Darilax

Indications

Darifenacin is used in adults to treat overactive bladder, which causes a sudden urge to pass urine, frequent urination and leaking of urine (urge incontinence).

How It Works

Darifenacin is an antimuscarinic medicine. It blocks M3 muscarinic receptors in the bladder muscle, which relaxes the muscle and reduces unwanted contractions. This lets the bladder hold more urine and reduces urgency and leaks.

Dosage and Administration

The usual adult starting dose is 7.5 mg once daily. After two weeks the doctor may raise it to 15 mg once daily if needed. Swallow the extended-release tablet whole with water, with or without food; do not chew, split or crush it. People with moderate liver problems, or who take certain interacting medicines, should not take more than 7.5 mg daily.

Interactions

• Strong CYP3A4 inhibitors such as Ketoconazole, Itraconazole, Clarithromycin or Ritonavir: raise Darifenacin levels; usually avoid or keep to 7.5 mg.
• Moderate inhibitors such as Erythromycin, Fluconazole, Diltiazem or Verapamil: dose should not exceed 7.5 mg.
• Medicines such as Flecainide, Thioridazine or tricyclic antidepressants such as Imipramine: their levels may rise.
• Other anticholinergic medicines: more dry mouth, constipation and blurred vision.

Contraindications

• Allergy to Darifenacin.
• Urinary retention (being unable to empty the bladder).
• Gastric retention (food staying too long in the stomach) or severe bowel problems such as severe ulcerative colitis or toxic megacolon.
• Uncontrolled narrow-angle glaucoma.
• Myasthenia gravis.
• Severe liver impairment.

Side Effects

The most common side effects are dry mouth and constipation. Others include headache, indigestion, nausea, dry eyes, blurred vision and stomach pain. It may reduce sweating, raising the risk of overheating in hot weather.

Get urgent medical help if you cannot pass urine, have severe constipation or stomach pain, eye pain with blurred vision, confusion, or signs of a severe allergic reaction such as swelling of the face, tongue or throat.

Pregnancy and Lactation

It is not recommended in pregnancy unless your doctor decides it is necessary. It may pass into breast milk, so it is best avoided during breastfeeding.

Precautions and Warnings

• Tell your doctor about prostate enlargement, bowel or stomach problems, reflux, glaucoma, liver problems or heart rhythm problems.
• Avoid overheating; drink enough fluids in hot weather.
• It may cause dizziness or blurred vision; take care when driving.

Overdose

An overdose may cause severe dry mouth, blurred vision, fast heartbeat, difficulty passing urine, flushing and confusion. Seek emergency medical help.

Therapeutic Class

Urinary antispasmodic, antimuscarinic (M3 selective).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.