Diethylcarbamazine (DEC) (Diethylcarbamazine Citrate)
Also sold as: Hetrazan, DEC, Banocide, Filaribits
Pregnancy
Cat C
Lactation
Caution
Schedule
H
Forms
Tablet 50mg +2
Indications
- Lymphatic filariasis (Wuchereria bancrofti, Brugia malayi, Brugia timori)
- Tropical pulmonary eosinophilia
- Loiasis (Loa loa)
- Mass drug administration (MDA) for filariasis elimination
Adult Dosing
Lymphatic filariasis (Wuchereria bancrofti, Brugia spp.)
6 mg/kg/day in 3 divided doses
12 days
Start with low dose on day 1 (50mg) and escalate to avoid severe Mazzotti-type reactions. WHO protocol: 1mg/kg day 1, 1mg/kg TDS day 2, 2mg/kg TDS day 3, then 6mg/kg/day TDS days 4–12.
Tropical pulmonary eosinophilia (TPE)
6 mg/kg/day in 3 divided doses
21 days
TPE responds dramatically to DEC — wheezing and eosinophilia resolve within 1–2 weeks. Incomplete treatment causes relapse.
Loiasis (Loa loa)
8–10 mg/kg/day in 3 divided doses
21 days
CAUTION: Screen for microfilaria count before treatment. If Loa loa microfilaremia >8,000 mf/mL, risk of fatal encephalopathy. Hospitalize and treat with extreme caution, starting at very low dose. Pre-treat with ivermectin to reduce microfilaria load if count very high.
Mass drug administration (MDA) — filariasis elimination
6 mg/kg single annual dose
Annual single dose combined with albendazole 400mg (WHO programme)
India's National Filaria Control Programme uses DEC + albendazole annual MDA
Pediatric Dosing
For MDA in children 2–5 years: 1 tablet of 100mg; 6–14 years: 2 tablets; adults: 3 tablets (based on ~100mg/dose in 50kg adult). Use syrup for young children.
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| Mild to moderate renal impairment | Use with caution — DEC is renally excreted; monitor for toxicity |
| Severe renal impairment (CrCl <30) | Reduce dose and frequency; limited guidance available — consult specialist |
Hepatic Adjustment
No specific dose adjustment established. DEC is metabolised in the liver; use with caution in significant hepatic impairment.
Pregnancy & Lactation
Pregnancy: Category C
Limited human data. Avoid in 1st trimester. WHO excludes pregnant women from MDA programmes. For symptomatic filariasis or TPE in pregnancy: delay treatment if possible; weigh risk-benefit carefully.
Lactation: Caution
Limited data on excretion in breast milk. WHO excludes breastfeeding women from MDA until infant is 1 week old. Individual treatment: use with caution.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| Rifampicin | May reduce DEC plasma levels by inducing hepatic metabolism. Clinical significance uncertain — monitor treatment response. | Moderate |
| Alcohol | Additive side effects — worsens nausea, dizziness, and Mazzotti reaction severity. Avoid alcohol during DEC treatment. | Minor |
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Side Effects
Common
- Mazzotti reaction — fever, headache, urticaria, pruritus, lymphadenopathy, joint pains (from dying microfilariae); more severe with higher microfilaria counts
- Nausea and vomiting
- Dizziness
- Headache
- Transient leucocytosis
- Scrotal/limb swelling (lymphatic filariasis — from dying adult worms)
Serious / Discontinue If
- Encephalopathy — in Loa loa patients with very high microfilaremia; potentially fatal
- Severe Mazzotti reaction — hypotension, bronchospasm, severe urticaria; manage with antihistamines, steroids, and supportive care
- Retinal haemorrhage — rare; reported in onchocerciasis patients (DEC should NOT be used for onchocerciasis — use ivermectin)
- Transient neurological symptoms in loiasis treatment
Contraindications
- Onchocerciasis (river blindness) — DEC causes severe Mazzotti reaction and retinal damage in onchocerciasis; use ivermectin instead
- Very high Loa loa microfilaremia (>30,000 mf/mL) — high encephalopathy risk
- First trimester of pregnancy
- Hypersensitivity to diethylcarbamazine
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Hetrazan 50mg | Pfizer India | ₹22/10 tab |
| Banocide 100mg | GSK India | ₹28/10 tab |
| DEC 50mg | Various (generic) | ₹15/10 tab |
Monitoring Required
- Microfilaria count (blood smear — nocturnal periodicity; collect blood between 10 PM–2 AM) at baseline to guide dosing in loiasis
- Monitor for Mazzotti reaction for 2–4 hours after each dose during escalation phase
- Eosinophil count and IgE in tropical pulmonary eosinophilia — should normalise with treatment
- Renal function in patients with pre-existing CKD
- Chest X-ray in TPE — bilateral infiltrates should resolve
- Lymph node and limb circumference in lymphatic filariasis — document progression
Patient Counseling Points
- Take medicine after meals to reduce stomach upset
- You may develop fever, itching, and joint pains especially in the first few days — this means the medicine is working and parasites are dying; take paracetamol and antihistamines for relief
- Do NOT stop the medicine if you get these reactions — contact your doctor for symptomatic relief
- The full 12-day or 21-day course must be completed even if you feel better early
- Avoid alcohol throughout the treatment course
- For lymphatic filariasis: this medicine kills the parasites but lymphoedema (leg swelling) already present requires separate physiotherapy and limb hygiene
- Patients with Loa loa (as identified by doctor): you must be treated in a hospital setting due to risk of serious brain reaction
- Annual DEC tablets (from government health worker) must be taken every year in filariasis-endemic areas to contribute to elimination
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Clinically reviewed by: Dr. Prakash Narayanan, MD (Medicine), DTM&H (London), Senior Consultant Infectious and Tropical Diseases
Last reviewed: 2026-04-01
References
- WHO Guideline: Preventive chemotherapy for lymphatic filariasis 2022
- WHO Model Prescribing Information — Diethylcarbamazine Monograph
- India National Filaria Control Programme (NFCP) — Ministry of Health & Family Welfare
- Hetrazan Prescribing Information — Pfizer India
- Dreyer G et al. — Lymphatic filariasis pathogenesis and treatment — Lancet Infect Dis 2000
- CDSCO Drug Monograph — Diethylcarbamazine
- Tropical pulmonary eosinophilia — Sharma et al., Indian J Chest Dis Allied Sci 2014