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→Thiopental
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.
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.
The commercial preparation is a sodium salt which requires dilution in water or saline. The resulting solution has a strong alkaline pH which is extremely irritant and if injected extravascularly it causes tissue necrosis and skin sloughing. It is best to inject via an intravenous catheter but if it is injected subcutaneously, then bathe immediately with saline and lidocaine solution which will cause a local vasodilation and help dissipate the subcutaneous thiopental.
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.
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.
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.