Bind to specific GABA_A receptor subunits (between α and γ) at CNS neuronal synapses increasing frequency of GABA-mediated Cl^- ion channel opening – enhance membrane hyperpolarization.  Dose-dependent depressant effects on the CNS including sedation, relief of anxiety, amnesia, hypnosis, anesthesia, coma, and respiratory depression

Extensions of CNS depressant effects, dependence liability, additive CNS depressant effects with ethanol and many other drugs

diplopia, nystagmus

Acute anxiety states, panic attacks, generalized anxiety disorder, insomnia and other sleep disorders, relaxation of skeletal muscle, anesthesia (adjunctive) seizure disorder

Bind to specific GABA_A receptor subunits (between α and γ) at CNS neuronal synapses increasing frequency of GABA-mediated Cl^- ion channel opening – enhance membrane hyperpolarization.  Dose-dependent depressant effects on the CNS including sedation, relief of anxiety, amnesia, hypnosis, anesthesia, coma, and respiratory depression

Extensions of CNS depressant effects, dependence liability, additive CNS depressant effects with ethanol and many other drugs

diplopia, nystagmus

Acute anxiety states, panic attacks, generalized anxiety disorder, insomnia and other sleep disorders, relaxation of skeletal muscle, anesthesia (adjunctive) seizure disorder

Bind to specific GABA_A receptor subunits (between α and γ) at CNS neuronal synapses increasing frequency of GABA-mediated Cl^- ion channel opening – enhance membrane hyperpolarization.  Dose-dependent depressant effects on the CNS including sedation, relief of anxiety, amnesia, hypnosis, anesthesia, coma, and respiratory depression

Extensions of CNS depressant effects, dependence liability, additive CNS depressant effects with ethanol and many other drugs

diplopia, nystagmus

Acute anxiety states, panic attacks, generalized anxiety disorder, insomnia and other sleep disorders, relaxation of skeletal muscle, anesthesia (adjunctive) seizure disorder

Antagonist at benzodiazepine binding sites on the GABA_A receptor.  Blocks actions of benzodiazepines, zolpidem, zaleplon, and eszopiclone, but not other sedative-hypnotics, ethanol, opioids, or general anesthetics

Agitation, confusion, possible withdrawal symptoms in benzodiazepine dependence

Reversing CNS depressant effects of benzodiazepine overdose and to hasten recovery following use of these drugs in anesthetic and diagnostic procedures

Bind to β subunit of the GABA_A receptor at CNS neuronal synapses increasing duration of GABA-mediated Cl^- channel opening.  Also inhibit glutamate.  Similar effects as benzodiazepines but steeper dose-response relationship

Extensions of CNS depressant effects (respiratory depression), dependence liability > benzodiazepines, induction of hepatic drug-metabolizing enzymes (induces P450), porphyria

Anesthesia (thiopental), insomnia, seizure disorders (phenobarbital)

Bind to β subunit of the GABA_A receptor at CNS neuronal synapses increasing duration of GABA-mediated Cl^- channel opening.  Also inhibit glutamate.  Similar effects as benzodiazepines but steeper dose-response relationship

Extensions of CNS depressant effects (respiratory depression), dependence liability > benzodiazepines, induction of hepatic drug-metabolizing enzymes (induces P450), porphyria

Anesthesia (thiopental), insomnia, seizure disorders (phenobarbital)

Bind selectively to α₁ subunit ofGABA _A receptor s, acting like benzodiazepines to enhance membrane hyperpolarization.  Rapid onset of hypnosis with few amnestic effects or day-after psychomotor depression or somnolence

Extensions of CNS depressant effects, dependence liability

Sleep disorders, especially those characterized by difficulty in falling asleep

Bind selectively to α₁ subunit ofGABA _A receptor s, acting like benzodiazepines to enhance membrane hyperpolarization.  Rapid onset of hypnosis with few amnestic effects or day-after psychomotor depression or somnolence

Extensions of CNS depressant effects, dependence liability

Sleep disorders, especially those characterized by difficulty in falling asleep

Bind selectively to α₁ subunit ofGABA _A receptor s, acting like benzodiazepines to enhance membrane hyperpolarization.  Rapid onset of hypnosis with few amnestic effects or day-after psychomotor depression or somnolence

Extensions of CNS depressant effects, dependence liability

Sleep disorders, especially those characterized by difficulty in falling asleep

Agonist at MT₁ and MT₂ melatonin receptors located in the suprachiasmatic nuclei of the brain. Rapid onset of sleep minimal rebound insomnia or withdrawal symptoms

Dizziness, fatigue, endocrine changes

Sleep disorders, expecially those characterized by difficulty in falling asleep
Not a controlled substance

Mechanism uncertain: partial agonist at 5-HT receptors but affinity for D₂ receptors also possible. Relieves anxiety without sedative, hypnotic, or euphoric effects.

Nonspecific chest pain, tachycardia, palpitations, dizziness, nervousness, tinnitus, GI distress, paresthesias and pupillary constriction may occur

Generalized anxiety states – slow onset (1-2 weeks), minimal psychomotor impairment

No additive CNS depression. No rebound or withdrawal signs, minimal abuse liability