Fosinopril:No evidence of significant CYP-dependent metabolism. 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) Fosinopril: Hydrolyzed by esterases in the liver to fosinoprilate, an ACE-inhibitor. Of this 75% is excreted in unchanged form by the kidneys, 20-30% as glucuriode conjugate and 1-5% as p-hydroxy metabolite. Hydrochlorthiazide: thiazide diuretic, sulfonamide congener. Eliminated in urine in unchanged form. Probably no CYP-affinity. Fosinopril: 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.