Schedule H

Oral

• Tablets: 50 mg, 100 mg

• Syrup: 120 mg/5 mL

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Lymphatic Filariasis (Wuchereria bancrofti, Brugia malayi)

Parameter Details

Starting dose 6 mg/kg/day orally in 3 divided doses

Titration Not applicable for standard treatment

Usual maintenance dose 6 mg/kg/day in 3 divided doses

Maximum dose 6 mg/kg/day (Total course: 72 mg/kg over 12 days)

Duration 12 days (may extend to 21 days per specialist discretion)

Key notes Administer after meals to reduce GI upset. In Mass Drug Administration (MDA) under NVBDCP: single dose of 6 mg/kg with Albendazole 400 mg ± Ivermectin 200 mcg/kg (IDA regimen).

1. Tropical Pulmonary Eosinophilia (TPE)

Parameter Details

Starting dose 6 mg/kg/day orally in 3 divided doses

Titration Not applicable

Usual maintenance dose 6 mg/kg/day in 3 divided doses

Maximum dose 6 mg/kg/day

Duration 21 days (extend to 28 days in suboptimal responders)

Key notes Monitor absolute eosinophil count (AEC) and clinical symptoms. Symptomatic improvement typically precedes eosinophil normalization. Relapse may occur — follow-up at 3 and 6 months recommended.

1. Loiasis (Loa loa) — Endemic travellers/returning residents

Parameter Details

Starting dose Day 1: 1 mg/kg single dose; Day 2: 1 mg/kg twice daily; Day 3: 1–2 mg/kg three times daily

Titration Gradual increase over 3–4 days to reach 6 mg/kg/day

Usual maintenance dose 6 mg/kg/day in 3 divided doses

Maximum dose 6 mg/kg/day

Duration 21 days

Key notes Assess microfilarial density before treatment. High Loa loa microfilaremia (>8000 mf/mL) carries risk of fatal encephalopathy. Specialist supervision mandatory. Slow titration essential to minimize Mazzotti-like reactions.

Secondary Indications — Adults (Off-label, if any)

Indication Dose Duration Notes Evidence

Visceral Larva Migrans (Toxocara) 6 mg/kg/day in 3 divided doses 7–10 days Specialist only — OFF-LABEL. Albendazole preferred first-line. Limited case series; Indian specialist practice

Important: Diethylcarbamazine is contraindicated in Onchocerciasis due to risk of severe ocular and systemic reactions. Ivermectin is the drug of choice for onchocerciasis.

PAEDIATRIC DOSING (Specialist Only)

Primary Indications

Indication Age Limit Dose Duration Key Notes

Lymphatic Filariasis ≥2 years Starting dose: 6 mg/kg/day in 2–3 divided doses 12 days Titration: Not applicable. Maximum: 6 mg/kg/day. For MDA: single dose 6 mg/kg with Albendazole. Monitor for fever, lymphadenitis, allergic reactions in first 3–5 days.

Tropical Pulmonary Eosinophilia ≥2 years Starting dose: 6 mg/kg/day in 2–3 divided doses 21 days Titration: Not applicable. Maximum: 6 mg/kg/day. Monitor AEC and respiratory symptoms. Extend to 28 days if response inadequate.

Loiasis ≥2 years Starting dose: 1 mg/kg/day; titrate to 6 mg/kg/day over 3–4 days 21 days Mandatory specialist supervision. Assess microfilarial load before treatment. Very high risk of encephalopathy in heavy infections.

Safety Monitoring (All Paediatric Patients):

• Monitor for fever, urticaria, and allergic reactions (especially Days 1–5)

• Baseline and periodic complete blood count with AEC

• Watch for signs of lymphangitis or lymphadenitis

Secondary Indications — Paediatric (Off-label, if any)

Not applicable — No validated off-label paediatric indications in Indian guidelines.

Statement: Diethylcarbamazine is not recommended below 2 years of age except under specialist supervision in exceptional circumstances (per NVBDCP and IAP guidance).

Mild to moderate impairment No specific dosing guidelines available. Use with caution.

• Known hypersensitivity to diethylcarbamazine

• Onchocerciasis (risk of severe ocular damage including permanent blindness — Mazzotti reaction)

• Co-existing Loa loa infection with high microfilarial load (>8000 mf/mL) without specialist supervision

• Active severe hepatic disease

• High microfilarial burden — increased risk of Mazzotti reaction (fever, hypotension, urticaria, angioedema)

• Concurrent Loa loa infection in patients from endemic areas (West/Central Africa)

• History of seizures or CNS disease

• Renal impairment — potential drug accumulation

• Hepatic impairment — altered metabolism

• Cardiac disease — rare reports of arrhythmias with severe hypersensitivity

• Elderly patients with multiple comorbidities

Parameter Details

Overall safety Limited controlled human data. No confirmed teratogenicity in animal studies or clinical experience.

Preferred timing May be used in 2nd and 3rd trimester when benefit outweighs risk

When to use Under specialist supervision; part of MDA programmes excludes pregnant women in first trimester

Preferred alternatives Single-dose Albendazole may be used in MDA (after 1st trimester)

Monitoring Maternal allergic/hypersensitivity reactions; routine antenatal fetal surveillance

Parameter Details

Compatibility Compatible with breastfeeding

Drug levels in milk Expected to be low

Preferred alternatives None required; DEC is acceptable

Infant monitoring Observe for rash, feeding difficulties, unusual irritability (rare)

Parameter Recommendation

Starting dose Consider initiating at lower end of dose range if comorbidities present

Titration Slower titration recommended, especially in Loiasis

Special risks Higher susceptibility to hypersensitivity reactions; risk of drug accumulation if renal function impaired; assess baseline renal and hepatic function before treatment

Monitoring Renal function; signs of CNS toxicity (confusion, dizziness)

Interacting Drug Effect Mechanism Recommendation

Ivermectin (in Loa loa co-infection) Increased risk of severe encephalopathy Rapid microfilarial killing releases inflammatory mediators Avoid ivermectin in patients with high Loa loa microfilaremia. Screen before MDA in endemic areas.

Interacting Drug Effect Recommendation

Corticosteroids May mask allergic/inflammatory responses Use concurrently to manage Mazzotti reaction, but be aware of symptom masking

Antihistamines May blunt recognition of early hypersensitivity signs Monitor carefully; do not rely on absence of rash/urticaria

Albendazole Additive antiparasitic effect; possible increased inflammatory response Used together in MDA; monitor for adverse reactions

• Fever (particularly in first 1–3 days — related to microfilarial death)

• Headache

• Malaise and fatigue

• Nausea, vomiting, anorexia

• Dizziness

• Arthralgia and myalgia

• Urticaria and pruritus

• Lymphadenitis and lymphangitis (in lymphatic filariasis)

Adverse Effect Notes

Mazzotti reaction Systemic hypersensitivity: fever, hypotension, tachycardia, urticaria, angioedema. May require hospitalisation and supportive care (corticosteroids, antihistamines, IV fluids).

Encephalopathy Particularly in heavy Loa loa microfilaremia. May be fatal. Presents with confusion, coma, seizures. Requires immediate discontinuation and intensive care.

Severe allergic reactions Anaphylaxis (rare)

Hepatotoxicity Transient elevation of transaminases (rare); monitor LFTs if prolonged therapy

Ocular damage In onchocerciasis (contraindicated) — punctate keratitis, chorioretinitis

Phase Parameters

Baseline Complete blood count with differential and AEC; liver function tests; renal function tests; microfilarial density (nocturnal blood smear for W. bancrofti/Brugia; day smear for Loa loa if relevant travel history)

During treatment (Days 1–5) Monitor for fever, hypotension, urticaria, signs of Mazzotti reaction. In Loiasis: watch for CNS symptoms (confusion, seizures).

Post-treatment Repeat AEC at 1 month (for TPE); repeat microfilarial count at 3–6 months to assess cure; clinical assessment for recurrence

• Banocide (GlaxoSmithKline)

• Hetrazan (various manufacturers)

• Filaribits

• DEC (generic — various manufacturers)

Note: Decaris is Levamisole, NOT Diethylcarbamazine — do not confuse.

Government supply Available free under NVBDCP (National Vector Borne Disease Control Programme) for MDA

Note: DEC is included in the National List of Essential Medicines (NLEM).

1. Always assess microfilarial density before initiating treatment in suspected Loiasis — high Loa loa load (>8000 mf/mL) may cause fatal encephalopathy.

1. Mazzotti reaction is due to dying microfilariae, not drug allergy. Manage with antihistamines and corticosteroids; do not necessarily discontinue treatment.

1. DEC is contraindicated in onchocerciasis — use ivermectin instead. Screen patients from endemic areas (Africa) before prescribing.

1. Tropical Pulmonary Eosinophilia requires 3 weeks of treatment — shorter courses lead to relapse. Follow up AEC at 1 month.

1. In MDA programmes, single-dose DEC (6 mg/kg) is combined with Albendazole ± Ivermectin for enhanced microfilaricidal effect.

1. Syrup formulation is useful for paediatric dosing and patients with swallowing difficulties.

diethylcarbamazine; DEC; filariasis; lymphatic filariasis; tropical pulmonary eosinophilia; TPE; antifilarial; Mazzotti reaction; loiasis; MDA; NVBDCP; NLEM India

RxIndia v1.0 — 10 Jul 2025

• CDSCO Product Information

• Indian Pharmacopoeia

• National List of Essential Medicines (NLEM) India

• National Vector Borne Disease Control Programme (NVBDCP) Guidelines

• ICMR Guidelines for Lymphatic Filariasis Elimination

• API Textbook of Medicine

• AIIMS Drug Formulary

• WHO Guidelines for MDA in Lymphatic Filariasis

• IAP Drug Formulary (Paediatric dosing)

• Harrison's Principles of Internal Medicine