II. Indications

  1. Scabies (refractory to Permethrin 5%)
  2. Head Lice
  3. Strongyloidiasis
  4. Onchocerciasis

III. Contraindications

  1. Pregnancy first trimester
  2. Weight <15 kg

IV. Mechanism

  1. Developed initially as veterinary anti-parasitic agent
  2. Related to macrolide Antibiotics
  3. Decreases Nerve Impulse transmission
    1. Potentiates GABA-gated chloride channels
    2. Results in Helminth paralysis

V. Medications

  1. Ivermectin 3 mg tablet
  2. Dose 200 mcg/kg equivalents
    1. Weight 15 to 24 kg: 3 mg
    2. Weight 25 to 35 kg: 6 mg
    3. Weight 36 to 50 kg: 9 mg
    4. Weight 51 to 65 kg: 12 mg
    5. Weight 66 to 79 kg: 15 mg

VI. Dosing: FDA Approved for Adult and Child (weight >=15 kg)

  1. General
    1. Take on an empty Stomach with water
  2. Strongyloidiasis
    1. Ivermectin 200 mcg/kg orally for 1 dose
    2. Consider repeat up to monthly doses in Immunocompromised patients (e.g. HIV Infection)
  3. Onchocerciasis
    1. Ivermectin 150 mcg/kg orally for 1 dose, repeated every 3 to 12 months

VII. Dosing: Off-Label for Adult and Child (weight >=15 kg)

  1. Scabies or Head Lice (not FDA approved)
    1. Ivermectin 200 mcg/kg orally for 1 dose, and repeat dose in 10 days
  2. Crusted Scabies
    1. Ivermectin 200 mcg/kg orally on days 1, 2, 8, 9, 15 (and consider on days 22 and 29 in more severe cases)
    2. Use in combination with full body Permethrin 5% daily for 7 days, then twice daily until resolution
  3. Public Lice
    1. Ivermectin 250 mcg/kg orally, then repeated in 2 weeks
  4. Cutaneous Larva Migrans
    1. Ivermectin 200 mcg/kg orally daily for 1 to 2 days
  5. Roundworm Infections
    1. Ivermectin 150 to 200 mcg/kg orally for 1 dose

VIII. Pharmacokinetics

  1. Peak Level: 3-6 hours after intake
  2. Half-Life: >12 hours
  3. Metabolized by Cyp 3A4
  4. Crosses blood brain barrier via P-Glycoprotein (ABCB1 Transporter)

IX. Adverse Effects: Mazzotti Reaction (Immunologic Reaction in Onchocerciasis to Parasite Death)

  1. Nausea
  2. Fever
  3. Headache
  4. Arthralgias
  5. Urticaria
  6. Ophthalmic complications

X. Adverse Effects: Toxicity or Overdose

  1. Background
    1. Lower Doses <500 mg in adults and <5mg/kg in children are typically without reaction
    2. High doses, however, may result in life threatening adverse effects (Seizures, coma, death)
      1. In 2021, patients were taking very high doses (>600 mg daily) for COVID-19 (based on little evidence of benefit)
      2. Patients also ingested high risk formulations (topical Ivermectin, veterinary Ivermectin)
    3. Findings typically resolve within 6-8 hours of ingestion
  2. Gastrointestinal Findings
    1. Nausea or Vomiting
    2. Abdominal Pain
    3. Diarrhea
  3. Neurologic Findings
    1. Headache
    2. Dizziness
    3. Hallucinations
    4. Confusion
  4. Cardiopulmonary Findings
    1. Hypotension
    2. Tachycardia
  5. Skin Findings
    1. Urticaria
    2. Edema
  6. Management
    1. See Unknown Ingestion
    2. Activated Charcoal
      1. Indicated in early presentation of large ingestion
    3. Supportive Management
      1. ABC Management
      2. Benzodiazepines for Seizures
      3. Consider Intravenous Lipid Emulsion

XI. Safety

  1. Safe in children >15 kg (33 pounds)
  2. Considered safe in Lactation (after first week of life)
    1. Poorly excreted into Breastmilk
  3. Pregnancy Category X in first trimester
    1. Unknown or Pregnancy Category C in later pregnancy

XII. Efficacy: Scabies

XIII. Drug Interactions

  1. Warfarin
    1. Ivermectin may increase INR levels

XV. References

  1. Hamilton (2020) Tarascon Pocket Pharmacopoeia
  2. Tomaszewski (2021) Crit Dec Emerg Med 35(9): 32
  3. Meinking (1995) N Engl J Med 333:26 [PubMed]
  4. Fawcett (2003) Am Fam Physician 68(6):1089-92 [PubMed]

Images: Related links to external sites (from Bing)

Related Studies

Cost: Medications

ivermectin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
IVERMECTIN 1% CREAM Generic $5.01 per gram
IVERMECTIN 3 MG TABLET Generic $3.68 each

Ontology: Ivermectin (C0022322)

Definition (NCI) A macrocyclic lactone derived from Streptomyces avermitilis with antiparasitic activity. Ivermectin exerts its anthelmintic effect via activating glutamate-gated chloride channels expressed on nematode neurons and pharyngeal muscle cells. Distinct from the channel opening induced by endogenous glutamate transmitter, ivermectin-activated channels open very slowly but essentially irreversibly. As a result, neurons or muscle cells remain at either hyperpolarisation or depolarization state, thereby resulting in paralysis and death of the parasites. Ivermectin does not readily pass the mammal blood-brain barrier to the central nervous system where glutamate-gated chloride channels locate, hence the hosts are relatively resistant to the effects of this agent.
Definition (MSH) A mixture of mostly avermectin H2B1a (RN 71827-03-7) with some avermectin H2B1b (RN 70209-81-3), which are macrolides from STREPTOMYCES avermitilis. It binds glutamate-gated chloride channel to cause increased permeability and hyperpolarization of nerve and muscle cells. It also interacts with other CHLORIDE CHANNELS. It is a broad spectrum antiparasitic that is active against microfilariae of ONCHOCERCA VOLVULUS but not the adult form.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D007559
SnomedCT 387559003, 96138006
English Ivermectin, ivermectin, ivermectin (medication), IVERMECTIN, Ivermectin [Chemical/Ingredient], Avermectin A1a, 5-O-demethyl-25-de(1-methylpropyl)-22,23-dihydro-25-(1-methylethyl)-, Ivermectin (product), Ivermectin (substance)
Swedish Ivermektin
Czech ivermektin
Finnish Ivermektiini
Russian IVERMEKTIN, ИВЕРМЕКТИН
Japanese イベルメクチン
Polish Iwermektyna, Ivermectin
Spanish ivermectina (producto), ivermectina (sustancia), ivermectina, Ivermectina
French Ivermectine
German Ivermectin
Italian Ivermectina
Portuguese Ivermectina

Ontology: Stromectol (C0723477)

Definition (MSH) Oral preparation of ivermectin.
Concepts Organic Chemical (T109) , Pharmacologic Substance (T121)
MSH D007559
English Stromectol, Ivermectin Merck Brand, Merck Brand of Ivermectin

Ontology: Mectizan (C0751253)

Concepts Organic Chemical (T109) , Pharmacologic Substance (T121)
MSH D007559
English Mectizan