Mycophenolate Mofetil/Mycophenolic Acid (MMF/MPA) Monitoring 

We now offer a new drug monitoring service for mycophenolate mofetil (MMF) or mycophenolic acid (MPA) in canines and felines. Introductory pricing is $75 for single samples and $120 for both peak and trough samples. 

MMF/MPA monitoring is both complicated and limited by the lack of studies correlating concentration and immune suppression in animals. Thus, avoiding toxicity and determining concentrations should be the primary goal. Without consensus regarding MMF therapeutic ranges in animals, establishing the individual patient’s therapeutic range is critical. 

Clinical Pharmacology and Disposition 

MMF is an immunosuppressant increasingly used to treat immune-mediated diseases in dogs and cats. MMF is a prodrug whose efficacy is based on conversion to an active metabolite, mycophenolic acid (MPA) and other MPA derivatives. MMF shows rapid oral absorption and reaches maximum concentration rapidly within 0.5 to 2 hours. The half-life of these metabolites is generally less than 12 hours, indicating the potential need for q 12 h dosing intervals, depending on the therapeutic indications. The short half-life also suggests that monitoring peak and trough concentrations is important. 

Without evidence and not knowing if peak or trough concentrations are more predictive of therapeutic response, the prudent approach is to measure a peak and trough to determine the individual patient’s MPA half-life (and potentially trough concentrations from that point on). If the patient cannot stay for 2-hour and 12-hour samples, the trough can be collected just before the next dose. The patient can be dosed and the peak collected after 1 or 2 hours. 

Note: if the half-life in the patient is short and the interval is 24 hours, concentrations may not be detectable at 24 hours. 

  • Sample requirements: 0.5mL Plasma (no separator gel tube) 
  • Peak sample: 1-2 hours post-dose 
  • Trough sample: Before the next dose 
  • Method: immunoassay detecting MPA and other active metabolites 
  • Shipping: Since MPA is temperature-sensitive, overnight shipping of sample(s) on ice is required. Do not ship samples on Friday or Saturday.