Flavoxate

Key facts

• Flavoxate is an antispasmodic that relaxes the bladder muscle to ease urgency, frequency and the pain of bladder spasms.
• You typically take it three or four times a day; effects on urgency are usually noticeable within a few days.
• Flavoxate has anticholinergic effects, so it's avoided in glaucoma and in any blockage of the urinary or digestive tract, where it can worsen retention.
• Seek urgent care for a fast or irregular heartbeat, or an inability to pass urine at all.

What flavoxate treats

Flavoxate treats symptoms of an irritable or overactive bladder: urgency, frequent urination, and the pain of bladder spasms, including discomfort linked to urinary tract infections or after urologic procedures. It eases the bladder's contractions; it does not treat infection itself, so an underlying UTI still needs its own treatment.

How flavoxate works

The bladder wall contains smooth muscle that contracts to push urine out. Flavoxate relaxes this smooth muscle directly and blocks some of the nerve signals that trigger overly strong or frequent contractions. This lets the bladder fill more comfortably and reduces the sudden, painful spasms that drive urgency.

Before you take it

• Do not take flavoxate if you have glaucoma, or an obstruction anywhere in your gastrointestinal or urinary tract, since it can worsen blocked flow.
• Tell your prescriber about any heart rhythm problems, since flavoxate's anticholinergic effect can add to those risks.
• Mention other medicines with anticholinergic effects, such as certain antihistamines or antidepressants, which can add to dry mouth, blurred vision and confusion.
• Use caution in hot weather; anticholinergic drugs reduce sweating and can raise the risk of overheating.

Side effects

Common effects include dry mouth, blurred vision, dizziness and constipation.

Stop and seek urgent medical care for any of these:

• A fast or irregular heartbeat, or fainting.
• Sudden difficulty breathing or swelling of the face, lips or throat.
• Complete inability to pass urine.
• Confusion or hallucinations, particularly in older adults.

Safety essentials

• Flavoxate is contraindicated in glaucoma and in GI or urinary tract obstruction. Confirm you don't have either before starting.
• Older adults are more sensitive to its anticholinergic effects, including confusion and urinary retention; a lower dose or an alternative may be safer.
• Rise slowly from sitting or lying down, since flavoxate can cause light-headedness.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.