Recommended Dosage and Usage of Mycophenolate Mofetil for Transplant Patients
The recommended dosage of mycophenolate mofetil (MMF) for preventing organ rejection in transplant patients varies by organ type: 1 g twice daily (2 g/day) for renal transplant patients, and 1.5 g twice daily (3 g/day) for cardiac and hepatic transplant patients. 1
Dosing by Organ Type
Renal Transplantation
- Adult patients: 1 g twice daily (2 g/day total) 1
- Pediatric patients (3 months to 18 years): 600 mg/m² twice daily (maximum 2 g/day) 1
- For children with body surface area of 1.25-1.5 m², 750 mg twice daily (1.5 g/day) 1
- For children with body surface area >1.5 m², 1 g twice daily (2 g/day) 1
- Higher doses (3 g/day) were studied in clinical trials but showed no efficacy advantage while demonstrating a worse safety profile 1
Cardiac Transplantation
- Adult patients: 1.5 g twice daily (3 g/day total) 1
- This higher dose is required for effective immunosuppression in cardiac transplant patients 2
Hepatic Transplantation
- Adult patients: 1.5 g twice daily (3 g/day total) 1
Administration Guidelines
- MMF should be administered on an empty stomach as food decreases maximum concentration (Cmax) by 40% 1
- In stable renal transplant patients, MMF may be administered with food if necessary 1
- Initial dose should be given as soon as possible following transplantation 1
- For missed doses, patients should take the dose as soon as remembered, unless it's close to the next scheduled dose 1
Mechanism of Action
- MMF is a prodrug that is rapidly converted to mycophenolic acid (MPA), the active metabolite 3
- MPA inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the de novo pathway of guanosine nucleotide synthesis 3
- This inhibition preferentially affects T and B lymphocytes because they are critically dependent on this pathway for proliferation 3
Monitoring and Dose Adjustments
- For patients with severe chronic renal impairment (GFR <25 mL/min/1.73 m²), doses greater than 1 g twice daily should be avoided 1
- If neutropenia develops (ANC <1.3 × 10³/μL), dosing should be interrupted or reduced 1
- Regular monitoring of complete blood count is recommended 4
- Liver function tests should be performed at least monthly 2
Adverse Effects
- Gastrointestinal disturbances are most common (diarrhea, nausea, vomiting, abdominal pain) 3, 4
- Hematologic effects include leukopenia, anemia, and thrombocytopenia 3
- Increased risk of infections, particularly viral infections 2
- Contraindicated during pregnancy and lactation due to teratogenic effects 2, 4
Special Considerations
- For patients with severe GI side effects, dose reduction may be necessary 4
- Enteric-coated mycophenolic acid formulation may be considered for patients with significant GI intolerance 4
- No dose adjustments needed for patients with hepatic impairment, though monitoring is advised 1
- MMF has shown efficacy in preventing acute rejection episodes compared to azathioprine in clinical trials 5
By following these dosing recommendations and monitoring guidelines, MMF can effectively prevent organ rejection while minimizing adverse effects in transplant recipients.