DITROPAN XL® (oxybutynin chloride) is an antispasmodic, anticholinergic agent. Each DITROPAN XL Extended Release Tablet contains 5 mg, 10 mg, or 15 mg of oxybutynin chloride USP, formulated as a once-a-day controlled-release tablet for oral administration. Oxybutynin chloride is administered as a racemate of R- and S-enantiomers.

Chemically, oxybutynin chloride is d,l (racemic) 4-diethylamino-2-butynyl phenylcyclohexylglycolate hydrochloride. The empirical formula of oxybutynin chloride is C₂₂H₃₁NO₃•HCl.

Its structural formula is:

Oxybutynin chloride is a white crystalline solid with a molecular weight of 393.9. It is readily soluble in water and acids, but relatively insoluble in alkalis.

DITROPAN XL also contains the following inert ingredients: cellulose acetate, hypromellose, lactose, magnesium stearate, polyethylene glycol, polyethylene oxide, synthetic iron oxides, titanium dioxide, polysorbate 80, sodium chloride, and butylated hydroxytoluene.

System Components and Performance

DITROPAN XL uses osmotic pressure to deliver oxybutynin chloride at a controlled rate over approximately 24 hours. The system, which resembles a conventional tablet in appearance, comprises an osmotically active bilayer core surrounded by a semipermeable membrane. The bilayer core is composed of a drug layer containing the drug and excipients, and a push layer containing osmotically active components. There is a precision-laser drilled orifice in the semipermeable membrane on the drug-layer side of the tablet. In an aqueous environment, such as the gastrointestinal tract, water permeates through the membrane into the tablet core, causing the drug to go into suspension and the push layer to expand. This expansion pushes the suspended drug out through the orifice. The semipermeable membrane controls the rate at which water permeates into the tablet core, which in turn controls the rate of drug delivery. The controlled rate of drug delivery into the gastrointestinal lumen is thus independent of pH or gastrointestinal motility. The function of DITROPAN XL depends on the existence of an osmotic gradient between the contents of the bilayer core and the fluid in the gastrointestinal tract. Since the osmotic gradient remains constant, drug delivery remains essentially constant. The biologically inert components of the tablet remain intact during gastrointestinal transit and are eliminated in the feces as an insoluble shell.

Last updated on RxList: 8/4/2009

DITROPAN XL® (oxybutynin chloride) is a once-daily controlled-release tablet indicated for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency.

DITROPAN XL is also indicated in the treatment of pediatric patients aged 6 years and older with symptoms of detrusor overactivity associated with a neurological condition (e.g., spina bifida).

DITROPAN XL® (oxybutynin chloride) must be swallowed whole with the aid of liquids, and must not be chewed, divided, or crushed.

DITROPAN XL may be administered with or without food.

Adults

The recommended starting dose of DITROPAN XL is 5 or 10 mg once daily at approximately the same time each day. Dosage may be adjusted in 5-mg increments to achieve a balance of efficacy and tolerability (up to a maximum of 30 mg/day). In general, dosage adjustment may proceed at approximately weekly intervals.

Pediatric Patients Aged 6 Years of Age and Older

The recommended starting dose of DITROPAN XL is 5 mg once daily at approximately the same time each day. Dosage may be adjusted in 5-mg increments to achieve a balance of efficacy and tolerability (up to a maximum of 20 mg/day).

DITROPAN XL® (oxybutynin chloride) Extended Release Tablets are available in three dosage strengths, 5 mg (pale yellow), 10 mg (pink), and 15 mg (gray) and are imprinted with “5 XL”, “10 XL”, or “15 XL”. DITROPAN XL Extended Release Tablets are supplied in bottles of 100 tablets.

5 mg	100 count bottle	NDC 50458-805-01
10 mg	100 count bottle	NDC 50458-810-01
15 mg	100 count bottle	NDC 50458-815-01

Storage

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature]. Protect from moisture and humidity.

For more information call 1-888-395-1232 or visit www.DITROPANXL.com. Manufactured by: ALZA Corporation, Vacaville, CA 95688. Manufactured for: Ortho Women's Health & Urology, Division of Ortho-McNeil-Janssen Pharmaceuticals, Inc. Raritan, NJ 08869.

Last updated on RxList: 8/4/2009

Adverse Events with DITROPAN XL

The safety and efficacy of DITROPAN XL® (oxybutynin chloride) was evaluated in a total of 580 participants who received DITROPAN XL in 4 clinical trials (429 patients) and four pharmacokinetic studies (151 healthy volunteers). The 429 patients were treated with 5-30 mg/day for up to 4.5 months. Three of the 4 clinical trials allowed dose adjustments based on efficacy and adverse events and one was a fixed dose escalation design. Safety information is provided for 429 patients from these three controlled clinical studies and one open label study in the first column of Table 3 below.

Adverse events from two additional fixed dose, active controlled, 12 week treatment duration, postmarketing studies, in which 576 patients were treated with DITROPAN XL 10 mg/day, are also listed in Table 3 (second column). The adverse events are reported regardless of causality.

Table 3: Incidence (%) of Adverse Events Reported by ≥ 5% of Patients Using DITROPAN XL (5-30 mg/day) and % of Corresponding Adverse Events in Two Fixed Dose (10mg/day) Studies

Body System	Adverse Event	DITROPAN XL 5-30 mg/day (n=429)	DITROPAN XL 10 mg/day (n=576)
General	Headache	10	6
	Asthenia	7	3
	Pain	7	4
Digestive	dry mouth	61	29
	Constipation	13	7
	Diarrhea	9	7
	Nausea	9	2
	Dyspepsia	7	5
Nervous	Somnolence	12	2
	Dizziness	6	4
Respiratory	Rhinitis	6	2
Special senses	blurred vision	8	1
	dry eyes	6	3
Urogenital	urinary tract infection	5	5

The most common adverse events reported by the 429 patients receiving 5-30 mg/day DITROPAN XL were the expected side effects of anticholinergic agents. The incidence of dry mouth was dose-related.

The discontinuation rate for all adverse events was 6.8% in the 429 patients from the 4 studies of efficacy and safety who received 5-30 mg/day. The most frequent adverse event causing early discontinuation of study medication was nausea (1.9%), while discontinuation due to dry mouth was 1.2%.

In addition, the following adverse events were reported by ≥ 1 to < 5% of all patients who received DITROPAN XL in the 6 adjustable and fixed dose efficacy and safety studies. Infections and infestations: nasopharyngitis, upper respiratory tract infection, sinusitis, bronchitis, cystitis; Psychiatric disorders: insomnia, depression, nervousness, confusional state; Nervous System Disorders: dysgeusia; Cardiac disorders: palpitations; Vascular disorders: hypertension; Respiratory, thoracic and mediastinal disorders:nasal dryness, cough, pharyngolaryngeal pain, dry throat; Gastrointestinal Disorders: gastroesophageal reflux disease, abdominal pain, loose stools, flatulence, vomiting; Skin and subcutaneous tissue disorders: dry skin, pruritis; Musculoskeletal and connective tissue disorders: back pain, arthralgia, pain in extremity; Renal and urinary disorders: urinary retention, urinary hesitation, dysuria; General disorders and administration site conditions: fatigue, edema peripheral, asthenia, chest pain; Investigations: blood pressure increased.

Postmarketing Surveillance

Because postmarketing 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. The following additional adverse drug reactions have been reported from worldwide postmarketing experience with DITROPAN XL: Psychiatric Disorders: psychotic disorder, agitation, hallucinations, memory impairment; Nervous System Disorders: convulsions; Cardiac Disorders: arrhythmia; tachycardia, QT interval prolongation; Vascular Disorders: flushing; Skin and Subcutaneous Tissue Disorders: rash; Renal and Urinary Disorders: impotence; Injury, poisoning and procedural complications: fall.

Additional adverse events reported with some other oxybutynin chloride formulations include: cycloplegia, mydriasis, and suppression of lactation.

The concomitant use of oxybutynin with other anticholinergic drugs or with other agents which produce dry mouth, constipation, somnolence (drowsiness), and/or other anticholinergic-like effects may increase the frequency and/or severity of such effects.

Anticholinergic agents may potentially alter the absorption of some concomitantly administered drugs due to anticholinergic effects on gastrointestinal motility. This may be of concern for drugs with a narrow therapeutic index.

Mean oxybutynin chloride plasma concentrations were approximately 2 fold higher when DITROPAN XL was administered with ketoconazole, a potent CYP3A4 inhibitor. Other inhibitors of the cytochrome P450 3A4 enzyme system, such as antimycotic agents (e.g., itraconazole and miconazole) or macrolide antibiotics (e.g., erythromycin and clarithromycin), may alter oxybutynin mean pharmacokinetic parameters (i.e., Cmax and AUC). The clinical relevance of such potential interactions is not known. Caution should be used when such drugs are co-administered.

Last updated on RxList: 8/4/2009

No information provided.

Central Nervous System Effects

Oxybutynin is associated with anticholinergic central nervous system (CNS) effects (See ADVERSE REACTIONS). A variety of CNS anticholinergic effects have been reported, including hallucinations, agitation, confusion and somnolence. Patients should be monitored for signs of anticholinergic CNS effects, particularly in the first few months after beginning treatment or increasing the dose. If a patient experiences anticholinergic CNS effects, dose reduction or drug discontinuation should be considered.

DITROPAN XL should be used with caution in patients with preexisting dementia treated with cholinesterase inhibitors due to the risk of aggravation of symptoms.

General

DITROPAN XL® (oxybutynin chloride) should be used with caution in patients with hepatic or renal impairment and in patients with myasthenia gravis due to the risk of symptom aggravation.

Urinary Retention

DITROPAN XL should be administered with caution to patients with clinically significant bladder outflow obstruction because of the risk of urinary retention (see CONTRAINDICATIONS).

Gastrointestinal Disorders

DITROPAN XL should be administered with caution to patients with gastrointestinal obstructive disorders because of the risk of gastric retention (see CONTRAINDICATIONS).

DITROPAN XL, like other anticholinergic drugs, may decrease gastrointestinal motility and should be used with caution in patients with conditions such as ulcerative colitis and intestinal atony.

DITROPAN XL should be used with caution in patients who have gastroesophageal reflux and/or who are concurrently taking drugs (such as bisphosphonates) that can cause or exacerbate esophagitis.

As with any other nondeformable material, caution should be used when administering DITROPAN XL to patients with preexisting severe gastrointestinal narrowing (pathologic or iatrogenic). There have been rare reports of obstructive symptoms in patients with known strictures in association with the ingestion of other drugs in nondeformable controlled-release formulations.

Carcinogenesis, Mutagenesis, Impairment of Fertility

A 24-month study in rats at dosages of oxybutynin chloride of 20, 80, and 160 mg/kg/day showed no evidence of carcinogenicity. These doses are approximately 6, 25, and 50 times the maximum human exposure, based on surface area.

Oxybutynin chloride showed no increase of mutagenic activity when tested in Schizosaccharomyces pompholiciformis, Saccharomyces cerevisiae, and Salmonella typhimurium test systems.

Reproduction studies with oxybutynin chloride in the mouse, rat, hamster, and rabbit showed no definite evidence of impaired fertility.

Pregnancy: Teratogenic Effects

Pregnancy Category B

Reproduction studies with oxybutynin chloride in the mouse, rat, hamster, and rabbit showed no definite evidence of impaired fertility or harm to the animal fetus. The safety of DITROPAN XL administration to women who are or who may become pregnant has not been established. Therefore, DITROPAN XL should not be given to pregnant women unless, in the judgment of the physician, the probable clinical benefits outweigh the possible hazards.

Nursing Mothers

It is not known whether oxybutynin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when DITROPAN XL is administered to a nursing woman.

Pediatric Use

The safety and efficacy of DITROPAN XL were studied in 60 children in a 24-week, open-label trial. Patients were aged 6-15 years, all had symptoms of detrusor overactivity in association with a neurological condition (e.g., spina bifida), all used clean intermittent catheterization, and all were current users of oxybutynin chloride. Study results demonstrated that administration of DITROPAN XL 5 to 20 mg/day was associated with an increase from baseline in mean urine volume per catheterization from 108 mL to 136 mL, an increase from baseline in mean urine volume after morning awakening from 148 mL to 189 mL, and an increase from baseline in the mean percentage of catheterizations without a leaking episode from 34% to 51%.

Urodynamic results were consistent with clinical results. Administration of DITROPAN XL resulted in an increase from baseline in mean maximum cystometric capacity from 185 mL to 254 mL, a decrease from baseline in mean detrusor pressure at maximum cystometric capacity from 44 cm H₂O to 33 cm H₂O, and a reduction in the percentage of patients demonstrating uninhibited detrusor contractions (of at least 15 cm H₂O) from 60% to 28%.

DITROPAN XL is not recommended in pediatric patients who can not swallow the tablet whole without chewing, dividing, or crushing, or in children under the age of 6 (See DOSAGE AND ADMINISTRATION).

Geriatric Use

The rate and severity of anticholinergic effects reported by patients less than 65 years old and those 65 years and older were similar (see CLINICAL PHARMACOLOGY, Pharmacokinetics, Special Populations: Geriatric).

Last updated on RxList: 8/4/2009

The continuous release of oxybutynin from DITROPAN XL® (oxybutynin chloride) should be considered in the treatment of overdosage. Patients should be monitored for at least 24 hours. Treatment should be symptomatic and supportive. Activated charcoal as well as a cathartic may be administered.

Overdosage with oxybutynin chloride has been associated with anticholinergic effects including central nervous system excitation, flushing, fever, dehydration, cardiac arrhythmia, vomiting, and urinary retention.

Ingestion of 100 mg oxybutynin chloride in association with alcohol has been reported in a 13-year-old boy who experienced memor loss, and a 34-year-old woman who developed stupor, followed by disorientation and agitation on awakening, dilated pupils, dry skin, cardiac arrhythmia, and retention of urine. Both patients fully recovered with symptomatic treatment.

DITROPAN XL® (oxybutynin chloride) is contraindicated in patients with urinary retention, gastric retention and other severe decreased gastrointestinal motility conditions, uncontrolled narrow-angle glaucoma and in patients who are at risk for these conditions.

DITROPAN XL is also contraindicated in patients who have demonstrated hypersensitivity to the drug substance or other components of the product.

Last updated on RxList: 8/4/2009

Oxybutynin chloride exerts a direct antispasmodic effect on smooth muscle and inhibits the muscarinic action of acetylcholine on smooth muscle. Oxybutynin chloride exhibits only one-fifth of the anticholinergic activity of atropine on the rabbit detrusor muscle, but four to ten times the antispasmodic activity. No blocking effects occur at skeletal neuromuscular junctions or autonomic ganglia (antinicotinic effects).

Oxybutynin chloride relaxes bladder smooth muscle. In patients with conditions characterized by involuntary bladder contractions, cystometric studies have demonstrated that oxybutynin increases bladder (vesical) capacity, diminishes the frequency of uninhibited contractions of the detrusor muscle, and delays the initial desire to void. Oxybutynin thus decreases urgency and the frequency of both incontinent episodes and voluntary urination.

Antimuscarinic activity resides predominantly in the R-isomer. A metabolite, desethyloxybutynin, has pharmacological activity similar to that of oxybutynin in in vitro studies.

Pharmacokinetics

Absorption

Following the first dose of DITROPAN XL® (oxybutynin chloride), oxybutynin plasma concentrations rise for 4 to 6 hours; thereafter steady concentrations are maintained for up to 24 hours, minimizing fluctuations between peak and trough concentrations associated with oxybutynin.

The relative bioavailabilities of R- and S-oxybutynin from DITROPAN XL are 156% and 187%, respectively, compared with oxybutynin. The mean pharmacokinetic parameters for R- and S-oxybutynin are summarized in Table 1. The plasma concentration-time profiles for R- and S-oxybutynin are similar in shape; Figure 1 shows the profile for R-oxybutynin.

Table 1: Mean (SD) R- and S-Oxybutynin Pharmacokinetic Parameters Following a Single Dose of DITROPAN XL 10 mg (n=43)

Parameters (units)	R-Oxybutynin		S-Oxybutynin
Cmax (ng/mL)	1.0	(0.6)	1.8	(1.0)
T (h)	12.7	(5.4)	11.8	(5.3)
t1/2 (h)	13.2	(6.2)	12.4	(6.1)
AUC(0-48) (ng·h/mL)	18.4	(10.3)	34.2	(16.9)
AUCinf (ng·h/mL)	21.3	(12.2)	39.5	(21.2)

Figure 1. Mean R-oxybutynin plasma concentrations following a single dose of DITROPAN XL 10 mg and oxybutynin 5 mg administered every 8 hours (n=23 for each treatment).

Steady-state oxybutynin plasma concentrations are achieved by Day 3 of repeated DITROPAN XL dosing, with no observed drug accumulation or change in oxybutynin and desethyloxybutynin pharmacokinetic parameters.

DITROPAN XL steady-state pharmacokinetics were studied in 19 children aged 5-15 years with detrusor overactivity associated with a neurological condition (e.g. spina bifida). The children were on DITROPAN XL total daily dose ranging from 5 to 20 mg (0.10 to 0.77 mg/kg). Sparse sampling technique was used to obtain serum samples. When all available data are normalized to an equivalent of 5 mg per day DITROPAN XL, the mean pharmacokinetic parameters derived for R- and S-oxybutynin and R- and S-desethyloxybutynin are summarized in Table 2. The plasma-time concentration profiles for R- and S-oxybutynin are similar in shape; Figure 2 shows the profile for R-oxybutynin when all available data are normalized to an equivalent of 5 mg per day.

Table 2: Mean ± SD R- and S-Oxybutynin and R- and S-Desethyloxybutynin Pharmacokinetic Parameters in Children Aged 5-15 Following Administration of 5 to 20 mg DITROPAN XL Once Daily (n=19) All Available Data Normalized to an Equivalent of DITROPAN XL 5 mg Once Daily

	R-Oxybutynin	S-Oxybutynin	R- Desethyloxybutynin	S- Desethyloxybutynin
Cmax (ng/mL)	0.7 ± 0.4	1.3 ± 0.8	7.8 ± 3.7	4.2 ± 2.3
Tmax (hr)	5.0	5.0	5.0	5.0
AUC (ng·hr/mL)	12.8 ± 7.0	23.7 ± 14.4	125.1 ± 66.7	73.6 ± 47.7

Figure 2. Mean steady state (±SD) R-oxybutynin plasma concentrations following administration of 5 to 20 mg DITROPAN XL once daily in children aged 5-15. Plot represents all available data normalized to an equivalent of DITROPAN XL 5 mg once daily.

Food Effects

The rate and extent of absorption and metabolism of oxybutynin are similar under fed and fasted conditions.

Distribution

Plasma concentrations of oxybutynin decline biexponentially following intravenous or oral administration. The volume of distribution is 193 L after intravenous administration of 5 mg oxybutynin chloride.

Metabolism

Oxybutynin is metabolized primarily by the cytochrome P450 enzyme systems, particularly CYP3A4 found mostly in the liver and gut wall. Its metabolic products include phenylcyclohexylglycolic acid, which is pharmacologically inactive, and desethyloxybutynin, which is pharmacologically active. Following DITROPAN XL administration, plasma concentrations of R- and S-desethyloxybutynin are 73% and 92%, respectively, of concentrations observed with oxybutynin.

Excretion

Oxybutynin is extensively metabolized by the liver, with less than 0.1% of the administered dose excreted unchanged in the urine. Also, less than 0.1% of the administered dose is excreted as the metabolite desethyloxybutynin.

Dose Proportionality

Pharmacokinetic parameters of oxybutynin and desethyloxybutynin (Cmax and AUC) following administration of 5-20 mg of DITROPAN XL are dose proportional.

Special Populations

Geriatric

The pharmacokinetics of DITROPAN XL were similar in all patients studied (up to 78 years of age).

Pediatric

The pharmacokinetics of DITROPAN XL were evaluated in 19 children aged 5-15 years with detrusor overactivity associated with a neurological condition (e.g., spina bifida). The pharmacokinetics of DITROPAN XL in these pediatric patients were consistent with those reported for adults (see Tables 1 and 2, and Figures 1 and 2 above).

Gender

There are no significant differences in the pharmacokinetics of oxybutynin in healthy male and female volunteers following administration of DITROPAN XL.

Race

Available data suggest that there are no significant differences in the pharmacokinetics of oxybutynin based on race in healthy volunteers following administration of DITROPAN XL.

Renal Insufficiency

There is no experience with the use of DITROPAN XL in patients with renal insufficiency.

Hepatic Insufficiency

There is no experience with the use of DITROPAN XL in patients with hepatic insufficiency.

Drug-Drug Interactions

See PRECAUTIONS: DRUG INTERACTIONS.

Clinical Studies

DITROPAN XL® (oxybutynin chloride) was evaluated for the treatment of patients with overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency in three controlled studies and one open label study. The majority of patients were Caucasian (89.0%) and female (91.9%) with a mean age of 59 years (range, 18 to 98 years). Entry criteria required that patients have urge or mixed incontinence (with a predominance of urge) as evidenced by ≥ 6 urge incontinence episodes per week and ≥ 10 micturitions per day. Study 1 was a fixed dose escalation design, whereas the other studies used a dose adjustment design in which each patient's final dose was adjusted to a balance between improvement of incontinence symptoms and tolerability of side effects. Controlled studies included patients known to be responsive to oxybutynin or other anticholinergic medications, and these patients were maintained on a final dose for up to 2 weeks.

The efficacy results for the three controlled trials are presented in the following tables and figures.

Number of Urge Urinary Incontinence Episodes Per Week

Study 1	N	DITROPAN*XL	N	Placebo
Mean Baseline	34	15.9	16	20.9
Mean (SD) Change from Baseline†	34	-15.8 (8.9)	16	-7.6 (8.6)
95% Confidence Interval for Difference	(-13.6,-2.8)*
(DITROPAN* XL-Placebo)
* The difference between DITROPAN* XL and placebo was statistically significant. †Covariate adjusted mean with missing observations set to baseline values

Study 2	N	DITROPAN*XL	N	oxybutynin
Mean Baseline	53	27.6	52	23.0
Mean (SD) Change from Baseline†	53	-17.6 (11.9)	52	-19.4 (11.9)
95% Confidence Interval for Difference	(-2.8,6.5)
(DITROPAN*XL-oxybutynin)
† Covariate adjusted mean with missing observations set to baseline values

Study 3	N	DITROPAN* XL	N	oxybutynin
Mean Baseline	111	18.9	115	19.5
Mean (SD) Change from Baseline†	111	-14.5 (8.7)	115	-13.8 (8.6)
95% Confidence Interval for Difference	(-3.0,1.6)**
1 (DITROPAN* XL - oxybutynin)
** The difference between DITROPAN* XL and oxybutynin fulfilled the criteria for comparable efficacy. †Covariate adjusted mean with missing observations set to baseline values

Last updated on RxList: 8/4/2009

Patients should be informed that heat prostration (fever and heat stroke due to decreased sweating) can occur when anticholinergics such as oxybutynin chloride are administered in the presence of high environmental temperature.

Because anticholinergic agents such as oxybutynin may produce drowsiness (somnolence) or blurred vision, patients should be advised to exercise caution.

Patients should be informed that alcohol may enhance the drowsiness caused by anticholinergic agents such as oxybutynin.

Patients should be informed that DITROPAN XL should be swallowed whole with the aid of liquids. Patients should not chew, divide, or crush tablets. The medication is contained within a nonabsorbable shell designed to release the drug at a controlled rate. The tablet shell is eliminated from the body; patients should not be concerned if they occasionally notice in their stool something that looks like a tablet.

DITROPAN XL should be taken at approximately the same time each day.

Last updated on RxList: 8/4/2009

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

OXYBUTYNIN EXTENDED-RELEASE - ORAL

(ox-ee-BYOU-tih-nin KLOR-ide)

COMMON BRAND NAME(S): Ditropan XL

USES: This is a long-acting form of oxybutynin that is used to treat overactive bladder and urinary conditions. It relaxes the muscles in the bladder to help decrease problems of urgency and frequent urination. Oxybutynin belongs to a class of drugs known as antispasmodics.

This medication is also used to treat children 6 years of age and older who have an overactive bladder due to certain nerve disorders (e.g., spina bifida).

HOW TO USE: Take this medication by mouth, usually once a day, or as directed by your doctor. It may be taken with or without food. The dosage is based on your medical condition and response to therapy. The length of treatment is determined by your doctor who may suggest periodic trials off the drug to evaluate whether you still need to be taking it.

Swallow this medication whole with the help of liquids. Do not crush, chew, or break the tablets; doing so can destroy the long action of the drug and may increase side effects.

Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time each day.

Inform your doctor if your condition persists or worsens.

SIDE EFFECTS: Dry mouth, drowsiness, headache, dizziness, nausea, vomiting, upset stomach, stomach pain, constipation, diarrhea, blurred vision, dry eyes, unusual taste in mouth, dry/flushed skin, stuffy nose, and cough may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute. To relieve dry eyes, use artificial tears or other eye lubricants. Consult your pharmacist for further advice.

To prevent constipation, maintain a diet adequate in fiber, drink plenty of water, and exercise. If you become constipated, consult your pharmacist for help in choosing a laxative (e.g., stimulant-type with stool softener).

For certain products of this drug, an empty tablet shell may appear in your stool. This is harmless.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: decreased sexual activity, difficulty urinating, fast/pounding heartbeat, signs of kidney infection (e.g., burning/painful/frequent urination, lower back pain, fever), mental/mood changes, swelling of arms/legs/ankles/feet, vision problems (including eye pain).

Tell your doctor immediately if any of these rare but very serious side effects occur: seizures, stomach/intestinal blockage (e.g., persistent nausea/vomiting, prolonged constipation).

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking oxybutynin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: active internal bleeding, untreated/uncontrolled glaucoma (narrow-angle), severe blockage/slowed movement of stomach/intestines (e.g., gastric retention, paralytic ileus), decreased bladder emptying activity (urinary retention).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: bladder disease (e.g., bladder outflow blockage), certain muscle disease (myasthenia gravis), heart disease (e.g., congestive heart failure, coronary artery disease, arrhythmias), high blood pressure, liver disease, kidney disease, loss of mental abilities (dementia), certain nervous system disorder (autonomic neuropathy), enlarged prostate gland (benign prostatic hypertrophy-BPH), stomach/intestinal disease (e.g., acid reflux disease, hiatal hernia, ulcerative colitis), severe throat/stomach/intestinal narrowing (strictures), overactive thyroid (hyperthyroidism).

This drug may make you dizzy, drowsy or cause blurred vision; use caution engaging in activities requiring alertness such as driving or using machinery. Limit use of alcoholic beverages.

This drug may increase the risk for heatstroke because it causes decreased sweating. Avoid becoming overheated in hot weather, saunas, and during exercise or other strenuous activity.

Caution is advised when using this drug in the elderly because they may be more sensitive to its effects.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

It is not known whether this drug passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop or change the dosage of any medicine before checking with them first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: anticholinergic drugs (e.g., atropine, glycopyrrolate, scopolamine ), other antispasmodic drugs (e.g., clidinium, dicyclomine, propantheline), certain anti-Parkinson's drugs (e.g., benztropine, trihexyphenidyl), belladonna alkaloids, bisphosphonate drugs (e.g., alendronate, etidronate, risedronate), desmopressin, drugs affecting liver enzymes that remove oxybutynin from your body (such as azole antifungals-including ketoconazole, macrolide antibiotics-including erythromycin, cimetidine, rifamycins-including rifabutin, St. John's wort, certain anti-seizure medicines-including carbamazepine), potassium tablets/capsules, pramlintide.

Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-anxiety drugs (e.g., diazepam), anti-seizure drugs (e.g., phenobarbital), medicine for sleep (e.g., zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., phenothiazines such as chlorpromazine or tricyclics such as amitriptyline), tranquilizers.

Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain drowsiness-causing ingredients. Ask your pharmacist about the safe use of those products.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include: delirium and paralysis.

NOTES: Do not share this medication with others.

MISSED DOSE: If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Information last revised August 2008 Copyright(c) 2008 First DataBank, Inc.