Pharmacokinetics and tolerability (Study 1) with particular reference to ocular safety (Study 2) of tiotropium Respimat soft mist inhaler: findings from two dose-ranging studies in healthy men.

Data are presented from two randomized, double-blind, placebo-controlled studies in which the tolerability of tiotropium Respimat Soft MistTM Inhaler (SMI), a new-generation, propellant-free device for use in COPD, and the ocular safety oftiotropium were examined. In Study 1, 36 healthy males received tiotropium 8, 16, or 32 microg (n = 9/dose) or placebo (n = 3/dose level), administered once daily via Respimat SMI for 14 days. Safety and pharmacokinetics were evaluated. In Study 2, 48 healthy males received tiotropium 0.02, 0.04, 0.08, 0.16, 0.28, or 0.40 microg (n = 6/dose) or placebo (n = 2/dose level), applied as two drops to one eye (the highest dose was a significant multiple of a percentage of the proposed Respimat SMI clinical dose that could be inadvertently deposited in the eye). Ocular parameters were measured over 24 hours. Tiotropium Respimat SMI at doses up to 32 microg was well tolerated in Study 1; typical dose-dependent anticholinergic adverse events of mild-to-moderate intensity were observed. In Study 2, ocular tiotropium administration did not affect pupil diameter, pupillary reflex, intraocular pressure, or accommodation. Tiotropium Respimat SMI was well tolerated. Inadvertent ocular exposure to tiotropium up to 0.40 g is unlikely to result in ocular adverse effects.

Pharmacokinetics of intravenous, single-dose tiotropium in subjects with different degrees of renal impairment.

Tiotropium, a new potent anticholinergic bronchodilator, is excreted mainly by the kidney. To investigate the pharmacokinetics of tiotropium in renal impairment, the authors evaluated the pharmacokinetics and safety after administration of a single dose of intravenous tiotropium 4.8 microg, given as an infusion over 15 minutes in subjects with normal renal function and a wide range of renal impairment based on measured creatinine clearance (normal: > 80 mL/min, n = 6; mild impairment: > 50-80 mL/min, n = 5; moderate impairment: 30-50 mL/min, n = 7; severe impairment: < 30 mL/min, n =6). As expected for a drug excreted predominantly in unchanged form by the kidneys, tiotropium plasma concentrations increased as renal impairment worsened, with mean values of 55.5 (16.2 percent geometric coefficient of variation [%gCV]), 77.1 (20.1 %gCV), 101 (29.8 %gCV), and 108 (27.3 %gCV) pgh/mL for AUC(0-4h) in the normal renal function and the mild, moderate, and severe renal impairment groups, respectively. The percentage of tiotropium dose excreted unchanged in the urine decreased from 60.1% of dose (17.7 %gCV) to 59.3% (14.4 %gCV), 39.9% (34.5 %gCV), and 37.4% (10.2 %gCV) in the normal renal function and the mild, moderate, and severe renal impairment groups, respectively. Plasma protein binding of tiotropium did not significantly change in the renal-impaired subjects. Two subjects with normal renal function experienced headache 10 hours after the infusion, which was mild and transient. No adverse events occurred in subjects with renal impairment. There were no clinically relevant changes in blood pressure, pulse rate, 12-lead ECG, physical examination, hematology, or clinical chemistry, compared with baseline values, in any subject after intravenous administration of tiotropium. Tiotropium should only be used in patients with moderate to severe renal insufficiency if the potential benefit outweighs the potential risks.