What is the recommended dose of ivermectin (antiparasitic medication) for a breastfeeding mother of a 4-month-old child?

Ivermectin Dosing in Breastfeeding Mothers

The recommended dose of ivermectin for a breastfeeding mother is 200 mcg/kg orally as a single dose, repeated in 2 weeks, and breastfeeding should continue without interruption. 1

Standard Dosing Regimen

The Centers for Disease Control and Prevention recommends 200 mcg/kg orally, repeated in 2 weeks for most parasitic infections including scabies, which is the most common indication. 2, 1 For a typical adult weighing 56 kg, this translates to approximately 12 mg (four 3-mg tablets) as a single dose, then repeated after 14 days. 1

Critical Administration Instructions

• Take ivermectin with food to increase bioavailability by 2.5 times and enhance drug penetration into the epidermis. 2, 1
• The second dose at 2 weeks is mandatory because ivermectin has limited ovicidal activity and cannot prevent recurrence from eggs present at the time of initial treatment. 2, 1

Safety During Breastfeeding

Ivermectin is compatible with breastfeeding and lactation should not be interrupted. 2 Multiple lines of evidence support this recommendation:

• The CDC classifies ivermectin as "human data suggest low risk" in pregnancy and probably compatible with breastfeeding. 2, 1
• Very low levels are excreted into breastmilk, making it likely compatible with breastfeeding. 2
• Actual measured concentrations in breastmilk after a 200 mcg/kg dose ranged from 1.4 to 20.8 ng/ml (mean 9.26 ng/ml), resulting in infant exposure of only 1.1 mcg/kg—which is 0.55% of the weight-adjusted maternal dose. 3
• This exposure level is far below the World Health Organization threshold for safe breastfeeding. 3
• Earlier studies measuring ivermectin in breastmilk after 150 mcg/kg doses found steady-state levels were low, with mean milk concentrations of 14.13 ng/ml. 4

Special Considerations for the 4-Month-Old Infant

While the mother can safely breastfeed, the 4-month-old infant should NOT receive direct ivermectin treatment if needed for their own parasitic infection. 2, 1

• Infants and young children should be treated with permethrin topical therapy instead of ivermectin. 2, 1
• Safety in children weighing <15 kg has not been fully established for direct treatment. 1
• However, exposure through breastmilk at the levels described above is considered safe. 3, 4

Dosing Adjustments

• No dose adjustment is required for renal impairment. 2, 1
• Use with extreme caution in severe liver disease, as the safety of multiple doses has not been established in this population. 2, 1

Critical Pitfalls to Avoid

• Do not skip the second dose at 2 weeks—this is mandatory for treatment success due to limited ovicidal activity. 2, 1
• Do not take on an empty stomach—food significantly increases bioavailability and therapeutic efficacy. 2, 1
• Do not interrupt breastfeeding—the minimal drug transfer to breastmilk poses no risk to the infant. 2, 3
• Treat all household and sexual contacts simultaneously within the previous month to prevent reinfection. 2, 1
• Understand that symptoms may persist for up to 2 weeks after successful treatment due to allergic dermatitis, not treatment failure. 1