Breast-feeding during maternal use of azathioprine

Management of the pregnant IBD patient

Women with inflammatory bowel disease (IBD) and the physicians who care for them must make difficult decisions on issues of conception, pregnancy, and breastfeeding with very limited and often contradictory information. This review provides the most current information on the inheritance of IBD, fertility, pregnancy outcomes, the management of disease during pregnancy, and the safety of medications in pregnancy and breastfeeding. We would like to emphasize that the information presented here must be individualized to the specific situation of each patient, their acceptance of risk, and their degree of disease severity.

Clinical pharmacology and pharmacogenetics of thiopurines

The thiopurine drugs-azathioprine (AZA), 6-mercaptopurine (6-MP), and thioguanine-are widely used to treat malignancies, rheumatic diseases, dermatologic conditions, inflammatory bowel disease, and solid organ transplant rejection. However, thiopurine drugs have a relatively narrow therapeutic index and are capable of causing life-threatening toxicity, most often myelosuppression. Thiopurine S-methyltransferase (TPMT; EC 2.1.1.67), an enzyme that catalyzes S-methylation of these drugs, exhibits a genetic polymorphism in 10% of Caucasians, with 1/300 individuals having complete deficiency. Patients with intermediate or deficient TPMT activity are at risk for excessive toxicity after receiving standard doses of thiopurine medications. This report reviews the recent advances in the knowledge of the mechanism of action as well as the molecular basis and interethnic variations of TPMT and inosine triphosphate pyrophosphatase (ITPase; EC 3.6.1.19), another enzyme implicated in thiopurine toxicity. In addition, an update on pharmacokinetics, metabolism, drug-drug interactions, safety, and tolerability of thiopurine drugs is provided.

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.

Drug therapy for inflammatory bowel disease in pregnancy and the puerperium

Inflammatory bowel disease (IBD) has a peak age of onset in the 3rd decade and a peak prevalent age in the fourth decade in most studies. As a result many patients affected by Crohn's disease and ulcerative colitis are females of reproductive age interested in bearing children. It has been shown that the most important factor in the success of a pregnancy in patients with IBD is the state of disease activity. Therefore, the goal prior to and during pregnancy is to best optimise control of the disease through medical therapy. Unfortunately, many medications utilised to treat IBD are potentially toxic and/or teratogenic, leaving many physicians and patients without a clear answer as to the safest methods of therapy. This review attempts to summarise the medical literature to date, as it pertains to the safety of medical therapy for IBD during pregnancy and the puerperium.

Therapy insight: the use of antirheumatic drugs during nursing

In 90% of cases, women with rheumatoid arthritis suffer a disease flare within 3 months of delivery of their baby. Drug treatment is, therefore, required; however, such therapies have implications for mothers who decide to nurse their infants. Unfortunately, because of a paucity of data, little is known about the transfer of antirheumatic drugs into breast milk, and even less is known about whether small amounts of these agents ingested during nursing could harm the infant. Our review of the literature indicates that paracetamol, prednisone, antimalarial agents, sulfasalazine and most NSAIDs can safely be used by lactating mothers. Expert opinions differ regarding the use of azathioprine, ciclosporin, and methotrexate during lactation because of varying views on the potential for short-term and long-term adverse effects. Evidence regarding the transfer of leflunomide and biologic drugs into breast milk is insufficient; therefore, until more studies are conducted, the use of these drugs in breastfeeding mothers should be restricted. At present, many patients feel they have to choose between postpartum disease control and lactation. Extended studies of the transfer of antirheumatic drugs into breast milk and the resulting consequences are, therefore, urgently needed.