Losartan potassium side effects
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Common Side Effects of Losartan Potassium
Losartan potassium is generally well tolerated, with most clinical trials reporting very few side effects, and the overall rate of side effects is similar to that of placebo. The most commonly reported side effects include dizziness, headaches, fatigue, nausea, vomiting, and anemia. Dizziness is the only side effect that occurs more frequently with losartan than with placebo. First-dose hypotension is uncommon, and losartan is associated with a low incidence of cough, even in patients who have experienced cough with ACE inhibitors 123.
Rare and Serious Adverse Effects
Although rare, losartan can cause serious side effects such as angioedema (swelling of the deeper layers of the skin) and acute hepatitis. These have been reported in a very small number of patients. There is also a case report of tremors and dysarthria (difficulty speaking) occurring shortly after taking losartan, though this appears to be extremely rare and resolved without specific treatment 13.
Effects on Potassium Levels: Hyperkalemia Risk
A notable side effect of losartan is its potential to increase serum potassium levels, leading to hyperkalemia. This risk is higher when losartan is used in combination with potassium-sparing diuretics (such as spironolactone or triamterene) or in patients with kidney problems. Studies have shown that losartan is an independent predictor of elevated potassium levels, and high potassium can increase the risk of adverse kidney outcomes, especially in patients with diabetes and nephropathy 156. High-dose losartan increases the risk of hyperkalemia but also reduces the risk of hypokalemia (low potassium), and the benefits of high-dose losartan are maintained across different potassium levels .
Special Considerations: Use in Pregnancy, Renal, and Liver Dysfunction
Losartan should not be used during pregnancy or breastfeeding, as it may harm fetal development or the newborn. Caution is also advised in patients with renal failure or liver dysfunction, as these conditions can increase the risk of adverse effects .
Drug Interactions and Laboratory Abnormalities
Losartan is mainly metabolized in the liver and is not significantly affected by drugs that induce or inhibit liver enzymes, such as phenobarbital or cimetidine. Clinically relevant adverse metabolic effects or laboratory abnormalities have not been commonly documented during losartan therapy, and renal function is generally preserved in patients with or without renal insufficiency 12.
Conclusion
Losartan potassium is a well-tolerated antihypertensive medication with a side effect profile similar to placebo in most patients. The most common side effects are mild, such as dizziness and headache. However, there is a risk of hyperkalemia, especially in patients with kidney disease or those taking potassium-sparing diuretics, and rare but serious reactions like angioedema can occur. Losartan should be avoided in pregnancy and used with caution in patients with renal or liver impairment. Regular monitoring of potassium levels and kidney function is recommended for patients on losartan, particularly those at higher risk.
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