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Active ingredient: Darifenacin - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

  • Urinary antispasmodics

Dosage Forms

  • Extended-release tablets (containing 7.5 mg or 15 mg darifenacin as hydrobromide salt)

Brands / Synonyms

Enablex; Enablex


For the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency and frequency.


Darifenacin is a competitive muscarinic receptor antagonist. In vitro studies using human recombinant muscarinic receptor subtypes show that darifenacin has greater affinity for the M3 receptor than for the other known muscarinic receptors (9 and 12-fold greater affinity for M3 compared to M1 and M5, respectively, and 59-fold greater affinity for M3 compared to both M2 and M4). Muscarinic receptors play an important role in several major cholinergically mediated functions, including contractions of the urinary bladder smooth muscle and stimulation of salivary secretion. Adverse drug effects such as dry mouth, constipation and abnormal vision may be mediated through effects on M3 receptors in these organs.

Mechanism of Action

Darifenacin selectively antagonizes the muscarinic M3 receptor. M3 receptors are involved in contraction of human bladder and gastrointestinal smooth muscle, saliva production, and iris sphincter function.


The mean oral bioavailability at steady state is estimated to be 15% and 19% for 7.5 mg and 15 mg tablets, respectively.


Overdosage can potentially result in severe central anticholinergic effects.

Biotrnasformation / Drug Metabolism

Hepatic. Primarily mediated by the cytochrome P450 enzymes CYP2D6 and CYP3A4.


ENABLEX® (darifenacin) extended-release tablets are contraindicated in patients with urinary retention, gastric retention or uncontrolled narrow-angle glaucoma and in patients who are at risk for these conditions. ENABLEX is also contraindicated in patients with known hypersensitivity to the drug or its ingredients.

Drug Interactions

The daily dose of ENABLEX should not exceed 7.5 mg when coadministered with potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir, nelfinavir, clarithromycin and nefazadone) . Caution should be taken when ENABLEX is used concomitantly with medications that are predominantly metabolized by CYP2D6 and which have a narrow therapeutic window, such as flecainide, thioridazine and tricyclic antidepressants (see CLINICAL PHARMACOLOGY). The concomitant use of ENABLEX with other anticholinergic agents may increase the frequency and/or severity of dry mouth, constipation, blurred vision and other anticholinergic pharmacological effects. Anticholinergic agents may potentially alter the absorption of some concomitantly administered drugs due to effects on gastrointestinal motility.

Drug Laboratory Test Interactions

Interactions between darifenacin and laboratory tests have not been studied.

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