Metyrosinedosage

The recommended initial dosage of metyrosine capsules for adults and children 12 years of age and older is 250 mg orally four times daily. This may be increased by 250 mg to 500 mg every day to a maximum of 4 g/day in divided doses. When used for preoperative preparation, the optimally effective dosage of metyrosine capsules should be given for at least five to seven days. Optimally effective dosages of metyrosine capsules usually are between 2 g/day and 3 g/day, and the dose should be titrated by monitoring clinical symptoms and catecholamine excretion. In patients who are hypertensive, dosage should be titrated to achieve normalization of blood pressure and control of clinical symptoms. In patients who are usually normotensive, dosage should be titrated to the amount that will reduce urinary metanephrines and/or vanillylmandelic acid by 50% or more. If patients are not adequately controlled by the use of metyrosine capsules, an alpha-adrenergic blocking agent (phenoxybenzamine) should be added. Use of metyrosine capsules in children under 12 years of age has been limited and a dosage schedule for this age group cannot be given.