Morales et al queried a database of 53,994 UK asthma patients, finding 1527 who were prescribed beta blockers, 441 with a brand-new prescription. The rate of oral steroid use in the 2 weeks prior to beta-blocker commencement was the same as in the 2 weeks after (0.9%). They did not examine exacerbation rates or steroid use longitudinally, but the original case reports blaming propranolol for asthma exacerbations occurred in people recently started on the drug. Thorax 2011;66:502-507.
Recent investigations suggest BB therapy may actually improve asthma. A 2002 meta-analysis found no significant adverse effects of beta-blocker therapy in people with mild-to-moderate asthma, and in fact, bronchodilator response increased with chronic beta-blocker treatment.