1. Clinical Overview
A fixed-dose combination (FDC) therapy designed for the broad-spectrum, single-dose treatment of mixed infections involving bacteria, anaerobic organisms, and fungi. It is particularly relevant in the Indian context for the empirical management of pelvic inflammatory disease (PID), bacterial vaginosis, and mixed genital/abdominal infections where polymicrobial etiology is suspected. The combination leverages the pharmacokinetic synergy of long-acting agents to ensure therapeutic coverage over several days from a single administration.
| Onset | Duration | Bioavailability |
|---|---|---|
| Azithromycin: 2-3 hours; Ornidazole: 1-2 hours; Fluconazole: 1-2 hours. | Azithromycin: 68-72 hours (due to long tissue half-life); Ornidazole: 24-48 hours; Fluconazole: 48-72 hours (maintains therapeutic levels in vaginal tissue for days). | Azithromycin: ~37% (oral); Ornidazole: >90% (oral); Fluconazole: >90% (oral). |
2. Mechanism of Action
The combination provides a triple-action attack on different microbial targets. Azithromycin inhibits bacterial protein synthesis, Ornidazole causes DNA strand breakage in anaerobic organisms, and Fluconazole inhibits fungal ergosterol synthesis, leading to a broad-spectrum effect against a polymicrobial infection.
3. Indications & Uses
- Single-dose treatment of mixed vaginal infections (Bacterial Vaginosis, Trichomoniasis, Vulvovaginal Candidiasis)
- Empirical therapy for Pelvic Inflammatory Disease (PID) of polymicrobial origin
- Surgical prophylaxis/treatment for mixed abdominal/pelvic infections (e.g., post-hysterectomy)
4. Dosage & Administration
Adult Dosage: Typically administered as a SINGLE DOSE: Azithromycin 1000mg + Ornidazole 750mg + Fluconazole 150mg, taken orally with food. In some protocols, it may be repeated after 7 days for PID or severe infection, but this is not standard. A single dose is the most common regimen.
Administration: Take as a single dose with a full glass of water, preferably after a meal to minimize gastrointestinal upset. The tablets should be swallowed whole, not crushed or chewed. For PID, it must be combined with a parenteral cephalosporin (e.g., Ceftriaxone) as per CDC/ICOG guidelines to cover N. gonorrhoeae.
5. Side Effects
Common side effects may include:
- Nausea, Abdominal pain/cramping, Diarrhea (mild)
- Headache, Dizziness
- Metallic/bitter taste in mouth (Ornidazole)
- Vaginal burning/itching (initial, with Fluconazole)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Warfarin | Fluconazole inhibits warfarin metabolism; increased INR and risk of bleeding. | Major |
| Cyclosporine, Tacrolimus | Fluconazole increases their blood levels, risk of nephrotoxicity. | Major |
| Phenytoin | Fluconazole increases phenytoin levels; phenytoin may decrease fluconazole levels. | Major |
| Rifampicin | Reduces serum levels of Azithromycin and Fluconazole, potentially reducing efficacy. | Moderate |
| Antacids (Al, Mg) | May reduce absorption of Azithromycin; administer at least 1 hour before or 2 hours after. | Moderate |
| Digoxin | Azithromycin may increase digoxin bioavailability, risk of toxicity. | Moderate |
| Statins (especially Simvastatin, Atorvastatin) | Increased risk of myopathy/rhabdomyolysis due to Azithromycin and Fluconazole. | Major |
| Oral Hypoglycemics (Sulfonylureas) | Fluconazole can increase their levels, causing hypoglycemia. | Major |
| Alcohol | Disulfiram-like reaction with Ornidazole (flushing, tachycardia, nausea). | Major |
7. Patient Counselling
- DO take the medication exactly as prescribed, as a single dose with food.
- DO complete any additional antibiotics (like an injection) prescribed by your doctor for full treatment.
- DO inform your doctor about all other medications, vitamins, and herbal supplements you are taking.
- DO NOT consume ANY alcohol, including cough syrups, tonics, or foods cooked with alcohol, for at least 3 days after taking this medicine.
- DO NOT take antacids within 1 hour before or 2 hours after this medicine.
- DO use effective contraception during treatment if you are of childbearing potential.
8. Toxicology & Storage
Overdose: Symptoms may include severe nausea, vomiting, diarrhea, lethargy, dizziness, seizures (from Ornidazole), and cardiac arrhythmias (from Azithromycin). In extreme cases, hepatotoxicity may occur.
Storage: Store below 30°C, in a cool, dry place, protected from light and moisture. Keep out of reach of children. Do not use after the expiry date printed on the pack.