The drug of first choice to treat myoclonus, especially certain types of action myoclonus, is clonazepam, a type of tranquilizer. Dosages of clonazepam usually are increased gradually until the patient improves or side effects become harmful. Drowsiness and loss of coordination are common side effects. The beneficial effects of clonazepam may diminish over time if the patient develops a tolerance for the drug. Many of the drugs used for myoclonus, such as barbiturates, phenytoin, and primidone, are also used to treat epilepsy.
Barbiturates slow down the central nervous system and cause tranquilizing or antiseizure effects.
Sodium valproate is an alternative therapy for myoclonus and can be used either alone or in combination with clonazepam. However, other studies indicate that 5-HTP therapy is not effective in all people with myoclonus, and, in fact, may worsen the condition in some patients. These differences in the effect of 5-HTP on patients with myoclonus have not yet been explained, but they may offer important clues to underlying abnormalities in serotonin receptors. The complex origins of myoclonus may require the use of multiple drugs for effective treatment. Although some drugs have a limited effect when used individually, they may have a greater effect when used with drugs that act on different pathways or mechanisms in the brain.