section name header

Pronunciation ⬇

dar-i-FEN-a-sin

Classifications ⬆ ⬇

Therapeutic Classification: urinary tract antispasmodics

Pharmacologic Classification: anticholinergics

Indications ⬆ ⬇

REMS

Action ⬆ ⬇

  • Acts as a muscarinic (cholinergic) receptor antagonist; antagonizes bladder smooth muscle contraction.
Therapeutic effects:
  • Decreased symptoms of overactive bladder.

Pharmacokinetics ⬆ ⬇

Absorption: 15–19% absorbed.

Distribution: Unknown.

Protein Binding: 98%.

Metabolism/Excretion: Extensively metabolized in the liver by the CYP2D6 isoenzyme, with some metabolism by the CYP3A4 isoenzyme; the CYP2D6 isoenzyme exhibits genetic polymorphism (∼7% of population may be poor metabolizers and may have significantly ↑ darifenacin concentrations and an ↑ risk of adverse effects). 60% excreted by the kidneys as metabolites, 40% in feces as metabolites.

Half-Life: 13–19 hr.

Time/Action Profile ⬆ ⬇

ROUTEONSETPEAKDURATION
POunknown7 hr24 hr



Contraind./Precautions ⬆ ⬇

Contraindicated in:

Use Cautiously in:

  • Moderate hepatic impairment (↓ dose);
  • Bladder outflow obstruction;
  • GI obstructive disorders, ↓ GI motility, severe constipation, or ulcerative colitis;
  • Myasthenia gravis;
  • Angle-closure glaucoma;
  • OB: Safety not established in pregnancy;
  • Lactation: Safety not established in breastfeeding;
  • Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

EENT: blurred vision

GI: constipation, dry mouth, dyspepsia, nausea

Metab: heat intolerance

Neuro: confusion, dizziness, drowsiness, hallucinations, headache

Misc: ANGIOEDEMA

Interactions ⬆ ⬇

Drug-drug:

Route/Dosage ⬆ ⬇

  • PO (Adults ): 7.5 mg once daily, may ↑ after 2 wk to 15 mg once daily.

Hepatic Impairment

  • PO (Adults ): Moderate hepatic impairment: Not to exceed 7.5 mg once daily.

Availability ⬆ ⬇

(Generic available)
  • Extended-release tablets: 7.5 mg; 15 mg

Assessment ⬆ ⬇

  • Monitor voiding pattern and assess symptoms of overactive bladder (urinary urgency, incontinence, frequency) before and periodically during therapy.
  • Monitor for anticholinergic effects (constipation, urinary retention, blurred vision), including CNS effects (headache, confusion, hallucinations, somnolence), especially with therapy initiation or dose ↑. If CNS effects occur, consider dose ↓ or discontinue darifenacin.

Implementation ⬆ ⬇

  • PO: Administer once daily with water, without regard to food. DNC: Swallow extended-release tablets whole; do not break, crush, or chew.

Patient/Family Teaching ⬆ ⬇

  • Instruct patient to take darifenacin as directed. If dose is missed, omit and take next day; do not take two doses in same day. Advise patient to read Patient Information before starting therapy and with each Rx refill in case of changes.
  • May cause dizziness, drowsiness, confusion, and blurred vision. Caution patient to avoid driving and other activities that require alertness until response to medication is known.
  • Inform patient that darifenacin may cause heat stroke in hot environments. Notify health care professional for ↓ sweating, dizziness, fatigue, nausea, fever.
  • Advise patient to immediately notify emergency health care professional for symptoms of angioedema (swelling of face, lips, tongue, or throat).
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
  • Rep: Advise women of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes ⬆ ⬇

  • Decreased symptoms of overactive bladder.

Canadian Brand Names ⬆

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