If you’ve received a diagnosis of depression, your doctor might suggest Pristiq (desvenlafaxine) as a treatment option for you. As a result, you could be looking for more information about the drug, such as details about dosage.

Pristiq is a prescription medication that’s used to treat major depressive disorder in adults. This is also called clinical depression.

Pristiq belongs to a group of drugs called serotonin-norepinephrine reuptake inhibitors (SNRIs).

This article describes the dosages of Pristiq, including its form, strengths, and how to take the drug. To learn more about Pristiq, see this in-depth article.

Note: This article covers Pristiq’s typical dosages, which are provided by the drug’s manufacturer. But when using Pristiq, always take the dosage that your doctor prescribes.

When you start treatment with Pristiq, your doctor or pharmacist will explain your dosage. (This is how much of the drug to take and how often.)

The information below describes dosages that are commonly used or recommended. But be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

What is Pristiq’s form?

Pristiq comes as extended-release tablets that you swallow. Extended-release tablets slowly release their contents over time in your body.

What strengths does Pristiq come in?

Pristiq is available in the following strengths:

  • 25 milligrams (mg)
  • 50 mg
  • 100 mg

What are the typical dosages of Pristiq?

Your dosage of Pristiq will depend on several factors, including:

  • your overall health
  • how severe your condition is
  • other medications you may be taking

The recommended dosage for Pristiq is 50 mg taken by mouth once per day. But the dosage can range from 50 mg to 400 mg per day.

If you need to stop Pristiq treatment, your doctor may prescribe a dosage of 25 mg per day. This is to help prevent withdrawal symptoms. For more information, see the “Pristiq and withdrawal and dependence” section below.

The usual maximum dosage of Pristiq is 400 mg per day. But this maximum may be lower for people who have liver or kidney disease.

If you have questions about your dosage of Pristiq, talk with your doctor.

Is Pristiq used long term?

Yes, Pristiq may be used long term if the drug is working to manage your symptoms of depression.

If you and your doctor determine that Pristiq is safe and effective for you, it’s likely that you’ll use it long term.

Dosage adjustments

In certain cases, your doctor may need to adjust your dosage of Pristiq. This depends on your condition and whether you have other health problems. For example, your dosage of Pristiq may be lower if you have serious kidney or liver disease.

Your doctor may also adjust your Pristiq dosage if you’re taking other medications. Be sure to let your doctor know about all drugs you’re taking, as well as any herbs, vitamins, and supplements.

When you start treatment with Pristiq, your doctor will monitor how you’re doing. They’ll adjust your dosage if needed.

Below are some answers to a few common questions about Pristiq.

Is Pristiq used to treat anxiety? If so, what’s the dosage?

Pristiq isn’t approved by the Food and Drug Administration (FDA) to treat anxiety.

But your doctor may prescribe Pristiq off-label for anxiety. “Off-label” means using a drug for purposes other than what it’s approved for by the FDA.

Keep in mind that Pristiq can also cause anxiety as a side effect, though this is rare.

If you have questions about taking Pristiq for anxiety, ask your doctor. And if you have both depression and anxiety, talk with your doctor about the benefits and risks of taking Pristiq.

Could I be prescribed a dosage of 150 mg or 200 mg of Pristiq?

The recommended dosage of Pristiq is 50 milligrams (mg) once per day. But if this dosage isn’t working to ease your symptoms of depression, your doctor may slowly increase your dosage. This can include doses of 150 mg or 200 mg. The maximum dosage of Pristiq is 400 mg per day.

If you have liver or kidney problems, your maximum dosage of Pristiq may be lower.

Note that studies of Pristiq haven’t shown doses higher than 50 mg to be more effective for treating depression. You may also experience more side effects from higher doses of the drug.

If you have questions about your dosage of Pristiq, talk with your doctor.

Should I take my Pristiq dose in the morning or at night?

Pristiq may cause insomnia (trouble falling asleep or staying asleep) or sleepiness.

The best time of day for you to take Pristiq may depend on how you react to the drug. It could take a few days to a few weeks to learn how the drug affects you.

If you have insomnia during Pristiq treatment, ask your doctor or pharmacist if you should take the drug in the morning.

But if you experience sleepiness that doesn’t go away, ask your doctor if you should take Pristiq in the evening.

In some cases, insomnia may be a warning sign of worsening depression or suicidal thoughts and behaviors. Tell your doctor right away if you experience any of these symptoms. See the boxed warning at the beginning of this article for more information.

If you accidentally miss taking your dose of Pristiq, take it as soon as you remember. But if it’s too close to your next dose, just skip the missed dose and continue with your normal schedule. Don’t take two doses of Pristiq at once. This can increase your risk of side effects.

If you need help remembering to take your dose of Pristiq on time, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

The dosage of Pristiq you’re prescribed may depend on several factors. These include:

  • how severe your condition is
  • other conditions you may have (see “Dosage adjustments” under “What is Pristiq’s dosage?”)
  • how you’re responding to treatment with Pristiq
  • other medications you may be taking

Your doctor will prescribe the lowest dosage of Pristiq that’s effective for your condition. This may help prevent side effects of the drug.

Pristiq comes as extended-release tablets that you take by mouth. Extended-release drugs gradually release their contents in your body over time.

You’ll likely take the drug once per day, with or without food.

It’s important to take Pristiq at the same time every day. So, try to choose a time that works best for you. For more about when to take this drug, see “Should I take my Pristiq dose in the morning or at night?” in the “Frequently asked questions” section.

Don’t crush, chew, or split Pristiq tablets. Doing so may change how the drug works. If you need help swallowing pills, take a look at these tips. Your doctor or pharmacist might also be able to suggest ways to make taking Pristiq easier.

Don’t use more Pristiq than your doctor prescribes. Using more than this can lead to serious side effects.

Symptoms of overdose

Symptoms caused by an overdose can include:

What to do in case you take too much Pristiq

Call your doctor right away if you think you’ve taken too much Pristiq. You can also call 800-222-1222 to reach the American Association of Poison Control Centers, or you can use its online resource. But if you have severe symptoms, call 911 (or your local emergency number) immediately or go to the nearest emergency room.

Pristiq may cause drug discontinuation syndrome. This is a form of withdrawal that may happen when your body becomes used to Pristiq. When you stop taking the drug, you may experience certain side effects.

Because of the risk of these side effects, it’s important not to suddenly stop taking Pristiq without first talking with your doctor.

Side effects from suddenly stopping Pristiq treatment can include:

* For more information, see “Boxed warning: Suicidal thoughts and behaviors in children and young adults” at the beginning of this article.

If you want to stop taking Pristiq, talk with your doctor. They’ll develop a treatment plan to help you slowly stop taking Pristiq. This will likely involve lowering your dosage, possibly over the course of several months.

For more information about Pristiq and withdrawal, talk with your doctor or pharmacist.

The sections above describe the typical dosages provided by the drug manufacturer. If your doctor recommends Pristiq for you, they’ll prescribe the dosage that’s right for you.

Remember, you shouldn’t change your dosage of Pristiq without your doctor’s recommendation. Only take Pristiq exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage.

Here are some questions you may want to ask your doctor:

  • Will you change my dosage of Pristiq if it’s not working well for me?
  • Would a different dosage raise or lower my risk of side effects from Pristiq?
  • Will my dosage of Pristiq be lower if I have end stage renal disease?

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Disclaimer: Healthline 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.