Mycophenolate Mofetil: Indications, Contraindications, and Side Effects
Indications
Mycophenolate mofetil is FDA-approved for prevention of organ rejection in solid organ transplantation (kidney, heart, and liver) and is used as a standard component of GVHD prophylaxis regimens 1.
Primary Approved Uses:
- Renal transplantation - Prevention of acute rejection
- Cardiac transplantation - Prevention of acute rejection
- Hepatic transplantation - Prevention of acute rejection 2, 1
Off-Label Uses (Supported by Guidelines):
The drug has expanded use beyond transplantation:
- Steroid-refractory acute GVHD - Shows efficacy with ORR of 47-48% and CR rates of 26-31%, particularly effective in lower grade GVHD 3
- Lupus nephritis - Recognized indication with supporting evidence 4, 5
- Autoimmune hepatitis - Effective as second-line therapy when patients are intolerant to or fail standard treatment with prednisolone/azathioprine 6
- Neuromyelitis optica spectrum disorders - Reduces ARR by 1.13 and EDSS by 0.85 7
- Immune thrombocytopenia - 52% response rate in severe cases 8
- Other immune-mediated diseases including pemphigus vulgaris, myasthenia gravis, polymyositis, and vasculitis 4, 9
Contraindications
The only absolute contraindication is hypersensitivity to mycophenolate mofetil, mycophenolic acid, or any component of the drug product 1.
Critical Warnings (Not Absolute Contraindications but Require Extreme Caution):
- Pregnancy - Major teratogenic risk; avoid pregnancy during treatment 1
- Active serious infections - Given immunosuppressive effects
- Severe neutropenia - Baseline severe bone marrow suppression
Side Effects
Most Common Adverse Effects (≥20% of patients):
Gastrointestinal effects are the most frequent:
- Diarrhea (31-51% depending on dose and organ type) 1
- Nausea and vomiting (27-34%)
- Abdominal pain (25-63%)
- Constipation (22-41%)
Hematologic effects:
- Leukopenia (23-46%) - Most common 3-6 months post-transplant 1
- Anemia (26-53%)
- Thrombocytopenia (24-42%)
Infectious complications:
- Increased risk of opportunistic infections including CMV tissue invasive disease 1
- Urinary tract infections (37%)
- Sepsis (27% in hepatic transplant patients)
Cardiovascular/Metabolic:
- Hypertension (28-78%)
- Peripheral edema (28-64%)
- Hyperglycemia (44-53%)
Serious Adverse Effects:
Life-threatening complications that require immediate attention:
- Severe infections - Bacterial, viral (especially CMV), fungal, and protozoal infections due to immunosuppression 1
- Gastrointestinal hemorrhage - Can be severe requiring hospitalization, particularly with high doses 1
- Bone marrow suppression - Severe neutropenia, anemia, thrombocytopenia requiring dose adjustment or discontinuation 1
- Malignancies - Increased risk of lymphoma and skin cancer (especially with prolonged sun exposure) 1
- Progressive multifocal leukoencephalopathy (PML) - Rare but fatal JC virus infection 1
Special Population Considerations:
Elderly patients (≥65 years) are at increased risk for:
- CMV tissue invasive disease
- Gastrointestinal hemorrhage
- Pulmonary edema 1
Dosing-Related Side Effects:
Adverse effects are dose-dependent. The standard maintenance dose is 1,500 mg/day (1g twice daily) 1, 4. Higher doses (2-3 g/day) used in transplantation increase the risk of:
Management Pearls:
- Do not stop MMF abruptly for diarrhea - Contact physician first 1
- Mandatory sun protection - Use SPF 30+ sunscreen and protective clothing due to skin cancer risk 1
- Regular blood count monitoring is essential, especially during the first 3-6 months 1
- Enteric-coated formulation (mycophenolate sodium) may reduce GI side effects 2
Drug-Specific Advantages:
Unlike calcineurin inhibitors, MMF:
- Does not cause nephrotoxicity 2, 10
- Does not increase blood pressure, cholesterol, or triglycerides 10
- Does not induce TGF-beta production (which is fibrogenic) 10
- Has a relatively benign side effect profile compared to other immunosuppressants 4, 9
The overall adverse event rate requiring discontinuation is approximately 20%, with most effects being manageable 4, 7.