Oxybutynine Eg (Oxybutynin Hydrochloride)

Oxybutynine Eg is an antispasmodic that acts on the urinary tract smooth muscle to improve bladder control.

• Overactive bladder: reduces urgency and frequency of urination.
• Urge urinary incontinence: lessens the amount of leakage.
• Neurogenic bladder dysfunction: helps manage involuntary bladder contractions.

• Oxybutynin hydrochloride antagonizes muscarinic (M3) receptors in the detrusor muscle of the bladder, decreasing acetylcholine‑mediated contractions. This anticholinergic action relaxes the bladder wall, increasing functional capacity and reducing involuntary voiding episodes.

Adverse reactions to oxybutynin vary in frequency and severity.

Common Side Effects

• Dry mouth: reduced salivary flow.
• Constipation: slowed gastrointestinal motility.
• Blurred vision: transient visual accommodation changes.
• Drowsiness: mild central nervous system sedation.
• Urinary retention: difficulty initiating voiding.

Serious or Rare Side Effects

• Tachycardia: rapid heart rate that may require monitoring.
• Severe allergic reaction: rash, itching, swelling, or anaphylaxis.
• Angle‑closure glaucoma: acute eye pain and visual disturbance.
• Hepatic dysfunction: elevated liver enzymes or jaundice.
• Urinary retention leading to acute urinary obstruction.

When prescribing oxybutynin, clinicians should consider several safety aspects.

• Assess renal and hepatic function: dose may need adjustment in impairment.
• Review cardiac history: monitor for tachycardia or arrhythmias.
• Evaluate glaucoma risk: avoid in patients with narrow‑angle glaucoma.
• Counsel on anticholinergic burden: caution in elderly patients prone to confusion.
• Monitor for urinary retention: advise patients to report difficulty voiding.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Oxybutynin may interact with other medications that influence anticholinergic load or cardiac conduction.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase oxybutynin plasma levels.
• QT‑prolonging agents (e.g., sotalol, quinidine): additive risk of arrhythmia.

Moderate Interactions (Monitor Closely)

• Other anticholinergics (e.g., diphenhydramine, ipratropium): heightened anticholinergic side effects.
• Beta‑blockers: may mask tachycardia.
• Digoxin: potential increase in serum digoxin concentration.
• Alcohol: may intensify drowsiness and dizziness.
• Antihistamines: additive dry‑mouth effect.