Anxiolytics, sedatives, and hypnotics

Anxiolytics, sedatives and hypnotics are medicines that work on the central nervous system to relieve anxiety, aid sleep, or have a calming effect.

The benzodiazepines are the main class of drugs that fit into this category. Although there are more than twenty benzodiazepine derivatives, only certain ones have been approved to treat anxiety (eg, alprazolam, clonazepam, diazepam, and lorazepam), sleeplessness (insomnia) (eg, estazolam, flurazepam, quazepam, temazepam and triazolam), or panic disorder (eg, alprazolam). Barbiturates are an older class of medicine that used to be used for these indications as well; however, barbiturates have a narrow therapeutic index (window of effectiveness before toxicity occurs), and are more likely to cause respiratory depression, coma and death, and are very rarely used nowadays. The main issue with use of benzodiazepines is dependence. Benzodiazepines differ in their propensity to cause sedation and in the length of time they act for. All benzodiazepines are thought to work by enhancing the inhibitory action of γ-aminobutyric acid (GABA).

Other drug classes that are also considered effective at relieving anxiety include the SSRIs, SNRIs, tricyclic antidepressants and buspirone; other medicines may also be prescribed off-label. These drugs are often preferred over benzodiazepines for anxiety because they are unlikely to cause dependence; however, they may not work as quickly as benzodiazepines. SSRIs typically have a delayed onset-of-action and may initially worsen anxiety.

Other drug classes that have a sedative effective include first-generation antihistamines, agonists of melatonin receptors, anesthetics, eszopiclone, zaleplon, zolpidem, zopiclone, and several others. Many of these drugs also have a hypnotic effect.