Duplicate Prescription Patterns in Patients With Substance Use Disorders.

This study sought to investigate the frequency and characteristics of duplicate prescriptions (DPs) in psychiatric inpatients with substance use disorders using a DP classification that differentiates between appropriate DPs (ADPs) and potentially inappropriate DPs (PIDPs). The study was conducted as a monocentric retrospective cross-sectional study on the addiction-specific ward of the Department of Psychiatry, Social Psychiatry and Psychotherapy of Hannover Medical School, a large university hospital in northern Germany. The outcome measures were the nature and frequency of PIDPs compared with ADPs. Medication records of 1174 patients enrolled between January 2016 and December 2021 were reviewed. The median age of the study population (27.8% female) was 48 years (interquartile range (IQR) 39-56). Patients took a median of 4 drugs (IQR 2-6). 12.8% of the study population were exposed to at least one PIDP (at least one grade-1 PIDP: 12.0%; at least one grade-2 PIDP: 1.3%; at least one grade-3 PIDP: 0.3%). Sedatives were the most common cause of grade-1 PIDPs, while grade-2 PIDPs were elicited predominantly by opioids. Nearly one third of the study population (29.0%) displayed at least one ADP. Physicians treating patients with substance use disorders should carefully monitor for PIDPs, particularly PIDPs elicited by sedatives and opioids. Addressing PIDPs may help prevent adverse drug reactions and reduce drug expenses.