Losartan/hydrochlorothiazide is a combination drug used as an antihypertensive, consisting of losartan (an angiotensin II receptor antagonist) and hydrochlorothiazide (a diuretic).
The losartan/hydrochlorothiazide combination preparation is marketed by Merck under the trade name Hyzaar and by Xeno Pharmaceuticals under the name Anzaplus. Merck, Sharp & Dohme market it as Ocsaar Plus in Israel. It is marketed as Cozaar comp in Sweden.
In 2010, the patent for the combination expired, and a number of pharmaceutical companies promptly filed and received approval to sell the generic losartan, with and without hydrochlorothiazide, in the United States. 
The recommended dosage of losartan-hydrochlorothiazide for people with high blood pressure (hypertension) will vary between losartan-hydrochlorothiazide 50 mg/12.5 mg and losartan-hydrochlorothiazide 100 mg/25 mg once a day. Based on the initial blood pressure response and/or losartan-hydrochlorothiazide side effects, the dosage may be increased or decreased. With each change in dosage, it may take up to a month to see the full effects of losartan-hydrochlorothiazide on lowering blood pressure.