Pristiq and Effexor are similar antidepressants, but there are some notable differences.

Antidepressants, like Pristiq and Effexor, can be an effective treatment for depression. Your doctor may also prescribe them for anxiety and other conditions.

Both medications can cause side effects and may interact with other medications. Consider talking with your doctor about your medical conditions, medications you are taking, and any concerns you have before starting either medication.

When used correctly, either may help with depression symptoms, but they have some differences in dose and side effects. Consider talking with your doctor about medication options that are best for you.

Pristiq and Effexor are both antidepressants that help regulate norepinephrine and serotonin. Both of these chemicals may play a role in depression.

When Effexor is metabolized in the body, it turns into desvenlafaxine, the active ingredient of Pristiq.

The main difference between the two medications is that Effexor may be used for general anxiety disorder (GAD) as well as some other off-label conditions.

Another difference is the potential for sexual and blood pressure-related side effects associated with Effexor. Pristiq does not have those warnings.


Recommended dosages are different for the medications. To prevent side effects, doctors typically start patients on 37.5 mg per day of Effexor before increasing to the minimum dose of 75 mg per day. Many people increase their dosage further to around 150 mg per day.

Pristiq is prescribed starting at 50 mg per day, and typically the dose is not increased.

How long they take to work

According to National Alliance on Mental Illness (NAMI), when taken as prescribed, you should notice that some physical symptoms of depression (sleep issues, appetite, and energy) improve within the first 1 to 2 weeks after starting the medication. It can take up to 6 or 8 weeks for your mood to improve.

NAMI says that, like Pristiq, with Effexor you should see some symptom improvement within 1 to 2 weeks. You likely will not experience full relief for about 6 to 8 weeks. Avoid stopping the medication suddenly to help prevent withdrawal symptoms.

Suicidal thoughts

Both Pristiq and Effexor include a black box warning about potentially causing suicidal thoughts or actions in both children and adults.

Drug interactions

Both medications may interact with other drugs such asmonoamine oxidase inhibitors (MAOIs), other antidepressants, and medications that can lead to bleeding (e.g., ibuprofen, warfarin, aspirin).

Both Pristiq and Effexor have a similar number of common side effects. For both, most of the common side effects typically go away within 1 to 2 weeks of starting the medication.

They both can cause less common side effects, including:

  • increased heart rate
  • increased salivation
  • irregular menstrual cycle
  • increased frequency in urination
  • changes in taste
  • low sodium
  • teeth grinding
  • low blood pressure
  • trouble urinating
  • angle-closure glaucoma
  • serotonin syndrome
  • hypertensive crisis (severely elevated blood pressure)

Pristiq can also cause side effects such as:

  • higher risk of heart attack
  • rash
  • increased liver enzymes

Effexor contains more compounds

When you talk with your doctor about your depression or anxiety, it is important to discuss your symptoms as well as review any medications you are taking, plans to become pregnant, and any other underlying health conditions you may have, such as bleeding disorders. Knowing this information can help your doctor recommend the safest medication for your needs.

Pristiq is one brand name for the medication desvenlafaxine produced by Pfizer. Desvenlafaxine is in a class of antidepressants known as serotonin-norepinephrine reuptake inhibitors (SNRIs).

A doctor may prescribe it to help with symptoms of deoression, such as feelings of worthlessness, depressed mood, and loss of interest in activities.

In some cases, a doctor may prescribe Pristiq for “off-label” uses. This means they may recommend it for conditions that the Food and Drug Administration (FDA) has not approved. Some off-label uses include treating:

Once you start taking Pristiq, you should not stop taking it suddenly. Suddenly stopping the medication can cause withdrawal symptoms, such as dizziness, nightmares, irritability, and others.

Common side effects

When you first start or switch to using Pristiq, you may experience some common side effects. After about a week or two, you should notice them improve. Common side effects include:

  • nausea
  • headache
  • decreased appetite
  • constipation
  • vomiting
  • dry mouth
  • diarrhea
  • nervousness
  • fatigue
  • increased sweating
  • restlessness
  • tremors
  • trouble sleeping

It may also increase the risk of premature birth when used during pregnancy. If side effects don’t improve or are causing distress, it’s important to talk with your doctor immediately.

Effexor is one brand name for venlafaxine. It is an SNRI antidepressant made by Pfizer and approved by the FDA for the treatment of:

  • depression
  • panic disorder
  • GAD
  • social anxiety disorder

Off-label uses include:

Your doctor may prescribe rapid-release or extended-release tablets.

Common side effects

When you take Effexor, you may experience short-term side effects that last 1 to 2 weeks. These can include:

  • feeling nervous
  • headaches
  • diarrhea
  • nausea
  • dry mouth
  • trouble sleeping
  • fatigue
  • sleepiness
  • restlessness
  • increase in sweating

While these symptoms may go away within a couple of weeks, some people experience ongoing sexual issues or high blood pressure. Consider talking with your doctor if you experience either of these side effects.

Effexor and Pristiq are both medications doctors prescribe to treat depression and anxiety disorder, as well as other off-label conditions.

Both medications can cause mostly temporary side effects and potentially some rare, more serious side effects. Effexor can also commonly cause sexual side effects as well as high blood pressure, both of which may not go away on their own.

When you talk to your doctor, you may find asking questions about your options helps. Here are a few questions to ask:

  • Is this the best option based on my other medications/medical conditions?
  • Do you think side effects are likely?
  • When should I let you know about side effects?
  • What is your plan if I develop high blood pressure or sexual problems from taking Effexor?