Z drugs (zopiclone, zaleplon, zolpidem)

The “Z drugs” which became increasingly common since their emergence on the market in the 1990’s, are non benzodiazepine hypnotics used for treatment of insomnia (1)

• it comprises of a group of three drugs
  • zaleplon - half life 1 hour
  • zolpidem - half life 2-3 hours
  • zopiclone - half life 5 hours (2)
• they were developed to overcome some of the disadvantages associated with benzodiazepine such as next day sedation, dependence and withdrawal
• they differ structurally from benzodiazepines but the pharmacological action is similar to them - act as agonists of the GABA receptor complex and enhance GABA mediated neuronal inhibition (3)

According to the summary of products characteristics (SPC), the duration of single treatment episode should not exceed 2-4 weeks (including tapering off where appropriate).

• in zaleplon - treatment should be as short as possible with a maximum duration of 2 weeks
• in zolpidem - treatment should usually vary from a few days to 2 weeks with a maximum of 4 weeks, including tapering off where appropriate
• in zopiclone - duration of treatment should be 2–5 days for transient insomnia and 2–3 weeks for short-term insomnia (3).

Note:

• there are no firm evidence of differences in the effects of z-drugs and the shorter-acting benzodiazepines (1)

Reference:

• (1) National Addiction Centre, King's College London and School of Social and Community Medicine 2011. The changing use of prescribed benzodiazepines and z-drugs and of over-the-counter codeine-containing products in England: a structured review of published English and international evidence and available data to inform consideration of the extent of dependence and harm.
• (2) Olson LG. Hypnotic hazards: adverse effects of zolpidemand other z-drugs. Aust Prescr 2008;31:146–9
• (3) National Institute for Clinical Excellence (NICE) 2004. Guidance on the use of zaleplon, zolpidem and zopiclone for the short-term management of insomnia