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 altering the microfilarial surface membranes, making them susceptible to host immune destruction. In the Indian context, it is a cornerstone of the National Filariasis Control Programme.
| Onset | Duration | Bioavailability |
|---|---|---|
| Rapid; microfilarial levels in blood drop within hours of administration. | Approximately 12-24 hours per dose; requires repeated dosing for full therapeutic effect. | Well absorbed (>85%) from the gastrointestinal tract. |
2. Mechanism of Action
Diethylcarbamazine (DEC) is a microfilaricide. Its exact mechanism is not fully elucidated but involves multiple actions: 1) It immobilizes microfilariae by inducing hyperpolarization of their muscle membranes. 2) It alters the surface membrane of microfilariae, exposing hidden antigens and making them more susceptible to phagocytosis and destruction by the host's immune system (antibody-dependent cellular cytotoxicity). 3) It may also impair the microfilarial microtubule function.
3. Indications & Uses
- Lymphatic Filariasis (caused by Wuchereria bancrofti, Brugia malayi)
- Tropical Pulmonary Eosinophilia (TPE)
4. Dosage & Administration
Adult Dosage: Filariasis: 6 mg/kg body weight per day, administered orally in divided doses (typically 300mg once daily or in 2-3 divided doses) for 12 days. For MDA programs in India: Single annual dose of DEC 300mg + Albendazole 400mg.
Administration: Take after food to minimize gastrointestinal upset. Tablets should be swallowed whole with a full glass of water. For MDA, directly observed therapy (DOT) is recommended.
5. Side Effects
Common side effects may include:
- Nausea, Vomiting, Anorexia
- Headache, Dizziness, Malaise
- Fever, Chills (due to dying microfilariae)
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Albendazole | Synergistic antifilarial effect; standard combination in MDA. | Major (Therapeutic) |
| Corticosteroids (e.g., Prednisolone) | May be used prophylactically to attenuate severe inflammatory reactions to dying microfilariae. | Moderate (Beneficial) |
| Drugs causing Alkaline Urine (e.g., Sodium Bicarbonate, Acetazolamide) | Decreases renal excretion of DEC, increasing plasma levels and risk of toxicity. | Moderate |
| CYP2D6/CYP3A4 Inhibitors (e.g., Fluoxetine, Ketoconazole) | May increase DEC plasma concentrations. | Moderate |
| Alcohol | May exacerbate CNS side effects like dizziness. | Minor |
7. Patient Counselling
- Do complete the full course of treatment as prescribed, even if symptoms improve.
- Do take the medicine after meals to reduce stomach upset.
- Do inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- Don't take this medicine if you have a known allergy to it.
- Don't take antacids or medications that make urine alkaline without consulting your doctor.
8. Toxicology & Storage
Overdose: Nausea, vomiting, headache, dizziness, hypotension, tachycardia, confusion, and potentially convulsions. Severe overdose may lead to respiratory depression.
Storage: Store below 30°C, in a cool, dry place, protected from light and moisture. Keep out of reach of children.