16.6 : 镇静剂和催眠药：巴比妥类药物

Sedatives and hypnotics are drugs that reduce anxiety, induce calmness, or promote sleep by suppressing the CNS.

Barbiturates, a class of sedative-hypnotics derived from barbituric acid, are classified based on their duration of action.

GABA's effects at the GABA_A receptor, causing neuronal hyperpolarization and reduced excitability.

Therapeutically, they exhibit sedative, hypnotic, anticonvulsant, anesthesia-inducing, and muscle-relaxing effects.

Clinically, barbiturates like phenobarbital help manage epilepsy, induce coma in brain injury and serve as a second-line insomnia treatment.

Their adverse effects include drowsiness, confusion, respiratory depression, and physical dependence. They can interact with other CNS depressants, intensifying their effects.

Overdose can cause severe CNS depression, leading to coma or even death.

Treatment of barbiturate poisoning includes supportive care and specific antidotes like sodium bicarbonate to enhance urinary excretion.

Though clinically invaluable, barbiturates are being replaced by safer alternatives like benzodiazepines.