Venlafaxine

Venlafaxine (Effexor, Efexor) is an antidepressant of the serotonin-norepinephrine reuptake inhibitor (SNRI) class first introduced by Wyeth in 1993. It is prescribed for the treatment of major depression and anxiety disorders, among other uses. Due to the pronounced side effects and suspicions that venlafaxine may significantly increase the risk of suicide, it is not recommended as a first line treatment of depression. However, it is often effective for depression not responding to SSRIs. Venlafaxine was the sixth most widely-used antidepressant based on the number of retail prescriptions in the US (17.1 million) in 2006.
==Indications==
===Approved===
Venlafaxine is used primarily for the treatment of major depression, generalized anxiety disorder, social anxiety disorder, and panic disorder in adults.
====Depression====
Venlafaxine was shown to be effective for depression in multiple double blind studies. Venlafaxine is similar in efficacy to the tricyclic antidepressants amitriptyline (Elavil) and imipramine and it was better tolerated than amitriptyline. Venlafaxine appears to have efficacy similar or somewhat better than sertraline (Zoloft) and fluoxetine (Prozac) depending on the criteria and rating scales used. In particular, higher doses of venlafaxine are more effective, and more patients achieved remission or were "very much improved". At the same time the efficacy was similar if the number of patients who achieved "response" or were "improved" was considered. A meta-analysis comparing venlafaxine and combined groups of SSRI or tricyclic antidepressants indicated superiority of venlafaxine.[3] Based on the same set of criteria, venlafaxine was similar in efficacy to an atypical antidepressant bupropion (Wellbutrin); however, the remission rate was significantly lower for venlafaxine.[4] Venlafaxine was also marginally inferior in efficacy to a newer SSRI escitalopram (Lexapro) and had twice higher frequency of the side effects, in particular, nausea, ejaculation disorder, somnolence and sweating.[5] In a double-blind study, patients who did not respond to an SSRI were switched to venlafaxine or citalopram. Similar improvement was observed in both groups.[6]
A popular magazine Consumer Reports, which in 2004 had rated venlafaxine as the most effective among six commonly prescribed antidepressants,[7] no longer recommends it. Fluoxetine, citalopram and bupropion have been chosen as Consumer Reports Best Buy drugs in the updated version of their guide, based upon effectiveness, safety, side effects, and cost.[8]
===Off-label / investigational uses===
Many doctors are starting to prescribe venlafaxine "off label" for the treatment of diabetic neuropathy (in a similar manner to duloxetine) and migraine prophylaxis (in some people, however, venlafaxine can exacerbate or cause migraines). Studies have shown venlafaxine's effectiveness for these conditions.[3][4] It has also been found to reduce the severity of 'hot-flashes' in menopausal women.[5][6]
Substantial weight loss in patients with major depression, generalized anxiety disorder, and social phobia has been noted, but the manufacturer does not recommend use as an anorectic either alone or in combination with phentermine or other amphetamine-like drugs.[2] Venlafaxine hydrochloride is in the phenethylamine class of modern chemicals, which includes amphetamine, methylendioxymethamphetamine (MDMA), and methamphetamine. This chemical structure likely lends to its activating properties, however some patients find Venlafaxine highly sedating despite its more common stimulatory effects.
Venlafaxine is not approved for the treatment of depressive phases of bipolar disorder; this has some potential danger as venlafaxine can induce mania, mixed states, rapid cycling and/or psychosis in some bipolar patients, particularly if they are not also being treated with a mood stabilizer.[2] Venlafaxine is perhaps one of the most likely of all modern antidepressants to trigger manic and hypomanic states.
Due to its action on both the serotoninergic and adrenergic systems, Venlafaxine is also used as a treatment to reduce episodes of cataplexy, a form of muscle weakness, in patients with the sleep disorder narcolepsy.[7]
Venlafaxine was found in one study to be equal to Anafranil in the treatment of OCD with fewer side effects.[8]
Due to its tendency to increase blood pressure and its modulative effects on the autonomic nervous system, venlafaxine is often used to treat orthostatic intolerance and postural orthostatic tachycardia syndrome.[9]
==Footnotes==
==External links==
===Drug information===
* U.S. Food and Drug Administration information on Effexor
* Efexor patient information leaflet Efexor patient information leaflet
* Effexor XR® prescribing information for healthcare professionals (pdf) (USA only)
* Detailed Patient/Parent Information on Effexor
* List of international brand names for Venlafaxine
===Diagnostic Tools===
* The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity
===Patient experiences===
*Stutz, Bruce "Self-Nonmedication" New York Times Magazine May 6, 2007
*