Before taking flavoxate, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: stomach/intestinal problems (such as blockage, bleeding, ileus, infection, acid-reflux disease, chronic constipation, ulcerative colitis), heart problems (such as fast/irregular heartbeat, heart failure), a certain eye condition (glaucoma), kidney problems, a certain muscle disease (myasthenia gravis), difficulty urinating (for example, due to enlarged prostate), overactive thyroid (hyperthyroidism).

This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

This medication can cause decreased sweating. To reduce the risk of a serious reaction to too much heat (heatstroke), avoid becoming overheated in hot weather, saunas, or during exercise or other strenuous activities.

Older adults may be more sensitive to the side effects of this drug, especially dizziness (more likely when standing up), drowsiness, constipation, trouble urinating, or confusion. Dizziness, drowsiness, and confusion can increase the risk of falling.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.