Does Cozaar contain a diuretic?

No, Cozaar (losartan) doesn't contain a diuretic.

Cozaar is in a group of drugs called angiotensin II receptor antagonists. It keeps blood vessels from narrowing, which lowers blood pressure and improves blood flow and helps the kidneys to eliminate extra fluid.

Cozaar is used to treat high blood pressure (hypertension). It is sometimes given together with other blood pressure medications.

http://www.drugs.com/cozaar.html

Hyzaar contains losartan and hydrochlorotiazide (a diuretic).

http://www.drugs.com/hyzaar.html