Pretreatment with phenoxybenzamine improves short-term survival and hemodynamic stability in dogs undergoing adrenalectomy for pheochromocytoma.

Phenoxybenzamine pretreatment significantly improves 14-day survival and reduces hemodynamic instability in dogs undergoing adrenalectomy for pheochromocytoma.

This retrospective study evaluated the effects of phenoxybenzamine (PBZ) pretreatment on hemodynamic instability (HDI) and short-term survival in dogs undergoing adrenalectomy for pheochromocytoma at a single institution between 1996 and 2024. Fifty-two dogs met inclusion criteria and were divided into two groups: 35 dogs that did not receive PBZ (NPBZ group) and 17 dogs that received PBZ pretreatment (PBZ group). The mean PBZ dosage was 1.1 mg/kg/day administered for a mean of 13.4 days prior to surgery. The study also assessed appropriate indices of HDI for this population, suggesting that systolic arterial pressure exceeding 200 mmHg is a more clinically relevant threshold in dogs with pheochromocytoma compared to previously used criteria. Among dogs requiring cavotomy, 6 of 22 in the NPBZ group experienced HDI versus 0 of 17 in the PBZ group, demonstrating a clear protective effect. Most notably, the 14-day survival rate was significantly higher in the PBZ group (94.1%) compared to the NPBZ group (62.9%). These findings support the use of PBZ as a preoperative pharmacologic strategy to reduce intraoperative catecholamine-mediated hemodynamic crises. Limitations include the retrospective design, single-institution data, and relatively small sample size. Nevertheless, the study provides meaningful clinical evidence supporting routine PBZ pretreatment prior to adrenalectomy in dogs diagnosed with pheochromocytoma to improve perioperative hemodynamic stability and short-term survival outcomes.

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