The muscarinic M1-receptor-selective antagonist, telenzepine, had no bronchodilatory effects in COPD patients

In a double-blind, placebo-controlled, randomized, cross-over trial, we studied the effects of the muscarinic M1-receptor-selective antagonist (+/-)-telenzepine (3 mg orally at 6 p.m. for 5 days) in 21 patients with chronic obstructive pulmonary disease (COPD). At enrollment all patients showed at least a 50% decrease in airway resistance (Raw) after inhalation of 400 micrograms fenoterol or 200 micrograms oxitropium bromide. Telenzepine did not have a significant effect on forced expiratory volume in one second (FEV1) or forced vital capacity (FVC). Also, no significant changes could be detected in daily spirometric profiles or Raw. The results indicate that short-term treatment with the M1-selective antagonist, telenzepine, does not improve airway function in COPD patients, at least after administration by the oral route.