flavoxate hydrochloride: clinical use

Prescribing considerations

• Confirm that symptomatic treatment will not mask a condition requiring investigation or cause-specific treatment.
• Use caution in renal impairment because renal clearance accounts for a substantial proportion of active-metabolite elimination.
• Not recommended for children younger than 12 years because safety and efficacy have not been established.
• Advise against driving or machinery use if somnolence or blurred vision develops.

Contraindications and cautions

• Hypersensitivity to flavoxate or an excipient.
• Gastrointestinal obstruction or ileus.
• Gastrointestinal haemorrhage.
• Achalasia.
• Urinary retention.
• Glaucoma.
• Myasthenia gravis.

Monitoring

• Review symptomatic response and continuing need for treatment.
• Check for urinary retention, visual disturbance, confusion, hypersensitivity and hepatic symptoms.
• Consider renal function when clinically relevant, particularly in known renal impairment.

Clinical pharmacology

Flavoxate is readily absorbed and extensively converted to methyl flavone carboxylic acid. It has direct urinary smooth-muscle antispasmodic activity involving cyclic AMP accumulation and calcium-blocking effects; metabolites are substantially eliminated in urine.

Formulation and product differences

• The selected product is a white film-coated tablet marked “F 200”.
• It contains lactose monohydrate and should not be used in certain rare hereditary disorders of carbohydrate absorption or metabolism.
• It contains less than 1 mmol sodium per tablet and is considered essentially sodium-free.

Tablet

Route: Oral

Strengths: 200 mg