NyQuil and Breastfeeding

Active Ingredients and Lactation Effects

• The Association of Anaesthetists suggests that anticholinergic medications, such as doxylamine or diphenhydramine found in many NyQuil formulations, may inhibit lactation through mechanisms similar to atropine 1
• Dextromethorphan and acetaminophen, the active ingredients in some NyQuil formulations, are generally considered compatible with breastfeeding when used appropriately, and are not documented to affect prolactin secretion or milk production 1

Clinical Algorithm for Decision-Making

• The American Academy of Pediatrics and other medical societies imply that avoiding regular or prolonged use of standard NyQuil, which contains antihistamines, is recommended if maintaining milk supply is a priority, particularly in the early postpartum period when lactation is being established 1
• Single-dose or short-term use of standard NyQuil is unlikely to cause significant supply issues in women with established lactation, according to the Association of Anaesthetists 1

Medications to Decrease Milk Supply

Medication Options

• Clonidine may reduce prolactin secretion and therefore could reduce milk production in the early postpartum period, with minimal secretion into milk and no reports of neonatal toxicity during breastfeeding, according to the Anaesthesia guideline society 2, 3
• Atropine, a tertiary amine, may inhibit lactation and is found in trace concentrations in breast milk, but may have antimuscarinic effects in the infant, as stated by the Anaesthesia guideline society 2, 4
• Patients taking cabergoline should be advised to follow "missed pill rules" if they are also taking oral hormonal contraceptives, as recommended by the Anaesthesia guideline society 5
• Metoclopramide and domperidone should be avoided as they are galactagogues that may increase milk supply rather than decrease it, according to the Anaesthesia guideline society 2, 4