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Prescribing antihistamines in pregnancy and lactation

What antihistamines are safe during pregnancy ?

General tips for prescribing antihistamines in pregnancy

The rule is to avoid using any drugs including antihistamines during the first trimester.
If indicated, first generation antihistamines should be prescribed e.g chlorpheniramine, dexchlorpheniramine and hydroxyzine.
Advise your patient to drink plenty of water while taking antihistamines during pregnancy to reduce the anticholinergic side effects.
Advise your patient to consult obstetrician-gynecologist if they notice any change in the frequency of baby’s movement or increased contractions after taking the drugs.
Second generation agents are better to be prescribed after the first trimester.

Pregnant women if indicated can use the following drugs especially in the second and third trimesters

Loratadine :10 mg once daily.
Cetirizine :10 mg once daily.

Chlorpheniramine: 4 mg orally every four to six hours, may also be safely used in pregnancy. it should be avoided close to delivery and during breastfeeding due to potential sedative effects.

Safe antihistamines in lactation

Lactating women if indicated may be treated with either:

Loratadine :10 mg once daily.
Cetirizine :10 mg once daily.

It is advised to avoid larger dose of Cetirizine or prolonged use because it may cause drowsiness in the infant or decrease the milk supply, particularly in combination with a sympathomimetic such as pseudoephedrine.

It is better to avoid using Loratadine in combination with sympathomimetic such as pseudoephedrine. According to he British Society for Allergy and Clinical Immunology, Loratadine in its lowest dose is the preferred choice in lactating women.

Chlorpheniramine : It is not the first choice in breast feeding because of its sedative effects, but if needed, it can be used single dose before sleep after the last breast feeding. Larger or prolonged doses have to be avoided.