Zopiklon

Additional information

Pharmacokinetics and dosing

Zopiclone has a half-life of 3.5-6 h. No differences in zopiclone pharmacokinetics have been seen between men and women [5].The absorption of zopiclone is similar in men and women and no sex differentiation in dosing has been recommended by the manufacturer [6].

Effects

No studies with a clinically relevant sex analysis regarding the effects of zopiclone have been found.

Adverse effects

In a study of driving capacity after medication with sleeping pills (9 men, 14 women) zopiclone 7.5 mg, but not zolpidem 10 mg, was found to increase the number of collisions in a driving simulator compared to placebo. No analysis based on sex was performed [1]. Also another study showed that zopiclone 7.5 mg, but not zolpidem 3.5 mg, impaired next-day driving, but with no differences between men and women [2].However, pooled data from four placebo-controlled studies (in all 50 men, 51 women) on the effects of zopiclone 7.5 mg on driving performance showed no differences between men and women [7]. A review article concludes that no difference in driving performance the day after intake of zopiclone 7.5 mg could be observed between healthy men and women [8].

Reproductive health issues

Regarding teratogenic aspects, please consult the Drugs and Birth Defects Database (in Swedish, Janusmed fosterpåverkan).

Other information

In two Swedish register-based studies [9, 10], older men were found to dispense more zopiclone. The first study (280,623 men, 450,482 women) analyzed all dispensed prescriptions to people aged ≥75 years during a 3-month period in 2005. The adjusted odds ratio for use of zopiclone in women versus men was 0.85 [9]. In the second study (645,429 men, 105,007 women), all dispensed prescriptions to patients between 75-89 years during a 4-month period in 2005 were analyzed. The adjusted odds ratio for use of zopiclone in women compared with men was 0.95 [10]. However, aggregated data from the Swedish Board of Health and Welfare shows that utilization of zopiclone has been higher among women than men (aged ≥ 75 years) in Sweden every year since 2006. A possible explanation to the different findings could be that the two studies focused on shorter time periods (3 and 4 months), while the aggregated data is based on one year data and the two Swedish studies were conducted only during the year 2005 [11].Also, studies from other countries show similar patterns. In a Danish register-based study in patients ≥65 years (5000 men, 5000 women), women redeemed more prescriptions of zopiclone, zolpidem and zaleplon than men (treatment ≥4 weeks: adjusted OR 1.36; treatment ≥6 months: adjusted OR 1.34) [3]. In a Norwegian register study in patients 18-69 years (73,144 men, 135,400 women), the incidence rates for zolpidem and zopiclone were also higher for women. The incidence rate was calculated as the number of incident users divided by the population at risk in Norway on January 1, 2006 [4].In a Canadian questionnaire study (518 men, 941 women), no sex differences in prescribing patterns of zopiclone were observed [12].