Can Losartan (angiotensin II receptor antagonist) exacerbate edema?

From the Guidelines

Losartan does not typically exacerbate edema and is often used to treat conditions that cause fluid retention. As an angiotensin II receptor antagonist (ARB), losartan helps reduce edema by blocking the effects of angiotensin II, which normally causes blood vessel constriction and sodium retention. By preventing these actions, losartan promotes vasodilation and increased sodium and water excretion by the kidneys, which generally decreases fluid retention and edema. This is why losartan is commonly prescribed for conditions like hypertension, heart failure, and diabetic nephropathy where edema may be present. According to the guidelines for the diagnosis and management of heart failure in adults 1, angiotensin converting enzyme inhibitors (ACEIs) are preferred over ARBs due to their greater experience and weight of evidence in support of their effectiveness, but ARBs like losartan can be used as an alternative. However, in rare cases, some patients might experience paradoxical edema when starting losartan therapy, particularly if they have severe heart failure or renal artery stenosis. If a patient develops unexpected edema while taking losartan, they should consult their healthcare provider promptly as it may indicate an underlying condition requiring attention rather than a direct effect of the medication itself. Some key points to consider when prescribing losartan include:

• Monitoring patients for signs of edema, especially those with a history of fluid retention
• Using diuretics in combination with losartan to maintain sodium balance and prevent edema
• Avoiding losartan in patients with bilateral renal artery stenosis or elevated levels of serum potassium
• Initiating treatment with losartan with caution in patients with very low systemic blood pressures or markedly increased serum levels of creatinine.

From the Research

Edema and Losartan

• Edema is a potential side effect of various antihypertensive therapies, including vasodilators and dihydropyridine calcium antagonists 2.
• Losartan, an angiotensin II receptor antagonist, has been reported to cause angioedema in some cases 3, 4.
• The mechanism of losartan-induced angioedema is not fully understood, but it may not be related to bradykinin excess 3.
• Studies have shown that losartan can cause angioedema in patients with a history of angioedema secondary to angiotensin-converting enzyme inhibitors 3, 4.

Comparison with Other Antihypertensive Agents

• Losartan has been compared to nifedipine GITS in terms of efficacy, tolerability, and quality of life, and was found to have superior tolerability with respect to edema 5.
• The addition of an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker, such as losartan, to a dihydropyridine calcium antagonist can reduce vasodilatory edema 2.
• Losartan/hydrochlorothiazide treatment has been shown to exert good blood pressure control, but its effect on high-molecular weight adiponectin levels was unchanged in one study 6.

Clinical Implications

• Clinicians should be aware of the potential risk of angioedema associated with losartan, particularly in patients with a history of angioedema secondary to angiotensin-converting enzyme inhibitors 3, 4.
• Losartan may not be a suitable alternative for patients who have experienced angioedema with angiotensin-converting enzyme inhibitors 3, 4.
• The use of losartan should be carefully considered in patients with a history of edema or angioedema, and patients should be monitored closely for signs and symptoms of edema 3, 4.