A vasodilatory antihypertensive drug lowers blood pressure by reducing systemic vascular resistance. Some patients treated with these agents may develop dependent edema.
Factors contributing to edema associated with vasodilating antihypertensive medications:
(1) water retention
(2) arteriolar dilatation with increased intracapillary pressure
(3) stimulation of the renin-angiotensin-aldosterone system
Risk factors for vasodilatory edema:
(1) drug type (see table below)
(2) a higher dose of the causative drug
(3) older age
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Risk of Vasdilatory Edema
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Antihypertensive Drugs
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highest
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minoxidil, hydralazine (direct arteriolar dilators)
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amlodipine, nifedipine (higher risk dihydropyridine calcium antagonists)
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lercanidipine, lacidipine (lower risk dihydropyridine calcium antagonists)
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alpha-blocker
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anti-adrenergic drugs (beta-blockers)
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lowest
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nondihydropyridine calcium antagonists
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Therapeutic decision-making:
(1) The addition of a diuretic does not reduce vasodilatory edema.
(2) Addition of an angiotension converting enzyme (ACE) inhibitor or angiotensin receptor blocking (ARB) agent to therapy with a dihydropyridine calcium antagonist is associated with less vasodilatory edema than increasing the antagonist's dose.
(3) Addition of a selective blocker of the renin-angiotensin system (such as the ARB valsartan) may reduce vasodilatory edema by dilating venules.
This drug-induced peripheral edema needs to be distinguished from onset or worsening of congestive heart failure.
