A recent study depicted that in infants with GERD due to congenital malformations such as EA or CDH, single rectal omeprazole (proton pump inhibitor) dose (1 mg/kg) results in consistent increases in intraesophageal and gastric pH similar to an oral dose. A rapid exposure in the therapeutic range is attained with a 1 mg/kg rectally-administered omeprazole dose.

For infants with pathological GERD, rectally administered omeprazole presents as an innovative, potent alternative, considering the challenges with existing oral formulations. In the Netherlands, an open-label randomized pilot study was carried out to investigate the efficacy and pharmacokinetics of rectal omeprazole in infants (6–12 weeks postnatal and bodyweight >3 kg) with EA or CDH-related GERD and compare these with oral omeprazole.

The study recruited 17 infants (13 with CDH and 4 with EA). Infants were randomly assigned to  receive a 1 mg/kg omeprazole dose rectally or orally. Based on the predefined criteria for 24-h intraesophageal pH, the percentage of infants for whom omeprazole was effective was the primary endpoint ascertained. The pharmacokinetic parameters, and the percentages of time that gastric pH was <3 or <4 were the secondary endpoints ascertained.

Rectally-administered omeprazole was found to be effective in higher infants compared to orally-administered omeprazole, as depicted in the following table:

After both rectal and oral omeprazole administration, the total reflux time in minutes and percentages and the number of reflux episodes of pH<4 remarkably declined, as shown in the following table:

Both oral and rectal omeprazole administration resulted in similar serum exposure. During the study, no study-specific adverse events were witnessed.  Thus, in infants with GERD due to congenital malformations such as EA or CDH, rectally-administered omeprazole appears to yield satisfactory results.