Adverse Respiratory Effect of Acute β-Blocker Exposure in Asthma A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background: beta-Blockers are avoided in asthma over concerns regarding acute bronchoconstriction. Risk is greatest following acute exposure, including the potential for antagonism of beta(2)-agonist rescue therapy. Methods: A systematic review of databases was performed to identify all randomized, blinded, placebo-controlled clinical trials evaluating acute beta-blocker exposure in asthma. Effect estimates for changes in respiratory function, symptoms, and beta 2-agonist response were pooled using random effects meta-analysis with heterogeneity investigated. Results: Acute selective beta-blockers in the doses given caused a mean change in FEV1 of 2 6.9% (95% CI, - 8.5 to - 5.2), a fall in FEV1 of >= 20% in one in eight patients (P =.03), symptoms affecting one in 33 patients (P =.18), and attenuation of concomitant beta(2)-agonist response of -10.2% (95% CI, - 14.0 to - 6.4). Corresponding values for acute nonselective beta-blockers in the doses given were - 10.2% (95% CI, - 14.7 to - 5.6), one in nine patients (P =.02), one in 13 patients (P =.14), and 2 20.0% (95% CI, - 29.4 to - 10.7). Following investigation of heterogeneity, clear differences were found for celiprolol and labetalol. A dose-response relationship was demonstrated for selective beta-blockers. Conclusions: Selective beta-blockers are better tolerated but not completely risk-free. Risk from acute exposure may be mitigated using the smallest dose possible and beta-blockers with greater beta(1)-selectivity. beta-Blocker-induced bronchospasm responded partially to beta(2)-agonists in the doses given with response blunted more by nonselective beta-blockers than selective beta-blockers. Use of beta-blockers in asthma could possibly be based upon a risk assessment on an individual patient basis.