see also:

• barbiturates
• induction agents for anaesthesia

• thiopentone is an ultra-short acting barbiturate primarily used as an induction agent to aid rapid sequence induction (RSI) for emergency intubation
• iv use only
  • IM use causes pain/necrosis
  • inadvertent intra-arterial injection of thiopentone → vasospasm
• consider alternatives if either:
  • hypotensive
  • head injury or acute stroke (secondary brain injury from transient hypotension is a risk)
  • porphyria
  • asthma - it can release histamine

• comes as a Pentothal 500mg/2.5% kit:
  • reconstitute by adding the 20ml of supplied sterile water to the powder-containing bottle and dissolve
  • use only if it is clear, free from precipitate and is not discolored
  • solution is 25mg/ml (500mg per 20ml)
  • use within 24 hours.

• iv induction dose: 3-5mg/kg
• reduce dose in elderly or those at risk of hypotension

• plasma:brain equilibration occurs within 1minute
• short acting due to redistribution (metabolised @ 12-16%/hr after single dose);
• large doses ⇒ myocard. depress.& decr. venous tone ⇒ decreased SV & cardiac output ⇒ hypotension
• potent resp. depressant
• decreased cerebral metabolism & cerebral blood flow (contrast with inhaled GAs!)
• may reduce hepatic & renal blood flow