Should I titrate her Mycophenolate Mofetil (MMF) dose?

MMF Dose Titration Decision

You should titrate her MMF dose based on clinical response, tolerability, and the specific indication being treated, with target dosing typically ranging from 1-1.5g twice daily for most autoimmune conditions, though lower doses may be appropriate in certain contexts.

Context-Dependent Dosing Strategy

For Nephrotic Syndrome (Pediatric or Adult)

• Start with 1200 mg/m²/day divided twice daily for children with steroid-dependent or frequently relapsing nephrotic syndrome 1
• For adults with body surface area >1.5 m², use 1g twice daily (2g total daily dose) 1, 2
• Continue for at least 12 months, as most patients relapse when MMF is stopped 1
• Target MPA area under the curve >50 µg·h/mL if therapeutic drug monitoring is available 1

For Lupus Nephritis

• Early maintenance phase: 750-1000 mg twice daily 1, 3
• This translates to approximately 1.5-2g total daily dose 1
• Maintain these doses until complete response is achieved, then consider tapering 1
• Total duration of immunosuppression should be ≥36 months (initial therapy plus maintenance) 1

For Transplant Patients

• Renal transplant: 1g twice daily (2g total) is the FDA-approved dose, though 1.5g twice daily was studied 2
• Cardiac/hepatic transplant: 1.5g twice daily (3g total) 2
• The 2g daily dose demonstrates a better safety profile than 3g daily in renal transplant patients 2

Critical Titration Considerations

When to Reduce Dose

Gastrointestinal intolerance:

• Switch to enteric-coated mycophenolic acid at 720-1080 mg twice daily (equivalent to MMF 1-1.5g twice daily) 1, 3
• Consider dose reduction to 500 mg twice daily for milder autoimmune conditions like psoriasis or Crohn's disease 4

Renal impairment:

• In patients with severe chronic renal impairment (GFR <25 mL/min/1.73 m²) outside immediate post-transplant period, avoid doses >1g twice daily 2
• ESRD patients with ANCA-associated vasculitis may require dose reduction to 1g daily total due to increased risk of severe anemia and leukopenia 5

Hematologic toxicity:

• If neutropenia develops (ANC <1.3 × 10³/µL), interrupt dosing or reduce dose 2
• Monitor CBC every 2-3 months during therapy 1

When to Increase Dose

Suboptimal response:

• If inadequate disease control after 2-3 months at lower doses, titrate upward from 500 mg twice daily to 1-1.25g twice daily 4, 6
• For severe autoimmune conditions (pemphigus vulgaris, inflammatory myopathy), doses up to 1.25g twice daily may be necessary 4, 6
• The initial response to MMF may be delayed, with improvement as drug levels increase over the first 10 weeks 1

Monitoring During Titration

• Check MPA blood levels if gastrointestinal intolerance develops or response is inadequate 3
• Target MPA AUC of 20-60 µg·h/mL for optimal efficacy and safety 3
• Monitor CBC, renal function, liver function tests regularly 7
• Avoid concurrent use with antacids (aluminum/magnesium), cholestyramine, iron, or activated charcoal as these inhibit absorption 3

Common Pitfalls to Avoid

• Do not discontinue MMF prematurely - most patients relapse when stopped before 12 months 1
• Do not assume dose equivalence across formulations - 360 mg sodium mycophenolate = 500 mg MMF 1
• Do not ignore delayed response - efficacy may take 10+ weeks to manifest fully 1
• Do not use standard transplant doses for all indications - autoimmune conditions often respond to lower doses (500 mg-1g twice daily) 4, 6