Darifenacin

About Darifenacin

Darifenacin is an antimuscarinic. It blocks the acetylcholine signals that make the bladder muscle contract, and it binds more strongly to the M3 receptor subtype, which is involved in bladder contraction, than to the other subtypes. It increases how much the bladder holds and reduces urgency, bathroom trips and urge leakage. Treatment starts at 7.5 mg once a day, and the prescriber may raise it to 15 mg after two weeks, depending on the response.

Dry mouth and constipation are the most frequent side effects; headache, indigestion, nausea and urinary tract infections also occur. Blurred vision and dizziness can affect driving, and like other anticholinergic drugs it can cause confusion, hallucinations or sleepiness. It reduces sweating, so heat illness is a risk in hot weather. Swelling of the face, lips, tongue or throat has been reported and needs emergency care.

It is not used with urinary retention, gastric retention or uncontrolled narrow-angle glaucoma, and needs care with bladder outlet obstruction, including an enlarged prostate, bowel obstruction, severe constipation, ulcerative colitis, myasthenia gravis or treated narrow-angle glaucoma. With moderate liver impairment or strong CYP3A4 inhibitors the dose stays at 7.5 mg, and it is not recommended in severe liver impairment. Age and kidney function need no dose change.

Taking Darifenacin

How to take it

Once a day with water, with or without food. Swallow the tablet whole; do not chew, split or crush it. The usual starting dose is 7.5 mg, which your prescriber may increase after two weeks.

If you miss a dose

Skip the missed dose and take the next one at the usual time. Do not take two doses in the same day.

Storage

At room temperature, protected from light, in a tightly closed container out of reach of children.

Interactions to know about

Strong CYP3A4 inhibitors such as ketoconazole, itraconazole, clarithromycin, ritonavir, nelfinavir and nefazodone raise its levels, so the dose is kept at 7.5 mg. It raises levels of some medicines broken down by CYP2D6, so flecainide, thioridazine and tricyclic antidepressants need care. Other anticholinergic medicines add to dry mouth, constipation and blurred vision. Because it reduces sweating, avoid overheating, and take care driving if it makes you dizzy or blurs your vision.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Darifenacin differs from pharmacy to pharmacy

With the brand gone, every quote is for a generic, and the tablets come from several manufacturers whose wholesale prices differ. A pharmacy that seldom fills darifenacin may need to order it and may price it as a slow-moving item, while one that stocks it routinely or includes it on a flat-price list can quote much less for the same tablet.

Other bladder medicines are priced on their own terms: generic oxybutynin is an older drug in the same class and mirabegron works differently, so the cash cost of treatment depends a lot on which medicine is chosen.

Ways to pay less for Darifenacin without insurance

• Compare quotes from more than one pharmacy; a less common generic can be priced very differently from place to place.
• Once the dose is settled, ask for a ninety-day supply.
• If cost is a barrier, ask the prescriber whether another bladder medicine, such as generic oxybutynin, would suit you.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Darifenacin

1. 1.When might my dose be increased, and how will we judge whether it is working?
2. 2.Does it interact with my antifungal, antibiotic, HIV or heart rhythm medicines?
3. 3.What can I do about dry mouth and constipation?
4. 4.Is it safe with my glaucoma or prostate problems?
5. 5.Which side effects mean I should stop and get help?

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