Table 5.

Thiopentone
Group	Barbiturate
Mechanism of Action/Pharmacodynamics	Stimulate GABA receptors Inhibit AMPA receptors
Neuroprotective effects	Reduces CBF, CMRO2 and ICP Reduces MAP, therefore variable effect on CPP Raises seizure threshold
Pharmacokinetics [6]	Hepatically metabolised 0.5% renal excretion unchanged Elimination t 1/2 11.6 h First to zero order kinetics if plasma high Significant accumulation
Advantages	Rapid onset of action as induction agent Favourable effects on CBF, CMRO2 and ICP Inexpensive
Disadvantages and major side effects	Accumulation with prolonged infusion Hypotension Gastroparesis Loss of thermoregulation Immunosuppression Hypokalaemia during infusion Hyperkalaemia on emergence Life threatening arrhythmias on coma emergence
Dosage	Induction of anaesthesia: 2–5 mg/kg EEG burst suppression: 40 mg/kg followed by infusion at 4–8 mg/kg/h, titrated to EEG
Other significant facts	May precipitate if given concurrently with IV muscle relaxants [7]
Appropriate uses in TBI	Induction of anaesthesia, with caution regarding hypotension Refractory elevated ICP Refractory status epilepticus