Exforge combines two anti-hypertensive drugs that have complementary mechanisms of action: amlodipine, a calcium (Ca+) channel blocker, and valsartan, an angiotensin II (Ang II) antagonist. Amlodipine blocks the influx of Ca+ into vascular smooth muscle and cardiac muscle, with a greater effect on vascular smooth muscle. It is a peripheral artery vasodilator that causes a reduction in peripheral vascular resistance and a reduction in blood pressure. Valsartan blocks the vasoconstrictive and aldosterone-secreting effects of Ang II by blocking its receptor sites in vascular smooth muscle and the adrenal gland.
Clinical trials:
In a placebo-controlled study, 1018 patients with mild-to-moderate hypertension were given three combinations of amlodipine + valsartan, or amlodipine alone (5mg), valsartan alone (80, 160, or 320mg), or placebo. At week 8, the combination treatments (doses of 5/80, 5/160, 5/320mg) were significantly better than their monotherapy components in the reduction of diastolic BP and systolic BP.
In a placebo-controlled study, 1250 patients with mild-to-moderate hypertension were given treatments of two combinations of amlodipine + valsartan (10/160 or 10/320mg), amlodipine alone (10mg), valsartan alone (160 or 320mg), or placebo. At week 8, the combination treatments were shown to be significantly better than their monotherapy components in reducing diastolic and systolic BP.
Adults:
Usual maintenance: 1 tab daily. May switch from both components taken separately to same dose in Exforge. Dose-limiting effects of either component taken separately: may switch to Exforge with a lower dose of that component; if inadequate response after 3–4 weeks, may titrate to max 10/320mg per day. May switch patients not controlled on any dihydropyridine CCB alone or ARB alone to Exforge.
Children:
Not recommended.
Precautions:
Correct hypovolemia before starting (may need to reduce diuretic) or monitor closely for hypotension. Severe heart failure (HF) (if renal function depends on renin-angiotensin-aldosterone system). Severe obstructive coronary disease. Recent MI. Severe aortic stenosis. Hepatic or severe renal impairment. Renal artery stenosis. Dialysis. Surgery. Pregnancy (Cat. C in 1st trimester, Cat. D in 2nd and 3rd trimesters). Nursing mothers: not recommended.
Interactions:
Concomitant K+ supplements, K+ sparing diuretics, K+ containing salt substitutes may lead to hyperkalemia and, in HF patients, increased serum creatinine.