Klonopin has a half-life of 18 to 50 hours, according to Drugs.com. This means that the Klonopin level in the body reduces by half every 18 to 50 hours after the last dose. This, however, is impacted by a few factors such as the metabolic rate of the user.
A person taking 1 milligram of Klonopin would have 0.05 milligrams in his system 18 to 50 hours after the last dose. Klonopin is a benzodiazepine, and it is prescribed for anxiety, seizure disorders and panic attacks, reports Drugs.com. Klonopin is highly addictive and can be deadly if stopped without medical advice. Signs of an overdose are extreme drowsiness, confusion, muscle weakness and fainting.