Sildenafil better than bosentan for newborns with PPHN: Study
Controlling blood pressure, reducing supplemental oxygen needs compared
Sildenafil is generally more effective than bosentan at controlling blood pressure and reducing the need for supplemental oxygen in infants with persistent pulmonary hypertension of the newborn (PPHN), a study shows.
The study, “Oral sildenafil versus bosentan for treatment of persistent pulmonary hypertension of the newborn: a randomized controlled trial,” was published in BMC Pediatrics.
PPHN is a form of pulmonary hypertension that affects babies. Before birth, the fetus gets oxygen from the mother through the umbilical cord. At birth, separating the baby from the placenta by clamping the umbilical cord requires switching to pulmonary gas exchange. But pulmonary blood flow only increases if the resistance of lung blood vessels to blood flow, called pulmonary vascular resistance, decreases rapidly.
In PPHN, the pulmonary arteries don’t open wide enough, restricting oxygen and blood flow.
The usual first-line treatment for PPHN is inhaled nitric oxide (iNO), a gas that works to relax blood vessels and reduce blood pressure. But iNO is fairly expensive and requires specialized equipment to administer, so it isn’t an option in many parts of the world.
Sildenafil and bosentan are oral therapies approved to treat pulmonary arterial hypertension. Sildenafil is approved under the names Revatio and Liqrev, whereas bosentan is sold as Tracleer and generics also are available. Both work to widen blood vessels and reduce blood pressure, albeit via different molecular mechanisms.
The better choice: sildenafil or bosentan
In resource-limited settings where other treatments aren’t available, the therapies may be used to help manage PPHN, but to see which is the better choice, scientists in India, along with collaborators in other countries, enrolled 36 babies with PPHN in a small clinical trial where half were treated with sildenafil and half with bosentan.
When the study was conducted, the researchers noted they didn’t have access to iNO in their clinic. In fact, only about 1 in 4 neonatal intensive care units in India has access to iNO, which underscores the need for more data on alternative treatments, they said.
The trial’s main goal was to compare how long it took sildenafil and bosentan to reduce pulmonary arterial systolic pressure (PASP), a measure of blood pressure in the lungs, by at least 25% within two days.
Sildenafil was significantly faster, the results showed. The infants treated with sildenafil met this treatment goal within an average of 36 hours, whereas it typically took four days on average for those on bosentan.
Patients on sildenafil also had a more notable decrease in their need for supplemental oxygen therapy after 24 hours, though the changes at 48 and 96 hours weren’t different than those with bosentan. Only three of the 18 patients given sildenafil required additional medications to control their PPHN, whereas more than half on bosentan needed additional medications to manage their condition.
Both therapies were generally well tolerated.
“We found that sildenafil was associated with a more rapid reduction of PASP and [supplemental oxygen] in neonates with PPHN, as compared to bosentan. Although both oral sildenafil and bosentan were well tolerated, the need to add other pulmonary vasodilators was more frequent in bosentan group,” wrote the scientists, who said the results should be interpreted with caution because only a few dozen patients were studied.
“Further research is needed to assess survival rates and determine long-term neurodevelopmental outcomes of neonates who have been treated with sildenafil and bosentan, as well as to evaluate their effectiveness in comparison to other pulmonary vasodilators,” they wrote.
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