Dosing and uses of Enablex (darifenacin)
Dosing Forms & Strength
tablet, extended release
- 7.5mg
- 15mg
Overactive Bladder
Indicated for overactive bladder with symptoms of urge incontinence, urgency, and frequency
Initial: 7.5 mg PO qDay
May be increased to 15 mg based on patient response as early as 2 weeks later
Do not increase dose if taking concomitant CYP3A4 inhibitors
Hepatic Impairment
Moderate: Do not exceed initial dose of 7.5 mg/day
Severe: Not recommended
Administration
Swallow with water, do not crush, chew or cut
Pediatric dosage forms and strengths
Safety and efficacy not established
Enablex (darifenacin) adverse (side) effects
>10%
Dry mouth (19-35%)
Constipation (15-21%)
1-10%
Abdominal pain (2-4%)
Dizziness (2%)
Dry eyes (2%)
Dyspepsia (3-8%)
Nausea (2-4%)
UTI (4-5%)
Vaginitis (>1%)
Back pain (>1%)
Rhinitis (>1%)
Abnormal vision (>2%)
Vomiting (>1%)
Weight gain (>1%)
Flu-like syndrome (1-3%)
Peripheral edema (>1%)
Postmarketing Reports
Dermatologic: Erythema multiforme, interstitial granuloma annulare
General: Hypersensitivity reactions, including angioedema with airway obstruction and anaphylactic reaction; hallucinations
Cardiovascular: Palpitations
Warnings
Contraindications
Urinary retention
Uncontrolled narrow-angle glaucoma
Severe hepatic impairment
Paralytic ileus
GI or Gu obstruction
Hypersensitivity
Cautions
Bladder outflow obstruction, controlled narrow-angle glaucoma, decreased GI motility, renal/hepatic impairment
Angioedema of the face, lips, tongue, and/or larynx have been reported, in some cases angioedema occurred after the first dose
CNS anticholinergic effects reported including headache, confusion, hallucinations, and somnolence
Heat prostration may occur in the presence of increased environmental temperature
Use caution in patients with decreased GI motility, hiatal hernia, reflux esophagitis, and ulcerative colitis
Use caution in patients with controlled narrow-angle glaucoma and patients with hepatic impairment, or myesthenia gravis
Pregnancy and lactation
Pregnancy category: C
Lactation: Excretion in milk unknown; use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Enablex (darifenacin)
Mechanism of action
Competitive muscarinic receptor antagonist of the M3 muscarinic receptor; receptor blocking limits bladder contractions, and reduce symptoms of bladder irritability/overactivity
Absorption
Protein Bound: 98%
Vd: 163 L
Peak plasma time: 7 hr
Metabolism
Liver, by CYP3A4 and CYP2D6
Elimination
Half-Life: 13-19 hr
Excretion: 60% urine; 40% feces
