Trospiuminteractions

Concomitant use with digoxin did not affect the pharmacokinetics of either drug. Some drugs which are actively secreted by the kidney may interact with trospium chloride tablets by competing for renal tubular secretion. Concomitant use with metformin immediate release tablets reduced exposure and peak concentration of trospium.

7.1 Digoxin

Concomitant use of trospium chloride tablets and digoxin did not affect the pharmacokinetics of either drug.

7.2 Drugs Eliminated by

Active Tubular Secretion Although demonstrated in a drug-drug interaction study not to affect the pharmacokinetics of digoxin, trospium chloride tablets has the potential for pharmacokinetic interactions with other drugs that are eliminated by active tubular secretion (e.g., procainamide, pancuronium, morphine, vancomycin, and tenofovir). Coadministration of trospium chloride tablets with these drugs may increase the serum concentration of trospium chloride tablets and/or the coadministered drug due to competition for this elimination pathway. Careful patient monitoring is recommended in patients receiving such drugs.

7.3 Antimuscarinic

Agents The concomitant use of trospium chloride tablets with other antimuscarinic agents that produce dry mouth, constipation, and other anticholinergic pharmacological effects may increase the frequency and/or severity of such effects. Trospium chloride tablets may potentially alter the absorption of some concomitantly administered drugs due to anticholinergic effects on gastrointestinal motility.

7.4 Metformin

Co-administration of 500 mg metformin immediate release tablets twice daily with trospium chloride 60 mg extended release reduced the steady-state systemic exposure of trospium by approximately 29% for mean AUC 0-24 and by 34% for mean C max.