Single-dose intraoperative methadone and QTc interval: a prospective observational cohort investigation.

Patients were 59 (median; range 18-86) yr of age, and received methadone (n=282, median 20 mg, IQR [15-20], range 10-60 mg) or no methadone (n=265, typically fentanyl, 250 μg [100, 350], 0-750 μg).

Secondary outcomes with methadone vs no methadone found that any QTcF>500 ms occurred less (3.5% vs 8.3%, RR 0.43); ΔQTcF>60 ms occurred less (4.6% vs 12.1%, RR 0.39); maximum ΔQTcF was less (28 ms vs 37 ms); and sex-specific thresholds were exceeded less (22.3% vs 33.6%) (all P<0.03).

There was no correlation between methadone dose and QTcF or ΔQTcF.