What to Know About Effexor (Venlafaxine)

Venlafaxine is an antidepressant drug that is FDA-approved to treat major depressive disorder, generalized anxiety disorder, social anxiety disorder, and panic disorder. It is also used off-label to treat a variety of other mental health conditions.

It is an oral tablet in the serotonin-norepinephrine reuptake inhibitor (SNRI) class, which blocks serotonin and norepinephrine’s reabsorption (or reuptake) back into nerve cells. Blocking their reuptake increases the levels of these neurotransmitters in the brain, which may improve focus and alertness and boost mood.

The brand name Effexor has been discontinued in the U.S., but Effexor XR (meaning extended release) is still available by prescription.

Jump to Key Takeaways

What Effexor Is Prescribed For

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 a medication to treat a condition other than what it 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.

What Kind of Side Effects to Expect

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

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.

Things to Know Before You Start 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)

Precautions

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.

Important Warnings and Drug 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

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 most significant in 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).

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

Key Takeaways

• Effexor (venlafaxine) is a serotonin-norepinephrine reuptake inhibitor (SNRI) that is used to treat depression, anxiety, ADHD, OCD, and other conditions.
• Common side effects of Effexor include constipation, diarrhea, drowsiness, headache, heartburn, nausea, and vomiting. 
• It’s important to avoid taking venlafaxine with certain medications, including MAOIs, lithium, and other medicines or supplements that affect serotonin levels. Caution should be used if you have a history of seizures, cardiovascular disease, high or low blood pressure, a history of mania, or kidney or liver disease.