Venlafaxine

Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin–norepinephrine reuptake inhibitor (SNRI) class.^[5][9] It is used to treat major depressive disorder, generalized anxiety disorder, panic disorder, and social anxiety disorder.^[9] Studies have shown that venlafaxine improves post-traumatic stress disorder (PTSD) as a recommended first-line treatment.^[10] It may also be used for chronic neuropathic pain.^[11] It is taken orally (swallowed by mouth).^[9] It is also available as the salt venlafaxine besylate (venlafaxine benzenesulfonate monohydrate) in an extended-release formulation (Venbysi XR).^[6]

Common side effects include loss of appetite, constipation, dry mouth, dizziness, sweating, insomnia, drowsiness and sexual problems.^[9] Severe side effects include an increased risk of suicide, mania, and serotonin syndrome.^[9] Antidepressant withdrawal syndrome may occur if stopped.^[9] A meta-analysis of randomized trials in depression found an increased rate of serious adverse events, particularly sexual dysfunction and anorexia, and several non-serious adverse effects, including nervousness, asthenia, and tremor.^[12] There are concerns that use during the later part of pregnancy can harm the baby.^[9] Venlafaxine's mechanism of action is not entirely clear, but it seems to be related to the potentiation of the activity of some neurotransmitters in the brain.^[9]

Venlafaxine was approved for medical use in the United States in 1993.^[9] It is available as a generic medication.^[9] In 2022, it was the 44th most commonly prescribed medication in the United States, with more than 13 million prescriptions.^[13][14]