Oxybutynin is an example of a class of medications known as anticholinergics. These medications work by blocking the signaling of a chemical known as acetylcholine, which is produced by the nervous system. Acetylcholine allows the body to send signals to muscles and other kinds of tissue. Thus, by blocking the action of acetylcholine, oxybutynin is able to have a number of different effects on the body.
Urinary
Oxybutynin is often prescribed for its ability to affect the urinary system, PubMed Health reports. It is most commonly used to treat overactive bladder, in which patients experience frequent, uncontrolled or urgent episodes of urination as a result of spasms of the bladder muscles. Oxybutynin works by blocking the nerve signals that stimulate contraction of the bladder muscles, helping relieve these muscle spasms. Oxybutynin can also be used for other conditions that affect the bladder muscles, such as spina bifida, a condition in which a malformation of the spinal canal blocks some of the inhibitory signaling to the bladder muscles. However, as a result of this decreased urge to urinate, patients who are taking oxybutynin are more likely to develop infections of the urinary tract, which can result in itching, burning or pain while urinating.
Gastrointestinal
Oxybutynin also can cause a number of side effects by reacting with the gastrointestinal system, Drugs.com notes. Use of oxybutynin can result in dry mouth as well as nausea, constipation, and mild stomach upset and pain. It may also result in diarrhea, heartburn or gas. In some cases these side effects can be severe and result in severe stomach pain or constipation, which may be indicative of a serious adverse reaction.
Neurological
Oxybutynin can cause a number of psychiatric effects. The most common of these, RxList.com states, are trouble falling or staying asleep and nervousness. Patients may also become agitated, confused or suffer from hallucinations. Other neurological side effects of oxybutynin include headache, dizziness and drowsiness. Occasionally oxybutynin can result in convulsions.
Allergic Reaction
Oxybutynin can trigger allergic reactions in some patients. An allergic reaction to oxybutynin may be as mild as the development of an itchy rash or hives, or it can cause swelling of the face, lips, tongue, hands and feet, according to Drugs.com. In the most serious instances, allergies to oxybutynin may result in swelling of the throat, which can result in difficulty breathing and pain when swallowing. This can also result in chest tightness and hoarseness. This type of allergic reaction is known as anaphylaxis and is a medical emergency.
Cardiac
Some of the side effects of oxybutynin affect the heart, notes Drugs.com. More mild cardiac problems that can arise from oxybutynin include elongation of the QT interval, which is a finding on an electrocardiogram, as well as an increased heart rate, which is known as tachycardia. Patients may also develop heart palpitations or experience irregularities in their heart rhythm.
