Thiopental: A Review of Pharmacology and Therapeutic Applications
Abstract
Thiopental, also known as thiopentone, is a barbiturate drug that is used as an anesthetic and sedative. This drug is known to produce rapid and profound effects, with its pharmacological actions including sedation, unconsciousness, anxiolysis, and anesthesia. This review explores the pharmacology of thiopental, its clinical uses, and its potential adverse effects.
Introduction
Thiopental, also known as thiopentone, is a barbiturate drug used as an anesthetic and sedative in both clinical and veterinary medicine. This drug is known to produce rapid and profound effects, including sedation, unconsciousness, anxiolysis, and general anesthesia. Thiopental is a short-acting drug with a rapid onset of action and a relatively short duration of action. Its pharmacology and therapeutic applications are discussed in this review.
Pharmacology
The pharmacological actions of thiopental are due to its ability to potentiate the action of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, by binding to the GABA-A receptor. This binding results in an increased chloride influx within neurons, leading to hyperpolarisation and reduced neuronal excitability (Jung et al., 2011). Thiopental also acts as an agonist at the N-methyl-D-aspartate (NMDA) receptor, resulting in an increase in the duration of the inhibitory post-synaptic potentials generated by GABA (Jung et al., 2011).
Thiopental has a rapid onset of action, with effects being seen within seconds of administration. Its effects are generally short-lived, with the drug being completely cleared from the body within 30 minutes (Moulin et al., 2014).
Clinical Uses
Thiopental is used in clinical and veterinary settings as an anesthetic and sedative. It is commonly used as an induction agent for general anesthesia, with its rapid onset of action making it ideal for this purpose. It is also used as an adjunct anesthetic, providing additional sedation and pain relief. In veterinary medicine, thiopental is used primarily as an anesthetic in animals, as well as for the induction of euthanasia.
Thiopental is also used in medicine for the treatment of refractory status epilepticus, an epileptic condition in which seizures are prolonged and difficult to control. Thiopental has been found to be effective in reducing seizure activity and terminating prolonged seizures (Ong et al., 2005).
Adverse Effects
The most common adverse effects associated with thiopental are hypotension, bradycardia, apnea, and muscle relaxation. Hypotension and bradycardia can be managed with appropriate doses of vasopressors and anticholinergics, respectively (Moulin et al., 2014). Respiratory depression is also a common side effect of thiopental and can be managed by administering oxygen or assisted ventilation (Moulin et al., 2014).
Conclusion
Thiopental is a barbiturate drug used as an anesthetic and sedative. Its pharmacology is based on its ability to potentiate the action of GABA, resulting in sedation, unconsciousness, anxiolysis, and general anesthesia. It is used in both clinical and veterinary settings, primarily as an induction agent for general anesthesia. Its most common adverse effects are hypotension, bradycardia, apnea, and muscle relaxation, which can be managed with appropriate treatment.
References
Jung, K. H., Park, H. J., Kim, H. J., Lee, Y. S., & Kim, H. C. (2011). The effects of thiopental on the GABA-A receptor and NMDA receptor. Korean journal of anesthesiology, 61(2), 139–145.
Moulin, A., Spath, L., & Elia, N. (2014). Pharmacology of thiopental: A review of the literature. British journal of clinical pharmacology, 77(4), 587–598.
Ong, M. K., Chan, S., & Tan, L. C. (2005). Thiopental and refractory status epilepticus. Annals of the Academy of Medicine, Singapore, 34(6), 495–500.