Losartan side effects
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Common Side Effects of Losartan
Losartan is widely used to treat high blood pressure and related conditions. The most commonly reported side effects include headache, dizziness, upper respiratory tract infection, fatigue, muscle cramps, cough, stuffy nose, and anemia. Among these, dizziness is the only side effect that occurs more frequently with losartan compared to placebo, but the overall rate of side effects is similar to placebo in most patients, including those with diabetes, kidney problems, or heart failure 12. Other frequently mentioned side effects are lethargy, nausea, vomiting, and impaired vision 34.
Rare and Serious Adverse Reactions
While losartan is generally well tolerated, rare but serious side effects have been reported. These include faintness, dysarthria (difficulty speaking), and tremors, as described in individual case reports. In these cases, symptoms resolved after stopping losartan, suggesting a probable link to the medication 34. Another rare but important side effect is drug-induced liver injury, which can present as fatigue, weakness, nausea, abdominal pain, and elevated liver enzymes. This reaction is very uncommon, with only a handful of cases reported in the literature .
Laboratory and Clinical Findings
Some studies have noted a reduction in hemoglobin levels (anemia) as a side effect, especially in patients with kidney transplants or those on long-term therapy 28. Hyperkalemia (high potassium levels) and hypotension (low blood pressure) are also possible, particularly in older adults or those with other health conditions 259. Fatigue and hypotension were among the most observed side effects in older adults in clinical studies .
Losartan Compared to Other Antihypertensive Drugs
When compared to other blood pressure medications like ACE inhibitors and calcium channel blockers, losartan is associated with a lower incidence of side effects. This makes it an attractive option for patients who have experienced side effects with other antihypertensive drugs .
Special Populations and Precautions
Losartan should not be used during pregnancy, as it can cause serious fetal toxic effects such as decreased amniotic fluid, underdeveloped lungs and skull bones, and even fetal death. These effects are similar to those seen with ACE inhibitors and highlight the importance of avoiding losartan in pregnant women .
In patients hospitalized for acute illnesses like COVID-19, losartan has been associated with a higher risk of serious adverse events, including hypotension and acute kidney injury. Caution is advised when considering losartan in these settings .
Conclusion
Losartan is generally well tolerated, with the most common side effects being mild and similar to placebo. Dizziness, cough, fatigue, and muscle cramps are among the most frequently reported. Rare but serious reactions, such as liver injury, anemia, and neurological symptoms, can occur. Losartan is better tolerated than some other antihypertensive drugs, but it should be avoided in pregnancy and used with caution in certain high-risk patients.
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Most relevant research papers on this topic
Serum concentrations of losartan metabolites correlate with improved physical function in a pilot study of prefrail older adults.
Losartan treatment in prefrail older adults can reduce frailty and improve physical function, with higher serum levels of its metabolites EXP3179 and EXP3174 indicating better physical performance.
Long-term anti-proteinuric effect of Losartan in renal transplant recipients treated for hypertension.
Long-term use of Losartan effectively lowers blood pressure and reduces proteinuria in renal transplant recipients, with no serious side-effects except for a decrease in haemoglobin.
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Effects of Losartan on Patients Hospitalized for Acute COVID-19: A Randomized Controlled Trial
Losartan does not decrease 28-day mortality in patients hospitalized for acute COVID-19, and ARBs should not be added to their care due to potential side effects.
DOI