Diarrhea & common immunosuppressants

Did you know that diarrhea increases the absorption of Prograf (tacrolimus, FK506)? Drug levels must be monitored closely in this setting to avoid tacrolimus-induced allograft toxicity. Tacrolimus is even considered a cause of diarrhea by some, though its usual counterpart in immunosuppresion, mycophenolate mofetil (MMF, Cell Cept) is more frequently associated with such GI side effects. A newer formulation of MMF, termed Myfortic, allegedly causes less GI side effects than Cell Cept, and can be used in patients in whom Cell Cept is simply not tolerated.