Tetrabenazine

Adults: Recommended dosing for Tetrabenazine: Tetrabenazine can be taken with or without food. Individualization of dose with careful weekly titration is required. 1st week's starting dose: 12.5 mg daily. 2nd week: 25 mg (12.5 mg twice daily). Then slowly titrate at weekly intervals by 12.5 mg to a tolerated done that reduces chorea. Doses of 37.5 mg and up to 50 mg per day should be administered in three divided doses per day with a maximum recommended single dose not to exceed 25 mg. Patients requiring doses above 50 mg per day should be genotyped for the drug-metabolizing enzyme CYP2D6 to determine if the patient is a poor metabolizer or an extensive metabolizer. Maximum daily dose in poor metabolizers: 50 mg with a maximum single dose of 25 mg. Maximum daily dose in Extended and intermediate metabolizers: 100 mg with a maximum single dose of 37.5 mg. If serious adverse reactions occur, titration should be stopped and the dose should be reduced. If the adverse reactions do not resolve, consider withdrawal of Tetrabenazine. Pediatric & geriatric use: Safety and effectiveness in pediatric patients have not been established. The pharmacokinetics of Tetrabenazine and its primary metabolites have not been formally studied in geriatric subjects.