1. Clinical Overview
Diethylcarbamazine citrate is a synthetic piperazine derivative and the drug of choice for the treatment of lymphatic filariasis caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori. It is also effective against tropical pulmonary eosinophilia (TPE) and loiasis. It acts by immobilizing microfilariae and altering their surface structure, making them susceptible to destruction by the host's immune system. In the Indian context, it is a cornerstone of the National Filariasis Control Programme.
| Onset | Duration | Bioavailability |
|---|---|---|
| Rapid; microfilariae disappear from peripheral blood within 24-48 hours. | Approximately 12-24 hours per dose; requires repeated dosing for complete macrofilaricidal effect. | Well absorbed (>85%) from the gastrointestinal tract. |
2. Mechanism of Action
The precise mechanism is not fully elucidated. It is believed to act by: 1) Immobilizing microfilariae by hyperpolarizing their muscle membranes. 2) Altering the surface membrane of microfilariae, exposing hidden antigens and making them susceptible to phagocytosis by the host's reticuloendothelial system and cytotoxic cells. 3) Impairing the microfilarial arachidonic acid metabolism. 4) At higher doses and prolonged therapy, it may have a weak macrofilaricidal effect on adult worms, possibly by affecting their muscular activity and metabolism.
3. Indications & Uses
- Lymphatic Filariasis (caused by Wuchereria bancrofti, Brugia malayi, Brugia timori)
- Tropical Pulmonary Eosinophilia (TPE)
4. Dosage & Administration
Adult Dosage: Filariasis: Day 1: 50 mg after meals, Day 2: 50 mg TID, Day 3: 100 mg TID, Days 4-21: 2 mg/kg TID. Alternative (MDA): Single dose of 6 mg/kg with Albendazole 400 mg annually. TPE: 2 mg/kg TID for 7-14 days.
Administration: Administer orally after meals to minimize gastrointestinal upset. Tablets should be swallowed whole with a full glass of water. For MDA programs, directly observed therapy (DOT) is recommended.
5. Side Effects
Common side effects may include:
- Nausea, vomiting, anorexia
- Headache, dizziness, drowsiness
- Fever, malaise
- Arthralgia, myalgia
- Itching, urticarial rash (due to dying microfilariae)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Albendazole | Synergistic antifilarial effect; used together in MDA. No significant PK interaction. | Moderate |
| Ivermectin | Increased risk of severe Mazzotti reaction in onchocerciasis. Contraindicated concurrently. | High |
| Corticosteroids (e.g., Prednisone) | Used to suppress or prevent severe inflammatory reactions to dying microfilariae. | Moderate (Therapeutic) |
| CYP2D6 Inhibitors (e.g., Fluoxetine, Paroxetine) | May increase DEC plasma levels, increasing risk of adverse effects. | Moderate |
| Alcohol | May enhance CNS depressant effects (dizziness, drowsiness). | Moderate |
7. Patient Counselling
- DO take the medicine exactly as prescribed, after meals.
- DO complete the full course of treatment even if you feel better.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DONT take this medicine if you have a known allergy to it.
- DONT consume alcohol while on this medication.
- DONT drive or operate heavy machinery if you experience dizziness.
8. Toxicology & Storage
Overdose: Nausea, vomiting, headache, dizziness, hypotension, tachycardia, confusion, and possibly seizures. Severe overdose may lead to respiratory depression and coma.
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.