A hypnotic (from Ancient Greek Hypnos, sleep), also known as a somnifacient or soporific, and commonly known as sleeping pills, are a class of psychoactive drugs whose primary function is to sleep induction and to treat insomnia (sleeplessness).
This group of drugs is related to . Whereas the term sedative describes drugs that serve to calm or Anxiolytic, the term hypnotic generally describes drugs whose main purpose is to initiate, sustain, or lengthen sleep. Because these two functions frequently overlap, and because drugs in this class generally produce dose-dependent effects (ranging from anxiolysis to loss of consciousness), 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 many factors known to disturb the human sleep pattern—a physician may instead recommend changes in the environment before and during sleep, better sleep hygiene, the avoidance of caffeine and alcohol or other stimulating substances, or behavioral interventions such as cognitive behavioral therapy for insomnia (CBT-I), before prescribing medication for sleep. When prescribed, hypnotic medication should be used for the shortest period of time necessary.
Among individuals with sleep disorders, 13.7% are taking or prescribed nonbenzodiazepines (Z-drugs), while 10.8% are taking , as of 2010, in the USA. Early classes of drugs, such as , have fallen out of use in most practices but are still prescribed for some patients. In children, prescribing hypnotics is not currently acceptable—unless used to treat or sleepwalking. Elderly people are more sensitive to potential side effects of daytime fatigue and cognitive impairment, 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 hypnotics and Z-drugs concluded that these drugs have adverse effects, such as dependence and accidents, and that optimal treatment uses the lowest effective dose for the shortest therapeutic time, with gradual discontinuation to improve health without worsening of sleep.
Falling outside the above-mentioned categories, the neurohormone melatonin and its analogues (e.g., ramelteon) serve a hypnotic function.
The principal mechanism of action of barbiturates is believed to be positive allosteric modulation of GABAA receptors.
Examples include amobarbital, pentobarbital, phenobarbital, secobarbital, and sodium thiopental.
Examples of quinazolinones include cloroqualone, diproqualone, etaqualone (Aolan, Athinazone, Ethinazone), mebroqualone, Afloqualone (Arofuto), mecloqualone (Nubarene, Casfen), and methaqualone (Quaalude).
Other drawbacks of hypnotics, including benzodiazepines, are possible Drug tolerance to their effects, rebound insomnia, and reduced slow-wave sleep and a withdrawal period typified by rebound insomnia and a prolonged period of anxiety and agitation.
The list of benzodiazepines approved for the treatment of insomnia is similar among most countries, but which benzodiazepines are officially designated as first-line hypnotics prescribed for the treatment of insomnia can vary distinctly between countries. Longer-acting benzodiazepines, such as nitrazepam and diazepam, have residual effects that may persist into the next day and are, in general, not recommended.It is not clear whether the newer nonbenzodiazepine (Z-drug) hypnotics are better than the short-acting benzodiazepines. The efficacy of these two groups of medications is similar. According to the US Agency for Healthcare Research and Quality, indirect comparison indicates that side effects from benzodiazepines may be about twice as frequent as from nonbenzodiazepines. Some experts suggest using nonbenzodiazepines preferentially as a first-line long-term treatment of insomnia. However, the UK National Institute for Health and Clinical Excellence (NICE) did not find any convincing evidence in favor of Z-drugs. A NICE review pointed out that short-acting Z-drugs were inappropriately compared in clinical trials with long-acting benzodiazepines. There have been no trials comparing short-acting Z-drugs with appropriate doses of short-acting benzodiazepines. Based on this, NICE recommended choosing the hypnotic based on cost and the patient's preference.
Older adults should not use benzodiazepines to treat insomnia unless other treatments have failed to be effective., which cites
Their mechanism of action is primarily at GABAA receptor.
Examples include zopiclone (Imovane), eszopiclone (Lunesta), zaleplon (Sonata), and zolpidem (Ambien). Since the generic names of all drugs of this type start with Z, they are often referred to as Z-drugs.Ryba, N.; Rainess, R. Z-drugs and Falls: A Focused Review of the Literature. The Senior Care Pharmacist 2020, 35 (12), 549-554. DOI: 10.4140/tcp.n.2020.549.
Research on nonbenzodiazepines is new and conflicting. A review by a team of researchers suggests the use of these drugs for people who have trouble falling asleep (but not staying asleep),Because the drugs have a shorter elimination half life they are metabolized more quickly: nonbenzodiazepines zaleplon and zolpidem have a half-life of 1 and 2 hours (respectively); for comparison, the benzodiazepine clonazepam has a half-life of about 30 hours. This makes the drug suitable for sleep-onset difficulty, but the team noted sustained sleep efficacy was unclear. as next-day impairments were minimal. The team noted that the safety of these drugs had been established, but called for more research into their long-term effectiveness in treating insomnia. Other evidence suggests that drug tolerance to nonbenzodiazepines may be slower to develop than with benzodiazepines. A different team was more skeptical, finding little benefit over benzodiazepines.
Synthetic analogues of melatonin, or melatonin receptor agonists, have also been made. Among these, ramelteon and tasimelteon are used for sleep disorders. Agomelatine is an antidepressant of this class, with some studies also reporting an effect on sleep.
In common use, the term antihistamine refers only to compounds that inhibit action at the H1 receptor.
Clinically, H1 antagonists are used to treat certain Allergy. Sedation is a common side effect, and some H1 antagonists, such as diphenhydramine and doxylamine, are also used to treat insomnia.
Examples include:
Research about using medications to treat insomnia evolved throughout the last half of the 20th century. Treatment for insomnia in psychiatry dates back to 1869, when chloral hydrate was first used as a soporific.
During the 1970s, and were introduced as safer alternatives to replace barbiturates; by the late 1970s, benzodiazepines emerged as the safer drug.
Benzodiazepines are not without their drawbacks; substance dependence is possible, and deaths from overdoses sometimes occur, especially in combination with alcohol or other . Questions have been raised as to whether they disturb sleep architecture.
Nonbenzodiazepines are the most recent development (1990s–present). Although it is clear that they are less toxic than barbiturates, their predecessors, comparative efficacy over benzodiazepines has not been established. Such efficacy is hard to determine without longitudinal studies. However, some psychiatrists recommend these drugs, citing research suggesting they are equally potent with less potential for abuse.
Other sleep remedies that may be considered "sedative–hypnotics" exist; psychiatrists will sometimes prescribe medicines off-label if they have sedating effects. Examples of these include mirtazapine (an antidepressant), clonidine (an antihypertensive medication), quetiapine (an antipsychotic), and over-the-counter allergy and antiemetic medications doxylamine and diphenhydramine. Off-label sleep remedies are particularly useful when first-line treatment is unsuccessful or deemed unsafe (as in patients with a history of substance use disorders).
Therefore, sedatives and hypnotics should be avoided in people with dementia, according to the clinical guidelines known as the Medication Appropriateness Tool for Comorbid Health Conditions in Dementia (MATCH-D).Citation error. See the inline comment on how to fix it. The use of these medications can further impede cognitive function for people with dementia, who are also more sensitive to side effects of medications.
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