The Use of Metyrosine in the Treatment of Pheochromocytoma and Paraganglioma Patients: A Review of the Literature

Metyrosine (α-methyl-parathyrosine) functions as an inhibitor of tyrosine hydroxylase, thereby impeding the conversion of tyrosine to 3,4-dihydroxyphenylalanine. This reaction represents the rate-limiting step in the synthesis of catecholamines. This review examines the mechanisms of metyrosine action and its application for treatment purposes. The published literature was collated from a range of scientific databases, including PubMed, SciFinder, ScienceDirect, Wiley Online Library, Google Scholar and Web of Science. The use of metyrosine has been demonstrated to reduce catecholamine biosynthesis in patients with catecholamine-secreting pheochromocytoma and paraganglioma. The safety and efficacy of metyrosine in the treatment of pheochromocytoma and paraganglioma is substantiated by empirical evidence from studies demonstrating its general tolerability and clinical practice use. Metyrosine has been shown to potentially mitigate the occurrence of surgical complications by enhancing intraoperative hemodynamics. Studies have demonstrated that the administration of metyrosine prior to pheochromocytoma and paraganglioma surgery reduces the risk of hypertensive crisis and severe hypertension, as well as intraoperative haemodynamic variability. It is imperative that further research is conducted to elucidate the pharmacokinetics, intricate molecular mechanisms, and safety profile of methyrone. To this end, the utilization of meticulously designed randomized clinical trials is crucial.