Paracetamol: Low extent of oxidative metabolism. Inducer of CYP 3A4. Three references consider it safe. Occasional patient reports of suspected porphyrinogenicity, but vast and significant clinical experience of non-porphyrinogenicity. Codeine: Opioid substrate for 2D6 and 3A4. Several references consider it safe for use.

Paracetamol: Anilide (acetaminophen) derivative metabolized by conjugation with glucuronic acid and sulfate. A small part (<4%) is oxidatively metabolized by CYPs and excreted as cysteine and mercapto conjugates. At low concentrations inducer of CYP 3A4, increasing activity and content. Australian list: safe. South African list: use French list: avoid, known to have precipitated an acute attack Thunell; patient inquiry: tolerated (n=28), possibly not tolerated (n=2 C. Andersson; patient inquiry: used without illeffecs (n=18). Used in Swedish porphyria ward . See e.g. Feierman et al. The paradoxical effect of acetaminophe on CYP3A4 activity and content in transfected HepG2 cells. Arch Biochem Biophys 2002 398: 109-17. Codeine: Opioide with analgetic and antitussive properties. Demetylated by CYP 2D6 and 3A4. Inhibitor of 2D6. EPI-list: safe South African list: use French list: authorized Anderson KE: Effects of antihypertensive drugs on hepatic heme biosynthesis, and evaluation of ferrochelatase inhibitors to simplify testing of drugs for heme pathway induction. Biochem Biophys Acta 543:313, 1978: safe Moore MR, Hift RJ: Drugs in the acute porphyrias. Cell Mol Biol 43:89, 1997: safe

Paracetamol: Uneventful use reported in 430 patients with acute porphyria. Codeine: Uneventful use reported in 27 patients with acute porphyria.