Oxybutynin Chloride

Pronunciation

Class: Antimuscarinics
VA Class: GU201
CAS Number: 1508-65-2
Brands: Ditropan, Ditropan XL, Oxytrol

Introduction

Genitourinary antispasmodic agent; a synthetic tertiary amine antimuscarinic agent.100 116

Uses for Oxybutynin Chloride

Overactive Bladder

Relief of symptoms of bladder instability associated with voiding (i.e., urgency, frequency, urinary leakage, urge incontinence, dysuria) in adults and pediatric patients > 5 years of age with uninhibited neurogenic or reflex neurogenic bladder (conventional tablets or oral solution).100

Treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency (extended-release tablets or transdermal system).116 119 120

Slideshow: How to Manage Your Overactive Bladder

Relief of symptoms of detrusor overactivity associated with a neurological condition (e.g., spina bifida) in pediatric patients ≥ 6 years of age (extended-release tablets).116

Conventional tablets as effective as extended-release tablets.116 119

Oxybutynin appears to be as effective as tolterodine (conventional tablets) in reducing urinary symptoms in patients with overactive bladder103 109 but is associated with a higher incidence of dry mouth.102 103 109 110 111

Primary Nocturnal Enuresis

Has been used in children for the treatment of primary nocturnal enuresis; however one study has determined that oxybutynin is not effective for management of primary nocturnal enuresis in children with a history of nocturnal enuresis and normal bladders.101

Oxybutynin Chloride Dosage and Administration

General

  • Discontinue therapy periodically to determine whether the patient can manage without the drug and to minimize any tendency for the patient to become resistant to the drug.c

  • Adjust dosage according to individual requirements and response.116

Administration

Administer orally100 116 or topically.120

Oral Administration

Administer extended-release tablets without regard to meals.116 117 118

Extended-release tablets should be swallowed intact with liquid, and should not be chewed, crushed, or broken.116

Administer extended-release tablets at approximately the same time each day.116

Topical Administration

After removal from protective pouch, apply transdermal system immediately to dry, intact skin on the abdomen, hip, or buttock.

A new application site should be selected with each new system; avoid reapplication to the same site within 7 days.120

Used system should be discarded in a manner that prevents accidental application or ingestion by children, pets, or others.120

Dosage

Conventional tablets, extended-release tablets, and oral solution available as oxybutynin chloride; dosage is expressed in terms of oxybutynin chloride.100 116

Transdermal system available as oxybutynin; dosage is expressed in terms of oxybutynin.120

Pediatric Patients

Overactive Bladder
Oral

Conventional tablets or oral solution: 5 mg twice daily for children ≥5 years of age.100

Extended-release tablets: 5 mg once daily for children ≥6 years of age.116 Adjust dosage according to individual response and tolerance;116 increase dosage at 7-day intervals in increments of 5 mg116 up to maximum dosage of 20 mg once daily.116

Adults

Overactive Bladder
Oral

Conventional tablets or oral solution: 5 mg 2–3 times daily.100

Extended-release tablets: 5 or 10 mg once daily.116 Adjust daily dosage according to individual response and tolerance;116 increase dosage at 7-day intervals in increments of 5 mg116 up to maximum dosage of 30 mg once daily.116

Topical

1 transdermal system (delivering 3.9 mg per day) twice weekly (every 3–4 days).120

Prescribing Limits

Pediatric Patients

Overactive Bladder
Oral

Conventional tablets or oral solution: Maximum 5 mg 3 times daily.100

Extended-release tablets: Maximum 20 mg once daily.116

Adults

Overactive Bladder
Oral

Conventional tablets or oral solution: Maximum 5 mg 4 times daily.100

Extended-release tablets: Maximum 30 mg once daily.116

Special Populations

Geriatric Patients

A lower initial dosage (2.5 mg 2 or 3 times daily) of conventional tablets or oral solution is recommended for frail geriatric patients.100 (See Geriatric Use under Cautions.)

Cautions for Oxybutynin Chloride

Contraindications

  • Conventional Tablets and Oral Solution
  • Patients with untreated angle-closure glaucoma or those with untreated narrow anterior chamber angles.100

  • Obstructive uropathy.100

  • Partial or complete obstruction of the GI tract, paralytic ileus, intestinal atony (in elderly or debilitated patients), megacolon, toxic megacolon complicating ulcerative colitis, or severe colitis.100

  • Myasthenia gravis.100

  • Unstable cardiovascular status in acute hemorrhage.100

  • Known hypersensitivity to oxybutynin or any ingredient in the formulations.

  • Extended-release Tablets and Transdermal System
  • Presence or risk of urinary retention.116 120

  • Presence or risk of gastric retention and other severe decreased GI motility conditions.116 120

  • Presence or risk of uncontrolled angle-closure glaucoma.116 120

  • Known hypersensitivity to oxybutynin or any ingredient in the formulations.100 116

Warnings/Precautions

Warnings

Risk of heat prostration (i.e., fever and heat stroke due to decreased sweating) when administered during hot weather.100 116 120

Diarrhea may be a symptom of partial intestinal obstruction, especially in patients with ileostomies or colostomies; in this instance, treatment with oxybutynin would be inappropriate and possibly harmful.100

General Precautions

Urinary Retention

Risk of urinary retention; use with caution in patients with clinically important bladder outflow obstruction.116 120

GI Effects

Risk of gastric retention; use with caution in patients with GI obstructive disorders.116 120

Risk of decreased GI motility; use with caution in patients with conditions such as ulcerative colitis or intestinal atony.116 120 Use in patients with ulcerative colitis may suppress intestinal motility, resulting in paralytic ileus and precipitating or exacerbating toxic megacolon.100

Use with caution in patients who have gastroesophageal reflux (GERD) and/or in those who are concurrently receiving drugs that can cause or exacerbate esophagitis (e.g., bisphosphonates).116 120 (See Specific Drugs under Interactions.)

As with other nondeformable material, extended-release tablets should be used with caution in patients with preexisting severe GI narrowing (pathologic or iatrogenic) since obstruction may occur.116

Myasthenia Gravis

Oxybutynin may increase risk of aggravating symptoms of myasthenia gravis.116 Use with caution in patients with myasthenia gravis.116 120

Other Concomitant Diseases

Use with caution in patients with autonomic neuropathy.100 Use of oxybutynin may exacerbate manifestations of hyperthyroidism, CHD, CHF, cardiac arrhythmias, hiatal hernia, tachycardia, hypertension, and prostatic hypertrophy.100

Specific Populations

Pregnancy

Category B.100 116 120

Lactation

Not known whether distributed into milk.100 116 120 Caution if used in nursing women.100 116 120

Pediatric Use

Safety and efficacy of conventional tablets and oral solution not established in children <5 years of age; use in these children not recommended.100

Safety and efficacy of extended-release tablets not established in children <6 years of age.116 Use of this preparation not recommended in children who cannot swallow the tablet whole without chewing, dividing, or crushing.116

Safety and efficacy of transdermal system not established in pediatric patients.120

Geriatric Use

No substantial differences in safety and efficacy relative to younger adults,116 120 but increased sensitivity cannot be ruled out.120 Use with caution in frail geriatric patients.100

Renal or Hepatic Impairment

Not studied in patients with renal or hepatic impairment; use with caution.116 120

Common Adverse Effects

Conventional or extended-release tablets or oral solution: dry mouth, dizziness, constipation, somnolence, impaired urination, nausea, blurred vision, dyspepsia, asthenia, pain, abdominal pain, headache, rhinitis, dry eyes, diarrhea, increased post-void residual volume, urinary tract infection.100

Transdermal system: application site reactions (e.g., pruritus, erythema, rash, vesicles, macules), dry mouth, constipation, diarrhea, abnormal vision, dysuria.120

Interactions for Oxybutynin Chloride

Metabolized principally by CYP3A4.116 120

No formal drug interaction studies have been performed with transdermal system.120

Drugs Affecting Hepatic Microsomal Enzymes

Inhibitors of CYP3A4: Potential pharmacokinetic interaction (increased oxybutynin concentrations).116

Drugs Affected by GI Motility

Potential pharmacokinetic interaction (altered absorption because of decreased GI motility).116

Specific Drugs

Drug

Interaction

Comment

Antacids

Concomitant administration of oxybutynin extended-release tablets with aluminum hydroxide, magnesium hydroxide, and simethicone did not substantially alter plasma concentrations of oxybutynin or desethyloxybutynin116

Anticholinergic Agents

Possible increased frequency and/or severity of adverse anticholinergic effects (e.g., dry mouth, constipation, somnolence)116

Azole antifungals (itraconazole, ketoconazole, miconazole)

Possible altered oxybutynin pharmacokinetics (e.g., increased oxybutynin concentrations)116

Use with caution116

Bisphosphonates

Bisphosphonates may cause or exacerbate esophagitis116 120

Use with caution116 120

Macrolide antibiotics (erythromycin, clarithromycin)

Possible altered oxybutynin pharmacokinetics (e.g., increased oxybutynin concentrations)116

Use with caution116

Oxybutynin Chloride Pharmacokinetics

Absorption

Bioavailability

Rapidly absorbed following oral administration (conventional tablets or oral solution); 100 undergoes extensive first-pass metabolism.120 Absolute bioavailability of oxybutynin is approximately 6%.120

Following oral administration of extended-release tablets, relative bioavailabilities of R- and S-oxybutynin are 156 and 187% respectively, compared with conventional oxybutynin formulations.116 119

Absorption of oxybutynin is bioequivalent when the transdermal system is applied to the abdomen, buttocks, or hip.120

Duration

Following oral administration (conventional tablets or oral solution), peak plasma concentrations are achieved within 1 hour.100

Following oral administration of extended-release tablets, plasma oxybutynin concentrations increase gradually for 4–6 hours, peak within 12–13 hours, and are maintained for up to 24 hours.116 119 Steady-state concentrations are achieved by the third day.116 In pediatric patients 5–15 years of age, peak plasma concentrations are achieved within approximately 5 hours.116

Following application of the transdermal system, oxybutynin plasma concentrations increase for approximately 24–48 hours, peak within 36–48 hours, and are maintained for up to 96 hours.120 Following multiple applications of the transdermal system, peak plasma concentrations are achieved within 10–28 hours.120 Steady-state concentrations are achieved with application of the second transdermal system.120

Food

Food may delay absorption and increase bioavailability of oxybutynin oral solution by 25%.100 Food does not appear to affect absorption of extended-release tablets.116 117 118

Distribution

Extent

Distributed in the brain, lungs, kidneys, and liver following oral administration in rats.c

Not known whether oxybutynin is distributed into milk in humans.100 116 120

Elimination

Metabolism

Metabolized to active (desethyloxybutynin) and inactive (phenylcyclohexylglycolic acid) metabolites116 119 120 principally via CYP3A4, which is found mainly in the liver and intestinal wall.116 120

Elimination Route

Excreted principally in urine as metabolites; <0.1% excreted as unchanged drug116 120 120 and <0.1% excreted as desethyloxybutynin.100 116 120

Half-life

Conventional tablets or oral solution: 2–3 hours100

Extended-release tablets: 13.2 and 12.4 hours for the R- and S-isomers of oxybutynin, respectively.116

Approximately 7–8 hours following removal of transdermal system.120

Special Populations

Not studied in patients with renal or hepatic impairment.116 120

Increased elimination half-life in frail geriatric patients.100

Decreased metabolism in healthy Japanese individuals compared with Caucasians.120

Stability

Storage

Oral

Conventional Tablets and Oral Solution

Tight, light resistant containers at 15–30°C .100

Extended-release Tablets

25°C (may be exposed to 15–30°C).116 Protect from moisture and humidity.116

Transdermal System

25°C (may be exposed to 15–30°C).120 Protect from moisture and humidity.120 Do not store outside sealed pouch.120

Actions

  • Racemic mixture of R- and S-isomers.120 Antimuscarinic activity resides predominantly in the R-isomer.116 120 Free base (oxybutynin) pharmacologically equivalent to oxybutynin chloride.120

  • Chemically and pharmacologically similar to some anticholinergic, antispasmodic, local anesthetic, and antihistaminic compounds.c

  • Exerts a direct spasmolytic action and inhibits the muscarinic action of acetylcholine on smooth muscle.100 116

  • Acts as a competitive antagonist of acetylcholine at postganglionic muscarinic receptors,120 resulting in relaxation of bladder smooth muscle.100 116 120 In patients with uninhibited neurogenic and reflex neurogenic bladders, oxybutynin diminishes the frequency of uninhibited contractions of the detrusor muscle and delays the initial desire to void, resulting in decreased urgency and the frequency of incontinent episodes and voluntary urination.100 116 120

  • Does not appear to exhibit antinicotinic effects (i.e., block acetylcholine effects at skeletal myoneural junctions or at autonomic ganglia).100 116

Advice to Patients

  • Risk of heat prostration (i.e., fever and heat stroke due to decreased sweating) when administered during hot weather.100 116 120

  • Risk of blurred vision, drowsiness, or somnolence;100 116 120 importance of exercising caution when driving or operating machinery.100 Alcohol or other sedative drugs may enhance drowsiness caused by oxybutynin.100 116 120

  • When dispensing extended-release tablets, advise patients not to become alarmed if they notice a tablet-like substance in their stools; this is normal since the tablet containing the drug is designed to remain intact and slowly release the drug from a nonabsorbable shell during passage through the GI tract.116

  • When dispensing the transdermal system, provide patients with a copy of manufacturer’s patient information.120

  • Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs and herbal supplements, as well as any concomitant illnesses (e.g., cardiovascular disease).100 116 120

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.100 116 120

  • Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Oxybutynin

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Topical

Transdermal System

3.9 mg/day (36 mg/43 cm2)

Oxytrol

Watson

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Oxybutynin Chloride

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Solution

5 mg/5 mL*

Ditropan Syrup (with methylparaben)

Ortho-McNeil

Tablets

5 mg*

Ditropan (scored)

Ortho-McNeil

Tablets, extended-release

5 mg

Ditropan XL

Ortho-McNeil

10 mg

Ditropan XL

Ortho-McNeil

15 mg

Ditropan XL

Ortho-McNeil

Comparative Pricing

This pricing information is subject to change at the sole discretion of DS Pharmacy. This pricing information was updated 10/2014. Actual costs to patients will vary depending on the use of specific retail or mail-order locations and health insurance copays.

Ditropan XL 10MG 24-hr Tablets (MCNEIL): 30/$127.98 or 90/$366.96

Ditropan XL 15MG 24-hr Tablets (JANSSEN): 30/$133.99 or 90/$383.98

Ditropan XL 5MG 24-hr Tablets (JANSSEN): 30/$135.99 or 90/$379.97

Oxybutynin Chloride 10MG 24-hr Tablets (MYLAN): 100/$295.97 or 300/$785.94

Oxybutynin Chloride 15MG 24-hr Tablets (MYLAN): 100/$307.99 or 300/$881.97

Oxybutynin Chloride 5MG 24-hr Tablets (MYLAN): 100/$299.99 or 300/$799.98

Oxybutynin Chloride 5MG/5ML Syrup (MORTON GROVE PHARMACEUTICALS): 120/$25.00 or 360/$52.99

Oxybutynin Chloride 5MG Tablets (QUALITEST): 60/$16.99 or 180/$38.97

Oxytrol 3.9MG/24HR Patches (WATSON LABS): 8/$250.80 or 24/$731.48

AHFS DI Essentials. © Copyright, 2004-2014, Selected Revisions August 1, 2005. American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.

References

100. Ortho-McNeil Pharmaceutical. Ditropan (oxybutynin chloride) tablets and syrup prescribing information. Raritan, NJ; 2003 Mar.

101. Lovering JS, Tallett SE, McKendry JBJ. Oxybutynin efficacy in the treatment of primary enuresis. Pediatrics. 1988; 81:104-6.

102. Pharmacia & Upjohn. Detrol (tolterodine) tablets—general review. Kalamazoo, MI; 1998 Jan.

103. Hills CJ, Winter SA, Balfour JA. Tolterodine. Drugs. 1998; 55:813-20. [PubMed 9617596]

104. Nilvebrant L, Hallén B, Larsson G. Tolterodine—a new bladder selective muscarinic receptor antagonist: preclinical pharmacological and clinical data. Life Sci. 1997; 60:1129-36. [PubMed 9121357]

105. Guay DRP. Tolterodine, a new antimuscarinic drug for treatment of bladder overactivity. Pharmacotherapy. 1999; 19:267-80. [IDIS 422545] [PubMed 10221366]

106. Nilvebrant L, Andersson KE, Gillberg PG et al. Tolterodine—a new bladder-selective antimuscarinic agent. Eur J Pharmacol. 1997; 327:195-207. [PubMed 9200560]

107. Ruscin JR, Morgenstern NE. Tolterodine use for symptoms of overactive bladder. Ann Pharmacother. 1999; 33:1073-82. [IDIS 434364] [PubMed 10534221]

108. Hampel C, Wienhold D, Benken N et al. Definition of overactive bladder and epidemiology of urinary incontinence. Urology. 1997; 50:4-14. [PubMed 9426746]

109. Abrams P, Freeman R, Anderstróm C et al. Tolterodine, a new antimuscarinic agent: as effective but better tolerated than oxybutynin in patients with an overactive bladder. Br J Urol. 1998; 81:801-10. [PubMed 9666761]

110. Anon. Tolterodine for overactive bladder. Med Lett Drugs Ther. 1998; 40:101-2. [PubMed 9813595]

111. Van Kerrebroeck PEVA, Serment G, Dreher E. Clinical efficacy and safety of tolterodine compared to oxybutynin in patients with overactive bladder. Neurourol Urodyn. 1997; 16:478-9.

112. Appell RA. Clinical efficacy and safety of tolterodine in the treatment of overactive bladder: a pooled analysis. Urology. 1997; 50(Suppl 6A):90-6. [PubMed 9426760]

113. Pharmacia & Upjohn, Kalamazoo, MI: Personal communication on tolterodine.

114. Reviewers’ comments (personal observations) on tolterodine.

115. Pharmacia & Upjohn Company. Detrol (tolterodine tartrate) tablets prescribing information. Kalamazoo, MI; 1998 Mar.

116. Ortho-McNeil Pharmaceutical. Ditropan XL (oxybutynin chloride) extended-release tablets prescribing information. Raritan, NJ; 2005 Jun.

117. Lukkari E, Castren-Kortekangas P, Juhakoski A et al. Effect of food on the bioavailability of oxybutynin from a controlled release tablet. Eur J Clin Pharmacol. 1996; 50:221-223. [IDIS 366453] [PubMed 8737763]

118. Lukkari E, Aranko K, Juhakoski A et al. Effect of time interval between food and drug ingestion on the absorption of oxybutynin from a controlled-release tablet. Pharmacol Toxicol. 1997; 81:31-34. [PubMed 9258982]

119. Alza. Ditropan XL (oxybutynin chloride) product monograph. Palo Alto, CA; 1999 Mar.

120. Watson Pharma, Inc. Oxytrol (oxybutynin) transdermal system prescribing information. Corona, CA; 2003 Feb.

c. AHFS drug information 2003. McEvoy GK, ed. Oxybutynin Chloride. Bethesda, MD: American Society of Health-System Pharmacists; 2003:3480-2.

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