Mycophenolate Mofetil — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Mycophenolate Mofetil?
Mycophenolate mofetil is an immunosuppressant used to prevent organ transplant rejection and treat autoimmune conditions. This medication is funded by Pharmac for transplantation under Special Authority.
What is Mycophenolate Mofetil Used For?
Mycophenolate mofetil (MMF) is used for prevention of acute rejection in renal, hepatic, and cardiac transplantation (in combination with ciclosporin and corticosteroids), and for autoimmune conditions including lupus nephritis, myasthenia gravis, and inflammatory bowel disease.
How Does Mycophenolate Mofetil Work?
MMF is hydrolysed to mycophenolic acid (MPA), which inhibits inosine monophosphate dehydrogenase (IMPDH) — an enzyme essential for the de novo synthesis of guanosine nucleotides in lymphocytes. Lymphocytes are uniquely dependent on the de novo pathway, so MMF selectively suppresses T and B lymphocyte proliferation without major effects on other rapidly dividing cells.
How to Take Mycophenolate Mofetil
Standard dose: 1–1.5 g twice daily (total 2–3 g/day), taken on an empty stomach for best absorption. Modified-release tablets (Myfortic® — mycophenolic acid sodium salt) can be taken once or twice daily with less GI irritation. Must not be crushed or opened (teratogen — avoid exposure in pregnancy).
Common Side Effects of Mycophenolate Mofetil
- GI symptoms (nausea, vomiting, diarrhoea, abdominal pain — most common — often improved with modified-release form)
- Leucopenia (low white cell count)
- Anaemia
- Fatigue
- Opportunistic infections
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Teratogenicity (causes miscarriage and serious congenital abnormalities — MUST NOT be used in pregnancy; Medsafe Pregnancy Prevention Programme applies)
- Progressive multifocal leukoencephalopathy (PML — rare fatal brain infection caused by JC virus reactivation)
- Lymphoma and skin malignancy (long-term immunosuppression)
- Severe infections
- Pure red cell aplasia (rare)
Drug Interactions
Mycophenolate Mofetil may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- Antacids, calcium, magnesium, iron (reduce absorption — separate administration)
- Cholestyramine and rifampicin (reduce MPA levels significantly — avoid)
- Aciclovir/ganciclovir (additive bone marrow suppression)
- Probenecid (increases MPA levels)
New Zealand Prescribing Information
Mycophenolate mofetil (CellCept® 250 mg capsules, 500 mg tablets; 200 mg/mL oral suspension) and mycophenolic acid (Myfortic® 180 mg, 360 mg tablets) are funded by Pharmac under Special Authority for transplantation. Women of childbearing potential must use two forms of effective contraception during treatment and for 6 weeks after stopping. The teratogenicity risk requires specific counselling and consent.
Frequently Asked Questions
Can I become pregnant while taking mycophenolate?
Absolutely not — mycophenolate is highly teratogenic (causes miscarriages and severe birth defects in up to 45% of exposed pregnancies). Two forms of effective contraception are mandatory during treatment and for 6 weeks after stopping. If you are considering pregnancy, inform your transplant team well in advance.
Why do I need to avoid antacids with mycophenolate?
Antacids containing magnesium or aluminium hydroxide (e.g., Mylanta®) form insoluble complexes with mycophenolic acid in the gut, significantly reducing its absorption. Take mycophenolate at least 2 hours before antacids, or preferably separate them by 4 hours.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: