Effexor, generally prescribed as the generic venlafaxine, received FDA approval as a novel treatment for major depression, generalized anxiety disorder and panic. It now finds off label application as treatment for diabetic neuropathy and other pain syndromes, PTSD, menopausal hot flashes and prevention of migraine headache.
Effexor both structurally and pharmaceutically appears related to tramadol. It lacks any chemical connection to the common antidepressant families - SSRI, TCA, MAO inhibitors. It functions as a serotonin and norepinephrine receptor inhibitor. Due to its side effect profile, venlafaxine was originally considered a second line treatment. As a result of extensive direct-to-consumer advertising it seems to have gained traction as a first line therapy.
All marketed antidepressants provide about the same degree of success but some individuals respond more favorably to one drug when compared to another. Effexor ranks near the top of the list of poorly tolerated drugs with more frequent discontinuations than with many other equally effective antidepressants.
Therapy begins with a relatively low dose with increases no more quickly than every 4 days. An immediate release form requires 2 or 3 doses each day while only 1 pill a day suffices with the extended release version. As with most antidepressants the full effect may be delayed for several weeks or months.
Common side effects include loss of appetite, vomiting, constipation, dry mouth, dizziness and sexual problems. Of more importance are the possibility of lung disease resulting in progressive shortness of breath. Significant weight loss and sustained elevation of the blood pressure may also occur.
Attempting to halt therapy may be met with the discontinuation syndrome in up to 20% of individuals. Symptoms often appear worse than those associated with other antidepressants possibly due to the relatively short half life of the drug. Manifestations may be misinterpreted as a flare of depression. Common complaints include agitation, anxiety, confusion, impaired concentration and balance, diarrhea and dry mouth. Other problems include nightmares, excessive perspiration, tremors, dizziness and electric shock like sensations.
The serotonin syndrome might result when co-prescribing Effexor with MAO inhibitors or serotonin reuptake inhibitors, lithium, tramadol, fentanyl or St. John’s wort. Symptoms include agitation, labile blood pressure, elevated body temperature, fast heart rate, incoordination, hallucinations and coma.
As an example of the wackiness of drug pricing, the cost for a month of therapy with the generic extended release venlafaxine with a free coupon from goodrx.com ranges between $6-$35. The same dose and quantity of name brand Effexor XR with the coupon sells for about $500. Go figure.