Schedule H

Oral

• Tablets: 100 mg (regular and chewable)

• Oral suspension: 100 mg/5 mL

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Soil-Transmitted Helminthiases (Ascariasis, Trichuriasis, Hookworm Infection)

Used for treatment of roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and hookworm (Ancylostoma duodenale, Necator americanus) infections.

Adult Dosing — Standard 3-day Regimen (preferred for polyparasitism):

Parameter Recommendation

Starting dose 100 mg twice daily

Titration Not applicable

Usual maintenance dose 100 mg twice daily

Maximum dose 100 mg twice daily (200 mg/day)

Duration: 3 days

Alternative Single-dose Regimen (primarily for Ascariasis only):

Parameter Recommendation

Starting dose 500 mg as single dose

Titration Not applicable

Usual maintenance dose Not applicable (single dose)

Maximum dose 500 mg single dose

Clinical Notes:

• Three-day regimen preferred when multiple STH infections suspected or in endemic areas

• Tablets may be chewed, swallowed whole, or crushed and mixed with food

• Minimal systemic absorption — acts primarily in GI tract

• Stool examination recommended at baseline and 2–4 weeks post-treatment to confirm cure

1. Enterobiasis (Pinworm Infection — Enterobius vermicularis)

Parameter Recommendation

Starting dose 100 mg as single dose

Titration Not applicable

Usual maintenance dose Not applicable (single dose)

Maximum dose 100 mg single dose

Duration: Single dose; repeat after 2–3 weeks to prevent reinfection from eggs

Clinical Notes:

• High reinfection rate — treat all household members simultaneously

• Emphasise hygiene measures (handwashing, nail cutting, washing bedding/underwear in hot water)

• Repeat dose essential as mebendazole does not kill eggs

1. Trichinellosis (Trichinella spiralis)

Parameter Recommendation

Starting dose 200–400 mg three times daily

Titration Not applicable

Usual maintenance dose 200–400 mg three times daily

Maximum dose 400 mg three times daily (1200 mg/day)

Duration: 3 days initially; may continue for 10–14 days in severe infections

Clinical Notes:

• Corticosteroids often co-administered for severe myositis

• Most effective against intestinal phase; limited efficacy once larvae encyst in muscle

• Specialist supervision recommended

1. Capillariasis (Capillaria philippinensis)

Parameter Recommendation

Starting dose 200 mg twice daily

Titration Not applicable

Usual maintenance dose 200 mg twice daily

Maximum dose 200 mg twice daily (400 mg/day)

Duration: 20–30 days

Clinical Notes:

• Endemic in some regions; prolonged treatment required

• Monitor for malabsorption and electrolyte abnormalities

Secondary Indications — Adults (Off-label)

Indication Dose Duration Notes

Hydatid Disease (Cystic Echinococcosis) 40–50 mg/kg/day in 3 divided doses (typically 400–600 mg TID); Maximum: 1.5–2 g/day 28-day cycles with 14-day drug-free intervals; 3–6 cycles or more OFF-LABEL — Specialist only (Surgery/Infectious Diseases). Used when albendazole contraindicated or not tolerated. Higher doses required due to poor absorption. Monitor LFTs and CBC. Based on WHO guidelines and Indian specialist practice.

Taeniasis (Taenia saginata, T. solium — intestinal) 100 mg twice daily for 3 days OR 200 mg twice daily for 3 days 3 days OFF-LABEL — Praziquantel or niclosamide preferred. May be used when alternatives unavailable. Based on Indian practice.

Strongyloidiasis 100 mg twice daily for 3 days 3 days OFF-LABEL — Ivermectin is drug of choice. Mebendazole has lower efficacy. Use only if ivermectin unavailable.

PAEDIATRIC DOSING (Specialist Only)

Primary Indications (Approved / Standard in India)

1. Soil-Transmitted Helminthiases (Ascariasis, Trichuriasis, Hookworm)

Age-based Dosing per IAP and WHO Guidelines:

Age Dose per Administration Frequency Duration

1–2 years 100 mg Single dose (Ascariasis) OR twice daily × 3 days (polyparasitism) 1 or 3 days

2 years 100 mg Twice daily 3 days

Alternative Dosing (Mass Deworming Programmes per MoHFW/WHO):

Age Single Dose Notes

12–24 months 250 mg (half tablet) single dose For preventive chemotherapy in endemic areas

≥2 years 500 mg single dose For preventive chemotherapy

Parameter Recommendation

Starting dose 100 mg twice daily (treatment) OR 500 mg single dose (mass deworming)

Titration Not applicable

Usual maintenance dose 100 mg twice daily (treatment regimen)

Maximum dose 100 mg twice daily for 3 days (200 mg/day)

Clinical Notes:

• Use oral suspension for children unable to chew or swallow tablets

• WHO and National Deworming Programme support mass deworming with single-dose regimen in endemic areas

• Tablets may be chewed or crushed and mixed with food

1. Enterobiasis (Pinworm Infection)

Age Dose Notes

≥1 year 100 mg single dose Repeat after 2–3 weeks

Clinical Notes:

• Treat all household members simultaneously

• Hygiene education essential

Minimum Age Statement: Not recommended in children below 1 year of age except under specialist supervision due to limited safety data in this age group.

Safety Monitoring:

• Clinical assessment for abdominal symptoms

• No routine laboratory monitoring for short courses

• For prolonged courses (hydatid disease): LFTs and CBC at baseline and every 2–4 weeks

Secondary Indications — Paediatrics (Off-label)

Indication Age Dose Notes

Hydatid Disease (Cystic Echinococcosis) All ages 40–50 mg/kg/day in 3 divided doses; Maximum: 50 mg/kg/day or adult maximum (whichever lower) OFF-LABEL — Specialist only (Paediatric Surgery/ID). 28-day cycles with 14-day intervals. Monitor LFTs, CBC. Albendazole preferred when available.

Visceral Larva Migrans (Toxocara) All ages 100–200 mg twice daily for 5 days OFF-LABEL — Albendazole preferred. Corticosteroids may be needed for severe ocular or CNS involvement.

No dose adjustment required.

Mebendazole has minimal systemic absorption (<10%); what is absorbed is primarily hepatically metabolised and excreted in faeces. Renal impairment does not significantly affect drug handling.

Note: Systemic exposure increases with hepatic impairment as mebendazole is hepatically metabolised. Risk of hepatotoxicity increases with prolonged high-dose therapy.

• Known hypersensitivity to mebendazole or other benzimidazole derivatives (albendazole, thiabendazole)

• Pregnancy (especially first trimester) — teratogenic in animal studies

• Hepatic impairment — increased risk of hepatotoxicity with prolonged use

• High worm burden (heavy Ascaris infection) — risk of worm migration and intestinal obstruction during treatment; consider pre-treatment with piperazine or using lower mebendazole doses initially in very heavy infections

• Inflammatory bowel disease — theoretical risk of increased systemic absorption

• Prolonged high-dose therapy (e.g., hydatid disease) — monitor for bone marrow suppression and hepatotoxicity

• Neurocysticercosis — treat with appropriate anti-inflammatory cover; dying parasites may trigger inflammation

• Concurrent use with enzyme-inducing drugs — reduced mebendazole efficacy possible

Parameter Recommendation

Safety Category Contraindicated, especially in first trimester; teratogenic effects demonstrated in animal studies (embryotoxicity at low doses); limited human data

Preferred Alternatives Pyrantel pamoate may be used for hookworm/roundworm in pregnancy when treatment cannot be delayed; generally defer deworming until postpartum if possible

When to Use May be considered after first trimester ONLY if untreated worm infection poses significant maternal/fetal risk and no safer alternative available; requires specialist decision and informed consent

Monitoring Fetal ultrasound monitoring; maternal LFTs if prolonged use

Note: WHO recommends avoiding mebendazole in first trimester; may be used in second/third trimester in mass drug administration settings where benefits clearly outweigh risks.

Parameter Recommendation

Breastfeeding Compatibility Compatible with breastfeeding

Drug Levels in Milk Negligible (minimal systemic absorption in mother)

Preferred Alternatives Not required; mebendazole is acceptable

Infant Monitoring No specific monitoring required

Parameter Recommendation

Starting dose Standard adult dose (100 mg twice daily for 3 days)

Titration Not applicable

Additional Risks Age-related hepatic impairment may increase systemic exposure; monitor for adverse effects if prolonged treatment required

Monitoring Hepatic function assessment if treatment exceeds 3 days

Interacting Drug Mechanism/Effect Management

Metronidazole Rare reports of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis when used concurrently; mechanism unclear Avoid concurrent use if possible; if essential, monitor closely for cutaneous reactions

Carbamazepine Strong CYP3A4 inducer; significantly reduces mebendazole plasma levels Avoid concurrent use for high-dose mebendazole therapy (hydatid disease); may reduce efficacy; consider albendazole alternative or increased mebendazole dose with monitoring

Phenytoin CYP3A4 inducer; reduces mebendazole levels As for carbamazepine

Phenobarbital CYP3A4 inducer; reduces mebendazole levels As for carbamazepine

Interacting Drug Effect Management

Cimetidine CYP inhibitor; may increase mebendazole plasma levels and systemic exposure Monitor for increased adverse effects if prolonged mebendazole use

Ritonavir and other HIV protease inhibitors May increase mebendazole levels through CYP inhibition Monitor for mebendazole toxicity; clinical significance uncertain for short courses

Albendazole No adverse pharmacokinetic interaction; sometimes used together for hydatid disease May be co-administered under specialist supervision

Praziquantel No significant interaction May be co-administered for mixed helminth/cestode infections

Warfarin Theoretical interaction; isolated reports of INR changes Monitor INR if concurrent use; clinical significance low for short courses

• Abdominal pain/cramps

• Diarrhoea

• Flatulence

• Nausea

• Headache

• Dizziness

• Transient rash/pruritus

Note: Adverse effects are generally mild and transient due to low systemic absorption. GI symptoms may also result from expulsion of worms.

Adverse Effect Clinical Significance

Hepatotoxicity Elevated transaminases, hepatitis; primarily with prolonged high-dose therapy (hydatid disease); monitor LFTs; discontinue if significant elevation

Bone marrow suppression Neutropenia, agranulocytosis, pancytopenia; rare; primarily with prolonged therapy; monitor CBC; discontinue if haematological abnormalities develop

Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis Very rare; reported with concurrent metronidazole; discontinue immediately if mucocutaneous reaction occurs

Alopecia Reversible; reported with prolonged high-dose therapy

Hypersensitivity reactions Urticaria, angioedema, anaphylaxis (rare); discontinue immediately

Glomerulonephritis Very rare; reported with prolonged use

Worm migration/obstruction May occur with heavy Ascaris burden; worms may migrate to bile ducts, appendix, or cause intestinal obstruction

For Short Courses (≤3 days — routine deworming):

Baseline:

• No routine laboratory monitoring required

• Stool microscopy to confirm diagnosis (when practical)

After Treatment:

• Stool examination 2–4 weeks post-treatment to confirm parasitological cure (if initial diagnosis confirmed)

• Clinical assessment for symptom resolution

For Prolonged Therapy (Hydatid Disease — 28-day cycles):

Baseline:

• Complete blood count (CBC) with differential

• Liver function tests (AST, ALT, bilirubin, ALP)

• Serum creatinine

During Treatment:

• LFTs and CBC every 2 weeks during each treatment cycle

• Discontinue if AST/ALT >5× ULN or significant haematological abnormalities

Long-term:

• Monitor for clinical response (imaging for hydatid cysts)

• Continue monitoring through all treatment cycles

• Mebex® (Cipla)

• Wormin® (Cadila)

• Vermox® (Janssen — limited availability)

• Mebentel® (Elder)

• Bendex® (Alkem)

• Meben® (various)

• Deworm® (various)

• Wormex® (various)

Note: No significant FDCs routinely marketed. Some brands available in combination with levamisole (use judiciously).

• Included in NLEM 2022

• NPPA price-controlled

• Available through government supply for National Deworming Day and routine public health programmes

• Very affordable and widely available

• Poor systemic absorption is advantageous: Mebendazole acts primarily in the gut lumen, making it ideal for intestinal helminths but less effective for tissue-dwelling parasites — for hydatid disease or neurocysticercosis, albendazole is preferred due to better systemic absorption

• Three-day regimen for polyparasitism: In endemic areas where multiple STH infections are common, the 3-day regimen (100 mg BD × 3 days) is more effective than single-dose therapy

• Repeat dose for pinworms: Single dose only kills adult worms; eggs continue to hatch — ALWAYS repeat dose after 2–3 weeks; treat all household members simultaneously

• Heavy Ascaris burden warning: In children with heavy roundworm infections, mass die-off of worms can rarely cause intestinal obstruction or worm migration — consider starting with lower doses or piperazine pre-treatment in heavily infected patients

• Tablets may be chewed or crushed: Useful for children and those with swallowing difficulties; tablets can be crushed and mixed with food

• Mass deworming programmes: National Deworming Day uses single-dose mebendazole (500 mg) or albendazole (400 mg) for school-age children — both are equally effective for this purpose

mebendazole; anthelmintic; deworming; soil-transmitted helminths; ascariasis; hookworm; whipworm; enterobiasis; pinworm; NLEM; paediatric-use; pregnancy-contraindicated; benzimidazole

RxIndia v1.0 — 10 Jan 2025

• CDSCO approved prescribing information

• Indian Pharmacopoeia (IP)

• National Formulary of India (NFI)

• National List of Essential Medicines (NLEM 2022)

• IAP Guidelines on Deworming in Children

• WHO Guidelines on Preventive Chemotherapy for Soil-Transmitted Helminthiases

• National Deworming Day Guidelines (MoHFW)

• API Textbook of Medicine

• AIIMS Standard Treatment Guidelines — Helminth Infections

• Goodman & Gilman's The Pharmacological Basis of Therapeutics