Skip to Content

Flavoxate Side Effects

For the Consumer

Applies to flavoxate: oral tablet

In addition to its needed effects, some unwanted effects may be caused by flavoxate. In the event that any of these side effects do occur, they may require medical attention.

Severity: Moderate

If any of the following side effects occur while taking flavoxate, check with your doctor or nurse as soon as possible:

  • Confusion
  • eye pain
  • skin rash or hives
  • sore throat and fever
Symptoms of overdose:
  • Clumsiness or unsteadiness
  • dizziness (severe)
  • drowsiness (severe)
  • fever
  • flushing or redness of face
  • hallucinations (seeing, hearing, or feeling things that are not there)
  • shortness of breath or troubled breathing
  • unusual excitement, nervousness, restlessness, or irritability

Minor Side Effects

Some of the side effects that can occur with flavoxate may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Drowsiness
  • dryness of mouth and throat
Less common or rare:
  • Blurred vision
  • constipation
  • difficult urination
  • difficulty concentrating
  • dizziness
  • fast heartbeat
  • headache
  • increased sensitivity of eyes to light
  • increased sweating
  • nausea or vomiting
  • nervousness
  • stomach pain

For Healthcare Professionals

Applies to flavoxate: oral tablet


Flavoxate is generally well tolerated and an estimated frequency of particular side effects is not available.[Ref]


Cardiovascular side effects have included tachycardia and palpitation.[Ref]


Gastrointestinal side effects have included nausea, vomiting, and dry mouth.[Ref]


Ocular side effects have included increased ocular tension, blurred vision, and altered accommodation.[Ref]

Nervous system

Nervous system side effects have included vertigo, headache, mental confusion, drowsiness, and nervousness. These effects may be exaggerated in elderly patients.[Ref]


Renal side effects have included dysuria, and obstructive uropathies of the lower urinary tract.[Ref]


Hypersensitivity side effects have included urticaria and other unspecified dermatoses, eosinophilia, and elevated temperature.[Ref]


Hematologic side effects have been reported rarely. A case of reversible leukopenia has been reported.[Ref]


1. "Product Information. Uripas (flavoxate)." SmithKline Beecham, Philadelphia, PA.

2. Baert L "Controlled double-blind trail of flavoxate in painful conditions of the lower urinary tract." Curr Med Res Opin 2 (1974): 631-5

3. Delaere KP, Michiels HG, Debruyne FM, Moonen WA "Flavoxate hydrochloride in the treatment of detrusor instability." Urol Int 32 (1977): 377-81

4. Pedersen E "Studies on the effect and mode of action of flavoxate in human urinary bladder and sphincter." Urol Int 32 (1977): 202-8

5. Jarvis GJ "A controlled trial of bladder drill and drug therapy in the management of detrusor instability." Br J Urol 53 (1981): 565-6

6. Bradley DV, Cazort RJ "Relief of bladder spasm by flavoxate. A comparative study." J Clin Pharmacol J New Drugs 10 (1970): 65-8

7. Hebjorn S "Treatment of detrusor hyperreflexia in multiple sclerosis: a double- blind, crossover clinical trial comparing methantheline bromid (Banthine), flavoxate chloride (Urispas) and meladrazine tartrat (Lisidonil)." Urol Int 32 (1977): 209-17

8. Milani R, Scalambrino S, Carrera S, Pezzoli P, Ruffmann R "Flavoxate hydrochloride for urinary urgency after pelvic radiotherapy: comparison of 600 mg versus 1200 mg daily dosages." J Int Med Res 16 (1988): 71-4

Not all side effects for flavoxate may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.