Venlafaxine

Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin-norepinephrine reuptake inhibitor (SNRI) class. It is used to treat major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder, and social phobia. It is taken by mouth. Common side effects include loss of appetite, constipation, dry mouth, dizziness, sweating, and sexual problems. Severe side effects include an increased risk of suicide, mania, and serotonin syndrome. Antidepressant withdrawal syndrome may occur if stopped. There are concerns that use during the later part of pregnancy can harm the baby. How it works is not entirely clear but it is believed to involve alterations in neurotransmitters in the brain. Venlafaxine was approved for medical use in the United States in 1993. It is available as a generic medication. In the United States the wholesale cost per dose is less than US$0.20 as of 2018. In 2016 it was the 51st most prescribed medication in the United States with more than 15 million prescriptions. Venlafaxine is used primarily for the treatment of depression, general anxiety disorder, social phobia, panic disorder, and vasomotor symptoms. Some doctors may 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, although agents that are marketed for this purpose (like pregabalin or duloxetine) are likely preferred. It has also been found to reduce the severity of 'hot flashes' in menopausal women and men on hormonal therapy for the treatment of prostate cancer. 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. Some open-label and three double-blind studies have suggested the efficacy of venlafaxine in the treatment of attention deficit-hyperactivity disorder (ADHD). Clinical trials have found possible efficacy in those with post-traumatic stress disorder (PTSD). A comparative meta-analysis of 21 major antidepressants found that venlafaxine, agomelatine, amitriptyline, escitalopram, mirtazapine, paroxetine, and vortioxetine were more effective than other antidepressants although the quality of many comparisons was assessed as low or very low. Venlafaxine was similar in efficacy to the atypical antidepressant bupropion; however, the remission rate was lower for venlafaxine. 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.