From ¹⁄₂ to 1 year old, full dose. From 3 to 6 months, ¹⁄₂ dose. From 1¹⁄₂ to 3 months, ¹⁄₄ dose. From 20 to 45 days, ¹⁄₈ dose. From 10 to 20 days, ¹⁄₁₆ dose.