Amiloride and Fosinopril and hydrochlorothiazide interaction

Hyperkalemia occurs commonly (about 10%) when amiloride is used without a kaliuretic diuretic.

When amiloride HCl is used concomitantly with a thiazide diuretic in patients without these complications, the risk of hyperkalemia is reduced to about 1-2 percent.

It is thus essential to monitor serum potassium levels carefully in any patient receiving amiloride, particularly when it is first introduced, at the time of diuretic dosage adjustments, and during any illness that could affect renal function.

The risk of hyperkalemia may be increased when potassium-conserving agents, including amiloride HCl, are administered concomitantly with an angiotensin-converting enzyme inhibitor, an angiotensin II receptor antagonist, cyclosporine or tacrolimus.

Diabetes Mellitus In diabetic patients, hyperkalemia has been reported with the use of all potassium-conserving diuretics, including amiloride HCl, even in patients without evidence of diabetic nephropathy.

Symptomatic hypotension is most likely to occur in patients who have been volume- and/or salt-depleted as a result of prolonged diuretic therapy, dietary salt restriction, dialysis, diarrhea, or vomiting.

The thiazide component of fosinopril sodium and hydrochlorothiazide may potentiate the action of other antihypertensive drugs, especially ganglionic or peripheral adrenergic-blocking drugs.

In such patients, fosinopril sodium and hydrochlorothiazide therapy should be started under close medical supervision; they should be followed closely for the first 2 weeks of treatment and whenever the dose of fosinopril or diuretic is increased.

In some studies of hypertensive patients with unilateral or bilateral renal artery stenosis, treatment with ACE inhibitors has been associated with increases in blood urea nitrogen and serum creatinine; these increases were reversible upon discontinuation of ACE inhibitor therapy, concomitant diuretic therapy, or both.

Some ACE-inhibitor-treated hypertensive patients with no apparent preexisting renal vascular disease have developed increases in blood urea nitrogen and serum creatinine, usually minor and transient, especially when the ACE inhibitor has been given concomitantly with a diuretic.