Mycophenolate Mofetil (MMF) Dosage and Usage Guidelines
The standard dosage of mycophenolate mofetil (MMF) is 1-1.5 grams twice daily (total daily dose of 2-3 grams) for most indications, with dosing adjusted based on the specific condition being treated, patient characteristics, and monitoring of adverse effects. 1, 2, 3
Indication-Specific Dosing
Transplantation
- Renal transplantation: 1 gram twice daily (2 g/day) 1
- Cardiac and hepatic transplantation: 1.5 grams twice daily (3 g/day) 1
- Pediatric transplantation: 600 mg/m² twice daily (maximum 2 g/day) 1
Autoimmune and Inflammatory Conditions
- Steroid-refractory acute GVHD: 1 gram twice daily for 35 days 2
- Inflammatory myopathies: Start at 500 mg twice daily, increase by 500 mg weekly to target dose of 1 gram twice daily (2 g/day), maximum 1.5 grams twice daily (3 g/day) if tolerated 2
- Atopic dermatitis: 0.5-3 grams/day, typically divided twice daily 2
- Psoriasis: 1-1.5 grams twice daily 2
Administration Guidelines
Initiation:
- Begin with lower doses and titrate up to minimize gastrointestinal side effects
- For inflammatory conditions: Start at 500 mg twice daily, increase by 500 mg weekly to target dose 2
Administration timing:
Formulations:
Monitoring Requirements
Baseline Assessment
- Complete blood count (CBC)
- Liver function tests (LFTs)
- Pregnancy test for women of childbearing potential
- Serum IgA level (if IVIG will be used concurrently)
Ongoing Monitoring
- CBC: Weekly for first month, then every 2 weeks for 2 months, then monthly 2, 3
- LFTs: Monthly 2, 3
- Therapeutic drug monitoring: Consider monitoring mycophenolic acid (MPA) levels in select cases
- Target MPA levels: 1-3.5 μg/mL for transplant recipients, 2-3 μg/mL for lupus nephritis 3
Adverse Effects Management
Common Adverse Effects
Gastrointestinal: Nausea, vomiting, diarrhea, abdominal cramping (most common) 2, 4
- Management: Consider enteric-coated formulation, spreading doses, temporary dose reduction
Hematologic: Leukopenia, anemia, thrombocytopenia 2
- Management: Dose reduction or temporary discontinuation if ANC < 1.3 × 10³/μL 1
Infections: Increased risk of viral, bacterial, and opportunistic infections 2, 3
- Management: Monitor for signs of infection, consider prophylaxis in high-risk patients
Special Considerations
Pregnancy: Contraindicated (Category D) - severe risk of congenital malformations 2, 3
- Women of childbearing potential must use two reliable forms of birth control 3
Renal impairment: Avoid doses greater than 1 gram twice daily in patients with severe renal impairment (GFR < 25 mL/min/1.73 m²) 1
Hepatic impairment: No dose adjustments needed for severe hepatic parenchymal disease 1
Treatment Response and Duration
- Initial response may be delayed (4-8 weeks)
- Maximum benefit typically observed after 3-6 months
- Treatment often continued long-term for sustained benefit 3
Important Drug Interactions
- Antacids containing aluminum and magnesium (decrease absorption)
- Antibiotics (decrease MMF levels through inhibition of enterohepatic recirculation)
- Tacrolimus (increases MPA levels)
- Cyclosporine (decreases MPA levels)
Pitfalls and Caveats
- Delayed efficacy: Initial response may be delayed compared to other immunosuppressants like cyclosporine 2
- Infection risk: Monitor closely for opportunistic infections, which can occur in up to 31% of patients 3
- Pregnancy risk: Severe teratogenic potential requires strict contraception 3
- Dose-dependent toxicity: Higher doses (3 g/day) show increased efficacy but also increased adverse effects, particularly GI symptoms and CMV infections 5
- Therapeutic drug monitoring: Consider monitoring MPA levels in patients with unexpected toxicity or poor response 3
MMF has proven to be an effective immunosuppressant across multiple indications with a generally favorable safety profile when properly monitored and dosed according to patient-specific factors.