Efficacy and safety of metyrosine in pheochromocytoma/paraganglioma: A multi-center trial in Japan

Mitsuhide Naruse, Fumitoshi Satoh, Akiyo Tanabe, Takahiro Okamoto, Atsuhiro Ichihara, Mika Tsuiki, Takuyuki Katabami, Masatoshi Nomura, Tomoaki Tanaka, Tadashi Matsuda, Tsuneo Imai, Masanobu Yamada, Tomohiro Harada, Nobuyuki Kawata, Kazuhiro Takekoshi

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


To assess the efficacy, safety, and pharmacokinetics of metyrosine (an inhibitor of catecholamine synthesis) in patients with pheochromocytoma/paraganglioma (PPGL), we conducted a prospective, multi-center, open-label study at 11 sites in Japan. We recruited PPGL patients aged ≥12 years requiring preoperative or chronic treatment, receiving α-blocker treatment, having baseline urinary metanephrine (uMN) or normetanephrine (uNMN) levels ≥3 times the upper limit of normal values, and having symptoms associated with excess catecholamine. Metyrosine treatment was started at 500 mg/day and modified according to dose-adjustment criteria up to 4,000 mg/day. The main outcome measure was the proportion of patients who achieved at least 50% reduction in uMN or uNMN levels from baseline. Sixteen patients (11 males/5 females) aged 12–86 years participated. After 12 weeks of treatment and at the last evaluation of efficacy, the primary endpoint was achieved in 31.3% of all patients, including 66.7% of those under preoperative treatment and 23.1% of those under chronic treatment. Sedation, anemia, and death were reported in 1 patient each as serious adverse drug reactions during the 24-week treatment. Metyrosine was shown to be tolerated and to relieve symptoms by reducing excess catecholamine in PPGL patients under both preoperative and chronic treatment.

Original languageEnglish
Pages (from-to)359-371
Number of pages13
Journalendocrine journal
Issue number3
Publication statusPublished - 2018


  • Catecholamines
  • Metyrosine
  • Multi-center clinical trial
  • Paraganglioma
  • Pheochromocytoma

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology


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