Darifenacin
ENABLEX
Pronunciation: dar-ee-FEN-a-sin
“Fenced-in Dairy Enabler”
“Red as a beet” crimson color theme → anticholinergic
What it isM3-selective muscarinic antagonist; urgency and urge incontinence from overactive bladder.
Why this oneIts bladder-focused M3 selectivity aims to spare cognitive M1 effects better than oxybutynin.
What limits itConstipation and dry mouth remain prominent; urinary retention and CYP2D6 or CYP3A4 interactions can end treatment.
Darifenacin prescription history
Animated chart of estimated U.S. prescriptions per year, Overactive bladder meds (1970–2026). Darifenacin enters in 2005 (estimated).
FDA-approved for
- overactive bladder (2004)
Principal riskConstipation and dry mouth
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Overactive bladder (urge incontinence, urgency, frequency) | Adults | 7.5 mg QD | 7.5-15 mg QD | 15 mg QD |
Titration May increase to 15 mg QD as early as 2 weeks after starting.
Renal Undefined
Hepatic Moderate (Child-Pugh B): do not exceed 7.5 mg QD. Severe (Child-Pugh C): not recommended.
Instructions
- Take orally once daily with water.
- May take with or without food.
- Swallow whole; do not chew, divide, or crush.
- With potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir, nelfinavir, clarithromycin, nefazodone): do not exceed 7.5 mg QD.
Available strengths
- ER tab 7.5, 15 mg
Contraindications
- Urinary retention
- Gastric retention
- Uncontrolled narrow-angle glaucoma
Cautions
- Urinary retention — caution in clinically significant bladder outflow obstruction
- Decreased GI motility/gastric retention — caution in GI obstructive disorders
- Caution in narrow-angle glaucoma
- CNS effects: somnolence — caution driving/operating machinery
Adverse reactions
- Constipation
- Dry mouth
- Headache
- Dyspepsia
- Nausea
- Urinary tract infection
Pregnancy No human data; not teratogenic in animals. Use only if benefit outweighs fetal risk.
Lactation No human data; present in rat milk.
Cost
Generic entry2015
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Memory aids: interaction avatars
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Self-check
- Which muscarinic receptor selectivity aims to spare cognition with darifenacin?
M3 selectivity, sparing M1 effects. - Which two adverse effects remain prominent?
Constipation and dry mouth.