Background: Case reports indicate dose increase, abuse, and dependence concerning zolpidem and zopiclone (so-called Z-drugs).
Methods: We conducted a cross-sectional study between 1 July and 31 December 2004 using claims data of the German health insurer Gmuender ErsatzKasse to examine high usage of these drugs.
Results: A total of 6959 subjects bought at least one packet of zolpidem or zopiclone, including 20.9% containing 90 daily doses (DDD) or more. High usage, defined as at least 180 DDD, was identified in 501 subjects (7.2%). Compared to other use, high usage was associated with GP visits only for the prescription of Z-drugs (odds ratio 2.01, 95% confidence interval 1.52-2.67), neuroleptics (odds ratio 2.53, 95% confidence interval 2.02-3.18), and polypharmacy (odds ratio 2.40, 95% confidence interval 1.84-3.15).
Conclusion: Zolpidem and zopiclone are often prescribed in higher doses or for long-term use. Such therapy regimens should be viewed critically.