Patients who use of multiple pharmacies concurrently (pharmacy shopping) and have overlapping prescriptions for opioid medications have a greater risk of opioid overdose events, according to a study in The Journal of Pain.

Researchers reviewed data on 90,010 Medicaid enrollees aged 18–64 who used ≥3 opioid prescriptions for ≥90 days from 2008–2010 to develop a threshold number of pharmacies or a specified length of time to define pharmacy-shopping behavior and identify at-risk patients. Within a 90-day interval, a threshold of four pharmacies had the greatest diagnostic odds ratios for opioid overdose events and was used to define pharmacy shopping.

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The patients with overlapping prescriptions had a higher overdose rate compared to those who participated in pharmacy shopping (18.5 per 1,000 person-years [PYs]) vs. 10.7 per 1,000 PYs). For those with both overlapping prescriptions and pharmacy shopping behavior, the overdose rate was higher compared to those with neither condition (26.3 per 1,000 PYs vs. 4.3 per 1,000 PYs). Patient review and restriction programs (PRRs) may restrict reimbursement for controlled prescription drugs to a single designated physician and pharmacy for patients whose use of overlapping prescriptions and multiple pharmacies cannot be justified, said the authors.

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