Losartan can increase the amount of potassium in the blood, a condition called hyperkalemia.
The official prescribing information recommends periodic monitoring of serum potassium, particularly when losartan is combined with other medicines that can also raise potassium levels.
High potassium may sometimes cause no obvious symptoms, but when symptoms occur they can include muscle weakness, unusual tiredness, tingling, or abnormal heart rhythms.
Blood tests are the reliable way to determine potassium levels.
## 9. Changes in Kidney Function
Losartan affects the system that regulates blood pressure and kidney function. In some patients, particularly those at higher risk, kidney function may worsen during treatment.
Official prescribing information recommends monitoring kidney function in susceptible patients, especially when certain medications such as NSAIDs are used at the same time.
Contact your healthcare provider if you notice a major decrease in urination, unusual swelling, marked weakness, or other concerning changes.
## 10. Swelling of the Face, Lips, Tongue, or Throat
