Venlafaxine (Effexor) is the first drug in the serotonin-norepinephrine reuptake inhibitors (SNRI) class. It was approved by the FDA for the treatment of depression in 1993.
At low doses, venlafaxine works as a selective serotonin reuptake inhibitor (SSRI) such as fluoxetine (Prozac). SNRIs are considered to be effective for the treatment of pain and migraine headaches. SSRIs are not. A review of studies that involved a total of 418 patients showed that SNRIs are effective for the prevention of migraines. The class of SNRIs includes duloxetine (Cymbalta), desvenlafaxine (Pristiq), milnacipran (Savella), and levomilnacipran (Fetzima). Milnacipran is the only SNRI that is approved by the FDA for the treatment of fibromyalgia rather than depression.
In treating migraines, a 60-patient trial showed that the 150 mg dose is more effective than 75 mg.
Venlafaxine is started at 37.5 or 75 mg dose. After a week or two, the dose is increased to 150 mg. The maximum daily dose of venlafaxine is 450 mg.
Potential side effects include insomnia, drowsiness, fatigue, nausea, dizziness, suicidal thoughts in depressed children and young adults, and others.
Just like with other SNRIs, sudden discontinuation of venlafaxine can cause withdrawal symptoms. These may include one or more of the following: dizziness, headache, nausea, diarrhea, paresthesia (pins-and-needles), irritability, vomiting, insomnia, anxiety, sweating, and fatigue. SNRIs are stopped after a slow and gradual reduction of the dose.
