Atenolol + Chlorthalidone

Atenolol and chlorthalidone have each been used on their own and together for treating high blood pressure. Studies show that combining them into a single tablet does not affect how well either drug is absorbed, so this combination offers a convenient way to take both medicines at once. Atenolol is a beta1-selective (cardioselective) beta-blocker: it lowers the heart rate both at rest and during exercise, reduces cardiac output, lowers systolic and diastolic blood pressure at rest and during exercise, and lessens the reflex rise in heart rate that occurs on standing (reflex orthostatic tachycardia). Chlorthalidone is a monosulfonamyl diuretic with a long duration of action and low toxicity. It increases urine output by markedly boosting the excretion of sodium and chloride at the distal convoluted tubule of the nephron.