Thiopental

Thiopental, also known as sodium thiopental or thiopentone, is a rapid-onset, ultra-short-acting barbiturate used primarily as an intravenous anesthetic for induction of general anesthesia. It produces unconsciousness within seconds and is usually followed by maintenance with other anesthetics.

Induction is achieved by intravenous administration, typically at 3-5 mg/kg, with adjustments for age and comorbidity. The onset is rapid, and the initial effects last about 5-10 minutes as the drug redistributes to non-neural tissues and is metabolized in the liver. It is usually followed by inhaled agents or adjuncts to complete anesthesia.

Pharmacology: Thiopental is a lipophilic barbiturate that enhances GABA-A receptor activity, increasing chloride influx and suppressing neuronal firing. Its rapid brain penetration accounts for the swift onset, while redistribution and hepatic metabolism confer a short duration of action. Excretion is primarily renal.

Adverse effects and cautions: Potential complications include respiratory depression or apnea, hypotension, and, rarely, injection-site pain. It should be used with airway support. It is contraindicated in acute porphyria and requires caution in liver disease and pregnancy, with careful monitoring.

Other notes: Historically used in lethal injection protocols as an induction agent in some jurisdictions; availability has fluctuated due to regulation and supply. Thiopental is a controlled substance in many countries.