5.1 Risk of Urinary Retention

Trospium chloride extended-release capsules should be administered with caution to patients with clinically significant bladder outflow obstruction because of the risk of urinary retention [see Contraindications ( 4)].

5.2 Angioedema

Angioedema of the face, lips, tongue and/or larynx has been reported with trospium chloride. 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 chloride should be promptly discontinued and appropriate therapy and/or measures necessary to ensure a patent airway should be promptly provided.

5.3 Decreased Gastrointestinal Motility

Trospium chloride extended-release capsules should be administered with caution to patients with gastrointestinal obstructive disorders because of the risk of gastric retention [see Contraindications ( 4)]. Trospium chloride extended-release capsules, 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.

5.4 Controlled Narrow-angle Glaucoma

In patients being treated for narrow-angle glaucoma, trospium chloride extended-release capsules should only be used if the potential benefits outweigh the risks, and in that circumstance only with careful monitoring [see Contraindications ( 4)].

5.5 Central Nervous System Effects

Trospium chloride extended-release capsules and trospium chloride immediate release are associated with anticholinergic central nervous system (CNS) effects [see  Adverse Reactions ( 6.2)] . 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 chloride extended-release capsules affect them. If a patient experiences anticholinergic CNS effects, dose reduction or drug discontinuation should be considered.

5.6 Patients with Severe Renal Impairment

Trospium chloride extended-release capsules are not recommended for use in patients with severe renal impairment (creatinine clearance less than 30 mL/minute) [see  Dosage and Administration ( 2),  Use in Specific Populations ( 8.6), and  Clinical Pharmacology ( 12.3)].

5.7 Alcohol Interaction

Alcohol should not be consumed within 2 hours of trospium chloride extended-release capsules administration. In addition, patients should be informed that alcohol may enhance the drowsiness caused by anticholinergic agents.

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, the adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The data described below reflect exposure to trospium chloride extended-release capsules in 578 patients for 12 weeks in two Phase 3 double-blind, placebo controlled trials (n=1165). These studies included overactive bladder patients of ages 21 to 90 years, of which 86% were female and 85% were Caucasian. Patients received 60 mg daily doses of trospium chloride extended-release capsules. Patients in these studies were eligible to continue treatment with trospium chloride extended-release capsules 60 mg for up to one year. From both these controlled trials combined, 769 and 238 patients received treatment with trospium chloride extended-release capsules for at least 24 and 52 weeks, respectively.

There were 157 (27.2%) trospium chloride extended-release capsules patients and 98 (16.7%) placebo patients who experienced one or more double-blind treatment-emergent adverse events (TEAEs) that were assessed by the investigator as at least possibly related to study medication. The most common TEAEs were dry mouth and constipation which, when reported, commonly occurred early in treatment (often within the first week). In the two Phase 3 studies, constipation, dry mouth, and urinary retention led to discontinuation in 1%, 0.7%, and 0.5% of patients treated with trospium chloride extended-release capsules 60 mg daily, respectively. In the placebo group, there were no discontinuations due to dry mouth or urinary retention and one due to constipation.

The incidence of serious adverse events was similar among patients receiving trospium chloride extended-release capsules and patients receiving placebo. No treatment-emergent serious adverse events in either treatment group were judged by the investigators as being possibly related to the study medication.

Table 1 lists those treatment-emergent adverse events from the trials that were assessed by the investigator as possibly related to study medication, reported in at least 1% of trospium chloride extended-release capsules patients, and were more common for the trospium chloride extended-release capsules group than for placebo.

Additional adverse events reported in less than 1% of trospium chloride extended-release capsules treated patients and more common for trospium chloride extended-release capsules than placebo, judged by the investigator at least possibly related to treatment were: vision blurred, feces hard, back pain, somnolence, urinary retention, and dry skin.

Table 2 lists all treatment-emergent adverse events for the trials reported in at least 2% of all trospium chloride extended-release capsules patients and more common for the trospium chloride extended-release capsules group than for placebo without regard to the investigator’s judgment on drug relatedness.

Additional adverse events reported in less than 2% of trospium chloride extended-release capsules treated patients and twice as frequent for trospium chloride extended-release capsules compared to placebo, regardless of reported relationship to treatment were: tachycardia, dry eyes, abdominal pain, dyspepsia, abdominal distension, constipation aggravated, nasal dryness, and rash.

In the open-label treatment phase, the most common TEAEs reported in the 769 patients with at least 6 months exposure to trospium chloride extended-release capsules were: constipation, and dry mouth. Urinary tract infection and rash was also reported in several patients, including one of each judged by the investigator to be possibly related to treatment. Several adverse events were reported as severe in the open-label treatment phase, including one urinary tract infection, two urinary retention events, and one aggravated constipation.

6.2 Post-marketing Experience

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.

7.1 Digoxin

Concomitant use of trospium chloride 20 mg twice daily and digoxin did not affect the pharmacokinetics of either drug [ see  Clinical Pharmacology  ( 12.3)] .

7.2 Antacid

While the systemic exposure of trospium on average was comparable with and without antacid containing aluminum hydroxide and magnesium carbonate, 5 out of 11 individuals in a drug interaction study demonstrated either an increase or decrease in trospium exposure, in presence of antacid. The clinical relevance of these findings is not known [ see  Clinical Pharmacology ( 12.3)] .

7.3 Metformin

Co-administration of 500 mg metformin immediate release tablets twice daily reduced the steady-state systemic exposure of trospium by approximately 29% for mean AUC 0-24 and by 34% for mean C max. The effect of a decrease in trospium exposure on the efficacy of trospium chloride extended-release capsules is unknown. The steady-state pharmacokinetics of metformin were comparable when administered with or without 60 mg trospium chloride extended-release capsules once daily under fasted condition. The effect of metformin at higher doses on trospium PK is unknown [ see  Clinical Pharmacology ( 12.3)] .

8.1 Pregnancy

Teratogenic Effects
Pregnancy Category C: There are no adequate and well-controlled studies of trospium chloride extended-release capsules in pregnant women.  Trospium chloride extended-release capsules 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 chloride extended-release capsules treatment are encouraged to contact their physician.

Trospium chloride was not teratogenic at statistically significant levels in rats or rabbits administered doses up to 200 mg/kg/day. This corresponds to systemic exposures up to approximately 16 and 32 times, respectively (based on AUC), the clinical exposure at the maximum recommended human dose (MRHD) of 60 mg. However, in rabbits, one fetus in each of the three treated dose groups (1, 1, and 32 times the MRHD) demonstrated multiple malformations, including umbilical hernia and skeletal malformations. A no effect level for maternal and fetal toxicity was observed at levels approximately equivalent to the clinical exposure at the MRHD (20 mg/kg/day in rats and rabbits). No developmental toxicity was observed in the offspring of female rats exposed pre- and post-natally to up to 200 mg/kg/day.

8.2 Labor and Delivery

The effect of  trospium chloride extended-release capsules on labor and delivery is unknown.

8.3 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 into human milk. Because many drugs are excreted into human milk, trospium chloride extended-release capsules should be used during lactation only if the potential benefit justifies the potential risk.

8.4 Pediatric Use

The safety and effectiveness of trospium chloride extended-release capsules in pediatric patients have not been established.

8.5 Geriatric Use

Of 1165 patients in Phase 3 clinical studies of trospium chloride extended-release capsules, 37% (n=428) were ages 65 and over, while 12% (n=143) were ages 75 and over.

No overall differences in effectiveness were observed between those subjects aged 65 and over and younger subjects. In trospium chloride extended-release capsules subjects ages 65 and over compared to younger subjects, the following adverse reactions were reported at a higher incidence: dry mouth, constipation, abdominal pain, dyspepsia, urinary tract infection and urinary retention. In subjects ages 75 and over, three reported a fall and in one of them a relationship to the event could not be excluded.

8.6 Renal Impairment

Severe renal impairment (creatinine clearance less than 30 mL/minute) may significantly alter the disposition of trospium chloride extended-release capsules. In a study of immediate-release trospium chloride, 4.2-fold and 1.8-fold increases in mean AUC (0-∞) and C max, respectively, were detected in patients with severe renal impairment. Use of trospium chloride extended-release capsules is not recommended in patients with severe renal impairment [ see  Warnings and Precautions ( 5.4) and  Clinical Pharmacology ( 12.3)] . The pharmacokinetics of trospium chloride have not been studied in patients with creatinine clearance ranging from 30 to 80 mL/min.

Trospium is known to be substantially excreted by the kidney, and the risk of adverse reactions may be greater in patients with impaired renal function.

8.7 Hepatic Impairment

There is no information regarding the effect of severe hepatic impairment on exposure to trospium chloride extended-release capsules. In a study of patients with mild and with moderate hepatic impairment, given 40 mg of immediate-release trospium chloride, mean C max increased 12% and 63%, respectively, and mean AUC (0-∞) decreased 5% and 15%, respectively, compared to healthy subjects. The clinical significance of these findings is unknown. Caution is advised, however, when administering trospium chloride extended-release capsules to patients with moderate to severe hepatic impairment.

12.1 Mechanism of Action

Trospium chloride is an antispasmodic, antimuscarinic agent.

Trospium chloride antagonizes the effect of acetylcholine on muscarinic receptors in cholinergically innervated organs including the bladder. Its parasympatholytic action reduces the tonus of smooth muscle in the bladder.

In vitro receptor binding studies have demonstrated the selectivity of trospium chloride for muscarinic over nicotinic receptors, and similar affinity for the M 2 and M 3 muscarinic receptor subtypes. M 2 and M 3 receptors are found in the bladder and may play a role in the pathogenesis of overactive bladder.

12.2 Pharmacodynamics

Placebo-controlled studies assessing the impact on urodynamic variables of an immediate-release formulation of trospium chloride were conducted in patients with conditions characterized by involuntary detrusor contractions. The results demonstrated that trospium chloride increases maximum cystometric bladder capacity and volume at first detrusor contraction.

Electrophysiology
The effect of 20 mg twice daily and up to 100 mg twice daily of an immediate-release formulation of trospium chloride on QT interval was evaluated in a single-blind, randomized, placebo and active (moxifloxacin 400 mg daily) controlled, 5-day parallel trial in 170 male and female healthy volunteer subjects aged 18 to 45 years. The QT interval was measured over a 24-hour period at steady state. Trospium chloride was not associated with an increase in individual corrected (QTcI) or Fridericia corrected (QTcF) QT interval at any time during steady state measurement, while moxifloxacin was associated with a 6.4 msec increase in QTcF.

In this study, asymptomatic, non-specific T-wave inversions were observed more often in subjects receiving trospium chloride than in subjects receiving moxifloxacin or placebo following five days of treatment. The clinical significance of T-wave inversion in this study is unknown. This finding was not observed during routine safety monitoring in overactive bladder patients from 2 placebo-controlled clinical trials in 591 patients treated with 20 mg twice daily of immediate-release trospium chloride, nor was it observed in 2 placebo-controlled clinical trials in 578 patients treated with trospium chloride extended-release capsules.

Also in this study, the immediate-release formulation of trospium chloride was associated with an increase in heart rate that correlated with increasing plasma concentration, with a mean elevation in heart rate compared to placebo of 9 beats per minute for the 20 mg dose and of 18 beats per minute for the 100 mg dose. In the two Phase 3 trospium chloride extended-release capsules trials the mean increase in heart rate compared to placebo was approximately 3 beats per minute in both studies.

12.3 Pharmacokinetics

Absorption: Mean absolute bioavailability of a 20 mg immediate-release dose is 9.6% (range 4.0 to 16.1%). Following a single 60 mg dose of trospium chloride extended-release capsules, peak plasma concentration (C max) of 2.0 ng/mL occurred 5.0 hours post dose. By contrast, following a single 20 mg dose of an immediate-release formulation of trospium chloride, C max was 2.7 ng/mL.

Effect of Food: Administration of trospium chloride extended-release capsules immediately after a high (50%) fat-content meal reduced the oral bioavailability of trospium chloride by 35% for AUC (0-Tlast) and by 60% for C max. Other pharmacokinetic parameters such as T max and t 1/2 were unchanged in the presence of food.

A summary of mean (± standard deviation) pharmacokinetic parameters for a single dose of 60 mg trospium chloride extended-release capsules is provided in Table 3.

The mean sample concentration-time (+ standard deviation) profile for trospium chloride extended-release capsules is shown in Figure 1.

Administration of trospium chloride extended-release capsules immediately after a high (50%) fat-content meal reduced the oral bioavailability of trospium chloride by 35% for AUC (0-Tlast) and by 60% for C max. Other pharmacokinetic parameters such as T max and t 1/2 were unchanged in the presence of food. Coadministration with antacid had inconsistent effects on the oral bioavailability of trospium chloride extended-release capsules.

Distribution: Protein binding ranged from 50 to 85%, depending upon the assessment method used, when a range of concentration levels of trospium chloride (0.5 to 50 mcg/L) were incubated in vitro with human serum.

The ratio of 3H-trospium chloride in plasma to whole blood was 1.6:1. This ratio indicates that the majority of 3H- trospium chloride is distributed in plasma.

Trospium chloride is widely distributed, with an apparent volume of distribution >600 L.

Metabolism:The metabolic pathway of trospium in humans has not been fully defined. Of the dose absorbed following oral administration, metabolites account for approximately 40% of the excreted dose. The major metabolic pathway of trospium is hypothesized as ester hydrolysis with subsequent conjugation of benzylic acid to form azoniaspironortropanol with glucuronic acid. CYP P450 does not contribute significantly to the elimination of trospium. Data taken from in vitro studies of human liver microsomes, investigating the inhibitory effect of trospium on seven CYP P450 isoenzyme substrates (CYP1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4), suggest a lack of inhibition at clinically relevant concentrations.

Excretion:The plasma half-life for trospium following oral administration of trospium chloride extended-release capsules is approximately 35 hours. After oral administration of an immediate-release formulation of 14C-labeled trospium chloride, a majority of the dose (85.2%) was recovered in feces and a smaller amount (5.8% of the dose) was recovered in urine. Of the radioactivity excreted into the urine, 60% was unchanged trospium.

The mean renal clearance for trospium (29.07 L/hour) is 4-fold higher than average glomerular filtration rate, indicating that active tubular secretion is a major route of elimination. There may be competition for elimination with other compounds that are also renally eliminated [see  Drug Interactions ( 7) ].

Drug Interactions

Digoxin: Concomitant use of 20 mg trospium chloride immediate release twice daily at steady state and a single dose of 0.5 mg digoxin in a crossover study with 40 male and female subjects did not affect the pharmacokinetics of either drug.

Antacid: A drug interaction study was conducted to evaluate the effect of an antacid containing aluminum hydroxide and magnesium carbonate on the pharmacokinetics of trospium chloride extended-release capsules (n=11). While the systemic exposure of trospium on average was comparable with and without antacid, 5 individuals demonstrated either an increase or decrease in trospium exposure, in presence of antacid.

Metformin: A drug interaction study was conducted in which trospium chloride extended-release capsules 60 mg once daily was co-administered with Glucophage ® (metformin hydrochloride) 500 mg twice daily under steady-state conditions in 44 healthy subjects. Co-administration of 500 mg metformin immediate release tablets twice daily reduced the steady-state systemic exposure of trospium by approximately 29% for mean AUC 0-24 and by 34% for mean C max. The effect of decrease in trospium exposure on the efficacy of trospium chloride extended-release capsules is unknown.The steady-state pharmacokinetics of metformin were comparable when administered with or without 60 mg trospium chloride extended-release capsules once daily under fasted condition. The effect of metformin at higher doses on trospium PK is unknown.

Specific Populations

Age: In a phase 3 clinical trial of trospium chloride extended-release capsules, the observed plasma trospium concentrations were similar in older (greater than or equal to 65 years) and younger (less than 65 years) OAB patients.

Pediatric: The pharmacokinetics of trospium chloride extended-release capsules were not evaluated in pediatric patients.

Race: Pharmacokinetic differences due to race have not been studied.

Gender: Gender differences in pharmacokinetics of trospium chloride extended-release capsules have not been formally assessed. Data from healthy subjects suggests lower exposure in males compared to females.

Hepatic Impairment: There is no information regarding the effect of severe hepatic impairment on exposure to trospium chloride extended-release capsules. In a study of patients with mild (Child-Pugh score 5 to 6) and with moderate (Child-Pugh score 7 to 8) hepatic impairment, given 40 mg of immediate-release trospium chloride, mean C max increased 12% and 63% respectively, and mean AUC (0-∞) decreased 5% and 15%, respectively, compared to healthy subjects.

Renal Impairment: The pharmacokinetics of trospium chloride extended-release capsules in patients with severe renal impairment has not been evaluated. In a study of an immediate-release formulation of trospium chloride, 4.2-fold and 1.8-fold increases in mean AUC (0-∞) and C max, respectively, were detected in patients with severe renal impairment (creatinine clearance less than 30 mL/minute), compared with healthy subjects, along with the appearance of an additional elimination phase with a long half-life (~33 hours vs. 18 hours). Use of trospium chloride extended-release capsules is not recommended in patients with severe renal impairment [see  Dosage and Administration ( 2) ]. The pharmacokinetics of trospium chloride have not been studied in people with creatinine clearance ranging from 30 to 80 mL/min.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis: Carcinogenicity studies with trospium chloride were conducted in mice and rats for 78 weeks and 104 weeks, respectively, at maximally tolerated doses. No evidence of a carcinogenic effect was found in either mice or rats administered up to 200 mg/kg/day (approximately 1 and 16 times, respectively (based on AUC), the expected clinical exposure levels at the maximum recommended human dose (MRHD) of 60 mg.

Mutagenesis: Trospium chloride was not mutagenic nor genotoxic in tests in vitro in bacteria (Ames test) and mammalian cells (L5178Y mouse lymphoma and CHO cells) or in vivo in the mouse micronucleus test.

Impairment of Fertility: No evidence of impaired fertility was observed in rats administered doses up to 200 mg/kg/day (about 16 times the expected clinical exposure at the MRHD, based on AUC).

17.1 Angioedema

Patients should be informed that trospium chloride extended-release capsules may produce angioedema which could result in life-threatening airway obstruction. Patients should be advised to promptly discontinue trospium chloride extended-release capsules therapy and seek immediate medical attention if they experience edema of the tongue, edema of the laryngopharynx, or difficulty breathing.

17.2 When Not to Use

Prior to treatment, patients should fully understand the risks and benefits of trospium chloride extended-release capsules. In particular, patients should be informed not to take trospium chloride extended-release capsules if they:

• have urinary retention;
• gastric retention;
• uncontrolled narrow-angle glaucoma;
• are allergic to any component of trospium chloride extended-release capsules .

17.3 Administration

Patients should be instructed regarding the recommended dosing and administration of trospium chloride extended-release capsules:

• Take one trospium chloride extended-release capsule daily in the morning with water.
• Take trospium chloride extended-release capsule on an empty stomach or at least 1 hour before a meal.
• Use of alcoholic beverages within 2 hours of dosing with trospium chloride extended-release capsule is not recommended.

17.4 Adverse Reactions

Patients should be informed that the most common side effects with trospium chloride extended-release capsules are dry mouth and constipation and that other less common side effects include trouble emptying the bladder, blurred vision, and heat prostration. Because anticholinergics, such as trospium chloride extended-release capsules, may produce dizziness or blurred vision, patients should be advised to exercise caution in decisions to engage in potentially dangerous activities until the drug’s effects have been determined.  Patients should be informed that alcohol may enhance the drowsiness caused by anticholinergic agents.