Preoperative Amlodipine Is Efficacious in Preventing Intraoperative HDI in Pheochromocytoma: Pilot RCT

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 closure). Results The median (IQR) episodes (2 [1-3] vs 0 [0-1]; P = 0.002) and duration of hypertension (19 [14-42] vs 0 [0-3] minutes; 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 2 groups. There was no perioperative mortality. 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). Conclusion 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.