The blood pressure lowering effect of ENaC blockers is not known

Potassium-sparing diuretics, which block the epithelial sodium channel (also called ENaC blockers), are a class of drugs commonly prescribed to prevent loss of potassium but also might help to lower elevated blood pressure. This class includes drugs such as amiloride (Midamor, Amilzide) and triamterene (Dyrenium, Dyazide). We asked how much this class of drugs lowers blood pressure, when used alone or when used as the second drug to treat hypertension. The available scientific literature was searched to find all the trials that had assessed this question. No trials were found studying the blood pressure lowering ability of ENaC blockers when used alone. We found 6 trials studying the blood pressure lowering ability of amiloride and triamterene, when added as a second drug, in 496 participants. All 6 trials studied the ENaC blockers at low doses and there was no blood pressure lowering effect. Trials studying these drugs at higher doses are needed in order to determine if they lower blood pressure. The harms associated with ENaC blockers could not be estimated in this review because of the low doses studied and the short duration of the trials.