Are antihistamines (anti histamine) safe during pregnancy?

From the Guidelines

Antihistamines are generally considered safe during pregnancy, with second-generation options being preferred due to their excellent safety records and minimal risk of congenital malformations. According to the study by 1, both first-generation and second-generation antihistamines have been found to be safe for use during pregnancy, with no significant increase in congenital malformations.

Key Points to Consider

• First-generation antihistamines like chlorpheniramine have been recommended as first-choice agents due to their observed safety and longevity of use, but their sedative qualities and possible effect on performance may make them less desirable choices.
• Second-generation antihistamines, such as loratadine and cetirizine, have been confirmed to be safe for use during the first trimester of pregnancy through large birth registries, case-control studies, and cohort studies 1.
• Some antihistamines, like diphenhydramine, should be used with caution due to potential concerns over cleft palate, while others like hydroxyzine should be used cautiously during the first trimester based on animal data.

Recommendations

• Second-generation antihistamines like loratadine and cetirizine are preferred first-line choices due to their excellent safety records and minimal risk of congenital malformations.
• First-generation antihistamines like chlorpheniramine can be used occasionally, but may cause drowsiness.
• It's best to avoid using antihistamines in the first trimester if possible, though the risk is considered minimal.
• Always consult with your healthcare provider before taking any medication during pregnancy, as individual circumstances may affect recommendations.

Non-Medication Approaches

• Avoiding allergens, using saline nasal sprays, and keeping windows closed during high pollen seasons can also help manage symptoms during pregnancy.

From the FDA Drug Label

If pregnant or breast-feeding: if breast-feeding: not recommended if pregnant: ask a health professional before use. If pregnant or breast-feeding, ask a health professional before use.

• Pregnancy safety of antihistamines is not explicitly stated in the drug labels.
• The labels for cetirizine 2 and loratadine 3 advise to ask a health professional before use in pregnancy.
• Therefore, the safety of antihistamines in pregnancy cannot be confirmed based on the provided drug labels.

From the Research

Antihistamines in Pregnancy

• There are no direct studies provided that assess the safety of antihistamines during pregnancy.
• However, the provided studies discuss the efficacy and properties of various antihistamines, including cetirizine 4, 5, 6, loratadine 4, 5, 7, and chlorpheniramine 4, 5, 7, 8.
• These studies suggest that antihistamines can be effective in treating allergic reactions and conditions, but they do not provide information on their safety during pregnancy.

Properties of Antihistamines

• Cetirizine is noted for its high potency and specificity as an antihistamine, with a unique property of inhibiting eosinophil migration 6.
• Loratadine and cetirizine are considered treatments of choice for chronic idiopathic urticaria 5.
• Chlorpheniramine is a first-generation antihistamine with a wide range of clinical applications, including potential use against COVID-19 8.

Clinical Applications

• Antihistamines are commonly used to treat allergic conditions, such as urticaria and allergic rhinitis 5, 7.
• Combination therapy with multiple antihistamines may be effective in treating a wide spectrum of symptoms, with potentially lower chances of tolerance and re-appearance of complaints 7.