• if you are allergic (hypersensitive) to losartan, hydrochlorothiazide or to any of the other ingredients in this medicine. • if you are allergic (hypersensitive) to other sulfonamide-derived substances (e. g. other thiazides, some antibacterial drugs such as co-trimoxazole, ask your doctor if you are not sure) • if you are, think you may be or are planning to become pregnant (see also “ Pregnancy and breast-feeding”) • if you are breast-feeding • if you have severely impaired liver function • if you have severely impaired kidney function or your kidneys are not producing any urine. • if you have low potassium, low sodium or high calcium levels which cannot be corrected by treatment • if you are suffering from gout