Although selective serotonin reuptake inhibitors (SSRIs) such as Prozac are a common treatment for depression, not every patient finds relief with them. Often people who don’t respond to these medications can be helped with another class of drugs called serotonin-norepinephrine reuptake inhibitors (SNRIs), such as Effexor.

Prescribed for major depression and anxiety disorders, Effexor, whose generic form is venlafaxine, was first released in 1993. Because of significant side effects and suspicions that the drug may increase the risk of suicide, however, it is not recommended as a first-line treatment. It is currently available in standard and extended-release capsule formulas.

Like other SNRIs, Effexor works by blocking the transporter proteins that are supposed to take serotonin and norepinephrine—key neurotransmitters that affect mood—out of the brain and back to their storage vesicles. Because these drugs have also been shown to increase the availability of dopamine, they are sometimes called serotonin-norepinephrine-dopamine reuptake inhibitors.

It usually takes about 3 to 4 weeks for a patient to feel the effects of Effexor and other SNRIs. The half-life of Effexor is relatively short, so patients are advised to adhere to a strict medication routine, taking usually two or three pills a day; missing even one dose can result in withdrawal symptoms. Side effects of Effexor can include high blood pressure, increased heart rate, and increased eye pressure. In addition, patients can develop a potentially fatal syndrome if they take Effexor around the same time they’ve taken other medications or substances that affect serotonin—migraine drugs, other antidepressants, or St. John’s wort, for example. Patients should not begin taking Effexor within 14 days of stopping treatment with any drug known as an MAO—or monoamine oxidase—inhibitor.

Effexor is in the phenethylamine class of chemicals, which includes amphetamine and methamphetamine. It can have stimulatory effects and can cause weight loss in patients with depression and anxiety disorder. Other patients find Effexor highly sedating.

ADDITIONAL FACTS

  1. Effexor is often prescribed off-label—for uses that have not been specifically approved by the Food and Drug Administration—to treat a wide variety of other conditions, including migraines, muscle weakness in narcoleptics, and hot flashes.
  2. At dosages higher than the recommended maximum of 375 milligrams per day, venlafaxine has been shown to cause memory loss.
  3. Effexor is perhaps one of the most likely antidepressants to trigger manic states—which include feelings of euphoria and risky behavior—in patients with undiagnosed bipolar disorder.