Clonazepam

Clonazepam, sold under the brand name Klonopin among others, is a benzodiazepine medication used to prevent and treat anxiety disorders, seizures, bipolar mania, agitation associated with psychosis, obsessive–compulsive disorder (OCD), and akathisia. It is a long-acting tranquilizer of the benzodiazepine class. It possesses anxiolytic, anticonvulsant, sedative, hypnotic, and skeletal muscle relaxant properties. It is typically taken orally (swallowed by mouth) but is also used intravenously. Effects begin within one hour and last between eight and twelve hours in adults.

Common side effects may include sleepiness, weakness, poor coordination, difficulty concentrating, and agitation. Clonazepam may also decrease memory formation. Long-term use may result in tolerance, dependence, and life-threatening withdrawal symptoms if stopped abruptly. Dependence occurs in one-third of people who take benzodiazepines for longer than four weeks. The risk of suicide increases, particularly in people who are already depressed. Use during pregnancy may result in harm to the fetus. Clonazepam binds to GABA_A receptors, thus increasing the effect of the chief inhibitory neurotransmitter γ-aminobutyric acid (GABA).

Clonazepam was patented in 1960 and went on sale in 1975 in the United States from Roche. It is available as a generic medication. In 2022, it was the 57th most commonly prescribed medication in the United States, with more than 11 million prescriptions. In many areas of the world, it is commonly used as a recreational drug.