Pharmacology Review

Abstract

Competitive inhibitors of heme oxygenase (HO) have been studied as interventional agents for neonatal hyperbilirubinemia. Several naturally occurring and synthetic metalloporphyrins have been shown to be potent inhibitors of HO activity and effective in reducing bilirubin concentrations in vitro and in vivo. Targeting HO may aid in preventing hyperbilirubinemia in newborns. Tin mesoporphyrin (SnMP) has emerged as a potential agent for reducing total bilirubin concentrations in preterm newborns. Adverse effects associated with SnMP use include photosensitization (which complicates its use in conjunction with phototherapy), and potential inhibition of several other enzymes that have essential roles in metabolism. Clinical studies of SnMP have shown that it prevents excessive neonatal hyperbilirubinemia and reduces the need for neonatal phototherapy in term and near-term infants. Because further research, specifically safety investigations, are complicated, use of SnMP should be reserved for neonates who are at especially high risk for developing bilirubin-induced neurologic dysfunction or participating in clinical trials.