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Thiopental (also ''Thiopentone'') causes a rapid loss of conciousness with time of onset being influenced by premedication agents. It is considered a '''ultra short acting''' barbituate, with effects seen within 15-30s following injection, and has a rapid recovery period, commonly 10-15 minutes. The duration and depth of anaesthetic, however, depends upon the ''amount'' of drug injected, ''speed'' of injection, and ''rate of distribution'' in non-fatty and fatty tissues.
Thiopental (also ''Thiopentone'') causes a rapid loss of conciousness with time of onset being influenced by premedication agents. It is considered a '''ultra short acting''' barbituate, with effects seen within 15-30s following injection, and has a rapid recovery period, commonly 10-15 minutes. The duration and depth of anaesthetic, however, depends upon the ''amount'' of drug injected, ''speed'' of injection, and ''rate of distribution'' in non-fatty and fatty tissues.
Thiopental comes as a yellowish powder, and once reconsituted, can be used for up to 24 hours if refridgerated.
Thiopental comes as a yellowish powder, which once reconsituted and stored correctly, can be used for up to 3-4 days.
As thiopental causes a reduction in intracranial pressure (ICP), it can be used in patients with head traumas, brain tumours or other reasons for a raised ICP.
Care needs to be taken upon injection that none of the thiopental goes extravascularly as it is '''highly irritant'''. If it is injected subcutaneously, then bathe immediately with saline and lidocaine solution.
Care should also be taken in sighthounds as they do not possess the enzyme to cleave the sulphur molecule from the thiopental, which is the first stage of metabolism of the drug, and so recovery may be prolonged in these patients.
===Pentobarbital===
===Pentobarbital===
Pentobarbital is an oxybarbiturate which is no longer available at anaesthetic doses, but used as an euthansia agent. It causes a rapid onset of anaesthesia (40-120s) but has a longer duration of action compared with thiopental (1-2 hours). Recovery is dependent on hepatic metabolism. Its main indication of use is for the treatment of intractable seizures, long term sedation in ICU and euthansia.