Barbiturates

Overview

Barbiturates drugs are derived from barbituric acid. Barbiturates are drugs that act as central nervous system depressants, and, by virtue of this, they produce a wide spectrum of effects, from mild sedation to total anesthesia. They are also effective as anxiolytics, as hypnotics, and as anticonvulsants. They have addiction potential, both physical and psychological. Barbiturates have now largely been replaced by benzodiazepines in routine medical practice – for example, in the treatment of anxiety and insomnia – mainly because benzodiazepines are significantly less dangerous in overdose. However, barbiturates are still used in general anesthesia, as well as for epilepsy. Barbiturates are derivatives of barbituric acid.

Mechanism of action

Although the exact mechanisms by which barbiturates affect the brain are not understood, it is thought that these drugs bind to sodium channels on neurons and prevent the flow of sodium ions. Because sodium ions cannot flow across the neuronal membrane, action potentials cannot be produced.

Barbiturates may also increase the flow of chloride ions across the neuronal membrane. This may occur through binding to the receptor for the neurotransmitter called GABA, and intensifying GABA receptors activity. The increased chloride ion flow reduces the chance that an action potential will be generated.

Examples:

All barbital has –bital at the end of drug name.

• Butabarbital
• Butalbital
• Phenobarbital sodium
• Secobarbital
• Amobarbital
• Given by IV or IM to terminate status epilepticus. It is not given orally.

Therapeutic uses

• Sedation
• Because it prevents the neural fire by in fluxing chloride ions in the neurons and preventing influx of sodium ions to fire
• Insomnia
• All Seizures except absence seizure
• Anxiolytics
• Antiepileptics