Oxybutynin, sold as under the brand names Ditropan among others, is a medication used to treat

overactive bladder Overactive bladder (OAB) is a condition where there is a frequent feeling of needing to urinate to a degree that it negatively affects a person's life. The frequent need to urinate may occur during the day, at night, or both. If there is loss ...

. It works similar to

tolterodine Tolterodine, sold under the brand name Detrol among others, is a medication used to treat frequent urination, urinary incontinence, or urinary urgency. Effects are seen within an hour. It is taken by mouth. Common side effects include heada ...

Darifenacin Darifenacin (trade name Enablex in United States and Canada, Emselex in the European Union) is a medication used to treat urinary incontinence due to an overactive bladder. It was discovered by scientists at the Pfizer research site in Sandwich, ...

, and Solifenacin. While used for

bed wetting Nocturnal enuresis, also informally called bedwetting, is urinary incontinence, involuntary urination while sleep, asleep after the age at which bladder control usually begins. Bedwetting in children and adults can result in emotional stress. Com ...

in children, evidence to support this use is poor. It is taken by mouth or applied to the skin. Common side effects include

dry mouth Xerostomia, also known as dry mouth, is dryness in the mouth, which may be associated with a change in the composition of saliva, or reduced salivary flow, or have no identifiable cause. This symptom is very common and is often seen as a side eff ...

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...

trouble sleeping Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

, and

urinary tract infections A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...

. Serious side effects may include

urinary retention Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of bladd ...

and an increased risk of

heat stroke Heat stroke or heatstroke, also known as sun stroke, is a severe heat illness that results in a body temperature greater than , along with red skin, headache, dizziness, and confusion. Sweating is generally present in exertional heatstroke, ...

. Use in

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

appears safe but has not been well studied while use in

breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that br ...

is of unclear safety. It is an

antimuscarinic A muscarinic receptor antagonist (MRA) is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine receptor. The muscarinic receptor is a protein involved in the transmission of signals through certain parts of th ...

and works by blocking the effects of acetylcholine on smooth muscle. Oxybutynin was approved for medical use in the United States in 1975. It is available as a generic medication. In 2020, it was the 97th most commonly prescribed medication in the United States, with more than 7million prescriptions.

Medical use

The immediate and slow release versions work equally. In people with

, transdermal oxybutynin decreased the number of incontinence episodes and increased average voided volume. There was no difference between transdermal oxybutynin and extended-release oral tolterodine. Tentative evidence supports the use of oxybutynin in

hyperhidrosis Hyperhidrosis is a condition characterized by abnormally increased sweating, in excess of that required for regulation of body temperature. Although primarily a benign physical burden, hyperhidrosis can deteriorate quality of life from a psycholog ...

(excessive sweating).

Adverse effects

Common adverse effects that are associated with oxybutynin and other

anticholinergics Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous sy ...

include: dry mouth, difficulty in

urination Urination, also known as micturition, is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, ...

, constipation, blurred vision, drowsiness, and dizziness. Anticholinergics have also been known to induce delirium. Oxybutynin's tendency to reduce sweating can be dangerous. Reduced sweating increases the risk of heat exhaustion and heat stroke in apparently safe situations where normal sweating keeps others safe and comfortable. Adverse effects of elevated body temperature are more likely for the elderly and for those with health issues, especially multiple sclerosis. ''N''-Desethyloxybutynin is an

active metabolite An active metabolite is an active form of a drug after it has been processed by the body. Metabolites of drugs An active metabolite results when a drug is metabolized by the body into a modified form which continues to produce effects in the body ...

of oxybutynin that is thought responsible for much of the adverse effects associated with the use of oxybutynin. ''N''-Desethyloxybutynin plasma levels may reach as much as six times that of the parent drug after administration of the immediate-release oral formulation. Alternative dosage forms have been developed in an effort to reduce blood levels of ''N''-desethyloxybutynin and achieve a steadier concentration of oxybutynin than is possible with the immediate release form. The long-acting formulations also allow once-daily administration instead of the twice-daily dosage required with the immediate-release form. The transdermal patch, in addition to the benefits of the extended-release oral formulations, bypasses the first-pass hepatic effect that the oral formulations are subject to. In those with overflow incontinence because of diabetes or neurological diseases like multiple sclerosis or spinal cord trauma, oxybutynin can worsen overflow incontinence since the fundamental problem is that the bladder is not contracting. A large study linked the development of dementia in those over 65 to the use of oxybutynin, due to its

anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous sys ...

properties.

Contraindications

Oxybutynin chloride is contraindicated in patients with untreated narrow angle

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye rem ...

, and in patients with untreated narrow anterior chamber angles—since anticholinergic drugs may aggravate these conditions. It is also contraindicated in partial or complete obstruction of the gastrointestinal tract, hiatal hernia,

gastroesophageal reflux disease Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

, paralytic ileus, intestinal atony of the elderly or debilitated patient,

megacolon Megacolon is an abnormal dilation of the colon (also called the large intestine). This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. In more extreme cases, the feces ...

toxic megacolon Toxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon (megacolon), accompanied by abdominal distension (bloating), and sometimes fever, abdominal pain, or shock. Toxic megacolon is usually a complica ...

complicating

ulcerative colitis Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and ...

, severe colitis, and myasthenia gravis. It is contraindicated in patients with

obstructive uropathy Obstructive uropathy is a structural or functional hindrance of normal urine flow, sometimes leading to renal dysfunction (obstructive nephropathy). It is a very broad term, and does not imply a location or cause. Presentation Symptoms, less lik ...

and in patients with unstable cardiovascular status in acute hemorrhage. Oxybutynin chloride is contraindicated in patients who have demonstrated hypersensitivity to the product.

Pharmacology

Oxybutynin chloride exerts direct antispasmodic effect on smooth muscle and inhibits the muscarinic action of acetylcholine on smooth muscle. It exhibits one-fifth of the

activity of atropine on the rabbit detrusor muscle, but four to ten times the antispasmodic activity. No blocking effects occur at skeletal neuromuscular junctions or autonomic ganglia (antinicotinic effects). Sources say the drug is absorbed within one hour and has an elimination half-life of 2 to 5 hours. There is a wide variation among individuals in the drug's concentration in blood. This, and its low concentration in urine, suggest that it is eliminated through the liver.

Chemistry

Oxybutynin contains one

stereocenter In stereochemistry, a stereocenter of a molecule is an atom (center), axis or plane that is the focus of stereoisomerism; that is, when having at least three different groups bound to the stereocenter, interchanging any two different groups c ...

. Commercial formulations are sold as the

racemate In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

. The (''R'')-enantiomer is a more potent anticholinergic than either the racemate or the (''S'')-enantiomer, which is essentially without anticholinergic activity at doses used in clinical practice. However, (''R'')-oxybutynin administered alone offers little or no clinical benefit above and beyond the racemic mixture. The other actions (calcium antagonism, local anesthesia) of oxybutynin are not stereospecific. (''S'')-Oxybutynin has not been clinically tested for its spasmolytic effects, but may be clinically useful for the same indications as the racemate, without the unpleasant anticholinergic side effects.

Brand names

Oxybutynin is available by mouth in generic formulation and under the brand names Ditropan, Lyrinel XL, Ditrospam, Kentera, and Aquiette, as a transdermal patch under the brand name Oxytrol, and as a topical gel under the brand name Gelnique.

References

External links

* {{Portal bar , Medicine Tertiary alcohols Alkyne derivatives Diethylamino compounds AbbVie brands Johnson & Johnson brands Carboxylate esters Muscarinic antagonists Wikipedia medicine articles ready to translate Cyclohexyl compounds