metyrosine /mətir″əsēn/ , an inhibitor of tyrosine hydroxylase, the rate-limiting enzyme for catecholamine synthesis. ▪ INDICATIONS: It is prescribed in the treatment of pheochromocytoma before surgery and may be used for long-term therapy if surgery is contraindicated. ▪ CONTRAINDICATIONS: Known hypersensitivity to this drug prohibits its use. ▪ ADVERSE EFFECTS: Among the more serious adverse effects are extrapyramidal reactions, including tremor and drooling. Sedation is common, and diarrhea and anxiety may occur.
