Association between oral sildenafil dosing, predicted exposure, and systemic hypotension in hospitalised infants.

Abstract

The relationship between sildenafil dosing, exposure, and systemic hypotension in infants is incompletely understood. The aim of this study was to characterise the relationship between predicted sildenafil exposure and hypotension in hospitalised infants. We extracted information on sildenafil dosing and clinical characteristics from electronic health records of 348 neonatal ICUs from 1997 to 2013, and we predicted drug exposure using a population pharmacokinetic model. We identified 232 infants receiving sildenafil at a median dose of 3.2 mg/kg/day (2.0, 6.0). The median steady-state area under the concentration-time curve over 24 hours (AUC24,SS) and maximum concentration of sildenafil (Cmax,SS,SIL) were 712 ng×hour/ml (401, 1561) and 129 ng/ml (69, 293), respectively. Systemic hypotension occurred in 9% of the cohort. In multivariable analysis, neither dosing nor exposure were associated with systemic hypotension: odds ratio=0.96 (95% confidence interval: 0.81, 1.14) for sildenafil dose; 0.87 (0.59, 1.28) for AUC24,SS; 1.19 (0.78, 1.82) for Cmax,SS,SIL. We found no association between sildenafil dosing or exposure with systemic hypotension. Continued assessment of sildenafil's safety profile in infants is warranted.