Oxytrol

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, 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 safety of OXYTROL was evaluated in a total of 417 patients who participated in two clinical efficacy and safety studies and an open-label extension. Additional safety information was collected in earlier phase trials. In the two pivotal studies, a total of 246 patients received OXYTROL during the 12-week treatment periods. A total of 411 patients entered the open-label extension and of those, 65 patients and 52 patients received OXYTROL for at least 24 weeks and at least 36 weeks, respectively.

No deaths were reported during treatment. No serious adverse events related to treatment were reported.

Adverse reactions reported in the pivotal trials are summarized in Tables 1 and 2 below.

Table 1: Number (%) of adverse reactions occurring in ≥ 2% of OXYTROL-treated patients and greater in the OXYTROL group than in the placebo group (Study 1).

Table 2: Number (%) of adverse reactions occurring in ≥ 2% of OXYTROL-treated patients and greater in the OXYTROL group than in the placebo group (Study 2).

Most adverse reactions were described as mild or moderate in intensity. Severe application site reactions were reported by 6.4% of OXYTROL-treated patients in Study 1 and by 5.0% of OXYTROL-treated patients in Study 2.

Adverse reactions that resulted in discontinuation were reported by 11.2% of OXYTROL-treated patients in Study 1 and 10.7% of OXYTROL-treated patients in Study 2. Most of these discontinuations were due to application site reaction. In the two pivotal studies, no patient discontinued OXYTROL treatment due to dry mouth.

In the open-label extension, the most common treatment-related adverse reactions were: application site pruritus, application site erythema, and dry mouth.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of OXYTROL. 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.

Nervous System Disorders: dizziness, somnolence, confusion

Psychiatric Disorders: hallucinations

The plasma concentration of oxybutynin declines within 1 to 2 hours after removal of transdermal system(s). Patients should be monitored until symptoms resolve. Overdosage with oxybutynin has been associated with anticholinergic effects including CNS excitation, flushing, fever, dehydration, cardiac arrhythmia, vomiting, and urinary retention. Ingestion of 100 mg oral oxybutynin chloride in association with alcohol has been reported in a 13 year old boy who experienced memory loss, and in 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 recovered fully with treatment directed at their symptoms.

Oxytrol is a prescription medication used to treat overactive bladder. Oxytrol belongs to a group of drugs called antispasmodics, which help to relax the bladder muscle. 

This medication comes in a transdermal (patch) form and is applied twice a week (every 3-4 days).

Common side effects of Oxytrol include dry mouth and application site reactions. Oxytrol can also cause blurred vision, drowsiness, and dizziness. Do not drive or operate heavy machinery until you know how Oxytrol affects you.

Apply Oxytrol exactly as prescribed.

Oxytrol comes as a transdermal (patch) form and is applied twice a week (every 3-4 days).

Apply Oxytrol  to clean, dry skin on abdomen, hip, or buttock. Select a new site for each new system (avoid reapplication to same site within 7 days). Wear patch under clothing; do not expose to sunlight.

Alcohol may intensify the effect of this medication.

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skipped the missed dose and take your next dose at the regular time. Do not apply two doses of Oxytrol at the same time.

• If you have an allergy to oxybutynin or any other part of Oxytrol (oxybutynin transdermal system).
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have any of these health problems: Bowel block, poorly controlled glaucoma, slow moving GI (gastrointestinal) tract, or trouble passing urine.

This is not a list of all drugs or health problems that interact with this medicine.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Oxytrol with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of a urinary tract infection (UTI) like blood in the urine, burning or pain when passing urine, feeling the need to pass urine often or right away, fever, lower stomach pain, or pelvic pain.
• Very bad dizziness or passing out.
• Feeling confused.
• Hallucinations (seeing or hearing things that are not there).
• Feeling agitated.
• Feeling very sleepy.
• Mood changes.
• Fever.
• Not sweating during activities or in warm temperatures.
• Very bad headache.
• Seizures.
• Trouble passing urine.
• A fast heartbeat.
• A heartbeat that does not feel normal.
• Fast breathing.
• Very hard stools (constipation).
• Very bad belly pain.
• Very bad irritation where Oxytrol is used.
• Very bad itching.

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

5.1 Urinary Retention

Administer Oxytrol with caution in patients with clinically significant bladder outflow obstruction because of the risk of urinary retention.

5.2 Risks in Patients with Gastrointestinal Disorders

Administer Oxytrol with caution to patients with gastrointestinal obstructive disorders because of the risk of gastric retention.

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

Oxytrol 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.

5.3 Central Nervous System Effects

Products containing oxybutynin are associated with anticholinergic central nervous system (CNS) effects. A variety of CNS anticholinergic effects have been reported, including headache, dizziness, somnolence, confusion and hallucinations. Patients should be monitored for signs of anticholinergic CNS effects, particularly after beginning treatment. Advise patients not to drive or operate heavy machinery until they know how Oxytrol affects them. If a patient experiences anticholinergic CNS effects, drug discontinuation should be considered.

5.4 Angioedema

Angioedema requiring hospitalization and emergency medical treatment has occurred with the first or subsequent doses of oral oxybutynin. In the event of angioedema, Oxytrol should be discontinued and appropriate therapy promptly provided.

5.5 Skin Hypersensitivity

Patients who develop skin hypersensitivity to Oxytrol should discontinue drug treatment.

5.6 Exacerbation of Symptoms of Myasthenia Gravis

Administer Oxytrol with caution to patients with myasthenia gravis, a disease characterized by decreased cholinergic activity at the neuromuscular junction.

No specific drug-drug interaction studies have been performed with Oxytrol.

7.1 Other Anticholinergics

The concomitant use of Oxytrol with other anticholinergic drugs, or with other agents that produce dry mouth, constipation, somnolence, 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.

7.2 Cytochrome P450 Inhibitors

Pharmacokinetic studies have not been performed with patients concomitantly receiving cytochrome P450 enzyme inhibitors, such as antimycotic agents (e.g., ketoconazole, itraconazole, and miconazole) or macrolide antibiotics (e.g., erythromycin and clarithromycin).

The plasma concentration of oxybutynin declines within 1 to 2 hours after removal of transdermal system(s). Patients should be monitored until symptoms resolve. Overdosage with oxybutynin has been associated with anticholinergic effects including CNS excitation, flushing, fever, dehydration, cardiac arrhythmia, vomiting, and urinary retention. Ingestion of 100 mg oral oxybutynin chloride in association with alcohol has been reported in a 13 year old boy who experienced memory loss, and in 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 recovered fully with treatment directed at their symptoms.

Oxytrol (oxybutynin transdermal system) is designed to deliver oxybutynin over a 3- to 4-day interval after application to intact skin. Oxytrol is available as a 39 cm2 system containing 36 mg of oxybutynin. Oxytrol has a nominal in vivo delivery rate of 3.9 mg oxybutynin per day through skin of average permeability (inter-individual variation in skin permeability is approximately 20%).

Oxybutynin is an antispasmodic, anticholinergic agent. Oxybutynin is administered as a racemate of R- and S-isomers. Chemically, oxybutynin is d, l (racemic) 4-diethylamino-2-butynyl phenylcyclohexylglycolate. The empirical formula of oxybutynin is C22H31NO3. Its structural formula is:

Oxybutynin is a white powder with a molecular weight of 357. It is soluble in alcohol, but relatively insoluble in water.

Oxytrol is a matrix-type transdermal system composed of three layers as illustrated in Figure 1. Layer 1 (Backing Film) is a thin flexible polyester/ethylene-vinyl acetate film that provides the matrix system with occlusivity and physical integrity and protects the adhesive/drug layer. Layer 2 (Adhesive/Drug Layer) is a cast film of acrylic adhesive containing oxybutynin and triacetin, USP. Layer 3 (Release Liner) is two overlapped siliconized polyester strips that are peeled off and discarded by the patient prior to applying the matrix system.

Figure 1: Side and top views of the Oxytrol system.(Not to scale)

You should not use Oxytrol if you have uncontrolled narrow-angle glaucoma, a blockage in your stomach or intestines, or if you are unable to urinate.