Ivermectin Dosing for Scabies Treatment
The recommended dose of ivermectin for treating scabies is 200 μg/kg orally, repeated in 2 weeks. 1, 2, 3
Standard Treatment Recommendations
- Ivermectin 200 μg/kg orally is recommended as the standard oral medication for uncomplicated scabies, with a second dose administered 2 weeks after the first dose 1, 2
- Ivermectin should be taken with food to increase bioavailability and enhance penetration into the epidermis 1, 2
- No dosage adjustments are required for patients with renal impairment 1, 2
- The second dose is necessary because ivermectin has limited ovicidal activity and may not effectively kill all eggs present at the time of initial treatment 1
Special Populations and Considerations
- For crusted (Norwegian) scabies, a more intensive regimen is recommended: combination therapy with topical 5% permethrin cream applied daily for 7 days, then twice weekly until cure, plus oral ivermectin 200 μg/kg on days 1,2,8,9, and 15 2
- Permethrin 5% cream is preferred over ivermectin for infants, young children, and pregnant or lactating women 1, 2
- Ivermectin should not be used in children weighing less than 15 kg due to potential safety concerns, although recent research suggests it may be safe in this population 1, 4
- The safety of multiple doses of ivermectin in patients with severe liver disease is not well established 1, 5
Treatment Efficacy and Follow-up
- Studies have shown high cure rates (85-100%) with the recommended ivermectin dosing regimen 6, 7, 4
- Higher efficacy is associated with doses exceeding 200 μg/kg and when the interval between doses is less than 10 days 4
- Rash and pruritus may persist for up to 2 weeks after successful treatment, which is not an indication for retreatment 2
- Consider retreatment if symptoms persist beyond 2 weeks or if live mites are observed 2
Common Pitfalls to Avoid
- Failure to administer the second dose of ivermectin after 2 weeks can lead to treatment failure 2, 8
- Not treating all close contacts simultaneously can result in reinfection 2
- Expecting immediate resolution of symptoms after treatment is unrealistic, as pruritus may persist for up to 2 weeks 2
- Environmental measures are important: bedding and clothing should be decontaminated by machine washing/drying using hot cycles, dry cleaning, or removing from body contact for at least 72 hours 1, 2
Alternative Treatments
- Permethrin 5% cream is considered first-line topical treatment for scabies and is often preferred over ivermectin due to its effectiveness, safety profile, and lower cost 1, 2
- Lindane (1%) is an alternative but should be used with caution due to potential toxicity and should be avoided in children under 10 years, pregnant or lactating women, and persons with extensive dermatitis 1, 2