Risk of Opioid Overdose Associated with Concomitant Use of Methadone and Statins.

Methadone has a high potential for risky drug-drug interactions that can lead to opioid overdose, yet evidence on the magnitude of this risk remains limited. Since methadone is transported via P-glycoprotein (P-gp), the use of statins that inhibit P-gp may elevate methadone plasma concentrations, potentially leading to opioid overdose. We explored this hypothesis by examining whether concomitant use of methadone and P-gp-inhibiting statins was associated with opioid overdose. Using Medicaid claims data from 2003 to 2020, we conducted a cohort study among new concomitant users of methadone and statins. We compared overdose rates among individuals exposed to P-gp-inhibiting statins (simvastatin, atorvastatin, or lovastatin) vs. those exposed to rosuvastatin (negative control), adjusting for baseline covariates. We identified 69,263 individuals newly exposed to methadone and a statin of interest; the overall incidence rate of opioid overdose was 26.0 per 1,000 person-years. Adjusted hazard ratios (HRs) for methadone + P-gp-inhibiting statins consistently showed no association, ranging from 0.76 (95% CI = 0.48-1.22) for atorvastatin to 0.78 (95% CI = 0.50-1.22) for simvastatin, compared with methadone + rosuvastatin. Similar results were observed in sensitivity analysis that treated all P-gp-inhibiting statins as a single exposure group, as well as analyses stratified by baseline diagnosis of opioid use disorder or overdose, the duration of baseline methadone use, and calendar year intervals. Our findings suggest that concomitant use of methadone with simvastatin, atorvastatin, or lovastatin is not associated with the risk of opioid overdose compared to concomitant use of methadone and rosuvastatin.