Zolpidem prescribing practices before and after FDA required product labeling changes

Introduction: Data indicate women have higher serum zolpidem concentrations than men the morning after taking an evening dose, potentially leading to increased risk of automobile accidents, falls, and injuries. On April 19, 2013, zolpidem product labeling was changed to recommend women be prescribed initial doses of no greater than 5 mg (immediate-release [IR]) or 6.25 mg (controlled-release [CR]) of zolpidem per night. 

Objectives: The objectives of this study were to determine how the product labeling change affected prescribing practices in men, women, young, and elderly patients newly starting zolpidem.

Study Design: Retrospective, pre-post study

Methods: A list of patients (n=288) who newly started zolpidem between 4/1/11-6/1/15 was stratified equally into groups based on gender (male and female), age (<65 years and ≥65 years), and prescription index date (prior to labeling change and after labeling change). Demographic data and zolpidem prescription data for each patient were retrospectively collected from the electronic medical record. "Low-dose" zolpidem was defined as 5 mg IR or 6.25 mg CR daily or less; any doses above 5 mg IR or 6.25 mg CR were considered "high-dose." Chi-square analysis was utilized to analyze the data.

Results: A greater proportion of men (26% vs. 50%; p=0.00355), women (51% vs. 69%; p=0.0267), and young (35% vs. 61%; p=0.00153) patients were prescribed initial low-doses of zolpidem after the product labeling change as compared to prior to the labeling change. Although the proportion of elderly patients prescribed low-dose zolpidem increased after the change, it was not statistically significant (43% vs. 58%; p=0.0667). 

Conclusions: While the 2013 zolpidem labeling change focused on women only, more men were initiated on low-dose zolpidem after the labeling change. The lack of change detected in zolpidem prescribing practices in elderly patients is likely due to previous labeling changes suggesting elderly patients take a maximum of 5 mg IR or 6.25 mg CR daily.