The effect of topical ophthalmic instillation of timolol and betaxolol on lung function in asthmatic subjects.
The propensity of systemic beta-adrenergic blockers to cause bronchoconstriction in patients with reactive airway disease is well recognized. A study was carried out to determine the prevalence of sensitivity to ophthalmic timolol in 24 asthmatic subjects at our institution and to determine the effect of ophthalmic betaxolol, a cardioselective beta-blocker efficacious in the treatment of glaucoma, in 8 subjects who were timolol-sensitive. Subjects received topical timolol 0.5%; ventilatory function, blood pressure, and heart rate were monitored over a 90-min period. The mean FEV1 fell from 2.47 to 1.93 L by 30 min after drug treatment to a minimal value of 1.86 L (-27.8%). There was a corresponding fall in FVC from 3.68 to 3.09 L by 30 min with a minimal value of 3.00 L(-20.7%). FEV1/FVC ratio also fell from 66.9 to 61.0% by 30 min, reaching a minimum of 60.0%. In 14 subjects (58.3%), the fall in FEV1 was greater than or equal to 20%, with a mean fall of 38.7% by 30 min and a maximal fall of 44.9%. The severity of timolol-sensitivity correlated with the extent of reduction in baseline percent predicted FEV1 and FVC and with exercise-induced bronchospasm. In addition, the administration of timolol reduced the bronchodilator response to below the pretimolol value. In 8 of the timolol-sensitive patients who underwent a double-blind crossover challenge with ocular instillation of betaxolol 1% and saline, betaxolol was well-tolerated and did not affect ventilatory function over a 4-h observation period. In addition, it did not prevent the FEV1 response to inhaled bronchodilator.(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D015784:Betaxolol; D001993:Bronchodilator Agents / Q000627:therapeutic use; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D011412:Propanolamines / Q000009:adverse effects*; D013999:Timolol / Q000009:adverse effects*; D014797:Vital Capacity
D001993:Bronchodilator Agents; D009883:Ophthalmic Solutions; D011412:Propanolamines; D013999:Timolol; D015784:Betaxolol