Preoperative amlodipine is efficacious in preventing intraoperative HDI in pheochromocytoma- pilot RCT.

BACKGROUND Preoperative blockade with α-blockers is recommended in patients with pheochromocytoma/paraganglioma (PPGL). The data on calcium channel blockade (CCB) in PPGL is scarce. We aimed to compare the efficacy of CCB and α-blockers on intraoperative haemodynamic 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 GITS (maximum 30mg, n=9) or amlodipine (maximum 20mg, n=11). The primary outcomes were the episodes and duration of hypertension (SBP≥160mmHg) and hypotension (MAP<60mmHg) and duration of HDI (hypertension and/or hypotension) as a percentage of total surgical time (from induction of anaesthesia to skin closure). FINDINGS The median (IQR) episodes (2 [1-3] vs. 0 [0-1], p 0·002) and duration of hypertension (19 [14-42] min vs. 0 [0-3] min, p 0·001) and intraoperative HDI duration (22·85±18.4% vs 2·44±2·4%, CI 8·68-32·14%, p 0·002) were significantly higher in the prazosin GITS arm than the amlodipine arm whereas episodes and duration of hypotension did not differ between the two groups. There was no perioperative mortality whereas one patient had intraoperative ST depression on the electrocardiogram. The drug-related adverse effects were pedal edema (1 in amlodipine), dizziness (1 in prazosin GITS), and tachycardia (6 in prazosin GITS and 3 in amlodipine). INTERPRETATION Preoperative blockade with amlodipine is an efficacious alternative to prazosin GITS in preventing intraoperative HDI in PPGL. Larger studies that compare preoperative blockade by amlodipine with other α-blockers like phenoxybenzamine and/or doxazosin in PPGL patients are warranted.