Side Effects of Effexor XR

By Andrew Yocum, MD
Medically reviewed checkmarkMedically reviewed
May 3, 2022

If you’re one of the 16.1 million Americans who suffer from depression, or one of the 40 million who suffer from an anxiety disorder, your doctor or healthcare provider may recommend an antidepressant medication such as Effexor XR. 

Effexor XR, an extended-release version of Effexor (venlafaxine), is a pill that’s taken once per day, and is approved by the U.S. Food and Drug Administration (FDA) for major depressive disorder (MDD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and panic disorder.

While it may help alleviate the symptoms of these disorders, it can also cause side effects, as most medications do.

These can be mild, like burping or yawning, or more severe and serious, like seizures or unusual bruising or bleeding.

Most side effects typically go away after a week or two of starting the medication. 

In this article, I’ll explain more about what Effexor XR is and how it works.

I’ll then go in-depth about the side effects patients may experience while taking the drug.

I’ll also discuss dosage and some things to know before starting Effexor XR. 

What is Effexor XR?

Effexor XR (venlafaxine hydrochloride) is a type of prescription antidepressant called a serotonin-norepinephrine reuptake inhibitor, or SNRI.

SNRIs work to increase the amount of the mood-regulating neurotransmitters serotonin and norepinephrine in the brain. 

Serotonin (sometimes referred to as the “happy chemical”) and norepinephrine (which boosts alertness, happiness, and concentration) carry signals between nerve cells in the brain, also called neurons.

Usually, when the signal is finished being carried, it’s reabsorbed, a process called “reuptake.” SNRIs block the reuptake of serotonin and norepinephrine into the neurons, making more serotonin and norepinephrine available in the brain.

This can help maintain mental balance.

Have questions about an Effexor prescription? Chat with a doctor today.
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Effexor XR vs. Effexor

Effexor is the immediate-release version of venlafaxine, and is taken as an oral tablet two or three times per day. Effexor XR has the same active ingredient, but is an extended-release capsule, meaning the medication is taken only once per day—the medication releases more slowly throughout the day.

Effexor is only approved to treat depression. Effexor XR is approved to treat depression and several anxiety disorders.

Effexor XR uses

Effexor XR is approved to treat major depressive disorder (MDD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and panic disorder in adults.

  • Major depressive disorder (MDD): Also called “clinical depression,” MDD is a mood disorder with symptoms that impact the way you think, feel, and react to situations, with symptoms like irritability, sadness, hopelessness, guilt, and worthlessness. These symptoms must be present for more than two weeks to be diagnosed with depression. 
  • Generalized anxiety disorder (GAD): GAD is marked by persistent feelings of worry or dread, with symptoms including feelings of nervousness, restlessness, trouble concentrating, and irritability. These symptoms must be present for at least six months to be diagnosed with GAD. 
  • Social anxiety disorder: An anxiety disorder marked by the extreme, persistent fear of interacting with, or being watched and judged by, others. When forced to perform in front of or be around others, people with social anxiety disorder may experience increased heart rate, increased sweating, trembling, difficulty making eye contact, and more. To be diagnosed with social anxiety disorder, these feelings must be present for at least six months and make it difficult to perform everyday tasks. 
  • Panic disorder: An anxiety disorder marked by persistent, unexpected bouts of intense fear—most often coupled with physical symptoms like chest pain, heart palpitations, or dizziness—and panic attacks unrelated to any real or justified fear. 

Side Effects of Effexor XR

Common side effects

Common side effects experienced while taking Effexor XR include:

  • Fatigue
  • Unusual dreams
  • Nausea or vomiting
  • Constipation or diarrhea
  • Dry mouth
  • Sexual dysfunction (trouble with orgasm, ejaculatory delay, etc.)
  • Changes to sleep
  • Headache
  • Increased heart rate
  • Dizziness 
  • Blurred vision
  • Tremors or shaking
  • Loss of appetite
  • Increased sweating
  • Feeling jittery or nervous

Most of Effexor XR’s mild side effects typically go away after a week or two of taking the medication.

However, side effects related to sexual dysfunction and high blood pressure do not tend to go away with time. 

Serious side effects

These severe side effects are less common:

  • Increased cholesterol
  • Angle-closure glaucoma (a condition which can lead to loss of vision)
  • Suicidal thoughts or behaviors
  • Changes in blood pressure
  • Mydriasis (enlarged pupils)
  • Seizures or convulsions
  • Increased risk of bleeding problems
  • Low blood sodium levels
  • Insomnia or trouble sleeping
  • Anxiety
  • Severe changes in weight
  • Increased risk of lung problems (like lung disease, pneumonia, etc.)
  • Severe allergic reactions
  • Manic or hypomanic behavior

Serotonin syndrome

When Effexor XR is combined with other drugs that affect serotonin levels, a serious condition called serotonin syndrome can occur.

Serotonin syndrome is a serious drug reaction that occurs when too much serotonin builds up in the body, leading to mild symptoms (like shivering and diarrhea) to more severe symptoms (like seizures and fever).

Serotonin syndrome can even be fatal if left untreated. 

Effexor XR Dosage

While your doctor will tell you how much Effexor XR you should take, the dosage typically ranges from 37.5 mg to 225 mg per day, with a typical dose of 75 mg per day.

Your doctor may start you off at a lower dose to start, then work you up to a higher dose as your body adjusts.

Effexor XR capsules should be taken once daily with food, and the capsule should be swallowed whole. 

What if I miss a dose?

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

If it’s almost time for your next dose, skip the missed dose and take the next dose as planned.

Never double up on your doses to “make up” for a missed dose. 

What if I overdose?

If you or someone you love may have taken too much Effexor XR, call your healthcare provider, poison control, or 9-1-1. 

Symptoms related to Effexor XR overdose include somnolence, nausea, dizziness, paresthesia of the limbs, and more, though no symptoms may be felt at all. 

Have questions about an Effexor prescription? Chat with a doctor today.
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Effexor XR Precautions

Before taking Effexor, you should be aware of the following:

  • Tell your doctor about all medications you are taking: This includes prescription medications, over-the-counter drugs, street drugs, and herbal or nutritional supplements. Certain medications and other drugs can interact with Effexor XR and cause serious side effects.
  • Be mindful of alcohol consumption: Effexor XR can cause drowsiness as well as blurred vision, and alcohol can heighten these side effects. Be especially mindful of how much you are drinking if you plan to drive. In general, it is not recommended to drink alcohol while taking SNRIs like Effexor XR. Talk to your prescriber before consuming alcohol while taking Effexor XR.
  • Effexor XR can heighten depression at first: Depression can become worse before it gets better when taking Effexor XR, especially the first few days after starting it. This is especially true for young adults. Tell your doctor if you or anyone in your family suffers from bipolar disorder or has attempted to commit suicide. Seek medical attention immediately if you are experiencing suicidal thoughts or behaviors.
  • Effexor XR can cause bleeding problems: Side effects of Effexor XR include high blood pressure, low sodium in the blood (hyponatremia), and other bleeding problems. Tell your doctor if you have had related issues.
  • Tell your doctor if you are breastfeeding, pregnant, or may become pregnant: Effexor XR can cause issues in newborns post-delivery if taken by the mother in the last few months of pregnancy.
  • Effexor XR can cause angle-closure glaucoma: Angle-closure glaucoma is a change in vision. Tell your doctor about any related eye problems. Your doctor may suggest you take an eye test before starting Effexor XR. 

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Frequently Asked Questions

How long do Effexor XR side effects last?
Most of Effexor XR’s side effects typically go away after a week or two of taking the medication. However, side effects related to sexual dysfunction and high blood pressure do not tend to go away with time.
Can Effexor make you gain weight?
It is possible to see an increase in weight while taking Effexor, but it is actually less likely to cause weight gain than some other antidepressants.
Why should you not take Effexor?
You should not take Effexor if you are allergic to its ingredients, or if it interacts with any other essential medications you take. Your doctor may also choose not to prescribe you Effexor if they believe its side effect profile will be detrimental to you. For example: if you have a history of mania or suicidal actions; if you have a history of bleeding problems; if you are breastfeeding, pregnant, or may become pregnant; or if you have eye problems that may make you more susceptible to angle-closure glaucoma.
Is Effexor XR good for anxiety?
Effexor XR is approved to treat three anxiety disorders in adults: GAD, social anxiety disorder, and panic disorder. However, anxiety and nervousness are two side effects related to Effexor XR. Whether or not it will be helpful for your anxiety is a question your doctor can answer.

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.

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).