Venlafaxine (Effexor, Effexor XR)

Venlafaxine has been available as an antidepressant since 1993. It is an SNRI (Serotonin-Norepinephrine Reuptake Inhibitor) antidepressant. Venlafaxine is not usually used as a first line antidepressant, but is effective in people who have had treatment failures with SSRIs or other antidepressants.

The Bottom Line: What You Really Need to Know


Venlafaxine is approved to treat Major Depressive Disorder, Generalized Anxiety Disorder, Social Adjustment Disorder and Panic Disorder. It is also used to treat Diabetic Peripheral Neuropathy, migraine headaches and hot flashes. It may be effective in the treatment of ADHD and borderline personality disorder.

Dosage and instructions

The usual adult dosage of venlafaxine is 75 mg/day. Venlafaxine should be taken in two or three divided doses; venlafaxine XR can be taken once a day.

You may take a smaller dose to begin with, as low as 37.5 mg/day and the dose can be increased in increments of 37.5-75 mg/day every 4-5 days until the desired effect is achieved. The maximum recommended daily dose is 225 mg/day.

People with liver or kidney disease may need a smaller dose.

How venlafaxine works

The exact mechanism of action of venlafaxine is not known, but it appears to work by inhibiting absorption of serotonin and norepinephrine at the nerve endings. It may have some effect on dopamine, too, especially at higher doses. It does not seem to have an effect on other neurotransmitters.

Side effects

The side effects most often reported with venlafaxine are:

Side effects usually go away after 2-4 weeks of treatment.


MAOI antidepressants: There can be a very dangerous and potentially fatal interaction between MAOIs and venlafaxine. At least two weeks should lapse between taking these medications.

Serotinergic medications: Venlafaxine can cause serotonin syndrome if it is taken concurrently with other serotonergic medications. Serotonin syndrome is a toxic reaction and can be as mild as shakes and anxiety or as severe as high fever, seizures, multiple system failure and death. Serotonergic medications that should not be taken with venlafaxine are:

Other medications that should be used with caution while taking venlafaxine are:


If you suddenly stop taking venlafaxine, you will probably suffer from very uncomfortable withdrawal symptoms. You have to gradually taper the medication before you stop taking it and you could still have some symptoms. The severity of symptoms and how long they last seems to be related to how much medication you were taking and how long you have been taking it. Withdrawal symptoms include:

Warnings, precautions and contraindications

Suicide risk: All antidepressants increase your risk of suicide and people should be closely monitored in the first weeks or months of therapy. Weekly physician or therapist visits and daily monitoring by family or friends are indicated. Any change in mood (deepening depression, mood swings, sudden happiness), unusual thoughts (thoughts of harming self or others, bizarre thoughts, paranoia), anxiety, aggression, irritability, hostility or unusual behavior should be reported immediately to the physician.

Bipolar disorder: Venlafaxine can initiate manic episodes in bipolar disorder, and has a greater tendency toward this than other medications. Mania can be severe and can be accompanied by rapid cycling and psychosis.

High blood pressure: Venlafaxine can raise your blood pressure. Your physician may want to monitor your blood pressure, especially if you have hypertension.

Seizures: Venlafaxine can trigger seizures in people with seizure disorder.

Bleeding: Venlafaxine can cause bleeding problems, usually easy bruising. Inability to clot can also occur, as can bleeding in the stomach or gastrointestinal tract.

Venlafaxine should be used with caution in people who have a history of drug abuse, those who have had a recent heart attack, those with liver, kidney or thyroid disease and people with high cholesterol. It can cause water intoxication in some people, especially the elderly.

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