Children with the CYP2C19 Poor Metabolizer Phenotype have worse asthma control after six months of lansoprazole treatment, according to a study published online April 6 in the Annals of the American Thoracic Society.

Lansoprazole is used to treat stomach and intestinal ulcers, gastroesophageal reflux disease (GERD), and erosive esophagitis.

Researchers from Nemours Children’s Hospital in Orlando, Fla, examined how metabolizer phenotype, based on genetic analysis of CYP2C19, affects asthma control. The Asthma Control Questionnaire was used to assess asthma control for a six-month clinical trial of lansoprazole in children with asthma. Participants were classified as placebo-treated; lansoprazole-treated extensive metabolizers; and lansoprazole-treated poor metabolizers.