvox (linezolid) to treat certain infections or intravenous methylene blue to treat methemoglobinemia (the blood's inability to carry oxygen throughout the body) and are about to start Pristiq

What Other Medications Interact With Pristiq?

Certain medications interact with Pristiq and increase the risk of severe side effects. Some of the drugs to avoid are:

  • Buspar (buspirone)
  • Bystolic (nebivolol)
  • Delsym (dextromethorphan)
  • Detrol (tolterodine)
  • Duragesic (fentanyl)
  • Lithobid (lithium)
  • Lopressor (metoprolol)
  • Saint John's wort
  • Strattera (atomoxetine)
  • Ultram (tramadol)
  • Zelapar (selegiline)
  • Zyvox (linezolid)

Also, be sure to talk with your healthcare provider about all prescription and nonprescription medications, vitamins, supplements, and herbal products you are taking or plan to take.

What Medications Are Similar?

Other drugs similar to Pristiq that are antidepressants include:

This is a list of drugs also used to treat depression. It is not a list of drugs suggested to be used with Pristiq. Do not take these drugs together except your healthcare provider tells you to. Ask your pharmacist or a healthcare practitioner if you have questions.

Frequently Asked Questions

  • What is Pristiq used to treat?

    Pristiq is used to treat depression in adults.

  • What are the common side effects of Pristiq?

    Some common side effects include:

    • Shakiness
    • Trouble sleeping
    • Constipation
    • Dry mouth
    • Loss of appetite
    • Excess sweating
    • Feeling dizzy, sleepy, tired, or weak
    • Upset stomach or throwing up
    • Male sexual function disorders
  • What should I do if I miss a dose of Pristiq?

    Take the missed dose as soon as you think of it. Skip the missed dose if it is very close to the next dose. Go back to your regular dosing schedule. Do not take double the amount or take extra doses.

How Can I Stay Healthy While Taking Pristiq?

Living with depression can be challenging, primarily when it affects your daily life and the people around you. The good news is that certain medicines like Pristiq may help you with your depression. While taking Pristiq, here are a few things to consider to keep you healthy:

  • Be patient with this drug; you may not see any results for two weeks from when you start taking it.
  • Keep taking this drug even if you feel better. Do not stop taking it all of a sudden.
  • Before starting any new drugs, including over-the-counter medications, talk to your healthcare professional. Using Pristiq with nonsteroidal anti-inflammatory drugs (NSAIDs), including Advil or Motrin (ibuprofen), Aleve (naproxen), and aspirin; other platelet drugs; Coumadin or Jantoven (warfarin) or other anticoagulants may increase your risk of bleeding.
  • Avoid drinking alcohol while taking this drug.
  • Your blood pressure may increase while on this medicine. Routinely check your blood pressure to catch any abnormal readings.
  • This drug may increase the chances of having eye problems. Regularly visit your eye care specialist for eye exams.
  • Pristiq may harm a fetus or infant. Speak to your medical provider if you are pregnant, plan to become pregnant, are breastfeeding, or plan to breastfeed.
  • This drug may cause symptoms of sexual dysfunction in both males and females. Speak to your medical provider about any changes in sexual function and potential management strategies.
  • Join a support group near you or online for an opportunity to share with and learn from others.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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