Darifenacin (patient information)

Why this medication is prescribed

Darifenacin is used to treat an overactive bladder (a condition in which the bladder muscles contract uncontrollably and cause frequent urination, urgent need to urinate, and inability to control urination). Darifenacin is in a class of medications called antimuscarinics. It works by relaxing the bladder muscles to prevent urgent, frequent, or uncontrolled urination.

How this medication should be used

Darifenacin comes as an extended-release (long-acting) tablet to take by mouth. It is usually taken once a day with plenty of liquid. This medication may be taken with or without food. Take darifenacin at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take darifenacin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them.

Your doctor will start you on a low dose of darifenacin and may increase your dose after 2 weeks.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Special precautions

Before taking darifenacin:

• tell your doctor and pharmacist if you are allergic to darifenacin or any other medications.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antidepressants such as amitriptyline (Elavil), amoxapine (Asendin), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Adapin, Sinequan), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil); antihistamines; clarithromycin (Biaxin); flecainide (Tambocor); ipratropium (Atrovent); itraconazole (Sporanox); ketoconazole (Nizoral); medications for irritable bowel disease, motion sickness, Parkinson's disease, ulcers, or urinary problems; nefazodone (Serzone); nelfinavir (Viracept); ritonavir (Norvir); and thioridazine (Mellaril). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had urinary obstruction (a blockage of urine flowing out of the bladder), any type of blockage in the digestive system, benign prostatic hypertrophy (enlargement of the prostate), severe constipation, ulcerative colitis (sores in the intestine that cause stomach pain and diarrhea), myasthenia gravis (a disorder of the nervous system that causes muscle weakness), glaucoma, or liver disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking darifenacin, call your doctor.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking darifenacin.
• you should know that darifenacin may cause blurred vision or make you dizzy. Do not drive a car or operate machinery until you know how this medication affects you.
• you should know that darifenacin causes decreased sweating, which may cause heat prostration (collapse because of high body temperature) in hot weather.

Special dietary instructions

Unless your doctor tells you otherwise, continue your normal diet.

What to do if you forget a dose

Skip the missed dose and continue your regular dosing schedule. Do not take two doses in the same day or a double dose to make up for a missed one.

Side effects

Minor side effects

Darifenacin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• dry mouth
• constipation
• upset stomach
• stomach pain
• diarrhea
• weakness
• dry eyes

Severe side effects

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• difficulty urinating or being unable to urinate
• burning pain during urination
• rash
• itching

Darifenacin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/MedWatch/report.htm] or by phone [1-800-332-1088].

Storage conditions needed for this medication

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

• vision problems

Other information

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Brand names

• Enablex®