Digoxin: Concomitant use of Trospium and digoxin did not affect the pharmacokinetics of either drug.
Drugs Eliminated by Active Tubular Secretion: Although demonstrated in a drug-drug interaction study not to affect the pharmacokinetics of digoxin, Trospium 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 with these drugs may increase the serum concentration of Trospium and/or the coadministered drug due to competition for this elimination pathway. Careful patient monitoring is recommended in patients receiving such drugs.
Antimuscarinic Agents: The concomitant use of Trospium 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 may potentially alter the absorption of some concomitantly administered drugs due to anticholinergic effects on gastrointestinal motility.
Metformin: Co-administration of 500 mg metformin immediate release tablets twice daily with Trospium 60 mg extended release reduced the steady-state systemic exposure of trospium by approximately 29% for mean AUC0-24 and by 34% for mean Cmax.
The following adverse reactions have been identified during post-approval use of trospium chloride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Gastrointestinal: gastritis
Cardiovascular: palpitations, supraventricular tachycardia, chest pain, syncope,
hypertensive crisis
Immunological: Stevens-Johnson syndrome, anaphylactic reaction, angioedema
Nervous System: dizziness, confusion, vision abnormal, hallucinations, somnolence and delirium
Musculoskeletal: rhabdomyolysis
General: rash
Pregnancy Category C: There are no adequate and well-controlled studies of Trospium in pregnant women. Trospium should be used during pregnancy only if the potential benefit to the patient outweighs the risk to the patient and fetus. Women who become pregnant during Trospium treatment are encouraged to contact their physician.
Nursing Mothers: Trospium chloride (2 mg/kg orally and 50 mcg/kg intravenously) was excreted, to a limited extent (less than 1%), into the milk of lactating rats (primarily as parent compound). It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, Trospium should be used during lactation only if the potential benefit justifies the potential risk to the newborn.
Risk of Urinary Retention: Trospium should be administered with caution to patients with clinically significant bladder outflow obstruction because of the risk of urinary retention.
Angioedema: Angioedema of the face, lips, tongue, and/or larynx has been reported with trospium chloride, the active ingredient in Trospium. In one case, angioedema occurred after the first dose of trospium chloride. Angioedema associated with upper airway swelling may be life threatening. If involvement of the tongue, hypopharynx, or larynx occurs, Trospium should be promptly discontinued and appropriate therapy and/or measures necessary to ensure a patent airway should be promptly provided.
Decreased Gastrointestinal Motility: Trospium should be administered with caution to patients with gastrointestinal obstructive disorders because of the risk of gastric retention. Trospium ,like other antimuscarinic agents, may decrease gastrointestinal motility and should be used with caution in patients with conditions such as ulcerative colitis, intestinal atony and myasthenia gravis.
Controlled Narrow-angle Glaucoma: In patients being treated for narrow-angle glaucoma, Trospium should only be used if the potential benefits outweigh the risks and in that circumstance only with careful monitoring.
Central Nervous System Effects: Trospium is associated with anticholinergic central nervous system (CNS) effects. A variety of CNS anticholinergic effects have been reported, including dizziness, confusion, hallucinations and somnolence. Patients should be monitored for signs of anticholinergic CNS effects, particularly after beginning treatment or increasing the dose. Advise patients not to drive or operate heavy machinery until they know how Trospium affects them. If a patient experiences anticholinergic CNS effects, dose reduction or drug discontinuation should be considered.
Anticholinergic Adverse Reactions in Patients with Moderate Renal Impairment: Trospium is substantially excreted by the kidney. The effects of moderate renal impairment on systemic exposure are not known but systemic exposure is likely increased. Therefore, anticholinergic adverse reactions (including dry mouth, constipation, dyspepsia, urinary tract infection, and urinary retention) are expected to be greater in patients with moderate renal impairment
Overdosage with antimuscarinic agents, including Trospium, can result in severe antimuscarinic effects. Supportive treatment should be provided according to symptoms. In the event of overdosage, electrocardiographic monitoring is recommended. A 7-month-old baby experienced tachycardia and mydriasis after administration of a single dose of trospium 10 mg given by a sibling. The baby’s weight was reported as 5 kg. Following admission into the hospital and about 1 hour after ingestion of the trospium, medicinal charcoal was administered for detoxification. While hospitalized, the baby experienced mydriasis and tachycardia up to 230 beats per minute. Therapeutic intervention was not deemed necessary. The baby was discharged as completely recovered the following day.
