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) and tropical pulmonary eosinophilia. It is also effective against loiasis (Loa loa) and is used in mass drug administration (MDA) programs in India under the National Filariasis Elimination Programme. It acts primarily by altering the microfilarial surface membranes, making them susceptible to host immune system destruction.
Adult: Filariasis: Day 1: 50mg after meals, Day 2: 50mg three times, Day 3: 100mg three times, then 6mg/kg/day in three divided doses for total 12 days. MDA (with Albendazole): Single dose of 6mg/kg (approx 300-400mg) annually. TPE: 6mg/kg/day in three divided doses for 14-21 days.
Note: Administer with or immediately after meals to reduce gastrointestinal upset. Tablets should be swallowed whole with a full glass of water. For MDA programs, directly observed therapy (DOT) is recommended.
The precise mechanism is not fully elucidated. It is believed to act by: 1) Immobilizing microfilariae by altering their surface membranes, making them more susceptible to phagocytosis by fixed tissue macrophages. 2) Possibly interfering with arachidonic acid metabolism in microfilariae. 3) Modifying host immune responses, enhancing adherence of granulocytes to microfilariae. It has minimal direct effect on adult worms (macrofilariae) but may impair their production of microfilariae.
Pregnancy: Category C: Animal studies show risk. Use only if potential benefit justifies potential fetal risk, especially in first trimester. Avoid in MDA programs for pregnant women.
Driving: May cause dizziness or drowsiness. Patients should be cautioned about driving or operating machinery until their response is known.
| Albendazole | Synergistic antifilarial effect; used together in MDA. No significant PK interaction. | Moderate |
| Corticosteroids (e.g., Prednisolone) | May be used prophylactically to attenuate Mazzotti reactions. No direct interaction. | Minor |
| Drugs that alkalinize urine (e.g., Sodium Bicarbonate, Acetazolamide) | Decreases renal excretion, increases plasma levels and half-life, raising toxicity risk. | Major |
| Drugs that acidify urine (e.g., Ammonium Chloride, Ascorbic Acid high dose) | Increases renal excretion, may reduce efficacy. | Moderate |
| CNS depressants (Alcohol, Benzodiazepines) | Additive sedative effect with dizziness. | Moderate |