oxybutynin, Ditropan; Ditropan XL; Oxytrol; Anturol; Gelnique
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
GENERIC NAME: oxybutynin
BRAND NAME: Ditropan; Ditropan XL; Oxytrol; Anturol; Gelnique
DRUG CLASS AND MECHANISM: Oxybutynin is an oral drug that is used for treating bladder spasms. Oxybutynin has a dual mechanism of action. Contraction of the smooth muscle of the bladder is stimulated by the release of acetylcholine by the nerves within the bladder and the attachment of the acetylcholine to receptors on the surface of the bladder's muscle cells. Oxybutynin suppresses involuntary contractions of the bladder's smooth muscle (spasms) by blocking the release of acetylcholine. This is called an "anticholinergic effect." Oxybutynin also directly relaxes the bladder's outer layer of muscle (the detrusor muscle). The FDA approved oxybutynin in July 1975.
PREPARATIONS: Tablets (immediate release): 5 mg; Tablets (extended release): 5, 10, and 15 mg; Transdermal delivery system or patch: 3.9 mg/day; Syrup: 5 mg/5 ml. Transdermal Gel: 3% or 10%.
STORAGE: Oxybutynin should be stored at room temperature, 15-30 C (59-86 F). It should be kept out of the reach of children.
PRESCRIBED FOR: Oxybutynin is used for adults with symptoms of overactive bladder such as sudden urges to urinate (urgency), urinary incontinence (the inability to control urination), and frequent urination. It also is used in children, aged 6 years and older, with symptoms of detrusor muscle hyperactivity associated with neurological conditions, such as spina bifida.
DOSING: The usual dose of immediate-release oxybutynin is 5 mg two to four times daily 2 to 3 times daily. Elderly patients sometimes start with a lower dose of 2.5 mg. T
he recommended dose using extended-release tablets is 5 to 30 mg once daily. The oral forms can be taken with or without food. The extended release tablets must not be chewed, crushed, or broken. The tablet shell is not absorbed and is eliminated in the feces.
The patch is applied twice weekly (every 3 to 4 days). The patch should be applied to dry, intact skin on the abdomen, hip, or buttock. A different application site should be used with each new patch, avoiding re-application to the same site within 7 days.
One sachet of the 10% gel or three pumps of the 3% gel should be applied to intact skin of the abdomen, upper arm, shoulder or thighs. Application sites should be rotated. Patients should wash hands immediately after applying the gel in order to avoid transferring oxybutynin to other parts of the body or other individuals.
DRUG INTERACTIONS: The use of oxybutynin in patients who are receiving other drugs with anticholinergic effects will likely result in an increased frequency and/or severity of anticholinergic side effects. Such effects include dry mouth, constipation, confusion, blurred vision, urinary retention (the inability to urinate) and an increased heart rate or palpitations. There are many such drugs. They include: diphenhydramine (Benadryl), dimenhydrinate (Dramamine), scopolamine (Trans-Scop), benztropine (Cogentin), disopyramide (Norpace), thioridazine (Mellaril), and amitriptyline (Elavil).
PREGNANCY: Studies of oxybutynin in pregnant rabbits, rats, and mice have not produced any evidence of harm in the fetus; however, since no controlled studies have been done in pregnant women, the potential benefit of this medicine needs to be weighed against any theoretical harm.
NURSING MOTHERS: It is not known if oxybutynin is excreted in human milk.
SIDE EFFECTS: The most common side effects of oxybutynin are dry mouth, constipation, tiredness, and headache. About 1 in every 14 patients taking oxybutynin tablets cannot tolerate it because of side effects. Diarrhea, urinary tract infections, blurred vision, and difficulty urinating also may occur. The transdermal patch or gel may also cause local reactions at the application sites such as itching and rash. Transdermal patches or gel cause fewer side effects than the tablets. Serious hypersensitivity reactions involving swelling of the throat, lips, and tongue also may occur.
Reference: FDA Prescribing Information
Last Editorial Review: 11/28/2004 12:43:03 PM
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