Medicinal chemistry of Thiopental Sodium

Introduction : Thiopental Sodium belongs to the group of Anesthetics particularly General Anesthetics as Intravenous Anesthetics.. Descri...

Introduction:
Thiopental Sodium belongs to the group of Anesthetics particularly General Anesthetics as Intravenous Anesthetics..

DescriptionA barbiturate that is administered intravenously for the induction of general anesthesia or for the production of complete anesthesia of short duration. It is also used for hypnosis and for the control of convulsive states. It has been used in neurosurgical patients to reduce increased intracranial pressure. It does not produce any excitation but has poor analgesic and muscle relaxant properties. Small doses have been shown to be anti-analgesic and lower the pain threshold. (From Martindale, The Extra Pharmacopoeia, 30th ed, p920)

Categories

• Hypnotics and Sedatives
• Anticonvulsants
• GABA Modulators
• Anesthetics, Intravenous

Analysis

sodium 5-ethyl-4,6-dioxo-5-(pentan-2-yl)hexahydropyrimidine-2-thiolate
Chemical Formula: C11H19N2NaO2S
Exact Mass: 266.11
Molecular Weight: 266.34
m/z: 266.11 (100.0%), 267.11 (13.0%), 268.10 (4.5%), 268.11 (1.3%)
Elemental Analysis: C, 49.61; H, 7.19; N, 10.52; Na, 8.63; O, 12.01; S, 12.04

Pharmacology of Thiopental Sodium

Indication	For use as the sole anesthetic agent for brief (15 minute) procedures, for induction of anesthesia prior to administration of other anesthetic agents, to supplement regional anesthesia, to provide hypnosis during balanced anesthesia with other agents for analgesia or muscle relaxation, for the control of convulsive states during or following inhalation anesthesia or local anesthesia, in neurosurgical patients with increased intracranial pressure, and for narcoanalysis and narcosynthesis in psychiatric disorders.
Pharmacodynamics	Thiopental, a barbiturate, is used for the induction of anesthesia prior to the use of other general anesthetic agents and for induction of anesthesia for short surgical, diagnostic, or therapeutic procedures associated with minimal painful stimuli. Thiopental is an ultrashort-acting depressant of the central nervous system which induces hypnosis and anesthesia, but not analgesia. It produces hypnosis within 30 to 40 seconds of intravenous injection. Recovery after a small dose is rapid, with some somnolence and retrograde amnesia. Repeated intravenous doses lead to prolonged anesthesia because fatty tissues act as a reservoir; they accumulate Pentothal in concentrations 6 to 12 times greater than the plasma concentration, and then release the drug slowly to cause prolonged anesthesia
Mechanism of action	Thiopental binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.

Structure and Synthesis of Thiopental Sodium