How Do Urinary Antispasmodic Agents Work?

Urinary antispasmodic agents are medications prescribed to treat bladder overactivity which can cause urinary urgency and incontinence. Urinary antispasmodic agents increase bladder capacity, delay the desire to void, decrease the frequency and urgency to urinate, and reduce pain caused by difficulty in urination.

Urinary antispasmodic agents relax the detrusor smooth muscle which contracts to release urine and prevent spasms of the muscles around the urinary tract. Urinary antispasmodic agents work in the following ways to decrease uninhibited bladder contractions:

• Block acetylcholine from stimulating muscarinic receptors, which are protein molecules on smooth muscle cells in the bladder lining. Acetylcholine is a natural chemical (neurotransmitter) that nerve endings secrete to make muscles contract.
• Block the activity phosphodiesterase, an enzyme that breaks down signaling molecules known as cyclic adenosine monophosphate (cAMP). An increase in cAMP concentration results in the relaxation of smooth muscles.

Urinary antispasmodic agents are available as:

• Oral tablets or syrups
• Topical gels
• Transdermal patches

Urinary antispasmodic agents are approved by the FDA for the treatment of the following conditions:

• Overactive bladder with symptoms of urge, incontinence, urgency, and frequency in adults
• Bladder overactivity caused by nerve damage
• Dysuria (painful urination) and urinary frequency in children

Side effects of urinary antispasmodic agents may include the following:

• Xerostomia (dry mouth)
• Somnolence (drowsiness)
• Pruritus (itching) at the application site from skin patches
• Constipation
• Nausea
• Abdominal pain
• Diarrhea
• Vomiting
• Application site reactions such as:
  • Erythema (redness)
  • Rash
  • Vesicles (blisters)
  • Macules (lesions)
• Asthenia (weakness)
• Dizziness
• Vertigo
• Fatigue
• Headache
• Hyperpyrexia (high temperature)
• Blurred vision
• Dry eyes
• Disturbance in ocular accommodation (eye focusing)
• Cycloplegia (eye accommodation disorder)
• Mydriasis (dilated pupils)
• Increased ocular tension
• Pain
• Rhinitis (inflammation of the nasal passage)
• Nasal congestion
• Dry throat
• Dysuria
• Urinary tract infection
• Eosinophilia (high level of eosinophils, a type of immune cells)
• Confusion
• Nervousness
• Impairment of mental alertness
• Memory impairment
• Delirium
• Hallucinations
• Hypertension (high blood pressure)
• Palpitations
• Tachycardia (rapid heartbeat)
• QT prolongation (abnormal ECG reading)
• Anorexia (loss of appetite)
• Frequent bowel movements
• Urticaria (hives)
• Fluid retention
• Hot flush
• Dysphonia (speech difficulty)
• Dysphagia (swallowing difficulty)
• Chest discomfort
• Thirst
• Memory impairment
• Concomitant use with carbamazepine
  • Vomiting
  • Drowsiness
  • Unsteadiness
  • Slurred speech
  • Nystagmus (involuntary eye movements)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of urinary antispasmodic agents include:

• Ditropan XL
• flavoxate
• Gelnique
• oxybutynin
• oxybutynin topical
• oxybutynin transdermal
• Oxytrol
• Oxytrol For Women