Novel Implementation of Genotype‐Guided Proton Pump Inhibitor Medication Therapy in Children: A Pilot, Randomized, Multisite Pragmatic Trial

: The efficacy of proton pump inhibitor (PPI) medications is highly dependent on plasma concentrations, which varies considerably due to cytochrome P450 (CYP2C19) genetic variation. We conducted a pragmatic, pilot study of CYP2C19 genotype-guided pediatric dosing of PPI medications. Children aged 5-17 years old with gastric-acid-related conditions were randomized to receive either conventional dosing of a PPI or genotype-guided dosing for a total of 12 weeks. Sixty children (30 in each arm) were enrolled and had comparable baseline characteristics. The mean daily omeprazole equivalent dose prescribed to participants across metabolizer phenotype groups was significantly different in the genotype-guided dosing arm (P < 0.001), but not in the conventional dosing arm. Prescribers waited for the genotype result before prescribing the PPI medication for 90% of the participants in the genotype-guided dosing arm. The number of participants who reported an infection was marginally lower in genotype-guided dosing vs. conventional dosing (20% vs. 44%; P = 0.07). Sinonasal symptoms were higher in the conventional dosing arm as compared with genotype-guided dosing arm: (2.6 (2.0, 3.4) vs. 1.8 (1.0, 2.3), P = 0.031). CYP2C19 genotype-guided PPI therapy is feasible in a clinical pediatric setting, well accepted by providers, resulted in differential PPI dosing, and may reduce PPI-associated infections. A future large scale randomized clinical trial of CYP2C19 genotype-guided pediatric dosing of PPI medications in children is warranted.