Cozaar Pill Side Effects

Cozaar, or losartan, is a prescription medication approved for the treatment of high blood pressure and diabetic neuropathy in type 2 diabetes. Cozaar belongs to a class of medications called the angiotensin II receptor blockers. It works to block the effects of angiotensin II, a chemical produced in the body. Angiotensin raises the blood pressure by narrowing the blood vessels. It also leads to the release of another chemical called aldosterone. Aldosterone causes sodium and water to be retained in the body, which may further increase the blood pressure.

Chest Pain

Cozaar may produce chest pain in many individuals. In people who have diabetic neuropathy, chest pain can occur in up to 12 percent of users. Chest pain may also be a sign of something more serious, such as heart attack. If you experience chest pain, seek medical attention immediately.


Fatigue is a common side effect seen with the administration of Cozaar. It is more common in individuals who have diabetic neuropathy; according to the “Drug Information Handbook,” about 14 percent of people may experience fatigue. Weakness is also present in users of Cozaar. Be careful driving or operating heavy machinery until you know how the drug will affect you. As your body begins to adjust to the new drug, these side effects will slowly decrease. If they worsen, contact your health care provider.


Diarrhea is a common side effect associated with the use of Cozaar. About 2 to 14 percent of individuals develop diarrhea, reports the “Drug Information Handbook.” Drink plenty of fluids to avoid this side effect. Eat small frequent meals and avoid eating food high in fat. If diarrhea becomes severe or if you develop bloody stools, seek medical attention right away.


Cozaar may produce a dry, persistent cough. Up to 11 percent of individuals may experience cough. The “Drug Information Handbook” explains that it occurs more commonly in individuals who developed a cough on an angiotensin-converting enzyme (ACE) inhibitor. ACE inhibitors, such as lisinopril, benazepril and ramipril, are medications used for the treatment of high blood pressure. If you develop this side effect, see your physician right away. You may require a different dose or a different medication.


Angioedema, which is described by the swelling lips, throat and mouth, may occur in users of Cozaar. It is a rare side effect seen in less than 1 percent of individuals. It is a life-threatening effect and requires emergency medical intervention.

About this Author

Karla Casco began writing in 2010 for LIVESTRONG.COM, focusing her work on diseases and treatments and their side effects. She has also created patient handouts, PowerPoint presentations and journal clubs. She holds a pharmacy intern license and has a doctorate in pharmacy from St. John’s University.