Summary
Mycophenolate mofetil (MMF) is the pro-drug of mycophenolic acid (MPA), an antiproliferative agent that interferes with purine synthesis, thereby suppressing the immune response. MMF/MPA are indicated for the prophylaxis of organ rejection in transplant recipients and are generally used concomitantly with other immunosuppressant medications, including ciclosporin and corticosteroids. MMF/MPA are also used off-license to control autoimmune conditions such as psoriasis and lupus nephritis.
MMF/MPA are contraindicated during pregnancy unless there is no possible alternative to prevent rejection of a transplanted organ. This is due to an increased risk of first trimester pregnancy loss and confirmed human teratogenic effects, including craniofacial anomalies (cleft lip and/or palate, microtia, external auditory canal atresia, micrognathia); microphthalmia, coloboma of iris and retina, and hypertelorism; complex congenital cardiac anomalies, including septal defects, conotruncal and outflow tract anomalies; oesophageal atresia, diaphragmatic hernia, and various vertebral and skeletal anomalies. The two largest cohort studies carried out to date report malformation rates of 11.6% and 26% among offspring exposed to MMF in the first trimester.
The UK Medicines and Healthcare products Regulatory Agency (MHRA) guidelines state that females of reproductive potential who are prescribed MMF or MPA should use at least one form of reliable contraception during treatment and for six weeks after cessation. Male patients or their untreated female partner should use reliable contraception during treatment and for at least 90 days after cessation. Readers are advised to consult the most up-to-date version of these guidelines before prescribing MMF or MPA.
Women taking MMF or MPA who are planning a pregnancy should be reviewed by a specialist so that, if possible, a suitable alternative medication regime can be implemented prior to conception. Women taking these drugs who report an unplanned pregnancy should be offered urgent review, either in clinic or by telephone, within one or two working days.
Women exposed to MMF or MPA during early pregnancy should be counselled about the risks to the fetus and offered detailed anomaly scans focussing on the craniofacial structures, the heart, abdomen and skeletal system. Clinicians should also be aware that case-specific assessment of risk could also be affected by other factors that may independently increase the risk of adverse pregnancy outcome. Please report all cases of MMF/MPA exposure to UKTIS.
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