Oxybutynin Hydrochloride

What it is and how it works

Mechanism of Action Oxybutynin relaxes bladder smooth muscle. Oxybutynin chloride exerts a direct antispasmodic effect on smooth muscle and inhibits the muscarinic action of acetylcholine on smooth muscle. No blocking effects occur at skeletal neuromuscular junctions or autonomic ganglia (antinicotinic effects). Antimuscarinic activity resides predominantly in the R-isomer. A metabolite, desethyloxybutynin, has pharmacological activity similar to that of oxybutynin in in vitro studies.

Indications

Oxybutynin chloride extended-release tablets are a muscarinic antagonist indicated for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency. Oxybutynin chloride extended-release tablets are also indicated for the treatment of pediatric patients aged 6 years and older with symptoms of detrusor overactivity associated with a neurological condition (e.g., spina bifida). Oxybutynin chloride extended-release tablets are a muscarinic antagonist indicated for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency. Oxybutynin chloride extended-release tablets are also indicated for the treatment of pediatric patients aged 6 years and older with symptoms of detrusor overactivity associated with a neurological condition (e.g., spina bifida).

Dosage and administration (summary)

Oxybutynin chloride extended-release tablets must be swallowed whole with the aid of liquids, and must not be chewed, divided, or crushed. Oxybutynin chloride extended-release tablets may be administered with or without food. Oxybutynin chloride extended-release tablets must be swallowed whole with the aid of liquids, and must not be chewed, divided, or crushed. Oxybutynin chloride extended-release tablets may be administered with or without food. Adults: Start with 5 mg or 10 mg, once daily at approximately the same time every day. Dose should not exceed 30 mg per day. Pediatric patients (6 years of age or older): Start with 5 mg, once daily at approximately the same time every day.

Contraindications

Oxybutynin chloride extended-release tablets are contraindicated in patients with urinary retention, gastric retention and other severe decreased gastrointestinal motility conditions, uncontrolled narrow-angle glaucoma. Oxybutynin chloride extended-release tablets are also contraindicated in patients who have demonstrated hypersensitivity to the drug substance or other components of the product. There have been reports of hypersensitivity reactions, including anaphylaxis and angiodema.

Warnings and precautions

Angioedema: Angioedema has been reported with oxybutynin. If symptoms of angioedema occur, discontinue Oxybutynin chloride extended-release tablets immediately and initiate appropriate therapy. Central Nervous System (CNS) effects: CNS effects have been reported with oxybutynin. If patient experiences anticholinergic CNS effects, consider dose adjustment or discontinuation of Oxybutynin chloride extended-release tablets.

Pregnancy

Pregnancy Pregnancy Category B. There are no adequate and well-controlled studies using Oxybutynin chloride extended-release tablets in pregnant women. Oxybutynin chloride extended-release tablets should be used during pregnancy only if the potential benefit to the patient outweighs the risk to the patient and fetus.

Storage and supply

Storage Store at 25°C (77°F); excursions permitted to 15–30°C (59–86°F) . Protect from moisture and humidity.

Source: Oxybutynin Chloride (Oxybutynin Chloride Extended Release) — US FDA prescribing information, 2023-05-31, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.