Hydrochlorothiazide and triamterene with sustained-release oxprenolol in the treatment of hypertension

A single-blind, three-way Latin square crossover study without wash-out periods was performed in a general practice. Thirty moderately hypertensive patients were studied to compare the antihypertensive effect of 160 mg sustained-release oxprenolol once daily, 25 mg hydrochlorothiazide/50 mg triamterene once daily or a combination of the two preparations once daily, each treatment being given for 1 month. Blood pressure control was significantly better with the combination than with either agent used separately. Pulse rates, as expected, were lower when sustained-release oxprenolol was taken either alone or in the combination. Adverse events led to withdrawal in 1 patient only. Otherwise, all treatments were well tolerated and compliance was excellent. Renal function tests indicated a slight increase in creatinine, urate and urea levels after the treatments which included hydrochlorothiazide compared with oxprenolol alone, although the results were of no clinical significance.