What to Know About Effexor (Venlafaxine)

An SNRI used to treat depression and anxiety

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What is the most important information I should know about Effexor (venlafaxine)?

  • You should not take venlafaxine if you have taken a monoamine oxidase inhibitor (MAOI) in the previous 14 days.
  • Tell your doctor if you have a history of seizures, brain injury/illness, heart disease, high/low blood pressure, or kidney/liver disease.

Venlafaxine is an antidepressant drug in a class called serotonin-norepinephrine reuptake inhibitors (SNRIs). It is an oral tablet that comes in both an immediate-release (Effexor) and extended-release (Effexor XR) formula. Both are used to treat depression in addition to a variety of other mental health conditions.

SNRIs work by blocking serotonin and norepinephrine's reabsorption (or reuptake) back into the nerve cells that released them. Blocking their reuptake increases the levels of these neurotransmitters in the brain. This may improve your focus and alertness and boost your mood.

Effexor has been discontinued in the U.S., but Effexor XR is still available by prescription. Unlike Effexor, Effexor XR only needs to be taken once a day.

Effexor Uses

Effexor is mainly used to treat anxiety and depression. The four conditions it has been FDA-approved to treat are:

Doctors also sometimes prescribe Effexor off-label to treat other conditions, including:

Off-label use is both legal and common. It simply means that a doctor is prescribing it to treat a condition other than what the medication has been officially indicated to treat. However, a 2017 study found that Effexor was one of the medications least likely to be prescribed for off-label use.

One study found that Effexor was one of the most effective antidepressants. While Effexor can be a strong antidepressant, individual effects and tolerance may vary. Working with your doctor to determine which option is right for you is crucial.

Common Effexor Side Effects

Like any medication, side effects may occur while taking Effexor. Be sure to contact your doctor if they don't go away or become bothersome. The most common side effects include:

  • Constipation
  • Diarrhea
  • Drowsiness
  • Feeling tired
  • Headache
  • Heartburn
  • Loss of appetite
  • Nausea
  • Sexual side effects
  • Vomiting

These side effects often improve over the first week or two as you continue taking the medication. Call your doctor if your symptoms become severe or don't go away.

Effexor may make you drowsy when you first start taking it, but this side effect often goes away or improves after a week or two. Some people may also experience insomnia or nightmares. Over time, you may also notice improvements in mood and increased energy levels.

Before Taking Effexor

Effexor should not be taken with or within two weeks of taking monoamine oxidase inhibitors (MAOIs). Examples of MAOIs include:

  • Emsam (selegiline)
  • Marplan (isocarboxazid)
  • Nardil (phenelzine)
  • Parnate (tranylcypromine)

Both Effexor and MAOIs increase serotonin levels in the brain. Severe and even fatal complications may result from such a combination.


Make sure your doctor knows your complete medical history. Effexor should be used with caution if you have:

  • Brain disease, damage, or a history of seizures: The risk of seizures may increase when taking Effexor.
  • Heart disease or high or low blood pressure: Effexor may occasionally make these conditions worse.
  • History of mania: The risk of developing mania may be increased while taking Effexor. This is very important for bipolar patients to watch for.
  • Kidney disease or liver disease: Higher blood levels of Effexor may occur, increasing the chance of side effects. Your doctor may need to adjust your dose.

How to Take Effexor

Effexor XR is taken once each day. Typical doses range from 37.5 mg to 225 mg, with a typical target dose of 75 mg per day. Your healthcare provider will typically start at a lower amount and gradually increase the dose until they determine the right dose for you.

The medication should be taken with food at any time of day, morning or night. However, if you have trouble sleeping after taking Effexor, it may be best to take your medication in the morning.

Warnings and Interactions

Warnings are established to both ensure the safe use and discontinuation of Effexor. Your doctor should monitor you for the following complications while you're taking Effexor.

Serotonin Syndrome

Be careful when mixing Effexor with other medicines that also affect serotonin levels, such as other antidepressants, lithium, and St. John's wort. Doing so can lead to an excessive serotonin buildup in the brain. This can cause a condition called serotonin syndrome.

Symptoms of serotonin syndrome include:

  • Confusion
  • Diarrhea
  • Dilated pupils
  • Fever
  • Loss of muscle coordination
  • Muscle stiffness
  • Sudden spikes in blood pressure or heart rate
  • Sweating or shivering
  • Twitching muscles
  • Unusual agitation or restlessness

Some cases of serotonin syndrome can be life-threatening. If you're taking Effexor and experience any of these symptoms, contact your doctor as soon as possible.

Risk of Overdose

You should always avoid drinking or using other drugs while you're taking Effexor. These substances may decrease the benefits of the medication, or they can result in a toxic overdose. The most common Effexor overdose effects include:

  • Changes in consciousness (ranging from sleepiness to coma)
  • Dilated pupils
  • Fast heart rate
  • Seizures
  • Vomiting

To reduce your risk of overdose, your doctor will only prescribe you the lowest possible dose in the smallest quantity.

Suicidal Thoughts and Actions

Children and young people (up to age 25) may experience increased suicidal thoughts and behaviors when taking antidepressant medications. The danger is greatest the first few months of treatment or when changing the dose.

Though this warning is true for all antidepressants, taking Effexor may increase your risk even more. A major study found that Effexor was associated with a higher risk of both completed and attempted suicide compared with other antidepressants, including Celexa (citalopram), Prozac (fluoxetine), and Prothiaden (dothiepin).

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Discontinuation Syndrome

Stopping Effexor abruptly may result in one of more of the following withdrawal symptoms:

  • Anxiety or worsening of depression
  • Dizziness
  • Gastrointestinal upset
  • Headaches
  • Irritability
  • Nausea
  • Nightmares
  • Paresthesias (prickling, tingling sensation on the skin)
  • Vomiting

It's important not to stop taking Effexor on your own. If you and your doctor decide you should stop Effexor, they can provide you with a tapering strategy to minimize any withdrawal symptoms.

9 Sources
Verywell Mind 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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By Marcia Purse
Marcia Purse is a mental health writer and bipolar disorder advocate who brings strong research skills and personal experiences to her writing.