Is it safe for a lactating woman with allergic rhinitis or asthma to take montelukast (Singulair) and levocetirizine (Xyzal) during breastfeeding?

Montelukast and Levocetirizine During Breastfeeding

Both montelukast and levocetirizine can be used during breastfeeding, with montelukast having particularly reassuring safety data showing minimal infant exposure (less than 1% of maternal dose passes into breast milk), while levocetirizine has more limited lactation data but is generally considered compatible with nursing. 1, 2, 3

Montelukast Safety During Lactation

Montelukast is the preferred agent and can be confidently recommended for breastfeeding mothers:

• Only approximately 1% of the maternal dose passes into breast milk, with extensive hepatic metabolism and plasma protein binding further limiting infant exposure 1, 4
• Direct measurement studies show average milk concentrations of only 5.3 ng/mL, with a relative infant dose of 0.68% of the maternal weight-adjusted dose—far below the 10% threshold considered safe 3
• Peak milk concentrations occur at 4 hours post-dose (9.7 ng/mL), well below therapeutic ranges for infants 3
• The benefits of breastfeeding generally outweigh the minimal risk of montelukast exposure 1, 4
• The FDA label states that montelukast is excreted in rat milk and advises caution in nursing mothers, but clinical data supports its safety 2

Practical Recommendations for Montelukast

• Consider timing breastfeeding immediately before taking the medication to further minimize infant exposure, though this is not strictly necessary given the low transfer 4
• Continue montelukast if it was effective for asthma control before or during pregnancy 1, 4

Levocetirizine Safety During Lactation

Levocetirizine can be used during breastfeeding, though data are more limited:

• Limited published data exist specifically on levocetirizine excretion in breast milk 1
• The American Academy of Allergy, Asthma, and Immunology recommends avoiding levocetirizine during the first trimester of pregnancy if possible, but this pregnancy caution does not necessarily extend to lactation 1, 4
• Other second-generation antihistamines (cetirizine, loratadine) have more accumulated safety data and may be preferred alternatives if switching is feasible 1, 4

Alternative Antihistamine Considerations

If concerns arise about levocetirizine:

• Cetirizine (the racemic mixture from which levocetirizine is derived) has more extensive lactation safety data 1, 4
• Loratadine and chlorpheniramine also have well-established safety profiles during breastfeeding 1, 4

Clinical Context for Combined Therapy

The combination of montelukast and levocetirizine is effective for treating allergic rhinitis with or without asthma:

• Combination therapy is more effective than monotherapy for controlling persistent allergic rhinitis symptoms 5, 6
• Both medications improve nasal symptoms, with the combination providing additive benefits 7, 6
• For patients with both allergic rhinitis and asthma, montelukast addresses both conditions simultaneously 8, 1

Important Caveats

• Poorly controlled asthma or severe allergic rhinitis poses greater risks to maternal health and infant care than the minimal medication exposure through breast milk 4, 9
• Do not discontinue effective asthma therapy during lactation without medical consultation 4, 9
• First-generation antihistamines should be avoided due to sedative effects that may impair maternal care and potential infant sedation 1
• The bilayer formulation technology used in fixed-dose combinations ensures drug stability but does not affect lactation safety 10