Are montelukast (Singulair) and levocetirizine (Xyzal) safe to use during pregnancy?

Safety of Montelukast and Levocetirizine During Pregnancy

Montelukast can be used during pregnancy if clearly needed for asthma control, while levocetirizine should be avoided in favor of antihistamines with better established safety profiles like cetirizine or loratadine. 1, 2

Montelukast Safety Profile

• Montelukast is classified as FDA Pregnancy Category B, indicating animal studies have not demonstrated risk to the fetus, but adequate controlled studies in pregnant women are limited 1, 3
• No teratogenicity was observed in animal studies at doses much higher than therapeutic human doses 1
• Limited data suggest no significantly increased risk of malformations, but the number of exposed women is insufficient to ensure complete safety for the fetus 4
• Cases of limb reduction defects have been rarely reported during worldwide marketing experience, but most women were also taking other asthma medications and a causal relationship has not been established 1
• Montelukast crosses the placenta following oral dosing in animal studies 1

Levocetirizine Safety Profile

• Limited specific safety data exists for levocetirizine use during pregnancy, particularly in the first trimester 2
• The American Academy of Allergy, Asthma, and Immunology recommends avoiding levocetirizine during the first trimester if possible 2
• Cetirizine and loratadine (FDA Pregnancy Category B) have more accumulated safety data than levocetirizine and should be preferred 2

Clinical Recommendations

For Asthma Management During Pregnancy:

• Montelukast can be continued or initiated for recalcitrant asthma during pregnancy, particularly in patients who have shown favorable response prior to pregnancy 3
• Use montelukast at the lowest effective dose during pregnancy 3
• Inhaled medications have been used for many years without documented adverse effects on the fetus, making them preferred first-line options for asthma control 3, 5
• Poorly controlled asthma poses greater risks to maternal and fetal health than medication use 3

For Allergic Rhinitis During Pregnancy:

• For antihistamine treatment during pregnancy, chlorphenamine, cetirizine, or loratadine are preferred due to their established safety records 2, 6
• Intranasal corticosteroids (particularly budesonide, which is Pregnancy Category B) or sodium cromolyn may be preferred options for allergic rhinitis during pregnancy 2, 3
• Saline nasal rinses are safe first-line options for rhinitis management during pregnancy 5
• Oral decongestants should not be used during pregnancy 5

Breastfeeding Considerations

• About 1% of montelukast passes into breast milk, but extensive metabolism and plasma protein binding are thought to limit infant exposure 3
• Studies in rats have shown that montelukast is excreted in milk, but it is not known if this occurs in humans 1
• For nursing mothers using montelukast, the benefits of breastfeeding generally outweigh the risk of exposure; consider breastfeeding prior to medication intake to further limit exposure 3
• Excretion of montelukast into breast milk is very low 4

Important Considerations and Pitfalls

• When considering medication use during pregnancy, balance maternal risk of therapy versus no therapy and the fetal risk of uncontrolled maternal disease with the risk of therapy on the newborn 5
• Assuming all antihistamines have equivalent safety profiles during pregnancy is a common pitfall 2
• While montelukast alone may be considered for use in pregnancy, the combination with levocetirizine lacks sufficient safety data for first trimester use 2
• Regular monitoring of asthma control is essential during pregnancy 3
• A 2009 study of 180 montelukast-exposed pregnancies found no increase in the baseline rate of major malformations, though birth weight was somewhat lower compared to controls 7

Alternative Approaches

• For allergic rhinitis, consider non-pharmacological approaches first before medication use 2
• If antihistamine treatment is necessary, use those with established safety profiles (chlorphenamine, cetirizine, or loratadine) 2, 6
• Sodium cromolyn nasal spray may be used as a second-line option for allergic rhinitis 2
• For asthma control, inhaled corticosteroids are generally preferred over oral medications during pregnancy 3, 5