Is Tacrolimus Dialysable?
No, tacrolimus is not dialyzable to any significant extent due to its poor aqueous solubility and extensive binding to erythrocytes and plasma proteins. 1
Pharmacokinetic Properties That Prevent Dialysis Removal
Tacrolimus has specific molecular characteristics that make it essentially non-removable by dialysis:
Poor aqueous solubility: Tacrolimus is practically insoluble in water, which fundamentally limits its presence in the aqueous dialysate compartment 1
Extensive protein and cellular binding: The drug demonstrates high binding to both plasma proteins and erythrocytes, sequestering it away from the dialyzable fraction of blood 1
Large volume of distribution: As a lipophilic macrolide, tacrolimus distributes extensively into tissues rather than remaining in the vascular compartment accessible to dialysis 2, 3
Clinical Evidence in Dialysis Patients
The lack of dialyzability has been demonstrated in clinical contexts:
Peritoneal dialysis removal: Only 0.002% of an oral tacrolimus dose was removed by peritoneal dialysis itself, confirming negligible clearance through this modality 4
Overdose management: The FDA label explicitly states that "it is anticipated that tacrolimus is not dialyzable to any significant extent" and notes there is no experience with charcoal hemoperfusion for overdose situations 1
Important Clinical Implications
For Transplant Recipients on Dialysis
Absorption issues, not removal: In peritoneal dialysis patients awaiting transplantation, tacrolimus malabsorption (not dialysis removal) is the primary concern, often related to excess fluid distribution in the gastrointestinal tract 4
Dosing considerations: Patients with renal impairment requiring dialysis have similar tacrolimus pharmacokinetics to those with normal renal function, as the drug is primarily metabolized hepatically via CYP3A4 rather than renally cleared 1
No dose adjustment needed for dialysis: Because dialysis does not remove tacrolimus, no supplemental dosing is required post-dialysis sessions 1
For Overdose Management
Supportive care only: In cases of tacrolimus overdose, dialysis offers no benefit for drug removal 1
Activated charcoal consideration: While oral activated charcoal has been reported in treating acute overdoses, experience has been insufficient to warrant routine recommendation 1
Symptomatic treatment: Management should focus on treating specific symptoms (tremors, hypertension, renal dysfunction) rather than attempting drug removal 1
Common Pitfall to Avoid
Do not reduce tacrolimus dosing in anticipation of dialysis sessions, as this will lead to subtherapeutic levels and increased rejection risk without any compensatory drug removal by the dialysis procedure 1, 4. The primary concern in dialysis patients is ensuring adequate absorption and maintaining therapeutic levels, not drug removal.