Off-label morphine sulfate as alternative to OSTs ups risks of death, overdose in OUD patients

Initiation of off-label morphine sulfate (MS) for nonchronic pain in patients with opioid use disorder (OUD) instead of conventional opioid substation treatments (OSTs) is associated with higher overdose, death, bacterial infection, abuse, and diversion risks, according to a study.

The authors compared the incidence of unintentional opioid-related overdose in the year following the prescription initiation in off-label MS users versus OST-maintained patients. Using the French nationwide healthcare data system, they retrospectively identified sequential cohorts of OUD patients on regularly dispensed MS, buprenorphine, or methadone between 1 April 2012 and 31 December 2014.

Cox regression method was used to compare the incidence of overdoses, deaths, doctor shopping, and complications of a viral, bacterial, or thrombotic nature.

In total, 1,075 OUD patients without chronic pain were included in the MS cohort, 20,834 in the buprenorphine cohort, and 9,778 in the methadone cohort. Overdose incidence in the MS cohort was 3.8 (95 percent confidence interval [CI], 2.1–6.8; p<0.01) higher than buprenorphine and 2.0 (95 percent CI, 1.1–3.6; p=0.02) higher versus methadone.

Death incidence was also higher in the MS cohort by 9.1 (95 percent CI, 3.2–25.9; p<0.01) compared to buprenorphine and by 3.9 (95 percent CI, 1.4–10.7) versus methadone. Incidences of other associated risks were also significantly higher in the MS group compared to OSTs, except for hepatitis C viral infection and thrombotic complications.

“These results question the relevance of prescribing MS as a safe opioid maintenance treatment, considering its health risk profile,” the authors said.