Acute intermittent porphyria is a contraindication of the use of which of the following?
A.
Enflurane
B.
Nitrous oxide (N2O)
C.
Ketamine
D.
Diazepam
E.
Thiopental
The answer is: E
Induction of anesthesia by parenteral administration of thiopental sodium and other barbiturates is absolutely contraindicated in patients who have acute intermittent porphyria. These patients have a defect in regulation of -aminolevulinic acid synthetase; thus, administration of a barbiturate that increases this enzyme may cause a dangerous increase in levels of porphyrins. Administration of a barbiturate would exacerbate the symptoms of gastrointestinal and neurologic disturbances, cause extensive demyelination of peripheral and cranial nerves, and could lead to death