A Single Dose of Sn-Mesoporphyrin Prevents Development of Severe Hyperbilirubinemia in Glucose-6-Phosphate Dehydrogenase-Deficient Newborns

Severe neonatal jaundice is a common clinical manifestation of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and the most difficult to manage; kernicterus is not an uncommon outcome. We assessed in healthy, direct Coombs test-negative Greek newborns of >/=38 weeks' gestational age 1) the current burden of G-6-PD deficiency-associated severe jaundice, and 2) the efficacy of preventive use of Sn-mesoporphyrin (SnMP), a potent inhibitor of heme oxygenase activity and thus of bilirubin production, in ameliorating jaundice in G-6-PD-deficient neonates. The studies were conducted at Metera Maternity Hospital in Athens, Greece. Enrolled newborns had the plasma bilirubin concentration (PBC) determined in cord blood and daily thereafter until a declining level was obtained and the case was closed. Intervention with phototherapy was dictated at exact, age-specific PBC levels. In our initial study, we enrolled consecutive mature healthy G-6-PD-deficient newborns as well as a threefold excess of G-6-PD-normal neonates born at approximately the same time (control group). For the SnMP trial, G-6-PD-deficient neonates were administered SnMP as a single intramuscular dose of 6 micromol/kg birth weight within 24 +/- 12 hours of age. SnMP was administered at 26.7 +/- 6.1 hours of age to 172 G-6-PD-deficient newborns (group A); 168 G-6-PD-normal (group B) and 58 G-6-PD-deficient (group C) newborns who were enrolled earlier provided the comparison groups. Except for the expected excess of males in the G-6-PD-deficient groups (A and C), there were no differences in the demographic characteristics among the 3 groups. The incremental changes in PBC from cord blood to 24 hours of age also were similar (group A: 4.13 +/- 1.32 mg/dL; group B: 4.05 +/- 1.34 mg/dL; group C: 4.39 +/- 1.07 mg/dL), but there were significant differences in the next period, 24 to 48 hours of age (group A: 0.63 +/- 1.44 mg/dL; group B: 1.69 +/- 1.5 mg/dL; group C: 2.45 +/- 1.72 mg/dL). Peak PBC was significantly different (group A: 7.81 +/- 3.04 mg/dL; group B: 8.68 +/- 3.1 mg/dL; group C: 11.24 +/- 3.76 mg/dL) as was the age at which peak PBC was recorded (group A: 56 +/- 29 hours of age; group B: 69 +/- 26 hours of age; group C: 83 +/- 29 hours of age). These differences in favor of group A were observed despite the fact that phototherapy was used in 15% of the newborns in group B and 31% of those in group C, whereas none of those treated with SnMP required phototherapy. Finally, in one female,