Pediatric Dosing of Mycophenolate Mofetil for an 11-Year-Old Girl
For an 11-year-old girl, mycophenolate mofetil should be dosed at 600 mg/m² twice daily (up to a maximum of 1 g twice daily), with the specific dose determined by her body surface area. 1
Body Surface Area-Based Dosing Algorithm
The FDA-approved dosing strategy for pediatric patients aged 3 months to 18 years follows this approach: 1
- BSA 1.25-1.5 m²: Administer 750 mg twice daily (1.5 g total daily dose) using capsules 1
- BSA >1.5 m²: Administer 1 g twice daily (2 g total daily dose) using capsules or tablets 1
- BSA <1.25 m²: Use oral suspension at 600 mg/m² twice daily 1
For an 11-year-old girl, the BSA typically falls in the range requiring either 750 mg or 1 g twice daily, depending on her height and weight.
Clinical Context Considerations
For Nephrotic Syndrome
If this patient has nephrotic syndrome (frequently relapsing or steroid-dependent), the KDIGO guidelines recommend starting at 1200 mg/m²/day divided into two doses, with a target MPA area under the curve >50 µg·h/mL if therapeutic drug monitoring is available. 2 The Ibadan consensus statement supports 600 mg/m² per dose twice daily with a minimum trial of 6 months to determine responsiveness, continuing for up to 24 months. 2
For Transplant Recipients
If this is a renal transplant patient, the standard pediatric dose of 600 mg/m² twice daily (maximum 2 g daily) applies, though research suggests this may result in higher-than-expected plasma levels and increased gastrointestinal side effects. 3, 4
Critical Monitoring Requirements
Monthly monitoring of white blood cell count is essential during mycophenolate mofetil therapy. 2 For nephrotic syndrome patients, CBC should be checked every 2-3 months. 2
Additional monitoring includes:
- Complete blood count within 2-3 weeks after starting therapy 5
- CBC 2-3 weeks after any dose increase 5
- CBC every 3 months on stable dosing 5
- If neutropenia develops (ANC <1.3 × 10³/µL), interrupt dosing or reduce the dose 1
Important Administration Details
Mycophenolate mofetil should be administered on an empty stomach, as food decreases peak concentration by 40%. 1 However, in stable patients, it may be given with food if necessary. 1
Avoid concurrent administration with antacids containing aluminum or magnesium, cholestyramine, iron supplements, or activated charcoal, as these inhibit absorption. 6
Duration of Therapy
The minimum treatment duration depends on indication:
- Nephrotic syndrome: At least 6 months to assess response, up to 24 months total 2
- Transplant maintenance: Typically indefinite 1
Most children relapse when mycophenolate mofetil is stopped prematurely, so continuation for at least 12 months is recommended before considering dose reduction. 2, 7
Common Pitfalls to Avoid
Gastrointestinal side effects occur more frequently in pediatric patients than adults, particularly at the 600 mg/m² twice daily dose. 3 If significant abdominal pain develops, consider switching to enteric-coated mycophenolic acid at equivalent doses (360 mg sodium mycophenolate = 500 mg mycophenolate mofetil). 2
Do not assume dose-proportional pharmacokinetics in children. Research demonstrates substantial interpatient variability (44%) and age-dependent dosing requirements, with younger children requiring higher doses per body surface area than adolescents. 8 Therapeutic drug monitoring should be considered if response is inadequate or side effects develop. 6, 7
For girls of childbearing potential, effective contraception is mandatory during treatment due to severe teratogenic risks (Category D in pregnancy). 2, 5