Oxybutynin Chloride - Uses, Dosage, Side Effects, and Drug Warnings

Overview:

Oxybutynin is approved by the Food and Drug Administration (FDA) for patients above the age of five years. The drug is used to treat an overactive bladder leading to increased urine frequency. Oxybutynin is also used in patients with a neurogenic bladder with unstable detrusor muscles. Oxybutynin is a class of drugs that belongs to anticholinergics or antimuscarinics and works by relaxing the bladder muscles.

How Does Oxybutynin Work?

It is an anticholinergic drug that causes antispasmodic activity against smooth muscle, including the bladder. N-desethyloxybutynin is the active metabolite that blocks the muscarinic effect of acetylcholine. Oxybutynin competitively inhibits the postganglionic muscarinic receptors 1, 2, and 3, leading to the relaxation of bladder smooth muscle. It results in an increase in bladder capacity and a decrease in urinary frequency. It also has been reported to delay the desire to void.

Uses:

• FDA-Approved Indications: Oxybutynin is indicated in patients with overactive bladder or symptoms of detrusor overactivity, including urinary frequency. Animal studies have revealed that the drug has an antispasmodic effect four to ten times of Atropine. Oxybutynin chloride can also be used in patients with detrusor instability associated with neurogenic bladders, such as spina bifida. It has been approved for patients above five years.

• Other Indications: Occasionally, Oxybutynin is used for the treatment of bladder spasms caused by indwelling Foley catheters (ureteral stents). However, this indication is not approved by FDA. It is also used to treat primary focal hyperhidrosis (sweat secretion more than needed for thermoregulation).

Forms of Dosage:

The Food and Drug Administration has approved certain dosage forms that include

• Immediate oral release.

• Oral extended-release.

• Topical gel.

• Transdermal patch (medicated adhesive patch placed on the skin to release a specific dose of the drug through the skin).

• Intravesical instillation (administration of a drug into the urinary bladder via a catheter).

• Rectal suppository (medication forms that are inserted into the rectum).

Warnings:

1. Pediatric Patients: Various studies conducted on the pediatric population have demonstrated that Oxybutynin extended-release tablets can be used in children older than six years of age. However, it is not recommended for children who cannot swallow the tablet as a whole without breaking or crushing it and children younger than six years.

2. Geriatric Patients: Studies indicate that there are no geriatric-specific problems that limit the administration of the drug in elderly patients.

3. Allergies: The patient should inform the doctor about the allergies experienced by this drug or any other drug. Allergies from food, dyes, or any preservatives should also be informed.

4. Breastfeeding: No authentic studies have been performed to determine the infant risk from the drug during breastfeeding. Before taking Oxybutynin while breastfeeding, the potential benefits should be evaluated against the potential risks.

For Patients:

Why Is Oxybutynin Chloride Used?

Oxybutynin chloride is used for treating an overactive bladder. In this condition, there is an uncontrollable contraction of the bladder muscles, causing an urgency to urinate, frequent urination, and an inability to control voiding.

Another use of Oxybutynin is as an extended-release tablet in patients with certain neurological conditions such as spina bifida, a disability that occurs due to improper closure of the spinal cord before birth.

How Should Oxybutynin Chloride Be Used?

• It is available as a syrup, a tablet, and a long-acting or extended-release tablet taken orally.

• Oxybutynin gives symptomatic relief but does not cure the condition.

• The syrup and tablets are usually administered two to four times daily. It is advised to take the drug around the same time every day. The patients should follow all the directions given by the doctor.

• It should be taken just as directed by the doctor, and the dosage should not be altered.

• The extended-release tablets should never be chewed or crushed and should be swallowed as a whole with a large amount of water. The extended-release tablet is usually once a day, with or without food.

• The syrup should be taken with a dose-measuring spoon so that the same correct amount of drug is taken each time.

• The doctor may start Oxybutynin with a low dose and increase the dose gradually once a week.

• Symptoms usually improve within the first two weeks of the treatment. However, it can take six to eight weeks to experience the complete benefit of the drug. The doctor should be informed if the symptoms do not resolve even after eight weeks.

• The drug should not be discontinued without informing the doctor.

What Special Precautions Should Be Taken Before Taking Oxybutynin?

1. Allergies: The doctor should be informed about a known allergy to Oxybutynin chloride or other medication. The patient should ask for the list of ingredients in the drug that they might be allergic to.

2. Medical History: The patient should tell the doctor about any other illness in the past or any comorbidities present.

3. Drug History: The patients must inform the doctor about any prescribed or non-prescribed medications they are taking. Further, the doctor should be aware of any vitamins or supplements (nutritional or herbal) the patient is taking.

The patients should mention if they are taking the following drugs:

• Amiodarone.

• Certain antibiotics, such as Clarithromycin.

• Erythromycin.

• Tetracycline.

• Antifungals such as Itraconazole, Miconazole, and Ketoconazole.

• Antihistamines.

• Nonsteroidal anti-inflammatory medications such as Aspirin, Ibuprofen, and Naproxen.

• Cimetidine.

• Diltiazem.

• Fluvoxamine.

• Ipratropium.

• Iron supplements.

• Drugs for human immunodeficiency virus (HIV) such as Nelfinavir, Indinavir, and Ritonavir.

• Medications for irritable bowel disease, Parkinson's disease, motion sickness, ulcers, or other urinary problems.

• Medications for osteoporosis such as Alendronate, Ibandronate, and Risedronate.

• Nefazodone

• Potassium supplements.

• Quinidine.

• Verapamil.

The doctor might change the doses of these medications or monitor the side effects carefully.

4. Glaucoma: The doctor should be informed if the patient has ever had glaucoma, an eye condition that can lead to loss of vision, or any condition that inhibits complete emptying of the bladder.

5. Certain Clinical Conditions: The patient should inform the doctor about a history of the following conditions or disorders

• Ulcerative colitis (a condition that leads to swelling in the lining of the large intestine and rectum).

• Hyperthyroidism (increased level of thyroid hormone in the body).

• Gastroesophageal reflux disease or GERD (a condition in which the contents of the stomach come to the esophagus and cause heartburn).

• Hiatal hernia where the stomach wall protrudes and may cause pain.

• Dementia.

• Myasthenia gravis (a neurological disorder causing muscle weakness).

• Parkinson's disease.

• Benign prostatic hypertrophy (BPH) enlargement of the prostate.

• Fast or irregular heartbeat.

• High blood pressure.

• Heart, liver, or kidney disease.

6. Pregnancy: The patient must inform the doctor if she is pregnant or planning to get pregnant. The patient should inform the doctor immediately if she becomes pregnant while taking Oxybutynin medications.

7. Geriatric Patients: If the patient is above 65 years of age, they should discuss the risk and benefits of taking the medications with the doctor.

8. Surgery: Before surgery, the patient should inform the doctor if they are taking Oxybutynin; even before dental surgery, the dentist should be informed.

9. Alcohol: Alcohol consumption can worsen the side effects of this drug. Hence, The doctor should be consulted about the safe use of alcohol while taking Oxybutynin.

10. Vigorous Exercise: Oxybutynin causes delayed body cooling after it gets very hot. The patient should avoid exposure to heat while taking this medication and inform the doctor if they experience signs of a heat stroke like nausea, dizziness, fast pulse, and headache.

What Special Dietary Instructions Should Be Followed?

The patient should consult the doctor about eating grapefruit and drinking grapefruit juice while taking this medication.

What Are the Side Effects of This Medication?

Oxybutynin may cause many side effects. The doctor must be informed if the side effects are serious and do not resolve. The common side effects are as follows:

• Dry mouth.

• Dryness of eyes, skin, or nose.

• Blurred vision.

• Changes in taste.

• Stomach ache.

• Constipation

• Diarrhea

• Nausea and heartburn.

• Fatigue.

• Swelling of the hands, feet, ankles, arms, or lower legs.

• Headache or dizziness.

• Confusion.

• Sleepiness or difficulty falling asleep and staying asleep.

• Nervousness.

• Joint or back pain.

Serious side effects of Oxybutynin include

• Rash.

• Urticaria or hives.

• Painful urination.

• Swelling of the eyes, tongue, face, lips, or throat.

• Hoarseness.

• Difficulty breathing (dyspnea).

• Difficulty in swallowing (dysphagia).

• Fast or irregular heartbeat.

Oxybutynin may lead to other side effects. The doctor should be informed immediately about these side effects.

What Should Be Done if a Dose Is Forgotten?

The missed dose should be taken once the patient remembers about it. However, if it is almost time for the next dose, the dose should be skipped, and a regular dosing schedule should be followed. For example, a double dose should not be taken to compensate for a missed one.

How Should Oxybutynin Chloride Be Stored and Disposed Of?

• The container of Oxybutynin chloride should be tightly closed and kept out of reach of children.

• Oxybutynin chloride should be stored at room temperature and not exposed to excessive moisture and heat.

• If Oxybutynin chloride is no longer required, it should be disposed of properly so that pets and children do not consume the medications by mistake.

What Should Be Done in Case of an Emergency or Overdose?

In case of an overdose, the poison control helpline should be informed immediately. Symptoms of overdose usually include

• Uncontrollable movement or shaking of a body part.

• Seizures.

• Irritability.

• Memory loss.

• Irregular heartbeat.

• Restlessness and confusion.

• Coma or loss of consciousness.

• Hallucinations.

• Slowed or difficult breathing.

• Agitation.

• Flushing.

• Fever.

• Vomiting

• Difficulty urinating.

• Inability to move.

• Wide pupils.

• Dry skin.

What Other Information Is Required?

• The patient should not advise others to take this medication without consulting a doctor.

• The patient can ask the pharmacist any questions about refilling the prescription.

• In patients taking extended-release, there might be a tablet-like thing seen in the stool. It is the empty tablet shell.

• It is essential to maintain a written list of all of the prescribed and non-prescribed (over-the-counter) drugs that are being taken by the patient, including other supplements like vitamins or minerals. The patient should carry this list for every visit to a doctor or a hospital. It is extremely important in case of emergencies.

For Doctors:

Indications:

• Oxybutynin chloride is used for treating an overactive bladder. In this condition, there is an uncontrollable contraction of the bladder muscles, causing an urgency to urinate, frequent urination, and an inability to control voiding.

• Another use of Oxybutynin is as an extended-release tablet in patients with certain neurological conditions such as spina bifida, a disability that occurs due to improper closure of the spinal cord before birth.

Pharmacology:

Pharmacokinetics:

Absorption:

• Oxybutynin is quickly absorbed after Oxybutynin chloride immediate-release tablets are taken orally.

• The absolute bioavailability of the drug is about 6 % (between 1.6 to 10.9 %).

• Cmax is achieved within one hour.

• Plasma half-life: two to three hours approximately.

Metabolism:

In the Liver: Oxybutynin chloride gets metabolized by the cytochrome P450 enzyme systems, usually through CYP3A4. The metabolism results in the formation of two metabolites:

• Metabolite phenyl cyclohexyl glycolic acid (pharmacologically inactive).

• Desethyl oxybutynin (pharmacologically active).

Food Effects:

Clinical data shows that if Oxybutynin is taken with food, the absorption is delayed, and bioavailability is increased by 25 %.

Distribution: After intravenous 5 milligrams, Oxybutynin chloride administration Oxybutynin has a large volume of distribution (193 liters). In addition, the enantiomers of Oxybutynin (R and S) are highly protein-bound (99 %).

Excretion: Oxybutynin is majorly metabolized in the liver, and less than 0.1 % of the dose gets excreted unaltered in the urine, and less than 0.1 % is excreted as a desethyl oxybutynin metabolite.

Dosage: The dose of the medicine depends on the following:

• Strength of the medicine.

• The number of doses taken each day.

• The time gap between doses.

Treatment of Bladder Problems:

1) For Oral Extended-Release Tablets:

Adults:

• Initial Dose: 5 or 10 milligrams once daily. The dose can be increased when needed. However, a dose of more than 30 milligrams per day is not recommended.

Children 6 Years and Older:

• Initial Dose: 5 milligrams once a day. The dose can be increased when needed. However, a dose of more than 30 milligrams per day is not recommended.

Children Younger Than 6 Years:

• Not recommended for use.

Geriatric Patients:

• Initial Dose: 2.5 milligrams two to three times daily. It has prolonged elimination with a half-life of 5 hours.

2) For Syrup or Tablets:

Adults and Children 12 Years and Older:

• 5 milligrams two or three times daily.

Children 5 to 12 Years:

• 5 milligrams two or three times daily. The dose can be increased by the doctor if needed. However, a dose of more than 15 mg per day is not recommended.

Children Younger Than 5 Years:

• Use and dose must be decided by the doctor.

3) Oxybutynin Transdermal Patch:

• 36 milligrams of Oxybutynin (average daily absorbed dose of 3.9 mg).

• It is delivered continuously for three to four days after application.

• The concentrations become more steady during the second phase of the application.

• The patch is usually applied to the abdomen, hip, or buttock.

• The safety of these transdermal patches has not been established in pediatric patients.

• 10 % Oxybutynin gel is available in sachets, and the contents must be applied to clean, dry, and intact skin.

The dose of this may vary from patient to patient, depending on the condition.

Pregnancy or Breastfeeding Considerations: Oxybutynin chloride comes under category B for pregnant patients. The safety of this drug has not been completely established for women who are pregnant or want to become pregnant. However, animal studies have not reported any harm to the fetus. No harmful effect has been reported in nursing mothers taking Oxybutynin.

Primary Focal Hyperhidrosis:

• Oxybutynin 2.5 milligrams is given once daily and gradually increased depending upon the tolerance between 5 to 10 milligrams/day in two divided doses.

• Extended-release oxybutynin dose is 5 to 10 milligrams once daily.

Missed Dose:

If a dose of the medicine is missed, it should be taken as soon as possible. However, if it is time for the next dose, the missed dose should be skipped, and a regular dosing routine should be followed.

Storage:

Oxybutynin should be stored in a closed container at room temperature.

• It should be kept away from heat, direct light, and moisture.

• It should not be frozen.

• It should be stored such that it is out of the reach of children.

• Expired medicines should not be stored.

• Oxybutynin chloride should be disposed of properly when not in use.

Adverse Effects:

Adverse Effects of Immediate-Release Oxybutynin Include

• Dry mouth (71.4%).

• Dizziness (16.6%).

• Constipation (15.1%).

• Somnolence (14.0%).

• Nausea (11.6%).

Less common side effects include

• Blurred vision (9.6%).

• Urinary hesitation (8.5%).

• Urinary retention (6.0%).

• Dyspepsia (6.0%).

Adverse Effects of Extended-Release Oxybutynin Include

• Dry mouth (29 to 61%).

• Constipation (7 to 13%).

• Somnolence (2 to 12%).

• Headache (6 to 10%).

• Diarrhea (7 to 9%).

• Nausea (2 to 9%).

• Blurred vision (1 to 8%).

• Dry eyes (3 to 6%).

Dry mouth is a dose-related side effect that caused discontinuation of this drug in 6.8% of patients.

In 5.4% of patients, application site reactions were reported for oxybutynin gel and 16.8% for Oxybutynin transdermal system.

Dry mouth was less commonly found in patients receiving transdermal oxybutynin than in the oral forms, reported as 7.5% for the gel and 9.6% for the patch.

Adverse effects are usually dose-related.

Contraindications:

Oxybutynin is contraindicated in patients:

• Urinary retention.

• Bladder obstruction.

• Poorly controlled narrow-angle glaucoma.

• Obstructive gastric disorders, or gastric dysmotility.

• In patients who have hypersensitivity to Oxybutynin chloride or its components.

Cautious use is recommended for elderly or weak patients, including patients with

• Dementia.

• Parkinson's disease.

• Myasthenia gravis.

• Renal or hepatic impairments.

Monitoring: Monitoring of the patients should be done for anticholinergic side effects associated with the central nervous system, such as

• Hallucinations.

• Agitation.

• Confusion.

• Somnolence (sleepiness or drowsiness).

Monitoring is essential in elderly patients within the initial few months of treatment or after an increased Oxybutynin dose.

Patients should be informed that increased drowsiness is associated with concomitant alcohol use.

Patients should also be told about the risk of taking oxybutynin in a high-temperature environment that may lead to heat stroke.

Using oxybutynin along with other anticholinergic medications can increase the frequency and severity of the adverse effects.

Toxicity: A medical professional should seek immediate care if an overdose is suspected.

Symptoms of overdose include

• Central nervous system overactivity.

• Fever.

• Cardiac arrhythmias.

• Vomiting.

• Respiratory failure.

• Paralysis.

• Coma.

Treatment of toxicity includes supportive care.

Drug Interactions:

Certain drugs should not be used together as two different drugs may interact with each other. In such cases, the doctor might change the dose, or necessary precautions must be taken. The doctor should be informed if the patient is taking the following medicines:

• Potassium.

• Potassium Citrate.

Use of Oxybutynin chloride with any of the following drugs is not recommended. The doctor must decide whether to treat with oxybutynin or use some other drug. Using Oxybutynin with any of the following drugs is usually not recommended but may be necessary in some cases. If both drugs are prescribed simultaneously, the doctor might change the dose of the drug or its frequency.

• Clozapine.

• Revefenacin.

• Scopolamine.

• Donepezil.

• Glucagon.

• Quetiapine.

• Glycopyrrolate.

• Secretin humans.

• Glycopyrronium tosylate.

• Methacholine.

• Tiotropium.

• Galantamine.

• Ketoconazole.

• Rivastigmine.

Other Interactions

• Certain drugs should not be administered at or around the time of meals or with certain types of food since interactions may occur.

• Tobacco and alcohol use with certain drugs may also cause interactions to occur.

• The healthcare professional should be informed about the use of food, alcohol, or tobacco intake before the administration of the drug.

Other Medical Problems

The presence of other comorbidities may affect the use of this drug. Therefore, the doctor should be informed about other medical problems, particularly:

• Ulcerative colitis (a condition that leads to swelling in the lining of the large intestine and rectum).

• Hyperthyroidism (increased level of thyroid hormone in the body).

• GERD, or gastroesophageal reflux disease, where GERD the stomach contents come to the esophagus and cause heartburn).

• Hiatal hernia where the stomach wall protrudes and may cause pain.

• Dementia.

• Myasthenia gravis (a neurological disorder causing muscle weakness).

• Parkinson's disease.

• Benign prostatic hypertrophy (BPH) is a male reproductive organ enlargement of the prostate.

• Fast or irregular heartbeat.

• High blood pressure.

• Heart, liver, or kidney disease.