A fixed-dose combination (FDC) antiprotozoal and antibacterial agent used primarily for the treatment of intestinal amebiasis and certain anaerobic bacterial infections. Metronidazole is a nitroimidazole antibiotic effective against anaerobic bacteria and protozoa, while Diloxanide furoate is a luminal amebicide that acts directly on the trophozoites in the intestinal lumen. This combination provides a synergistic effect for eradicating both luminal and systemic forms of *Entamoeba histolytica*.
Adult: Typically: Metronidazole 400 mg + Diloxanide Furoate 500 mg, three times daily for 5-10 days. For amebic liver abscess: Often Metronidazole 400-800 mg TDS for 5-10 days, followed by a luminal agent.
Note: Take with or after food to minimize gastrointestinal upset. Swallow the tablet whole with a full glass of water. Complete the full course even if symptoms improve.
Metronidazole: After entering microbial cells, its nitro group is reduced by nitroreductase enzymes, forming cytotoxic intermediates that damage DNA, inhibit nucleic acid synthesis, and cause cell death. It is selectively toxic to anaerobic organisms. Diloxanide Furoate: Its exact mechanism is unclear but it is directly amebicidal, likely by disrupting protein synthesis or interfering with the parasite's microtubule function. It acts primarily in the intestinal lumen.
Pregnancy: Category B (Diloxanide), Category B/C (Metronidazole - varies by source). Contraindicated in first trimester. Use in second/third trimester only if potential benefit justifies potential fetal risk. Avoid high-dose or prolonged therapy.
Driving: May cause dizziness, vertigo, confusion, or ataxia. Patients should be cautioned about operating machinery or driving until their response is known.
| Alcohol | Disulfiram-like reaction (flushing, headache, nausea, vomiting, tachycardia) | Major |
| Warfarin | Metronidazole inhibits warfarin metabolism, increasing INR and bleeding risk | Major |
| Lithium | Metronidazole may increase lithium levels, risk of toxicity | Major |
| Phenytoin, Phenobarbital | Enzyme inducers may reduce Metronidazole efficacy; Metronidazole may increase phenytoin levels | Moderate |
| Cimetidine | May increase Metronidazole levels by inhibiting metabolism | Moderate |
| 5-Fluorouracil | Metronidazole may reduce clearance, increasing toxicity risk | Moderate |
Same composition (Metronidazole (NA) + Diloxanide (NA)), different brands: