Treatment of Flatworm Infections
The recommended treatment for flatworm infections depends on the specific parasite: praziquantel is the drug of choice for most trematode (fluke) and cestode (tapeworm) infections, while albendazole is preferred for certain tissue cestode infections like neurocysticercosis. 1, 2
Treatment by Parasite Type
Trematodes (Flukes)
- Praziquantel is the treatment of choice for schistosomiasis and most other fluke infections (blood flukes, lung flukes, and most liver flukes), typically given at 50 mg/kg/day divided over 1-15 days depending on the specific parasite 1, 2
- Praziquantel works by activating a specific ion channel (TRPMPZQ) in the parasite, causing calcium influx, paralysis, and death 3, 4
- Important exception: Fasciola hepatica (liver fluke) is resistant to praziquantel due to a different binding pocket structure in its TRPMPZQ channel 5, 3
Cestodes (Tapeworms)
Intestinal Tapeworms
- Praziquantel remains the primary treatment for intestinal tapeworm infections, including Taenia species 1, 2
- Alternative: Albendazole can be used for intestinal cestode infections 1
Neurocysticercosis (Tissue Infection with Taenia solium Larvae)
- For parenchymal brain cysts: Albendazole 15 mg/kg/day (up to 1200 mg/day) for 8-30 days is recommended, with most protocols using 15 days 1
- Always administer corticosteroids concurrently to control inflammation from dying parasites, as treatment causes acute exacerbation of symptoms between days 2-5 1
- For intraventricular cysts: Surgical removal via neuroendoscopy is preferred over medical therapy when feasible, as most cases can be cured without subsequent antiparasitic drugs 1
- Praziquantel (50-100 mg/kg/day for 7-21 days) is an alternative but interacts with steroids, decreasing its serum concentrations 1
Monitoring Requirements for Albendazole
- Monitor for hepatotoxicity and leukopenia when treatment exceeds 14 days, as elevated liver enzymes occur in up to 16% of patients and leukopenia in up to 10% 1, 6, 7
- Discontinue promptly if significant elevations occur; transaminases normalize in almost all cases after stopping the drug 1
Key Clinical Considerations
Drug Administration
- Albendazole absorption improves significantly when taken with fatty meals, which is critical for achieving therapeutic levels 1
- Praziquantel interacts with phenytoin and carbamazepine, lowering their serum levels 1
Common Pitfalls
- Do not withhold corticosteroids during antiparasitic treatment of neurocysticercosis—the inflammation from parasite death can cause seizures, increased intracranial pressure, and potentially death in massive infections 1
- Screen household contacts and food handlers for tapeworm carriage in neurocysticercosis cases, as they pose public health risks; notify local health authorities 1
- Treatment failure is rare; persistent symptoms usually indicate reinfection rather than drug resistance 6
Mechanism of Action Differences
- Praziquantel acts rapidly by targeting the TRPMPZQ ion channel, causing immediate calcium influx and paralysis 3, 4
- Albendazole has better cerebrospinal fluid penetration and is not affected by concurrent steroid use, making it superior for CNS infections 1
- The ~300-fold variation in praziquantel sensitivity across flatworm species explains why it is highly effective against schistosomes and most tapeworms but ineffective against Fasciola 5