Side effects of losartan
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Side Effects of Losartan
Losartan is a widely used antihypertensive medication that functions as an angiotensin II receptor antagonist. While it is generally well-tolerated, it is important to be aware of its potential side effects.
Common Side Effects: Headache, Dizziness, and Fatigue
The most frequently reported side effects of losartan include headache, upper respiratory tract infection, dizziness, and asthenia (fatigue) . These side effects are generally mild and occur at similar rates in patients treated with placebo, except for dizziness, which is slightly more common in losartan-treated patients .
Respiratory Issues: Cough
Cough is another side effect associated with losartan, occurring in about 3.1% of patients, which is comparable to the 2.6% incidence in placebo-treated patients . This is significantly lower than the incidence of cough in patients treated with angiotensin-converting enzyme (ACE) inhibitors, which is around 8.8%.
Metabolic Effects: Hyperkalemia and Anemia
Losartan has been reported to cause hyperkalemia (elevated potassium levels) and anemia in some patients . These side effects are particularly important to monitor in patients with compromised renal function or those taking other medications that affect potassium levels.
Rare but Serious Side Effects: Pancreatitis and Parkinsonism
Although rare, losartan has been associated with serious side effects such as acute pancreatitis and worsening of Parkinson's disease symptoms. A case study reported a patient developing acute pancreatitis shortly after starting losartan, with symptoms resolving upon discontinuation of the drug. Another case described a patient with Parkinson's disease experiencing a significant worsening of symptoms, including bradykinesia and freezing episodes, which improved after stopping losartan.
Impact on Insulin Sensitivity and Glucose Metabolism
Losartan appears to be metabolically neutral, with no significant adverse effects on insulin sensitivity, glucose tolerance, or lipid metabolism. This makes it a suitable option for hypertensive patients with metabolic concerns.
Long-term Safety: Renal Function and Proteinuria
Long-term use of losartan has been shown to be safe in renal transplant recipients, effectively lowering blood pressure and reducing proteinuria without adversely affecting graft function. However, a significant reduction in hemoglobin levels was observed, indicating the need for regular monitoring of blood parameters.
Drug Interactions: Digoxin and Other Medications
Losartan does not significantly alter the pharmacokinetics of digoxin, a medication often used in patients with heart conditions, indicating that it can be co-administered without major concerns. However, caution is advised when losartan is combined with other drugs that affect the cytochrome P450 system, such as phenobarbital, rifampin, or fluconazole, due to potential interactions.
Conclusion
Losartan is generally well-tolerated with a favorable safety profile. Common side effects include headache, dizziness, and fatigue, while serious side effects like pancreatitis and worsening of Parkinson's symptoms are rare. Regular monitoring is recommended for patients with renal impairment or those on multiple medications to manage potential side effects effectively.
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