Unsuspected bronchospasm in association with topical timolol--a common problem in elderly people: can we easily identify those affected and do cardioselective agents lead to improvement?
The extent of impairment of respiratory function in a group of 52 elderly, glaucomatous patients receiving topical timolol therapy was investigated. To predict those patients who were likely to benefit from changing therapy, symptoms were elicited by direct questioning, and lung spirometry was measured before and after inhalation of salbutamol. Changing from timolol to either pilocarpine or the cardioselective betaxolol produced improvement in lung function tests. Mean peak flow increased from 278 l/min to 328 l/min (p < 0.001), forced expiratory volume in 1s (FEV1) from 1.66 l to 1.85 l (p < 0.001) and forced vital capacity (FVC) from 2.41 to 2.64 l (p < 0.001). Spirometry in a control group of 20 subjects was unchanged. Nineteen of 47 patients demonstrated a clinically significant (defined as 15% or more) increase in all values of lung function tests. Change to pilocarpine or betaxolol was equally effective in producing improvement but betaxolol had fewer side-effects. The presence of exertional dyspnoea, cough with sputum, raised dyspnoea score and improved lung function tests after salbutamol identified those patients experiencing clinically significant bronchospasm with an 89% specificity and 74% sensitivity.