Barbiturate

Class of drugs derived from barbituric acid

Structural formula of barbituric acid, the core structure of barbiturates.

Barbiturates are a class of sedative and hypnotic medications that are derived from barbituric acid. They were first synthesized in the late 19th century and have been used in medicine for their anxiolytic, anticonvulsant, and anesthetic properties. However, due to their potential for addiction and overdose, their use has declined in favor of safer alternatives such as benzodiazepines.

History

The first barbiturate, barbital, was synthesized in 1903 by German chemists Emil Fischer and Joseph von Mering. It was marketed under the trade name Veronal and was used as a sleeping aid. Over the following decades, numerous barbiturates were developed, each with varying durations of action and potency.

Pharmacology

Barbiturates act as central nervous system depressants. They enhance the action of the neurotransmitter gamma-aminobutyric acid (GABA) by binding to the GABA_A receptor, leading to increased chloride ion influx and hyperpolarization of neurons. This results in a sedative effect, reducing anxiety and inducing sleep.

Classification

Barbiturates are classified based on their duration of action:

• Ultra-short-acting: Used for anesthesia induction (e.g., thiopental).
• Short-acting: Used for insomnia and preoperative sedation (e.g., pentobarbital).
• Intermediate-acting: Used for anxiety and insomnia (e.g., amobarbital).
• Long-acting: Used for epilepsy and seizure control (e.g., phenobarbital).

Medical Uses

Barbiturates have been used in the treatment of various conditions, including:

• Seizure disorders: Long-acting barbiturates like phenobarbital are used to control seizures.
• Anesthesia: Ultra-short-acting barbiturates are used to induce anesthesia.
• Insomnia: Short-acting barbiturates were historically used as sleep aids.

Risks and Side Effects

Radar plot showing the harm assessment of various drugs, including barbiturates.

Barbiturates have a narrow therapeutic index, meaning the difference between a therapeutic dose and a toxic dose is small. Overdose can lead to respiratory depression, coma, and death. Chronic use can result in tolerance, dependence, and withdrawal syndrome.

Legal Status

Due to their potential for abuse and addiction, barbiturates are classified as controlled substances in many countries. Their medical use is now limited, and they are often replaced by safer alternatives.

Related Pages

• Benzodiazepine
• Sedative
• Hypnotic
• Anxiolytic

Generic structure of barbiturates, showing the barbituric acid core.

See Also

• Central nervous system depressant
• Drug overdose
• Substance dependence