Valsartan: Not metabolised. Hydrochlorothiazide: South African list: use. French list: autorisé. Australian list: unsafe associated with attacks. Thunell, patient report (n=1): tolerated. Andersson, patient reports (n=10): tolerated. Martindale: Hydrochlorothiazide has been associated with acute attacks of porphyria and is unsafe in porphyric patients. EPI-list: sulfonamides on the unsafe list.

Valsartan: Angiotensin II receptor antagonist. Bioavailability 23 %. Eliminated in unchanged form. Less potent inhibitor of CYP 2C9. Hydrochlortiazide: Tiazide diuretic, sulfonamide congener. Eliminated in urine in unchanged form. Probably no CYP-affinity. Hydrochlortiazide: South African list: use. French list: autorisé. Australian list: unsafe associated with attacks. Thunell, patient report (n=1): tolerated. Andersson, patient reports (n=10): tolerated. Martindale: Hydrochlortiazide 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 3 patients with acute porphyria.