What are the safe antihistamines (anti-histamine) for use during pregnancy?

Safe Antihistamines During Pregnancy

Second-generation antihistamines like cetirizine and loratadine are considered the safest antihistamine options during pregnancy, with chlorpheniramine being the preferred first-generation option when necessary. 1

First-Line Antihistamine Options During Pregnancy

Second-Generation Antihistamines

• Cetirizine - FDA Pregnancy Category B; confirmed safety through large birth registries and cohort studies 1
• Loratadine - FDA Pregnancy Category B; has substantial safety data during pregnancy 1

First-Generation Antihistamines

• Chlorpheniramine - Long established safety record; often recommended as first-choice when a first-generation agent is needed 1

Antihistamines to Use with Caution

• Diphenhydramine - Though commonly used during pregnancy with good overall safety data, there have been some concerns about a possible association with cleft palate 2
• Fexofenadine - Animal studies show no teratogenicity, but human pregnancy epidemiological data is limited 2, 1
• Desloratadine, azelastine, levocetirizine - Limited data available on use during pregnancy 2, 1

Antihistamines to Avoid

• Hydroxyzine - Should be used cautiously, particularly during the first trimester, based on concerning animal data 1

Important Considerations

Timing of Medication Use

• The first trimester is the most critical period for potential congenital malformations due to medication use, as this is when organogenesis occurs 2, 1
• Exercise particular caution with any medication during this period

Alternative Approaches

• Intranasal cromolyn sodium - Excellent safety profile; can be considered as first-line therapy for rhinitis symptoms during pregnancy 3
• Intranasal corticosteroids (e.g., budesonide) - May be safer than oral medications due to minimal systemic absorption 4

Medications to Avoid in Combination

• Oral decongestants should be avoided during the first trimester due to conflicting reports of association with congenital malformations such as gastroschisis and small intestinal atresia 2
• Risk increases when decongestants are combined with acetaminophen or salicylates 2

Treatment Algorithm for Allergic Symptoms During Pregnancy

1. First-line options:

   • Intranasal cromolyn sodium
   • Second-generation antihistamines (cetirizine or loratadine)
   • Chlorpheniramine if a first-generation antihistamine is specifically needed

2. Second-line options (if first-line ineffective):

   • Intranasal corticosteroids (budesonide preferred)
   • Other second-generation antihistamines with more limited pregnancy data

3. Short-term use only (when absolutely necessary):

   • Diphenhydramine (with awareness of potential risks)
   • Topical decongestants (brief courses only)

Common Pitfalls to Avoid

• Assuming all antihistamines carry equal risk during pregnancy
• Using combination products containing decongestants, especially during first trimester
• Discontinuing necessary treatment due to unfounded fears, which may lead to poorly controlled symptoms affecting maternal and fetal wellbeing 5
• Starting immunotherapy during pregnancy (though it may be continued if already established and effective) 2

Remember that the benefits of treating significant allergic symptoms during pregnancy often outweigh the potential risks of medication, as uncontrolled symptoms can negatively impact both maternal and fetal outcomes 6.