Acetylsalicylic acid: Insignificant CYP 2C9 metabolism. Repeatedly experienced to be safe in acute porphyria. Several references consider it safe. Caffeine: Widely used as beverage, no observations of porphyrinogenic side effects.

(To be edited, initial data ST OCT 04) Acetylsalicylic acid: Water soluble light analgesic, inhibitor of prostaglandin synthesis. Metabolized by conjugation with glycine. Acetylsalicylic acid: MFM James, RJ Hift. Porphyrias. Br J Anaesth 2000; 85, 143-53: use EPI-list: safe South African list: use French list: use Kalman, Bonkovsky: safe Merck Index: safe Eales L: Porphyria and the dangerous life-threatening drugs. S Afr Med J 56:914,1979: safe. Thunell; patient inquiry: tolerated n=20)

Uneventful use reported in 22 patients with acute porphyria.