[Alpha-methyl-paratyrosine in the treatment of malignant pheochromocytoma]

Alpha-methyl-paratyrosine (Demser) is a specific inhibitor of tyrosine hydroxylation to dopa. It is administered orally and may be given in combination with symptomatic treatments to reduce the hypersecretion of catecholamines. We report two cases of malignant phaeochromocytoma in which this drug was used. A pharmacological study of the compound is presented, and the literature on its long-term use in the treatment of malignant phaeochromocytoma is reviewed. In our second patient, who received alpha-methyl-paratyrosine for 9 months, a study of changes in differential catecholamine excretion showed that the urinary catecholamines were redistributed, with an increase in the dopamine/norepinephrine ratio. An HPLC study of urinary excretion of catecholamines demonstrated that their levels cannot be significantly increased by excretion of alpha-methyl-paratyrosine or its metabolites.