R. E. Ruffin

Inhaled verapamil in histamine-induced bronchoconstriction

Fifteen asthmatic subjects participated in a double-blind trial comparing the protective effects of inhaled verapamil, salbutamol, and saline against inhaled histamine. Inhaling verapamil between four repeated histamine inhalation tests produced no significant protection against histamine-induced bronchoconstriction, while there was significant protection with salbutamol (p less than 0.001). Inhaling verapamil before a single inhalation test produced limited but significant protection (p less than 0.05) compared with a saline control in eight asthmatic subjects. This small protective effect in the two-treatment study of eight asthmatics suggests that either the protective effect of verapamil is variable among subjects or a preceding histamine inhalation test blocks the verapamil effect.

Combination bronchodilator therapy in asthma

This study has compared the short-term bronchodilator effects of inhaled anticholinergic (ipratropium bromide) and sympathomimetic (fenoterol) agents alone and in combination in 18 asthmatic patients. the study was of double-blind, placebo-controlled, crossover design. The combination of 60 micrograms ipratropium bromide and 200 micrograms of fenoterol had a greater bronchodilator effect than lower dose combinations or either drug alone. Small but significant gains may be made with combination inhaled bronchodilator therapy.

The effect of bucindolol on the airway function of asthmatics

SummaryThe airway and cardiovascular effects of separate single oral doses of 50, 100 and 200 mg of bucindolol were compared to those of placebo in a double-blind trial in 16 patients with mild to moderately severe asthma. Heart rate (HR), blood pressure (BP), forced vital capacity (FVC), forced expired volume in one second (FEV1), maximum expiratory flow at 50% of vital capacity (FEF50) and maximum expiratory flow at 75% of expired vital capacity (FEF75) were measured before and at intervals for 4 h, when salbutamol (200 µg) was inhaled and the measurements repeated 15 min later. There was an interval of at least 4 days between each drug treatment day.Four of the 16 patients developed clinically significant bronchoconstriction with 50 mg (3) or 100 mg (1) of bucindolol and were withdrawn from the study. The remaining patients showed impaired bronchodilator response to salbutamol for each bucindolol dose as compared to placebo. No significant BP or HR effects were measured. Two patients withdrew because of circumstances unrelated to bucindolol induced bronchoconstriction. The development of bucindolol induced bronchoconstriction in this group of mild to moderate asthmatics was not predicted by the level of baseline pulmonary function, or the level of histamine responsiveness. However, there was a weak relationship between bucindolol induced bronchoconstriction and salbutamol induced bronchodilation. There was no definitive asthmatic characteristic to predict the likelihood of significant bucindolol induced bronchoconstriction in this asthmatic population.

THE EFFECT OF INHALED FENOTEROL AND IPRATROPIUM BROMIDE ON PROPRANOLOL INDUCED BRONCHOCONSTRICTION IN THE ASTHMATIC AIRWAYS

1. The provocative dose of inhaled propranolol, (PC20P, mg/mL) needed to induce a 20% reduction in the forced expired volume in 1 s (FEV1, L) was determined for 15 adult asthmatics following randomized pre‐treatment with placebo, ipratropium bromide (40, 160 μg) and fenoterol (200, 800 μg) aerosols using a double‐blind protocol.

The effect of trifluoperazine on bronchial responsiveness in asthma.

1. The protective effects of oral trifluoperazine (TFP) (7mg) against standardized methacholine and histamine inhalation tests (MIT and HIT) were examined 2 and 22 h post‐treatment in eight stable asthmatics using a randomized double‐blind protocol.