Treatment of Recurrent Urinary Schistosomiasis
For recurrent urinary schistosomiasis (Schistosoma haematobium), treat with praziquantel 40 mg/kg as a single oral dose, and repeat treatment 6-8 weeks later if symptoms persist or reinfection is suspected. 1
Initial Treatment Approach
- Administer praziquantel 40 mg/kg as a single oral dose for S. haematobium (urinary schistosomiasis), which is the WHO-recommended standard treatment 1, 2
- This regimen achieves cure rates of 68-92% with egg reduction rates exceeding 90-95% 2, 3
- Treatment is highly effective and safe, with only mild to moderate adverse events (abdominal pain, headache, pruritus) that resolve within 24 hours 2, 3
Management of Treatment Failure or Recurrence
If parasitological failure occurs (persistent egg excretion at follow-up), repeat praziquantel 40 mg/kg 6-8 weeks after initial treatment. 1 This timing is critical because:
- Immature schistosomes are relatively resistant to praziquantel 1
- The 6-8 week interval allows maturation of any surviving parasites, making them susceptible to treatment 1
- Consider adding a short course of oral prednisolone (20 mg/day for 5 days) if acute symptoms are severe, as this alleviates symptoms without affecting cure rates 1
Diagnostic Confirmation Before Retreatment
Before retreating, confirm active infection through:
- Microscopy of terminal urine samples (last portion of voided urine) to detect S. haematobium eggs 1
- Serology (though it remains positive for years after cure and cannot assess treatment success) 1
- Abdominal/pelvic ultrasound if complications are suspected 1
Alternative Dosing Considerations
While 40 mg/kg remains the standard, the evidence shows:
- Higher doses (60 mg/kg) offer no significant efficacy advantage over 40 mg/kg for schistosomiasis, with cure rates of 92.8% vs 91.7% respectively 4
- Higher doses cause more adverse events (83% vs 73% experiencing at least one adverse event) 4
- In non-endemic settings where reinfection is not a concern, some clinicians use alternative regimens (higher doses or multi-day courses), though this practice lacks strong evidence 5
Common Pitfalls to Avoid
- Do not use 60 mg/kg dosing for S. haematobium - this is reserved for S. japonicum and S. mekongi from Asia-Pacific regions 1
- Do not rely on serology alone to assess cure, as antibodies persist for years after successful treatment 1
- Do not treat too early after initial therapy - wait 6-8 weeks before repeating treatment to allow immature worms to mature 1
- Do not assume treatment failure without parasitological confirmation - symptoms may persist temporarily even after successful parasite clearance 3