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THE EFFECT OF INHALED FENOTEROL AND IPRATROPIUM BROMIDE ON PROPRANOLOL INDUCED BRONCHOCONSTRICTION IN THE ASTHMATIC AIRWAYS
Author(s) -
Latimer K. M.,
Ruffin R. E.
Publication year - 1990
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1990.tb01363.x
Subject(s) - ipratropium bromide , fenoterol , bronchoconstriction , ipratropium , medicine , placebo , bronchodilator , anesthesia , propranolol , asthma , inhalation , alternative medicine , pathology
SUMMARY 1. The provocative dose of inhaled propranolol, (PC 20 P, mg/mL) needed to induce a 20% reduction in the forced expired volume in 1 s (FEV 1 , 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. 2. Fenoterol 200 μg, 800 μg increased the baseline FEV 1 0.28±0.16, 0.32±0.16 L ( P = 0.04, P = 0.008 respectively). Fenoterol 800 μg moved the PC 20 P rightwards from placebo geometric mean 10.95, 95% Confidence Intervals (95% CI) 4.43–27.22 mg/mL to mean 20.41, 95% CI 10.13 to 40.64 mg/mL ( P = 0.01). Fenoterol 200 μg was not protective; mean PC 20 16.22, 95% CI 7.83–34.35 mg/mL ( P = 0.08). Neither 40 or 160 μg ipratropium changed the FEV 1 or PC 20 P values compared with placebo; increase in FEV 1 0.15±0.27 L ( P = 0.22), 0.24±0.12 L ( P = 0.14) and geometric mean PC 20 P 16.59±0.57 mg/mL 95% CI 8.01–34.51 mg/mL ( P = 0.90), 15.48±0.66 mg/mL, 95% CI 6.72–36.05 mg/mL ( P = 0.34) respectively after ipratropium treatments. 3. Bronchoconstriction induced by inhaled propranolol (P) appears to be only weakly antagonized by inhaled β‐agonist and not reduced by antimuscarinic anticholinergic aerosol. This finding argues against the activation of a cholinergic reflex to explain propranolol induced bronchoconstriction (PIB).