Context: Preoperative blockade with α-blockers is recommended in patients with pheochromocytoma/paraganglioma (PPGL). The data on calcium channel blockade (CCB) in PPGL are scarce. Objective: We aimed to compare the efficacy of CCB and α-blockers on intraoperative hemodynamic instability (HDI) in PPGL.

Methods: In the interim analysis of this monocentric, pilot, open-label, randomized controlled trial, patients with solitary, secretory, and nonmetastatic PPGL were randomized to oral prazosin gastrointestinal therapeutic system (GITS) (maximum 30 mg, n = 9) or amlodipine (maximum 20 mg, n = 11). The primary outcomes were the episodes and duration of hypertension (systolic blood pressure ≥ 160 mmHg) and hypotension (mean arterial pressure < 60 mmHg) and duration of HDI (hypertension and/or hypotension) as a percentage of total surgical time (from induction of anesthesia to skin…