Oral Medication for Scabies
Ivermectin is the oral medication prescribed for scabies, administered at 200 µg/kg as two doses separated by 14 days. 1
Dosing and Administration
- Standard regimen: Oral ivermectin 200 µg/kg given on day 1, repeated on day 14-15 1
- Must be taken with food to increase bioavailability and enhance penetration into the epidermis 1
- The two-dose regimen is critical—single-dose treatment fails in 42% of cases compared to only 2% failure with two doses 2
- Ivermectin has limited ovicidal activity, which is why the second dose 14 days later is essential to kill newly hatched mites 1
Patient Selection and Contraindications
Weight restrictions:
- Should not be used in children weighing less than 15 kg 1
- Some guidelines suggest avoiding use in patients under 15 kg due to potential neurotoxicity from blood-brain barrier penetration 1
Renal and hepatic considerations:
- No dose adjustment needed for renal impairment 1
- Safety of multiple doses in severe liver disease is unknown 1
Special Populations
Crusted (Norwegian) scabies requires intensive combination therapy:
- Oral ivermectin 200 µg/kg on days 1,2,8,9, and 15 1
- Additional doses on days 22 and 29 may be required for severe cases 1
- Must be combined with topical scabicide (5% permethrin or 5% benzyl benzoate) applied daily for 7 days, then twice weekly 1
Alternative Oral Options
While ivermectin is the established oral treatment, albendazole 800 mg/day for three consecutive days per week has been reported as an alternative when ivermectin is unavailable, though this is based on limited case report evidence 3
Important Clinical Pearls
Common pitfalls leading to treatment failure:
- Using only a single dose instead of two doses 14 days apart 2
- Not taking medication with food, reducing bioavailability 1
- Failing to simultaneously treat household and sexual contacts 1
- Inadequate decontamination of bedding and clothing 1
Post-treatment expectations:
- Pruritus and rash may persist for up to 2 weeks after successful treatment due to allergic dermatitis 1
- This is NOT an indication for retreatment unless live mites are observed 1
- Retreatment should only be considered if symptoms persist beyond 2 weeks or live mites are documented 1
Topical Permethrin Remains First-Line
While the question asks about oral medication, it's critical to note that topical permethrin 5% cream remains the recommended first-line treatment for uncomplicated scabies according to CDC guidelines 1. Ivermectin serves as an alternative regimen when topical therapy cannot be tolerated or has failed 1.