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 system destruction. In India, it is a critical component of the National Filariasis Control Programme.
Adult: Filariasis: Day 1: 50 mg after meals, Day 2: 50 mg TID, Day 3: 100 mg TID, then 6 mg/kg/day in 3 divided doses for total 12 days. For MDA: Single dose of 6 mg/kg with Albendazole 400 mg.
Note: Administer orally after meals to minimize GI upset. Tablets should be swallowed whole with a glass of water. For MDA, directly observed therapy (DOT) is recommended.
Diethylcarbamazine (DEC) immobilizes microfilariae and alters their surface membranes, exposing them to phagocytosis by fixed tissue macrophages. It also impairs microfilarial muscular activity. Its action on adult worms is less clear but may involve disruption of intracellular processing and transport of proteins.
Pregnancy: Category C: Animal studies show risk. Use only if potential benefit justifies potential fetal risk, especially in first trimester. Avoid in MDA programs.
Driving: May cause dizziness and drowsiness. Patients should be cautioned against driving or operating machinery until their response is known.
| Albendazole | Synergistic antifilarial effect; used together in MDA. | Moderate |
| Ivermectin | Increased risk of severe Mazzotti reaction in onchocerciasis; contraindicated. | High |
| CYP2D6 Inhibitors (e.g., Fluoxetine, Paroxetine) | May increase DEC plasma levels, increasing toxicity risk. | Moderate |
| Alcohol | May enhance CNS depressant effects like dizziness and drowsiness. | Moderate |
| Antihistamines | May be used to mitigate allergic reactions from DEC, but may mask early reaction signs. | Low |