Barbiturate

Lore & Background

Barbiturates were long used as anxiolytics and hypnotics, with intermediate-acting forms reducing time to fall asleep and increasing total sleep time while reducing REM sleep. They have been largely replaced by benzodiazepines for these purposes due to lower toxicity in overdose, but are still employed as anticonvulsants such as phenobarbital and primidone. In high doses, barbiturates are used for medical aid in dying, requiring ingestion of 90 to 100 pills with antiemetics, and are also used in combination with muscle relaxants for euthanasia and lethal injection in capital punishment, as well as in small-animal veterinary medicine.

Reader's Guide

Barbiturates are significant for their historical role in treating anxiety, insomnia, and seizures, and for their continued use in specific medical contexts such as epilepsy and anesthesia. Their high addiction potential and dangerous withdrawal syndrome—considered one of the most severe of any addictive substance—led to their replacement by safer alternatives like benzodiazepines. The withdrawal process can be fatal, requiring conversion to a long-acting benzodiazepine and slow tapering. Barbiturates also have a controversial history in interrogation, where sodium thiopental and sodium amytal were used under the mistaken belief they acted as truth serums, though this practice is no longer legally admissible due to risks of false memories. In supramolecular chemistry, barbiturates have been used to design artificial receptors and molecular devices, unrelated to their drug effects.

Did You Know?

• Barbiturates have been used in euthanasia and capital punishment by lethal injection, often combined with a muscle relaxant.
• Sodium thiopental, an ultra-short-acting barbiturate, is mistakenly called a truth serum; it does not force truth but may reduce inhibitions and impair memory.
• Barbiturate withdrawal is considered one of the most dangerous withdrawals of any known addictive substance, potentially causing fatal seizures.
• Barbiturates in overdose with other CNS depressants like alcohol or benzodiazepines are more dangerous due to additive respiratory depressant effects.