Klonopin also known as clonazepam is also a seizure medicine, also called an anti-epileptic drug. Klonopin is used to treat certain seizure disorders including absence seizures or Lennox-Gastaut syndrome in adults and children. Klonopin is also used to treat panic disorder including agoraphobia in adults. Dosage is based on your medical condition, age, and response to treatment. For children, the dose is also based on weight. Older adults usually start with a lower dose to decrease the risk of side effects. Do not increase your dose, take it more often, or take it for a longer time than directed.