Prescribing Guides
Ivermectin Prescribing Guide for Indian Clinical Practice
Ivermectin prescribing guide for Indian clinicians covering antiparasitic pharmacology, scabies and filariasis dosing, MDA programmes and NEET PG points.
MedNext Editorial Team | 2026-08-01 | 8 min read
Ivermectin Prescribing Guide for Indian Clinical Practice
Ivermectin prescribing guide for Indian clinicians covering antiparasitic pharmacology, scabies and filariasis dosing, MDA programmes and NEET PG points.
Ivermectin is a broad-spectrum antiparasitic agent essential in Indian dermatology (scabies), tropical medicine (filariasis, strongyloidiasis), and public health (mass drug administration programmes). Understanding its approved indications and the evidence against off-label uses is important.
Clinical Pharmacology Overview
Ivermectin is a macrocyclic lactone derived from Streptomyces avermitilis. It binds selectively to glutamate-gated chloride channels (GluCl) found in invertebrate nerve and muscle cells, causing chloride influx, membrane hyperpolarisation, paralysis, and death of the parasite. Mammals lack accessible glutamate-gated chloride channels, providing the drug's safety margin. Ivermectin also interacts with GABA-gated chloride channels.
Pharmacokinetics: Well absorbed orally. Peak plasma concentration at 4 hours. Highly protein-bound (93%). Extensively metabolised in the liver by CYP3A4. Half-life is approximately 18 hours (parent compound) and 3 days (metabolites). Excreted almost entirely in faeces. Does not cross the intact blood-brain barrier in significant amounts (P-glycoprotein efflux limits CNS entry).
Indian Brand Names
- Ivecop (Menarini/Stemline)
- Ivermectol (Zydus Cadila)
- Ascapil (Shalaks Pharma)
- Bandy-I (Mankind Pharma)
- Ivrea (Dr. Reddy's)
Approved Indications in Indian Clinical Practice
- Scabies (oral alternative to topical permethrin)
- Strongyloidiasis
- Onchocerciasis (river blindness) -- relevant to MDA programmes
- Lymphatic filariasis (in MDA, combined with albendazole)
- Head lice (oral, when topical treatment fails)
- Cutaneous larva migrans
- Intestinal nematodes (second-line)
Dosing in Adults
Scabies: 200 mcg/kg orally as a single dose. Repeat after 1-2 weeks. Take on empty stomach with water.
Crusted scabies: 200 mcg/kg on days 1, 2, 8, 9, 15 (with concurrent topical permethrin 5%).
Strongyloidiasis: 200 mcg/kg once daily for 1-2 days.
Onchocerciasis: 150 mcg/kg orally as a single dose every 6-12 months.
Filariasis MDA: 200 mcg/kg single dose + albendazole 400 mg (in areas co-endemic with Loa loa or where DEC is contraindicated).
Head lice: 200 mcg/kg as a single dose, repeat after 7 days.
Note: Ivermectin should be taken on an empty stomach with water (unlike albendazole, which needs fatty food). However, some recent guidelines suggest taking with food for scabies to improve absorption.
Important Drug Interactions
- CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir): may increase ivermectin levels
- CYP3A4 inducers (rifampicin, carbamazepine): may reduce ivermectin efficacy
- Warfarin: may enhance anticoagulant effect (monitor INR)
- Alcohol: may increase CNS depression
- Benzodiazepines, barbiturates: theoretical additive CNS effects
- P-glycoprotein inhibitors: may increase CNS penetration (relevant in mdr1a-deficient individuals)
Side Effects and Monitoring
Common: dizziness, nausea, diarrhoea, pruritus (may worsen initially in scabies -- Mazzotti-like reaction).
Mazzotti reaction (in onchocerciasis): fever, rash, hypotension, arthralgia, lymphadenopathy due to dying microfilariae. More severe with higher microfilarial loads.
Serious: encephalopathy in Loa loa co-infection with high microfilarial burden (due to CNS microfilarial die-off). Hepatotoxicity (rare).
Monitoring: clinical response. In onchocerciasis MDA, assess for Loa loa co-infection before treatment. No routine blood monitoring needed for single-dose treatment.
Special Populations
Pregnancy: Category C. Generally avoided in pregnancy due to insufficient human data. WHO MDA programmes exclude pregnant women.
Lactation: Excreted in breast milk at low levels. WHO considers it compatible with breastfeeding after the neonatal period.
Children: Not recommended in children under 15 kg body weight (limited safety data).
Renal impairment: No dose adjustment (hepatic metabolism, faecal excretion).
Hepatic impairment: Use with caution in significant liver disease.
NEET PG High-Yield Points
- Mechanism: opens glutamate-gated chloride channels (GluCl) -- hyperpolarisation and paralysis
- Derived from Streptomyces avermitilis (macrocyclic lactone)
- Drug of choice for onchocerciasis (river blindness)
- Drug of choice for Strongyloides stercoralis
- Loa loa encephalopathy -- fatal adverse effect in high-microfilarial-load patients
- Does NOT cross intact BBB (P-glycoprotein efflux) -- safety depends on this
- Mazzotti reaction in onchocerciasis treatment
- Oral treatment of scabies -- increasingly used in India for outbreaks
- No benefit in COVID-19 (TOGETHER trial, ACTIV-6 trial)
- Acts on invertebrate-specific ion channels -- no mammalian equivalent
Indian Regulatory Status
Ivermectin is a Schedule H drug under the Drugs and Cosmetics Act. It is included in the NLEM of India. Available as 3 mg and 6 mg tablets, and as topical formulations. The Government of India uses ivermectin in mass drug administration programmes for lymphatic filariasis elimination. The CDSCO approved it for its parasitic indications. Following the COVID-19 controversy, the ICMR explicitly removed ivermectin from COVID-19 treatment protocols.
Frequently Asked Questions
What is the dose of ivermectin for scabies?
200 mcg/kg orally as a single dose, repeated after 1-2 weeks. For crusted (Norwegian) scabies, multiple doses are needed (days 1, 2, 8, 9, 15 along with topical permethrin). Oral ivermectin is increasingly preferred in India for scabies outbreaks in institutions and when topical treatment is impractical.
Is ivermectin effective against COVID-19?
Large, well-designed clinical trials (TOGETHER trial, ACTIV-6) showed no clinically meaningful benefit of ivermectin for COVID-19 treatment or prevention. The WHO, ICMR, and major medical societies do not recommend ivermectin for COVID-19. Earlier positive results came from small, low-quality studies, some of which were retracted.
Why is ivermectin dangerous in Loa loa co-infection?
In patients co-infected with Loa loa (African eye worm) and high microfilarial loads, ivermectin can cause fatal encephalopathy due to massive microfilarial die-off in the CNS. This is primarily relevant in Central and West African MDA programmes, not in India, but is a high-yield pharmacology concept.
What is ivermectin's mechanism of action?
Ivermectin binds to glutamate-gated chloride channels in invertebrate nerve and muscle cells, causing hyperpolarisation, paralysis, and death. These channels do not exist in mammals in accessible locations, providing the drug's selectivity. It also affects GABA-gated channels in some parasites.
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