Tenoretic 100 mg/25 mg is used to treat high blood pressure (hypertension) in adults, and it also helps to prevent complications like heart attacks and strokes. It’s a combination medication containing two active ingredients: atenolol (a beta-blocker) that slows the heart and reduces its force, and chlorthalidone (a diuretic or water pill) that increases urine production to remove excess water and salt from the body.