Sleep Medications Compared

Zolpidem is the most prescribed sleep medication in the United States. It is available in three formulations: immediate-release tablets (Ambien), extended-release tablets (Ambien CR), and an oral spray (Zolpimist). Immediate-release zolpidem is designed for sleep onset — falling asleep — while the CR formulation has a two-layer design intended to help with both falling and staying asleep. Zolpimist delivers the same immediate-release dose as a sublingual-style spray for patients who have difficulty swallowing tablets.

In 2013 the FDA mandated lower recommended doses for women, who metabolize zolpidem more slowly than men. The FDA specifically warned that next-morning blood levels of zolpidem after taking Ambien CR can remain high enough to impair driving in many people, particularly women. Despite being positioned as safer than benzodiazepines, zolpidem carries significant risks including dependence, complex sleep behaviors (sleepwalking, sleep-driving), and memory impairment.

Lunesta (eszopiclone) is unique among Z-drugs in that it is FDA-approved without a specified limitation on duration of use — the FDA removed the "short-term use" restriction, making it the only hypnotic with an open-ended label for chronic insomnia. It is the active isomer of zopiclone, a related compound widely used outside the United States. Eszopiclone was among the first sleep drugs studied in long-term clinical trials, with data supporting efficacy over six months.

A notable and distinctive side effect of eszopiclone is a bitter or metallic taste that many patients experience and that can persist into the next day. The FDA also requires the label to warn against driving the day after taking the 3 mg strength due to residual morning impairment, particularly in women.

Zaleplon has the shortest half-life of any Z-drug — approximately one hour — which gives it a distinct profile. It is useful specifically for difficulty falling asleep (sleep-onset insomnia) rather than staying asleep. Because it is cleared so quickly, it can be taken in the middle of the night if a patient wakes and has at least four hours remaining before they need to be awake, without significant next-morning hangover. It is not appropriate for patients whose main complaint is waking up too early or staying asleep through the night.

The ultra-short action also means zaleplon's window for misuse is narrower compared to longer-acting drugs, though it remains Schedule IV. It is also approved to treat short-term insomnia and is available generically.

Temazepam is the most commonly prescribed benzodiazepine for sleep in the United States. Unlike some other benzodiazepines used for insomnia, temazepam does not have long-acting active metabolites — it is metabolized directly to glucuronide conjugates, giving it a relatively intermediate half-life without significant accumulation over multiple nights. This makes it somewhat more favorable than flurazepam or quazepam for short-term sleep treatment, though next-morning sedation is still possible.

It is FDA-approved specifically for insomnia and remains on the market in generic form. Like all benzodiazepines, it is associated with physical dependence with regular use, rebound insomnia on discontinuation, and should be used for short periods only.

Triazolam is a short-acting benzodiazepine with a rapid onset and brief duration, making it suited for sleep-onset insomnia. Its short half-life (1.5–5.5 hours) means it is generally cleared before morning, reducing daytime sedation compared to longer-acting benzodiazepines. However, triazolam has a controversial history — it has been associated with rebound insomnia and anterograde amnesia (inability to form new memories) at higher doses, leading to restrictions or bans in several countries outside the United States. It remains available in the US at lower doses.

It carries the same dependence and withdrawal risks as other benzodiazepines, and abrupt discontinuation after extended use can cause significant rebound anxiety and insomnia.

Flurazepam is a long-acting benzodiazepine that produces several active metabolites, the most important being desalkylflurazepam, which has a half-life of 40–100 hours or more. This means sedative effects accumulate significantly with repeated nightly use — by the end of a week, daytime sedation can be substantial and progressive. The drug effectively has pharmacological activity continuing for two to four days or longer after the last dose.

Because of this accumulation and prolonged sedation, flurazepam is on the Beers Criteria — a list of medications considered potentially inappropriate for older adults — and is rarely a first-choice option today. It was once commonly used but has been largely replaced by shorter-acting alternatives with better daytime safety profiles. It remains available generically.

Quazepam is another long-acting benzodiazepine with active metabolites that persist for one to four days. It is selective for the BZ1 (omega-1) subtype of the GABA-A receptor — similar to Z-drugs — which was proposed to reduce muscle relaxant and amnestic effects compared to non-selective benzodiazepines. Despite this theoretical advantage, its extremely long-acting metabolites still pose significant accumulation and next-day impairment risks, particularly with repeated use.

Like flurazepam, quazepam is on the Beers Criteria and is not commonly used as a first-line hypnotic today. It remains available in a brand-name formulation. It is most prescribed when a prescriber specifically needs a long-acting effect for a particular patient's sleep pattern.

Belsomra (suvorexant) was the first orexin receptor antagonist approved by the FDA, in 2014. It blocks both orexin-1 and orexin-2 receptors, preventing orexin from binding and promoting wakefulness. In clinical trials, suvorexant reduced the time to fall asleep and the time spent awake during the night compared to placebo, with improvements maintained over three months of study.

Because it works by quieting wakefulness signaling rather than broadly sedating the brain, suvorexant tends to produce a different subjective experience than Z-drugs — patients often describe sleep that feels more natural. Next-morning somnolence has been reported, and the FDA label warns about driving impairment the next day. Suvorexant also has an interaction risk with CYP3A4 inhibitors (such as some antifungals and HIV medications), which can significantly increase blood levels.

Dayvigo (lemborexant) is the second dual orexin receptor antagonist approved in the US, in 2019. Like suvorexant, it blocks both OX1R and OX2R receptors, but it has a shorter half-life (17–19 hours for lemborexant vs. ~12 hours for suvorexant — similar in practice). Clinical trials with lemborexant included a head-to-head comparison against zolpidem CR, in which lemborexant showed a statistically significant improvement in subjective sleep quality and residual next-morning effects.

Lemborexant may carry a slightly lower next-morning impairment risk at its lowest strength compared to the highest strength of suvorexant, based on driving simulation studies included in the FDA review. It is also available as 5 mg and 10 mg tablets, with the 5 mg being the starting recommendation for most patients.

Rozerem (ramelteon) is FDA-approved for insomnia characterized by difficulty with sleep onset. It is a selective agonist at melatonin MT1 and MT2 receptors — the same receptors activated by endogenous melatonin — which helps regulate the circadian sleep-wake cycle. By binding these receptors with much higher affinity than melatonin itself, ramelteon produces a stronger, more consistent sleep-onset effect than OTC melatonin supplements.

Ramelteon is the only prescription sleep aid with no DEA scheduling — the FDA determined it has no abuse potential. It does not cause the next-morning impairment, complex sleep behaviors, or dependence associated with GABA-acting sleep medications. It is particularly useful for patients who are at elevated risk for dependence, have a substance use history, or need a long-term solution without controlled substance concerns. It is not effective for sleep-maintenance insomnia (waking in the middle of the night).

Trazodone is an antidepressant classified as a serotonin antagonist and reuptake inhibitor (SARI). At the low doses typically used for sleep — well below antidepressant doses — trazodone's sedating effects (mediated primarily through H1 antihistamine and alpha-1 adrenergic blockade) predominate over its antidepressant mechanism. It is one of the most frequently prescribed medications for insomnia in the United States, even though this use is off-label.

Trazodone's appeal for sleep includes the absence of dependence, no scheduling, low abuse potential, and low cost as a generic. However, it can cause next-morning grogginess, orthostatic hypotension (dizziness on standing), and — rarely — priapism (prolonged painful erection), which is a medical emergency. It should not be combined with other serotonergic drugs without medical supervision.

Silenor is a very low-dose formulation of doxepin — a tricyclic antidepressant — that is FDA-approved specifically for insomnia characterized by difficulty staying asleep (sleep-maintenance insomnia). At the 3 mg and 6 mg doses used in Silenor, the antidepressant and anticholinergic effects of doxepin are minimal; the predominant action is potent H1 antihistamine blockade, which produces sustained sleep-maintenance effects throughout the night. Generic doxepin at much higher antidepressant doses (25–150 mg) is also prescribed off-label for sleep, though it carries more anticholinergic side effects at those doses.

Low-dose doxepin (Silenor) is one of the few options FDA-approved for sleep maintenance without being a controlled substance, making it useful for patients who need long-term help staying asleep and for whom controlled substances are not appropriate.

Mirtazapine (Remeron) is a noradrenergic and specific serotonergic antidepressant (NaSSA) with powerful H1 antihistamine activity, particularly at lower doses. At antidepressant doses (15–45 mg), mirtazapine consistently produces strong sedation — and paradoxically, the 15 mg dose tends to be more sedating than 30 mg or 45 mg, because at higher doses the noradrenergic stimulation partially counteracts the antihistamine sedation. This dose-dependent paradox makes it unusual among sedating medications.

Mirtazapine is often prescribed off-label for insomnia, particularly in patients who also have depression, anxiety, or poor appetite (it stimulates appetite and can cause significant weight gain). It is not a controlled substance, carries low dependence risk, and is available generically at low cost. Because of its long half-life, next-morning sedation — particularly at lower doses — can be significant.

Diphenhydramine is the active ingredient in the majority of OTC nighttime sleep products sold in the US, including Benadryl (in nighttime formulations), ZzzQuil, and Unisom SleepTabs (the tablet form — not to be confused with Unisom SleepMelts, which contain doxylamine). It is a first-generation antihistamine with strong H1 blocking and significant anticholinergic activity. The sedation is a side effect of the antihistamine action, which is why the same drug is used both as an allergy medication and as a sleep aid.

Tolerance develops rapidly — within three to seven days of consecutive use — meaning it becomes markedly less effective as a sleep aid with regular use. It is generally recommended only for occasional use. In older adults, diphenhydramine is on the Beers Criteria due to heightened risks of cognitive impairment, urinary retention, falls, and delirium. It has no dependence potential in the traditional pharmacological sense, but some people develop habitual use due to its ready availability.

Doxylamine is a first-generation antihistamine similar to diphenhydramine but with a longer half-life (approximately 10 hours), which tends to produce more pronounced next-morning sedation. It is the active ingredient in Unisom SleepMelts and some Unisom tablet formulations. Doxylamine is also a component of Diclegis/Bonjesta, FDA-approved for nausea and vomiting of pregnancy, which attests to its safety during pregnancy — though this does not mean it is appropriate to use as a sleep aid during pregnancy without medical guidance.

Like diphenhydramine, doxylamine has anticholinergic activity, develops rapid tolerance, and is on the Beers Criteria for older adults. Its longer half-life compared to diphenhydramine means residual morning sedation tends to be greater.

Melatonin is a hormone produced by the pineal gland that regulates the sleep-wake cycle. As a supplement, it has the strongest evidence among OTC sleep supplements, particularly for circadian rhythm disorders — jet lag, shift work sleep disorder, and delayed sleep phase syndrome. Evidence for general insomnia is more modest. Melatonin is widely used at doses 5–10x higher than the body naturally produces; some research suggests lower doses (0.5–1 mg) may be more physiologically appropriate for sleep timing rather than sedation.

Valerian root is an herbal supplement long promoted for sleep and anxiety. Clinical trial results have been inconsistent — some studies show modest benefit for sleep latency and quality, others show no difference from placebo. Valerian may interact weakly with GABA receptors and sedative medications. It is generally considered safe for short-term use, but quality control varies significantly between supplement manufacturers.

Magnesium glycinate is a form of magnesium bound to glycine — an amino acid with mild inhibitory neurotransmitter properties. Some evidence suggests magnesium supplementation may improve sleep quality, particularly in older adults or those with magnesium deficiency. The glycinate form is better tolerated gastrointestinally than magnesium oxide. Evidence is limited to small studies; it is generally safe at normal supplemental doses but should be used with caution in kidney disease.