Clonazepam is a benzodiazepine drug having anxiolytic, anticonvulsant, muscle relaxant, and hypnotic properties. It is marketed by Roche under the trade name Klonopin in the United States and Rivotril in Argentina, Australia, Brazil, Canada, Mexico and Europe. Other names such as Ravotril, Rivatril, Clonex, Paxam, or Kriadex are known throughout the rest of the world.^{[citation needed]} Clonazepam has an unusually long elimination half-life of 18–50 hours, making it generally considered to be among the long-acting benzodiazepines. Clonazepam is a chlorinated derivative of nitrazepam and therefore a chloro-nitrobenzodiazepine.

Clonazepam has a slow onset with a peak four hours after ingestion. It has high effectiveness rate and low toxicity in overdose but, as most medications, it may have drawbacks due to adverse reactions including paradoxical effects and drowsiness. Other long-term effects of benzodiazepines include tolerance, benzodiazepine dependence, and benzodiazepine withdrawal syndrome, which occurs in a third of people treated with clonazepam for longer than four weeks. Clonazepam is classified as a high potency benzodiazepine.