Diloxanide Furoate: Drug Index
Primary Indication and Mechanism
Diloxanide furoate is the drug of choice for treating asymptomatic carriers of Entamoeba histolytica, functioning as a luminal amebicide that prevents conversion of trophozoites to invasive cyst forms. 1, 2
- The drug achieves high luminal concentrations in its ester form, providing greater efficacy than metronidazole for asymptomatic intestinal amebiasis 3
- Acts through structural similarity to chloramphenicol at the dichloroacetamide group, blocking protein synthesis in E. histolytica trophozoites 3
- Prevents progression to invasive disease and eliminates the source of transmission 1
Standard Dosing Regimen
For Asymptomatic Carriers
- 500 mg orally three times daily for 10 days 4, 1, 2
- This regimen achieves an 86-93% parasitological cure rate in asymptomatic carriers 1, 5
As Sequential Therapy After Tissue Amebicides
- Following metronidazole or tinidazole treatment for symptomatic intestinal or extraintestinal amebiasis, all patients must receive diloxanide furoate 500 mg three times daily for 10 days to eliminate intestinal cysts and prevent relapse 4, 6
- This sequential approach is essential even when stool microscopy is negative post-treatment with tissue amebicides 4
Efficacy Data
- Parasitological cure achieved in 86% of asymptomatic cyst passers who completed the full 10-day course with follow-up stool examination ≥14 days post-treatment 2
- In comparative trials, diloxanide furoate demonstrated 88-93% cure rates in asymptomatic patients, significantly superior to metronidazole/tinidazole (29-56% cure rates) 5
- When combined with metronidazole and chloroquine, effectively treats amoebic abscesses with parasite clearance rates of 81-96% 3
Safety Profile and Adverse Effects
Common Adverse Effects (14% overall incidence)
Less Common Effects
Age-Related Tolerability
- Children aged 20 months to 10 years experience significantly fewer adverse effects (3%) compared to patients >10 years (12%), making diloxanide furoate particularly well-tolerated in pediatric populations 2
Critical Clinical Distinctions
When NOT to Use Diloxanide Furoate Alone
- Do not use as monotherapy for symptomatic intestinal amebiasis or invasive disease 1
- Symptomatic patients require tissue amebicides (metronidazole 750 mg three times daily for 5-10 days or tinidazole) followed by diloxanide furoate 4
- Extraintestinal amebiasis requires metronidazole/tinidazole (with chloroquine for hepatic abscess) followed by diloxanide furoate 6
When Diloxanide Furoate IS Indicated
- Asymptomatic carriers with confirmed E. histolytica cysts in stool 1, 2
- Sequential therapy after tissue amebicides for any form of amebiasis 4, 6
- Patients who failed metronidazole/tinidazole for asymptomatic carriage 5
Post-Treatment Monitoring
- Perform follow-up stool examination at least 14 days after completing treatment to confirm parasite elimination 4, 2
- Three stool specimens collected on different days should be examined for optimal sensitivity 4
Alternative Luminal Amebicide
- Paromomycin 30 mg/kg/day divided into 3 oral doses for 10 days is an FDA-approved alternative for asymptomatic carriers 1
Key Clinical Pitfalls to Avoid
- Never treat asymptomatic carriers with tissue amebicides (metronidazole/tinidazole) alone, as these do not eliminate intestinal cysts and will result in treatment failure 1
- Do not confuse positive serology in asymptomatic individuals with active disease requiring tissue amebicides—antibodies may persist from previous infections 1, 7
- Always complete the full 10-day course; shorter durations compromise efficacy 2
- Distinguish between pathogenic E. histolytica and non-pathogenic species before initiating treatment, as non-pathogenic strains do not require therapy 6