Indications
- Scabies (Sarcoptes scabiei).
- Cutaneous larva migrans (Ancylostoma braziliense).
- Demodex.
- Gnathostomiasis.
- Head lice.
- Onchocerciasis (microfilariae of Onchocerca volvulus, not adult forms).
- Intestinal strongyloidiasis.
- Ascariasis
Dosage
- CUTANEOUS LARVA MIGRANS: single dose of 12 mg in adults or 150–200 mcg/kg in children.
- DEMODEX: 200 µg/kg PO once with water and weekly with permethrin
- HEAD LICE: a single 200 mcg/kg PO once on day 1 and day 8 with water.
- ONCHOCERCIASIS: 150 µg/kg PO once every 3 to 12 months with water, may need to repeat treatment.
- SCABIES: 200 µg/kg PO once with water, repeated in a week to 10 days.
- GNATHOSTOMIASIS :200 mcg/kg/day for 1–2 days.
Weight-based guidelines for ivermectin dose(200 µg/kg)
| Patient weight (kg) | Dose (mg) = number of 3 mg tablets |
| 15–24 | 3 mg = 1 tab |
| 25–35 | 6 mg = 2 tab |
| 36–50 | 9 mg = 3 tab |
| 51–65 | 12 mg= 4 tab |
| 66-79 | 15 mg= 5 tab |
| ≥80 | calculate as 200 µg/kg |
Mechanism of action
- Ivermectin binds selectively and with high affinity to glutamate-gated chloride ion channels in invertebrate nerve and muscle cells.
- Binding results in increased permeability of cell membranes to chloride ions, with hyperpolarization of the nerve or muscle cells
- which results in paralysis and death
Side effects
- GI: nausea, vomiting, diarrhea.
- Elevated transaminases > cholestasis.
- Neurologic: dizziness > drowsiness, headache, tremor.
- Stevens–Johnson syndrome.
- Mazzotti-like reaction and ocular side effects.
- Leukopenia.
- Tachycardia, facial edema, orthostatic hypotension.
Contraindications
- Hypersensitivity to drug/class.
- Hyper-reactive onchodermatitis (sowda).
- Pregnancy.
Interactions
- Ivermectin may enhance the anticoagulant effect of warfarin.
Pregnancy &Lactation
- Pregnancy category: C , generally not recommended for scabies in pregnant women.
- Lactation: Enters breast milk (AAP Committee states compatible with nursing).
Precautions
- Dose adjustment is needed with biliary obstruction, but renal failure is not likely to affect metabolism.
- Potential CNS toxicity in infants and young children.
- It is not recommended for use in children under 5 years of age or weighing less than 15 kg.
- Severely ill or debilitated individuals and those with neurological disease (due to potential neurotoxicity at high doses).
Drug Info
- Ivermectin alone often fails in crusted scabies.
- Bioavailability is increased when the drug is administered with a high-fat meal.
- Safety not established for children weighing (15 kg) or breastfeeding mothers.
- Oral ivermectin is not licensed for use in scabies in most countries.