Oral Ivermectin for Scabies: CDC Recommendations

Dosing and Administration

• The CDC recommends oral ivermectin 200 µg/kg given on day 1 and repeated 14 days later; this two‑dose regimen is essential for cure. 1
• Ivermectin should be taken with food to improve absorption and epidermal penetration. 1
• Because ivermectin has limited ovicidal activity, the second dose 14 days after the first is required to eradicate newly hatched mites. 1

Patient Selection and Contraindications

• Ivermectin is not recommended for patients weighing less than 15 kg due to risk of neurotoxicity; this applies to children under this weight threshold. 3
• No dose adjustment is needed for patients with renal impairment. 1
• The safety of repeated ivermectin dosing in individuals with severe hepatic disease is currently unknown. 1

Special Populations – Crusted (Norwegian) Scabies

• For crusted scabies, the CDC advises oral ivermectin 200 µg/kg on days 1, 2, 8, 9, and 15; additional doses on days 22 and 29 may be added for severe disease. 1
• Treatment must be combined with a topical scabicide (5 % permethrin or 5 % benzyl benzoate) applied daily for 7 days, then twice weekly. 1

Prevention of Treatment Failure

• Administering ivermectin without food reduces bioavailability and increases the risk of therapeutic failure. 1
• All household and sexual contacts should receive simultaneous treatment to prevent reinfestation. 1
• Proper decontamination of bedding and clothing is required to avoid re‑exposure. 1

Post‑treatment Expectations and Retreatment Criteria

• Post‑treatment pruritus and rash may persist for up to 2 weeks due to allergic dermatitis and do not indicate treatment failure. 1
• Retreatment is not indicated unless live mites are observed; it should be considered only if symptoms continue beyond 2 weeks or live mites are documented. 1

First‑Line Therapy Context

• According to CDC guidelines, 5 % permethrin cream remains the first‑line treatment for uncomplicated scabies; oral ivermectin is an alternative when topical therapy is not tolerated or has failed. 5