Adverse events in a behavioral treatment trial in methadone maintenance

Abstract

Background/Aims Drug users in clinical trials have morbidity unrelated to the intervention being studied and little is known about rates of adverse events (AEs) from behavioral interventions. This study investigated the rate of AEs in a trial of methadone maintained patients. Methods AEs were collected weekly in methadone-maintained cocaine users participating in a randomized study of two behavioral treatments. Pre-existing morbidity were excluded. Events were assigned MedDRA codes (Medical Dictionary for Regulatory Activities) and categorized as opiate-related or not related. Incidence density ratios (IDRs) were calculated to determine the association of AE incidence with participant characteristics and intervention. Results 286 participants reported 884 AEs in 7680 person-weeks. The most common were: infections (26.8%), gastrointestinal (20.5%), musculoskeletal/connective tissue (12.3%), general disorders (10.0%), and injury, poisoning and procedural complications (7.6%). Fourteen AEs required hospitalization. 136 were likely opiate-related. AEs were more common in females (IDR=1.38, p<0.0001), Caucasians (IDR=0.73, p<0.0001), and under age 40 (IDR=0.84, p=0.0047). Incidence did not differ with treatment group, psychiatric comorbidity, or cocaine use. Conclusions AEs were common, most likely not related to methadone, and did not differ across treatment groups. Knowing the expected rate/nature of AEs in substance abuse trials may help improve AE reporting. Clinical Pharmacology & Therapeutics (2005) 77, P71–P71; doi: 10.1016/j.clpt.2004.12.164