Common Side Effects of Losartan
Losartan, an angiotensin II receptor blocker used for high blood pressure and heart failure, commonly causes dizziness (up to 4% of users), back pain (2-3%), nasal congestion, and diarrhea. These often improve as the body adjusts.[1][2]
Serious Side Effects and Warnings
Rare but serious risks include low blood pressure (hypotension), especially in dehydrated patients or those on diuretics; high potassium levels (hyperkalemia); and kidney problems, with symptoms like swelling, fatigue, or reduced urine output. Allergic reactions occur in under 1%, featuring rash, itching, or swelling. It's contraindicated in pregnancy due to fetal harm risk.[1][3]
What Happens If You Get Hyperkalemia from Losartan?
Symptoms include muscle weakness, irregular heartbeat, or nausea. Risk rises with kidney issues, potassium supplements, or drugs like spironolactone. Doctors monitor blood levels and may adjust dose or switch meds.[2][4]
Side Effects in Elderly Patients or Those with Kidney Disease
Older adults face higher rates of dizziness and falls from low blood pressure. In kidney impairment, losartan can worsen function, so starting doses are lower (25-50 mg) with frequent checks.[1][3]
How Long Do Side Effects Last?
Most mild effects like dizziness fade within days to weeks. Persistent issues may need dose reduction. Serious ones like kidney decline require immediate medical attention.[2]
Losartan vs. Other ARBs: Side Effect Differences
Losartan has a similar profile to valsartan or irbesartan but slightly higher cough risk (1-2% vs. near-zero for ARBs generally). ACE inhibitors like lisinopril cause more cough (up to 10%).4
Managing Side Effects While Taking Losartan
Stay hydrated, rise slowly from sitting, and avoid potassium-rich foods unless advised. Report chest pain, severe dizziness, or yellowing skin promptly. No alcohol excess, as it amplifies low blood pressure.[1][2]
[1]: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/losartan-potassium-label
[2]: https://www.mayoclinic.org/drugs-supplements/losartan-oral-route/side-effects/drg-20067341
[3]: https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/020386s066lbl.pdf
[4]: https://www.ncbi.nlm.nih.gov/books/NBK526065/