Adherence rates during a randomized controlled trial evaluating the use of blinded acetaminophen and ibuprofen in children with asthma.

Abstract

BACKGROUND/AIMS\nWhen conducting clinical trials comparing over-the-counter (OTC) medications, the wide availability of these treatments are a potential challenge to maintaining study integrity. We seek to describe adherence to a study protocol involving widely available OTC medications.\n\n\nMETHODS\nTo prospectively evaluate associations between acetaminophen use and asthma in 300 children aged 1-5\u202fyears, we conducted a double blind, randomized, controlled trial where parents administered blinded forms of either acetaminophen or ibuprofen as needed to their children over a 48\u202fweek period. Written and verbal instructions encouraged the exclusive use of the blinded study medication and discouraged OTC use. Adherence was determined by evaluating the frequency of use of per-protocol blinded study medication compared to off-protocol use of OTC medications.\n\n\nRESULTS\n4195 doses of acetaminophen or ibuprofen were received by children during the study which included 3664 doses (87.3%) of blinded study medication adhering to the protocol and 531 doses (12.7%) of OTC products deviating from the protocol with better adherence among those randomized to ibuprofen as compared to acetaminophen (89.5% vs. 85.5% of doses, p\u202f<\u202f0.01). Individually, 227 participants (75.7%) remained fully adherent by not receiving any OTC medications. Pre-study preference for either acetaminophen or ibuprofen by the participants families was not associated with differential rates of adherence to the blinded medication.\n\n\nCONCLUSION\nThis parallel study demonstrated greater than 85% of acetaminophen or ibuprofen doses were blinded study medications adhering to the protocol while less than 15% were OTC deviations from the protocol. This successfully implemented study design provides a template to comparatively evaluate these and other OTC medications.