Sedating antihistamines cause sedation as they are highly lipid soluble and readily cross the blood brain barrier.
Both eszopiclone and sustained-release zolpidem are effective for both sleep-onset and sleep-maintenance insomnia, with a reduced abuse potential and long-term efficacy of up to 6 months as compared with nonselective benzodiazepine receptor agonists.
Barbiturates are nonselective CNS depressants that used to be the mainstay of treatment to sedate patients or to induce and maintain sleep.
In modern medicine they have been largely replaced by the benzodiazepines, primarily because they can induce tolerance, physical dependence and serious withdrawal symptoms.
The older sedative-hypnotics that have a prolonged half-life increase the risk for next-day sedation and daytime psychomotor impairment and pose an increased risk for abuse and dependence.
Other complications of benzodiazepine use include tolerance, withdrawal, abuse, and rebound insomnia.