Table 3.

Factors known to trigger or exacerbate acute attacks of porphyria [11].

Exacerbating Factors	Common Unsafe Drugs
Drugs and chemicals—especially	➢ Excess alcohol
	➢ Barbiturates
	➢ Estrogens
	➢ Hydantoins
	➢ Progestagens
	➢ Sulfonamides
	➢ All drugs that are suicide substrates or potent inducers of cytochrome P450
Dieting; fasting; deficiency of carbohydrate intake (gastric bypass surgery)	-
Exhaustion—emotional or physical	-
Intercurrent acute illnesses	-

Note: More extensive list of drugs and their status are available from the websites of American Pophyria Foundation [58], European Porphyria Network [59] and University of Cape Town Poprhyria Service [60]