Atenolol and chlorthalidone in combination in the management of older hypertensive patients: a randomized clinical trial.

In a double-blind, crossover study in 100 elderly hypertensive patients, the hypotensive effect of a fixed combination of atenolol (50 mg) with chlorthalidone (12.5 mg) was compared with that of each of its component drugs given alone. Patients were allocated at random into two groups: one group received treatment for 4 weeks with either the combination or atenolol alone before being crossed over to the alternative medication for a further 4 weeks; the other group received either the combination or chlorthalidone alone and followed the same treatment pattern. Dosage was a single tablet per day given in the morning. Blood pressure and pulse rate were measured approximately 24 hours after dosing at the end of each treatment period. The results showed that significantly lower blood pressures were achieved, both in the standing and lying positions, with the combination than with either atenolol or chlorthalidone used alone. Combination treatment was well tolerated, few side-effects being reported and there was no significant disturbance of plasma electrolytes.