High blood pressure not controlled by losartan or a thiazide diuretic alone. It is a maintenance combination, not a starting treatment.

The two work on different parts of the same problem. Losartan blocks the angiotensin II receptor so blood vessels relax and the kidneys stop holding salt and water. Hydrochlorothiazide acts directly on the kidney tubule to send more sodium and water out in the urine, lowering the volume of blood the heart has to move. Together they lower pressure more than either can alone.

Dizziness, tiredness, headache, passing more urine, and changes in blood salts, particularly low potassium and low sodium from the diuretic. Gout can flare, and blood sugar and cholesterol may drift up.

Not for use in pregnancy. Blood tests are needed to watch kidney function and salts, especially in the first weeks and after any dose change. Tell your doctor about gout, diabetes, lupus, severe kidney or liver disease, or an allergy to sulfonamides. Take the dose in the morning so the extra urine does not disturb your sleep, and take care in hot weather or during illness with vomiting or diarrhoea, which can cause dehydration. It is a prescription medicine in Pakistan.