Single low-dose treatment with praziquantel for Diphyllobothrium nihonkaiense infections

Intern Med. 2003 Jan;42(1):41-3. doi: 10.2169/internalmedicine.42.41.


Objective: To investigate whether praziquantel is effective against diphyllobothriasis nihonkaiense at doses less than the conventional dose.

Patients and methods: Fourteen Japanese men with diphyllobopthriasis nihonkaiense were treated with a single administration of praziquantel at 5-10 mg/kg.

Results: Twelve patients expelled a complete integrated Diphyllobothrium nihonkaiense with its scolex. One patient expelled an integrated D. nihonkaiense without its scolex, and one patient expelled 2 complete integrated D. nihonkaiense with their scolex, and an integrated D. nihonkaiense without its scolex. The lack of eggs in stool samples was confirmed in these 2 patients after the end of therapy. All patients had not expelled proglottides after the end of therapy for more than 1 year. No side effects were identified in any of the patients.

Conclusion: All patients were considered to be cured. Our results indicate that the oral administration of a single dose of praziquantel at 5-10 mg/kg is effective and safe against D. nihonkaiense infections.

MeSH terms

  • Administration, Oral
  • Adult
  • Aged
  • Animals
  • Anthelmintics / administration & dosage*
  • Diphyllobothriasis / drug therapy*
  • Diphyllobothrium / isolation & purification
  • Feces / parasitology
  • Humans
  • Male
  • Middle Aged
  • Praziquantel / administration & dosage*


  • Anthelmintics
  • Praziquantel