Are metoclopramide (Maxalon) and ondansetron safe during breastfeeding?

Safety of Metoclopramide (Maxalon) and Ondansetron in Breastfeeding

Both metoclopramide (Maxalon) and ondansetron are safe to use during breastfeeding, with metoclopramide being explicitly compatible and even used therapeutically to increase milk supply, while ondansetron lacks human milk transfer data but is considered acceptable based on its pharmacological properties.

Metoclopramide (Maxalon) Safety Profile

Metoclopramide is fully compatible with breastfeeding and is actually used as a galactagogue to enhance milk production. 1

Key Safety Points:

• Explicitly approved for use in lactating women by the Association of Anaesthetists and American Academy of Pediatrics 1, 2
• May increase milk supply by raising maternal serum prolactin levels through central dopamine antagonism 2, 3
• Low oral bioavailability (30%) means minimal infant exposure even though it passes into breast milk 2
• No need to interrupt breastfeeding or pump and discard milk when taking metoclopramide at recommended doses 2

Important Practical Consideration:

• Ensure access to a breast pump if there is any delay in infant feeding, as metoclopramide can increase milk supply rapidly before the infant can effectively remove it, potentially leading to engorgement 1, 3

FDA Labeling Information:

The FDA label states that "metoclopramide is passed into human milk and may harm your baby" and advises discussing feeding options with your doctor 4. However, this conservative warning contrasts with clinical guideline consensus that supports its safety and compatibility with breastfeeding 1, 2.

Ondansetron Safety Profile

Ondansetron is considered acceptable for use during breastfeeding despite the absence of human milk transfer studies. 1

Key Safety Points:

• No human studies exist on transfer into breast milk, though animal data are available 1
• Likely low milk levels based on its pharmacological properties 1
• Used in clinical practice for nausea and vomiting in breastfeeding women, particularly those with hyperemesis gravidarum 5

FDA Labeling Information:

The FDA label acknowledges that "it is not known whether ondansetron is present in human milk" and states that "when a drug is present in animal milk, it is likely that the drug will be present in human milk" 6. The label recommends considering "the developmental and health benefits of breastfeeding along with the mother's clinical need for ondansetron" 6.

Clinical Algorithm for Use

For Metoclopramide:

1. Can be used without restriction in breastfeeding women for nausea, vomiting, or gastroparesis 1, 2
2. Standard dosing: 10 mg three times daily (maximum 30 mg/day) 2
3. Monitor for increased milk production and ensure breast pump availability 1, 3
4. Be aware of maternal side effects: restlessness, drowsiness, and rare but serious movement disorders (though these are maternal concerns, not infant safety issues) 4

For Ondansetron:

1. Can be used when clinically indicated for nausea and vomiting in breastfeeding women 1, 5
2. Preferred in situations where metoclopramide's galactagogue effect is undesirable or when metoclopramide is contraindicated 5
3. No special precautions needed regarding timing of breastfeeding relative to dosing 1

Common Pitfalls to Avoid

• Do not unnecessarily discontinue breastfeeding based on overly conservative product labeling for either medication 5, 7
• Do not confuse metoclopramide's galactagogue effect with a safety concern—this is actually a therapeutic benefit in many situations 2, 3
• Do not assume ondansetron is unsafe simply because human milk transfer data are lacking; its pharmacological properties suggest low risk 1
• Be cautious with co-sleeping or feeding while drowsy if the mother experiences sedation from metoclopramide 1

Comparative Context

When comparing these antiemetics to alternatives, prochlorperazine has low oral bioavailability and is also compatible with breastfeeding 1, while cyclizine has no reported data but is unlikely to cause adverse effects with short-term use 1. Metoclopramide remains the most studied and explicitly endorsed antiemetic for breastfeeding women 2, 8.