Thiopentone

Sodium Pentothal, Sodium Thiopental

Mechanism :

Thiopentone Sodium is an ultrashort-acting depressant of the central nervous system which induces hypnosis and anesthesia, but not analgesia.

Indication :

• General anaesthesia
• Status epilepticus

Contraindications :

Contraindicated in porphyria, dyspnea or respiratory obstruction e.g. acute severe asthma. Should only be used by a trained anaesthetist or intensivist. Ventilation must be available when used to treat status epilepticus. Use should not generally be for more than 48 hours as delayed recovery of consciousness has been encountered with prolonged use. Avoid intra-arterial injection and extravasation as tissue necrosis may result due to the alkaline pH of 10.6. Caution in patients with asthma or pharyngeal infection as can cause cough, laryngospasm and bronchospasm; in hypotension, hypovolemia, shock, severe anemia, hyperkalemia, severe cardiovascular disease, hepatic and renal dysfunction, myasthenia gravis, muscular dystrophy, adrenocortical insufficiency, raised intracranial pressure and metabolic disorders.

Dosing :

Adverse Effect :

Respiratory depression, myocardial depression, cardiac arrhythmias, prolonged somnolence and on recovery: Sneezing, coughing, bronchospasm, laryngospasm and shivering. Anaphylactic and anaphylactoid reactions to thiopentone have been reported. Rarely, immune hemolytic anemia with renal failure and radial nerve palsy have been reported.

Interaction :

Antiepileptics: Thiopental is an inducer of liver enzymes and may reduce blood levels of many drugs metabolised by the liver including antiepileptics.

Sulphonamides: May potentiate the effects of thiopental.
ACE Inhibitors, Angiotensin II Antagonists, Antihypertensives and Anti-Psychotics: May increase the hypertensive effects of thiopental.
Some Phenothiazines, especially Promethazine: Can increase excitatory phenomena produced by thiopental.
Cyclizine: May have a similar effect.
Opiates: Can potentiate CNS depression.

Hepatic Dose :