Tiotropium bromide, a new long-acting antimuscarinic bronchodilator: a pharmacodynamic study in patients with chronic obstructive pulmonary disease (COPD). Dutch Study Group.
The objective of the present study was to investigate the dose-dependent bronchodilator efficacy and duration of action of the newly developed antimuscarinic agent tiotropium bromide in patients with chronic obstructive pulmonary disease (COPD). In a randomized, double-blind, placebo-controlled, crossover design, patients inhaled single doses of 10-80 micrograms tiotropium bromide and placebo, formulated in lactose powder capsules. The washout period between test doses was 72 h. Thirty five patients were enrolled in the trial (32 males and 3 females; mean age 64 yrs). Baseline forced expiratory volume in one second (FEV1) (mean 1.34 L) was less than 65% of predicted and was < 70% of forced vital capacity (FVC). All subjects had a smoking history of more than 10 pack-years. The mean reversibility of FEV1 after inhalation of 40 micrograms ipratropium bromide was 28%. Pulmonary function testing was performed before and at regular time intervals for up to 32 h after test drug administration. Compared to placebo, tiotropium bromide produced significant improvements in FEV1, FVC, peak expiratory flow rate (PEFR) and forced mid-expiratory flow (FEF25-75%). The bronchodilator response was almost immediate; peak improvement in FEV1 was reached 1-4 h after test drug inhalation, and the duration of action extended to 32 h after the 20, 40 and 80 micrograms doses. A clear dose-response relationship was seen for peak FEV1 and for the average FEV1 over differing time periods during the 32 h observation period, 80 micrograms of test drug being superior to the 10 micrograms dose. Peak improvement in FEV1 ranged 19-26% of test-day baseline for tiotropium bromide doses compared to 16% for placebo. The large improvement for placebo is probably due to carry-over effect which was significant. After excluding carry-over effect, the peak response to placebo decreased to 11%, whilst for tiotropium bromide doses it ranged 20-25%; standard error for mean difference was about 4%. There was no evidence of systemic anticholinergic effects. In this population of patients with COPD, tiotropium bromide was found to be a safe and long-acting bronchodilator, demonstrating a clear dose-response relationship following single dose administration.
Maesen
F P
FP
Department of Respiratory Diseases, De Wever Hospital, Heerlen, The Netherlands.
Smeets
J J
JJ
Sledsens
T J
TJ
Wald
F D
FD
Cornelissen
P J
PJ
D000280:Administration, Inhalation; D000368:Aged; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012602:Scopolamine Derivatives / Q000008:administration & dosage / Q000627:therapeutic use*; D013997:Time Factors; D000069447:Tiotropium Bromide; D016896:Treatment Outcome
D001993:Bronchodilator Agents; D012602:Scopolamine Derivatives; D000069447:Tiotropium Bromide