Bendroflumethiazide is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention. Nadolol is in a group of drugs called beta-blockers. Beta-blockers affect the heart and circulation (blood flow through arteries and veins). The combination of bendroflumethiazide and nadolol is used to treat high blood pressure (hypertension). Bendroflumethiazide and nadolol may also be used for other purposes not listed in this medication guide.