The effects of treatments with labetalol and hydrochlorothiazide on ventilatory function of asthmatic hypertensive patients with demonstrated bronchosensitivity to propranolol

Abstract

Fifty-two asthmatic patients with mild to moderate hypertension were screened for bronchosensitivity to propranolol in a double-blind randomized fashion after a 2-week minimum placebo run-in period. Thirty-five patients qualified on the basis of a decrease in 1-second forced expiratory volume FEV1 by greater than or equal to 20% after 80 mg of propranolol with no more than a +/- 15% change after placebo. Of these patients, 18 were then randomly assigned to antihypertensive treatment with labetalol at doses that were increased at weekly intervals (100, 200, 400, 600 mg BID) and 17, with hydrochlorothiazide (HCTZ) (25 or 50 mg BID) as needed for control of hypertension. At each placebo washout visit and at each of the four active drug-treatment phase visits, spirometric measurements were obtained just prior to the morning dose of medication and again 2 hours later on the initial visit (i.e., following the initial dose of active treatment) and on each visit when the dosage was increased. Neither HCTZ nor labetalol (average daily doses at the end of the study were 88 and 555 mg, respectively) caused bronchoconstriction: Mean FEV1 did not change from the baseline neither prior to the morning dose (evaluation of the "chronic" treatment effect) nor 2 hours after dosing (evaluation of "acute" treatment effect). Three patients in each treatment group reported increased dyspnea and two on labetalol and one on HCTZ had increased wheezing; the mean weekly isoproterenol usage per patients was similar for the two treatments (1.3 times/week/pt for labetalol and 1.6 times/week/pt for HCTZ).(ABSTRACT TRUNCATED AT 250 WORDS)