Impact of Nonselective and Selective α−1 Adrenergic Blockers on the Sedative Efficacy of Dexmedetomidine in Urologic Surgery: A Prospective, Observational Study

BACKGROUND: This study aimed to compare the impact of α−1 adrenergic blockers – nonselective (alfuzosin, doxazosin, and terazosin) and selective (silodosin and tamsulosin) – on the sedative effects of the α−2 adrenergic agonist dexmedetomidine (DMT) in patients undergoing urologic surgery. The primary outcome was the sedative effect of DMT as determined by the bispectral index (BIS) and Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale scores. MATERIAL/METHODS: One hundred eighteen patients undergoing elective urologic surgery with spinal anesthesia were recruited. Patients were assigned based on their medication status to group N (no medication; n=33), group NS (nonselective α−1 blocker; n=27), or group S (selective α−1 blocker; n=58). Mean blood pressure (MBP), heart rate (HR), oxygen saturation (SpO(2)), BIS, and MOAA/S scale scores were recorded at 5-minute (min) intervals after DMT administration. RESULTS: Group NS had significantly higher BIS scores than groups N and S at 25 min (P=0.045) and 30 min (P=0.030) after DMT administration, indicating lower sedation levels. MBP significantly differed between the 3 groups at all time points, with group N experiencing a lower MBP than groups NS and S. No significant differences were found between the groups in MOAA/S scale scores, SpO(2), or HR. CONCLUSIONS: Nonselective α−1 adrenergic blockers can reduce the sedative effects of DMT. Consequently, there may be a need for individualized anesthesia management considering the specific subtype of α−1 adrenergic blocker medication.