Can flavoxate be used to treat ureteric stones?

Flavoxate is Not Recommended for Ureteric Stones

Flavoxate should not be used for the treatment of ureteric stones as it is not recommended in any urological guidelines for stone management. 1, 2

Evidence-Based Management of Ureteric Stones

The American Urological Association (AUA) and Endourological Society guidelines provide clear recommendations for ureteric stone management, which do not include flavoxate:

First-line Treatment Options

• For stones ≤10 mm: Shockwave lithotripsy (SWL) or ureteroscopy (URS) are the recommended first-line treatments 1, 2
• For stones >10 mm: URS is preferred over SWL due to higher stone-free rates 2
• For stones >20 mm: Percutaneous nephrolithotomy (PCNL) is recommended as first-line therapy 1

Medical Expulsive Therapy

• Alpha-blockers (like tamsulosin) have been traditionally used as medical expulsive therapy, though recent evidence has challenged their efficacy 3
• Flavoxate is not mentioned in any guidelines for stone management

Why Flavoxate is Not Appropriate for Ureteric Stones

Flavoxate is a smooth muscle relaxant that has been studied and used primarily for:

• Urgency and urge incontinence 4, 5, 6
• Overactive bladder symptoms
• Uninhibited detrusor contractions

The mechanism of action of flavoxate involves:

• Anticholinergic effects
• Smooth muscle relaxation properties

However, there is no evidence supporting its use specifically for ureteric stones. While it theoretically could relax ureteral smooth muscle, no studies have demonstrated efficacy for stone passage.

Proper Management of Ureteric Stones

For patients with ureteric stones, the following approach is recommended:

1. Initial assessment:

   • CT urogram with 10-minute delayed images (sensitivity 97%) is the gold standard for diagnosis 2
   • Assess for signs of infection or obstruction requiring urgent intervention

2. For obstructing stones with suspected infection:

   • Urgent drainage of the collecting system is mandatory with either:
     • Ureteral stent, or
     • Percutaneous nephrostomy 1, 2

3. Stone-specific treatment:

   • For stones ≤10 mm: SWL or URS (stone-free rates: URS 90% vs. SWL 72%) 2
   • For stones >10 mm: URS preferred 2
   • For stones >20 mm: PCNL recommended 1

Potential Pitfalls

1. Delaying proper intervention: Using unproven medications like flavoxate may delay definitive treatment, potentially leading to complications like obstruction, infection, or renal damage

2. Infection risk: Failure to recognize and urgently drain obstructing stones with infection can lead to urosepsis and significant morbidity/mortality 1, 2

3. Inappropriate treatment selection: Using medications without evidence rather than established interventions (SWL, URS, PCNL) based on stone size and location

Remember that for patients with obstructing stones and suspected infection, urgent drainage of the collecting system is mandatory to prevent serious complications 1.