Sustained High Blood Pressure with Antidepressant Venlafaxine Extended Release (EFFEXOR XR)

The Food and Drug Administration (FDA) has updated the professional product label for the antidepressant venlafaxine extended-release capsules (EFFEXOR XR) to warn about prolonged periods of high blood pressure in patients using the drug to treat panic disorder. Venlafaxine is manufactured by Wyeth, Inc. The drug accounted for almost 18 million prescriptions in 2004. 

The Warnings Section in the professional product label for the drug now states that in pre-approval clinical trials in patients with panic disorder, 0.9 percent (9/973) of patients taking between 75 milligrams and 225 milligrams per day of venlafaxine experienced sustained episodes of high blood pressure.

Venlafaxine is also FDA approved to treat generalized anxiety disorder, major depressive disorder, and social anxiety disorder. Sustained major episodes of high blood pressure have also been seen when the drug is used to treat these conditions.

Sustained increases in blood pressure could have adverse consequences for patients. The professional product label for extended-release venlafaxine recommends that patients taking the drug have regular blood pressure monitoring. For those patients who do experience a sustained increase in blood pressure while taking the drug, either a dose reduction or discontinuation of the drug should be considered.

Venlafaxine must not be stopped suddenly. Abrupt discontinuation or dose reduction of venlafaxine has been found to be associated with the appearance of new symptoms. The frequency with which these problems occur is related to the dose level and the length of treatment, meaning that those who have taken larger doses and those who have used venlafaxine for a longer period of time are more likely to suffer the adverse effects of withdrawal.

The reported symptoms of withdrawal include agitation, loss of appetite, anxiety, confusion, impaired coordination, diarrhea, dizziness, dry mouth, a feeling of being unwell or unhappy, muscular twitching, fatigue, headaches, mild mania, insomnia, nausea, nervousness, nightmares, sensory disturbances including shock-like electrical sensations, drowsiness, sweating, tremor, vertigo, and vomiting.

Even though the percentage of patients taking extended-release venlafaxine who develop episodes of high blood pressure is small – presumably around  0.9 percent – the 18 million prescriptions dispensed in 2004 translates into thousands of patients experiencing drug-induced high blood pressure.

What You Can Do

DO NOT stop taking venlafaxine without first talking with the healthcare provider who prescribed the drug.

Your blood pressure should be checked regularly if you are taking venlafaxine.

If you are taking venlafaxine and experience an episode of increased blood pressure you should talk to the prescribing healthcare provider about lowering the dose or stopping the drug.