What induction agent is contraindicated for a patient with a history of acute intermittent porphyria?

The correct selection is sodium thiopental, which is contraindicated for patients with a history of acute intermittent porphyria. This condition affects heme production and can lead to the accumulation of porphyrins, which may provoke acute attacks when triggered by certain medications. Sodium thiopental, a barbiturate, can exacerbate symptoms by promoting the production of porphyrins and causing further disruptions in heme biosynthesis. Therefore, administering this drug to individuals with acute intermittent porphyria can lead to severe complications.

Ketamine and etomidate are generally considered safer alternatives for induction in patients with this condition, as they do not have the same propensity to influence porphyrin metabolism. Succinylcholine, while it is a neuromuscular blocker, is not specifically contraindicated due to porphyria; however, it is always used with caution, as it can cause complications in other neuromuscular disorders.