Azathioprine and breastfeeding: is it safe?

Azathioprine treatment during lactation

BACKGROUND

Thiopurines are widely used to maintain remission in inflammatory bowel disease. Treatment during pregnancy is generally recommended to improve the chance of a normal birth outcome, but advice concerning breastfeeding is conflicting. Aim To estimate the exposure of breastfed infants to 6-mercaptopurine, as a metabolite of azathioprine, from maternal milk.

METHODS

Eight lactating women with inflammatory bowel disease receiving maintenance therapy with azathioprine 75-200 mg daily were studied. Milk and plasma samples were obtained 30 and 60 min after drug administration and hourly for the following 5 h.

RESULTS

The variation in the bioavailability of the drug was reflected in a wide range of peak plasma values of 6-mercaptopurine within the first 3 h. A similar curve, but with an hour's delay and at significantly lower concentrations varying from 2-50 microg/L, was seen in maternal milk. After 6 h an average of 10% of the peak values were measured.

CONCLUSIONS

The major part of 6-mercaptopurine in breast milk is excreted within the first 4 h after drug intake. On the basis of maximum concentration measured, the infant ingests mercaptopurine of <0.008 mg/kg bodyweight/24 h. The findings confirm that breastfeeding during treatment with azathioprine seems safe and should be recommended, considering the extensive beneficial effects.

Immunosuppressant therapy in pregnant organ transplant recipients

Transplant recipients are becoming pregnant with increasing frequency, and successful pregnancy outcomes have now been reported for women with all types of solid organ transplants. To prevent rejection of the transplanted organ, these patients are maintained on a life-long immunosuppressive regimen that must also be continued through pregnancy. Controlled human studies of the safety of these drugs have not been conducted, and knowledge regarding the pharmacokinetics of these medications in pregnancy is limited. Significant experience and safety data regarding the use of some of the more common immunosuppressants in pregnancy have, however, been accumulated from large case series and national registries. These observational studies suggest that successful pregnancy outcomes are possible in female organ transplant recipients, although sporadic adverse outcomes have been reported after immunosuppressant use in pregnancy. In this chapter, we will outline the information available regarding the use of immunosuppressive medications in pregnant transplant recipients as well as general concepts regarding fetal exposure to immunosuppressants.

Eczema in pregnancy

Many women with eczema experience flares during pregnancy, and management must take account of the possible effects of some treatments on the fetus