Cannabis Patients on Opioid Substitution Therapy Face Significant Drug Interaction Risks

89.4% of inpatients with CUD were taking at least one potentially interacting drug. Levomethadone, buprenorphine, and morphine were the most common drugs involved in potentially serious cannabis-drug interactions. 196 drug-drug interactions were also identified, with 25.5% classified as 'avoid combination' and 74.5% as 'consider therapy modification.'

Retrospective analysis of medication charts from 301 inpatient cases with cannabis use disorder on an addiction-specific ward over six years. Cannabis-drug interactions screened via drugs.com classification; drug-drug interactions via UpToDate Lexicomp.

Patients with cannabis use disorder frequently take medications that interact with cannabinoids, especially opioid substitution therapies. The finding that nearly 9 in 10 patients had at least one potential interaction underscores the need for routine interaction screening in addiction treatment settings.

Cannabis is often treated as a low-risk substance, but its metabolic interactions with other drugs are real and underappreciated. In addiction medicine, where patients are often on multiple psychoactive medications, systematic interaction checking should be standard practice, not an afterthought.

Retrospective design using a single addiction ward in Germany. Potential interactions identified by databases may not all be clinically significant. Could not assess whether identified interactions actually caused adverse events. Population was predominantly male, limiting generalizability.