Enalapril: No evidence of CYP-dependent metabolism. Some clinical experience as well as two references point to non- porphyrinogenicity. Hydrochlorothiazide: Not metabolised. Probably no CYP-affinity. Clinical experience of non-porphyrinogenicity. Conflicting evidence.

Enalapril: ACE-inhibitor. Hydrolyzed to enalaprilate, otherwise not metabolized. Hydrochlorthiazide: Thiazide diuretic. Eliminated in urine in unchanged form. No observations of CYP interaction. Enalapril: Andersson, patient report (n=7) tolerated. South African list: use with care. French list: avoid. 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 are on the unsafe list.

Uneventful use reported in 1 patient with acute porphyria.