Small occasional doses of carbinoxamine are probably acceptable during breastfeeding. Larger doses or more prolonged use may cause drowsiness and other effects in the infant or decrease the milk supply, particularly in combination with a sympathomimetic such as pseudoephedrine or before lactation is well established. The manufacturer recommends avoiding breastfeeding during carbinoxamine use because severe toxicity has occurred in children under 2 years. The nonsedating antihistamines are preferred alternatives.