Hypnotic (also called soporific) drugs are a class of psychoactives whose primary function is to induce sleep and to be used in the treatment of insomnia, and in surgical anesthesia. When used in anesthesia to produce and maintain unconsciousness, "sleep" is metaphorical as there are no regular sleep stages or cyclical natural states; patients rarely recover from anesthesia feeling refreshed and with renewed energy. Because drugs in this class generally produce dose-dependent effects, ranging from anxiolysis to production of unconsciousness, they are often referred to collectively as sedative-hypnotic drugs. Hypnotic drugs are regularly prescribed for insomnia and other sleep disorders, with over 95% of insomnia patients being prescribed hypnotics in some countries. Many hypnotic drugs are habit-forming and, due to a large number of factors known to disturb the human sleep pattern, a physician may instead recommend alternative sleeping patterns, sleep hygiene, and exercise, before prescribing medication for sleep. Hypnotic medication when prescribed should be used for the shortest period of time possible.
The benzodiazepine and nonbenzodiazepine hypnotic medications also have a number of side effects such as daytime fatigue, and cognitive impairments. In children, prescribing hypnotics is not yet acceptable unless if used to treat night terrors or somnambulism. Elderly people are more sensitive to these side effects and a meta analysis found that the risks generally outweigh any marginal benefits of hypnotics in the elderly. A review of the literature regarding benzodiazepine hypnotic and Z drugs concluded that these drugs caused an unjustifiable risk to the individual and to public health, and lack evidence of long-term effectiveness due to tolerance. The risks include dependence, accidents, and other adverse effects. Gradual discontinuation of hypnotics leads to improved health without worsening of sleep. Preferably they should be prescribed for only a few days at the lowest effective dose, and avoided altogether wherever possible in the elderly.
Benzodiazepines are the most well-known and most frequently-prescribed hypnotic medications, although their use in recent years is being increasingly replaced by newer nonbenzodiazepine hypnotic drugs and the hormone melatonin. Benzodiazepines are effective in the short term but tolerance to their hypnotic effects develops after 1 or 2 weeks, thus making them ineffective for long-term use. They are also a cause of hospital admissions, especially in the elderly who are more sensitive to their effects. When used for extended periods of time, Benzodiazepine withdrawal syndrome will always develop upon their discontinuation. This is characterized by excessive insomnia, anxiety, confusion, disorientation, hot flashes, uncontrollable cold sweats, diaphoresis, chills, fever, uncontrollable perspiration, persistent unrelenting nightmares every night and perceptual disturbances. More severe withdrawal symptoms which occur can include seizures (some of which can be fatal), visual and auditory hallucinations, suicidal ideation, extremely severe panic attacks, depersonalization, tremors, delirium, delirium tremens and if not treated as an emergency by a proper medical staff death from a seizure can occur. Benzodiazepine withdrawal is a medical emergency and should be treated as such. It is a common misconception that drugs such as heroin, oxycodone, and other opiates are the most physically dangerous in withdrawal. Benzodiazepine addiction, is a far more dangerous dependency to have because unlike dependence to opiates and other drug classes, benzodiazepines and their counter-parts the z-drugs (Ambien for example) can be lethal in withdrawal. Prescription hypnotics (benzodiazepines and nonbenzodiazepines included) should therefore be taken for the shortest duration of time with the least frequency possible, so as to avoid tolerance, drug dependence, and the adverse effects of long term use.
Benzodiazepines tend to exert their hypnotic effects at high dosage compared to the more moderate dosage needed for anxiolytic effects to be felt. The downside of the hypnotic properties of benzodiazepines is that they actually worsen the sleep architecture and thus the quality of sleep. They are also associated with an increased risk of road traffic accidents.
Nonbenzodiazepines have demonstrated efficacy in treating some sleep disorders. Limited, inconclusive evidence suggests that tolerance to nonbenzodiazepines is slower to develop than with benzodiazepines. Data is also limited with regard to long-term effects of nonbenzodiazepines; further research into the safety and long-term effectiveness of nonbenzodiazepines has been recommended in a review of the literature.
These drugs include:
- GABAA PAMs
- Benzodiazepines -- see List of benzodiazepines
- Chloral hydrate
- Diethyl ether
- Ethanol (alcohol)—also used as a hypnotic, though not medicinally. To quote the British National Formulary: "Alcohol is a poor hypnotic because its diuretic action interferes with sleep during the latter part of the night. Alcohol also disturbs sleep patterns, and so can worsen sleep disorders."
- Melatonin agonists
- Mixed MoA (antihistamines, 5-HT2A antagonists, anticholinergics, alpha blockers, and/or dopamine antagonists)
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