Medical outcomes associated with nonmedical use of methadone and buprenorphine

Background: There exists a significant amount of misinformation regarding methadone and buprenorphine, and a belief that toxicity associated with nonmedical use of methadone and nonmedical use of buprenorphine is similar in severity and outcomes. Objective: The objective of this study is to compare outcomes associated with nonmedical use of methadone vs. nonmedical use of buprenorphine in patients presenting to the Emergency Department (ED) and reported to poison centers. Methods: This was a retrospective cohort study using data from the American Association of Poison Control Centers from January 1, 2003 to December 31, 2009 (7 years). Inclusion criteria were nonmedical use of methadone or buprenorphine (or buprenorphine/naloxone) as a single substance by history, age 18 years or older, ingestions only, evaluated in an ED. Outcome measures were clinical effects, treatments, disposition, and final medical outcomes. Results: Of 1,920 cases, 1,594 were in the methadone group and 326 were in the buprenorphine group. Frequently reported clinical effects were lethargy, 59.2% vs. 29.4%, and respiratory depression, 28.7% vs. 2.5%, for methadone and buprenorphine groups, respectively. Hospitalization rates were 67.4% in the methadone group and 32.2% in the buprenorphine group. Half of all patients in the methadone group were admitted to the intensive care unit (ICU) vs. only 15% of all the patients in the buprenorphine group. Twenty-six patients in the methadone group died vs. no deaths in the buprenorphine group. There were significant differences in the distribution of clinical effects, disposition, and medical outcomes (p < 0.001). Conclusions: Patients who use methadone nonmedically have higher hospitalization rates, greater ICU utilization rates, and considerably worse medical outcomes when compared with patients who use buprenorphine nonmedically.