Flavoxate (Genurin)

Article by Pharmacist Duong Thanh Hai - Clinical Pharmacist - Faculty of Pharmacy - Vinmec Times City International Hospital

Flavoxate is a smooth muscle relaxant used to relieve pain, urinary frequency and bedwetting in patients with inflammatory urinary tract disorders such as cystitis, urethritis, and prostatitis. This medication is also used to relieve bladder-urethral spasms caused by instrumentation or surgery.

Flavoxate is taken orally. If the patient has an upset stomach, the medicine can be taken with food. Dosage for children over 12 years old and adults is 100-200 mg/dose, 3-4 times a day. Dosage depends on the condition and response to therapy. Your doctor may reduce your dose the day after your symptoms have improved.
The duration of treatment depends on the cause of the disease. Therefore, you should not increase your dose or take it more often, as this will not improve your symptoms faster and may increase your risk of side effects.

Flavoxate has anticholinergic activity, so nausea, vomiting, dry mouth, headache, drowsiness, dizziness, blurred vision and nervousness may occur with use. If any of these side effects persist or get worse, tell your doctor or pharmacist right away.
To reduce some side effects when using the drug, you can:
Suck on sugar-free hard candy or shaved ice, chew gum, drink water to relieve dry mouth. To prevent constipation, eat enough fiber, drink enough water, and exercise. Sometimes additional laxatives may be needed, so consult your pharmacist for the right medication. Because the drug can cause drowsiness, dizziness and blurred vision, caution should be exercised when driving or operating machinery that requires high concentration. This medicine may reduce sweating. To reduce the risk of a serious reaction to extreme heat (heatstroke), extreme heat from hot weather, saunas, or during intense exercise should be avoided. Older adults may be more sensitive to the side effects of this medicine, especially dizziness (which is more likely to happen when standing up), drowsiness, constipation, trouble urinating, or confusion. Caution should be exercised as dizziness, drowsiness and confusion may increase the risk of falls.
Some of the following are rare but serious side effects that require discontinuation and immediate medical attention: Mental/mood changes (e.g. confusion), eye pain, chest pain, rapid heartbeat, signs signs of infection, increased difficulty/painful urination.

Flavoxate should not be used if the patient has the following conditions:
Stomach/intestinal obstruction (eg, pyloroduodenal, ileal obstruction) Stomach or intestinal bleeding Bladder obstruction. The safety and effectiveness of flavoxate hydrochloride have not been established in children younger than 12 years of age. Therefore, it is not recommended for children in this age group.
Because there are no adequate and well-controlled studies in pregnant women. Similarly, there are no data on the excretion of the drug into breast milk. Therefore, this medicine should only be used when absolutely necessary and consulted by a doctor before use.

Interactions can change the way the medicine works or increase the risk of serious side effects. Some products that may interact with Flavoxate are:
Drugs that also have anticholinergic effects (e.g. atropine, motion sickness drugs such as scopolamine, parkinsonian - trihexyphenidyl). Bisphosphonate osteoporosis medications (eg, alendronate, etidronate, risedronate). Inform your doctor or pharmacist if you are taking or will be taking these medicines. In case the patient does not see improvement in using the drug, the patient needs to go to a medical facility to see a doctor, from which the appropriate treatment method is available.