Schistosomiasis medical therapy

The mainstay of treatment for schistosomiasis is pharmacotherapy. Praziquantel is the drug of choice in treating schistosomiasis. Corticosteroids should be administered in addition to praziquantel in patients with symptoms due to neuro-schistosomiasis and patients with severe katayama fever. The goals of treatment of schistosomiasis are to eradicate the helminth and correct any sequelae of infection. While praziquantel is safe and highly effective in curing an infected patient, it does not prevent re-infection by cercariae and is thus not an optimum treatment for people living in endemic areas.

• 1. Schistosoma mansoni, S. haematobium, S. intercalatum^[1]

• Preferred regimen: Praziquantel 40 mg/kg per day PO in qd or bid for one day
• Alternative regimen (1): Oxamniquine 20 mg/kg PO single dose^[2][3]
• Alternative regimen (2): Artemisinin no dose is established yet^[1]
• Alternative regimen (3): Mefloquine 250 mg PO single dose
• Note: There is no benefit in associating the alternative therapies to praziquantel.
• Note: Praziquantel is not effective against larval/egg stages of the disease.^[4]

• 2. S. japonicum, S. mekongi^[1]

• Preferred regimen: Praziquantel 60 mg/kg per day PO bid for one day
• Alternative regimen (1): Artemisinin no dose is established yet
• Alternative regimen (2): Mefloquine 250 mg PO single dose
• Note: There is no benefit in associating the alternative therapies to Praziquantel.

• 3. Katayama Fever

• Preferred regimen: Prednisone 20-40 mg/day PO for 5 days, THEN Praziquantel^[5]
• Praziquantel should be used after 4-6 weeks of exposure because it cannot kill the larvae stages of the Schistosoma.
• Praziquantel should be used after acute schistosomiasis syndrome symptoms have resolved.
• Praziquantel together with corticosteroids, only when ova are detected in stool or urine samples.^[6]

• Praziquantel is first-line therapy for infection with all five Schistosoma species.
• Praziquantel is also used as part of mass chemotherapy campaigns in endemic areas to decrease individual worm burden.
• Not effective against immature schistosomes (schistosomules).
• Not useful for treatment of cercarial dermatitis (i.e, cutaneous schistosomiasis or swimmer’s itch) caused by transient, self-limited infection with Austrobilharzia species.
• Very well tolerated; adverse effects are usually mild and transient and do not require treatment.
• Women who are breastfeeding should not breastfeed on the day of treatment.
• Rifampin significantly reduces the bioavailability of praziquantel and, thus, should be discontinued 4 weeks before treatment.
• Schistosome eggs may take weeks to pass out of the intestinal and bladder wall; therefore, egg passage continues for approximately a month after treatment.

• Corticosteroids are indicated as an adjunctive treatment (in addition to praziquantel) in patients with symptoms due to:
  • Neuro-schistosomiasis (transverse myelitis, seizures, or other symptoms of increased intracranial pressure)
  • Patients presenting with severe Katayama fever
• Corticosteroids help to alleviate acute allergic reactions and mass effects caused by excessive granulomatous inflammation in the CNS.

• Artemisinin compounds are employed in the eradication of migrating schistosome larvae in recently infected patients.
• Artemether also may provide chemoprophylactic protection against S.mansoni and S haematobium.