Can loratadine be used during pregnancy?/nBackground: A woman is pregnant in week 11. She has used

Fråga: Can loratadine be used during pregnancy? Background: A woman is pregnant in week 11. She has used second-generation antihistamines against allergy throughout the pregnancy so far, initially cetirizine but from week 6 she switched to loratadine. The reason for this change is unclear. The patient would prefer to continue with loratadine, as her allergy problems are profound.

Sammanfattning: Even though data in the Swedish Medical Birth Registry indicates that the risk of hypospadia might be increased by loratadine exposure in early pregnancy, a causal relationship has not been established. In the present case, continued use of loratadine seems justified since there appears to be a strong medical need of treatment, and that a reduction of current exposure will not have a significant impact on risk, as the first trimester of pregnancy approaches the end.

Svar: The issue of antihistamine use during pregnancy has been discussed previously by DRIC, and several documents can be retrieved from the database Drugline (1). The conclusion in recent Drugline documents was that loratadine is considered safe to use during pregnancy, since no general increase in the frequency of malformations was noticed in the Swedish Medical Birth Registry (2) where almost 1500 loratadine exposed women were entered. Systematic clinical studies on the subject are lacking, however.

Today, more than 3000 exposed women are registered in the Swedish Medical Birth Registry (2). The overall frequency of malformations in the children of loratadine-exposed women is still not increased. Importantly however, there appears to be an over-representation of hypospadia, with 13 cases in the registry compared to 6 expected. The Swedish Medical Products Agency has announced that the 15 cases found in their files, represent a signal of possible loratadine-induced hypospadia (3). However, a causal relationship has not been established. The issue is subject to further investigation within the European Union and clinical studies are required. It should be noted that similar figures have not been reported from other countries. The official comment by the Medical Products Agency is that loratadine (and desloratadine) should be avoided in pregnancy unless a physician has been consulted to confirm that there is a strong medical need of the drug (3). Loratadine is available over-the-counter in Sweden.

According to the Swedish leading expert in the field, the apparent risk of hypospadia associated with loratadine is only 2-3 times increased, corresponding to an individual risk of less than one percent (4). Furthermore, it is important to stress that there is no causal relationship established between loratadine and hypospadia, no reason to recommend any other modern antihistamine in the place of loratadine, and finally that exposure to loratadine is not a medical reason for termination of pregnancy (4).

For cetirizine, the number of exposed women in the Medical Birth Registry is somewhat lower than for loratadine and therefore less conclusive. There is neither any increase of the general malformation frequency in these women, nor any over-representation of cases of hypospadia (3 out of 1750 exposed) (2).

Concerning the patient in question, there appears to be a strong clinical indication for continued treatment. Furthermore, the pregnant woman is approaching the end of the first trimester where after malformations should not be possible to induce chemically. In conclusion, continued use of loratadine seems justified.