Efavirenz as a psychotropic drug.
Antiretroviral drugs are the mainstay of treatment for human immunodeficiency virus (HIV) infection. Lifelong highly active antiretroviral therapy (HAART) is indicated to prevent disease progression to acquired immunodeficiency syndrome (AIDS). Efavirenz was a first-line component of HAART across the world for many years. The purpose of this article is to review the psychotropic properties of efavirenz, which are the most important adverse events associated with the drug and commonly result in treatment discontinuation. A PubMed search was conducted using efavirenz as a search term, which returned 4655 results. Titles and abstracts of articles were screened for relevance, and all relevant articles published in English were included in the narrative review. Acute exposure to efavirenz may cause profound perceptual disturbances (delusions and hallucinations) whereas chronic exposure may be associated with abnormal dreams and other sleep disturbances, anxiety, depressed mood and suicidality. It may also be abused as a hallucinogen, especially in individuals with a history of poly-substance abuse. Recent research indicates that efavirenz directly affects monoaminergic neurotransmission and may partially substitute for psychedelic drugs, such as lysergic acid diethylamide (LSD). Efavirenz acts as a serotonin 5-HT2A receptor antagonist, a serotonin-dopamine reuptake inhibitor, an inhibitor of monoamine oxidase (MAO) and a vesicular monoamine transporter 2 (VMAT2) inhibitor, which are mechanisms common with many psychotropic drugs. Efavirenz interacts with many of the same molecular targets as the empathogen methylendioxymethamphetamine (MDMA), but the effects of the 2 drugs may differ. The exact mechanism of action of efavirenz as a psychotropic drug remains unclear and future studies should focus on evaluating whether prolonged exposure could lead to irreversible side effects.