Cilazapril: No evidence of significant CYP-dependent metabolism. Occasional observations of tolerance. Two references stating (probable) non-porphyrinogenicity. Hydrochlorthiazide: Not metabolised. Probably no CYP-affinity. Clinical experience of non-porphyrinogenicity. Conflicting evidence.

(To be edited, initial data ST OCT 04) Cilazapril: Hydrolyzed to cilazaprilate, a long term ACE- inhibitor. Excreted (90%) in unchanged form by the kidneys. Hydrochlorthiazide: thiazide diuretic. Eliminated in urine in unchanged form. No observations of CYP interaction. Cilazapril: Swedish experience (n=2): safe. South African list: use with care. French list: authorized. Hydrochlorthiazide: South African list: use. French list: authorized. Australian list: unsafe associated with attacks. Thunell, patient report (n=1): tolerated. Andersson, patient reports (n=10): tolerated. Martindale: Hydrochlorthiazide has been associated with acute attacks of porphyria and is considred unsafe in porphyric patients. EPI-list: sulfonamides on the unsafe list.

Uneventful use reported in 1 patient with acute porphyria.