Summary of Use during Lactation

Because of its lack of sedation and low milk levels, maternal use of loratadine would not be expected to cause any adverse effects in breastfed infants. Loratadine might have a negative effect on lactation, especially in combination with a sympathomimetic agent such as pseudoephedrine. The British Society for Allergy and Clinical Immunology recommends loratadine at its lowest dose as a preferred choice if an antihistamine is required during breastfeeding.[1]

Drug Levels

After a single oral dose of 40 mg of loratadine in 6 women, average peak milk levels of 29.2 (range 20.4 to 39) mcg/L occurred at two hours after the dose. In addition, average desloratadine peak milk levels of 16 (range 9 to 29.6) mcg/L occurred at 5.3 hours after the dose. The total amount excreted in milk over 48 hours was 11.7 mcg of loratadine and its metabolite. However, the dose administered was four times greater than the usual dose of the drug, so a total dose of about 3 mcg would be expected with a 10 mg dose. The calculated average and maximum expected doses of loratadine plus desloratadine in milk were 0.46 and 1.1% and of the maternal weight-adjusted dose, respectively, after the 40 mg dose.[2]

Effects in Breastfed Infants

A survey of 51 mothers who took loratadine during breastfeeding between 1999 and 2001 was conducted by a teratogen information service. Most of the infants were over 2 months old and loratadine was generally taken for one week or less. Two mothers reported minor sedation in their infants, one at 3 days of age and one at 3 months of age. Both mothers were taking a dose of 10 mg daily. Weight gain and psychomotor development were similar to infants in a control group of breastfed infants unexposed to medications.[3] An extension of the study that compared the results of this study (plus one additional patient) to that of a control group of 88 mothers who took a drug known to be safe while breastfeeding. No differences in sedation or any other side effects (p=0.606) in the infant were found between mothers who took loratadine during breastfeeding and those of the control group.[4]

Effects on Lactation and Breastmilk

Antihistamines in relatively high doses given by injection can decrease basal serum prolactin in nonlactating women and in early postpartum women.[5][6] However, suckling-induced prolactin secretion is not affected by antihistamine pretreatment of postpartum mothers.[5] Whether lower oral doses of antihistamines have the same effect on serum prolactin or whether the effects on prolactin have any consequences on breastfeeding success have not been studied. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

One mother out of 51 mothers who took loratadine while nursing reported that she had decreased milk production after taking loratadine 10 mg daily for less than one week at 4 months postpartum.[3]

Alternate Drugs to Consider

Desloratadine, Fexofenadine

References

1.

Powell RJ, Du Toit GL, Siddique N et al. BSACI guidelines for the management of chronic urticaria and angio-oedema. Clin Exp Allergy. 2007;37:631-50. [PubMed: 17456211]

2.

Hilbert J, Radwanski E, Affine MB et al. Excretion of loratadine in human breast milk. J Clin Pharmacol. 1988;28:234-9. [PubMed: 2966185]

3.

Messinis IE, Souvatzoglou A, Fais N et al. Histamine H1 receptor participation in the control of prolactin secretion in postpartum. J Endocrinol Invest. 1985;8:143-6. [PubMed: 3928731]

4.

Merlob P, Stahl B. Prospective follow-up of adverse reactions in breast-fed infants exposed to loratadine treatment (1999-2001). BELTIS Newsl. 2002;Number 10:43-51.

5.

Merlob P. Prospective follow-up of adverse reactions in breast-fed infants exposed to maternal loratadine treatment (1999-2002). Unpublished manuscript.

6.

Pontiroli AE, De Castro e Silva E, Mazzoleni F et al. The effect of histamine and H1 and H2 receptors on prolactin and luteinizing hormone release in humans: sex differences and the role of stress. J Clin Endocrinol Metab. 1981;52:924-8. [PubMed: 7228996]

Substance Name

Loratadine

CAS Registry Number

79794-75-5

Drug Class

• Breast Feeding
• Lactation
• Antihistamines
• Nonsedating Antihistamines