Sildenafil treatment for pulmonary hypertension: IV initiation and conversion to oral

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Pulmonary hypertension is a condition in which blood pressure in the pulmonary circulation is too high, increasing the work the heart needs to do in order to pump blood to the lungs. While underlying causes should be treated wherever possible, it is often helpful to lower pulmonary blood pressures using medications; usually, this is relatively short term, but can be longer term in some patients.

Sildenafil is a phosphodiesterase inhibitor which promotes vasodilation by prolonging the half-life of cyclic guanosine monophosphate (GMP). While sildenafil is available orally, in some very unwell patients it may be initiated intravenously at first, until they are well enough to switch to enteral administration.

The following case considers the treatment of a 2.7 kg child admitted with persistent pulmonary hypertension of the newborn (PPHN). Parenteral sildenafil is administered by continuous intravenous infusion following an initial short infused loading dose. The overall regime is a loading dose of 400 micrograms/kg administered over 3 hours, then a continuous infusion thereafter of 1.6 mg/kg/day (Steinhorn, 2009; Chetan, 2022).