For the NICE no differences in effectiveness between the drugs for insomnia
Hypnotics may be indicated, but only for short periods in severe form of insomnia, which alters the normal daily life.
The NICE (National Institute for Clinical Excellence) believes that there are no clinical advantages employ a hypnotic class of drugs Z (zaleplon, zolpidem, zopiclone), or a short-acting benzodiazepine, and therefore should be prescribed the drug the lowest price.
Insomnia is a disorder highly subjective. Furthermore sleep duration may vary from night to night.
The causes of insomnia have different physical or psychiatric co-morbidities, concomitant drug treatment or substance abuse (drugs, alcohol, and caffeine).
Insomnia is more common among women and its incidence increases with age.
Benzodiazepines are much used as hypnotics.
The limit of these drugs is the high incidence of dependence (10-30% of chronic users).
The factors most associated with an increased risk of developing dependency include: short-acting, prolonged use, high dose, and high power.
The use of benzodiazepines should be limited to severe insomnia and should be used in doses as low as possible, and for a period not exceeding 4 weeks.
Zaleplon, zolpidem and zopiclone are hypnotic other than benzodiazepines but act as agonists of the GABA receptor.
Patients not responding to a hypnotic probably will not respond to another hypnotic. (Xagena2004)