What are the anaesthetics contraindicated in porphyria?

The correct answer identifies sodium thiopentone and etomidate as anesthetics that are contraindicated in patients with porphyria. Porphyrias are a group of rare inherited or acquired disorders that affect the production of heme, a vital component of hemoglobin. In these conditions, certain drugs can precipitate or exacerbate attacks, leading to significant morbidity.

Sodium thiopentone is a barbiturate that can trigger acute attacks of porphyria. This is primarily because it induces hepatic enzymes that are involved in heme synthesis, thereby increasing the demand for heme and potentially leading to a buildup of porphyrins, which can result in neurological and abdominal symptoms associated with porphyric crises.

Etomidate is another anesthetic that has a similar effect and is contraindicated for the same reason. Although it is less commonly associated with porphyric attacks compared to sodium thiopentone, it is still advised to avoid its use in these patients due to its potential to interfere with heme synthesis, albeit to a lesser extent.

In summary, both sodium thiopentone and etomidate disrupt the delicate balance of heme production in individuals with porphyria, leading to potential complications, making their use in this population