Common side effects of losartan include dizziness, stuffy nose, back pain, diarrhea, tiredness, low blood sugar, chest pain, and high or low blood pressure.

An irregular heartbeat (arrhythmia) has been reported with losartan but is rare. The dizziness associated with losartan usually occurs early in treatment or with an increase in dosage. It usually disappears with continued use.

If there is anything you are specifically concerned about talk with your doctor. Losartan (Cozaar) is in a group of drugs called angiotensin II receptor antagonists. Losartan widens the blood vessels which lowers blood pressure and improves blood flow.

Losartan is used to treat high blood pressure (hypertension). It is also used to lower the risk of stroke in certain people with heart disease.

Losartan is used to slow long-term kidney damage in people with type 2 diabetes who also have high blood pressure.

For more information see: losartan side effects in detail.