Successful hemodialysis in a phenytoin overdose: case report and review of the literature

Phenytoin overdose treated with hemodialysis using a high cut‐off dialyzer

“…Compared to a previous report using a modern dialyzer, we obtained a higher phenytoin clearance (80 mL/min vs. 44 mL/min). We hypothesize that this was more due to a higher achievable blood flow (381 mL/min vs. 241 mL/min), a higher dialysate flow (750 mL/min vs. 500 mL/min), and especially a larger surface area of the Theralite filter (2.1 m 2 vs. 1.8 m 2 ), rather than the dialyzer's ability to remove bound phenytoin.…”

“…The use of ECTR for elimination enhancement of phenytoin in patients with overt toxicity have traditionally been restricted to hemoperfusion and therapeutic plasma exchange because of phenytoin's high protein binding (≅90%). Recent reports, however, have shown promise with hemodialysis using high‐efficiency dialyzers, because of phenytoin's low binding constant to albumin (K = 6 × 10 3 /mol/L), which provides a constant pool of unbound freely diffusible phenytoin. In 2015, the EXTRIP Workgroup published a neutral recommendation for the use of ECTR in cases of severe phenytoin toxicity, with intermittent HD as the ECTR of choice …”

Tandem plasmapheresis with hemodialysis in phenytoin intoxication: a case report

“…4 In severe intoxication hemodialysis has been used to accelerate elimination of total body burden of the drug. 8 This sequential PP and HD as one tandem procedure was first described by Siami et al 9 Our rationale for combined approach is that plasmapheresis removes protein bound drug from circulation. Following that free phenytoin is released from stores into circulation.…”

A Stepwise Approach for the Management of Poisoning with Extracorporeal Treatments

“…For example, salicylate's PB falls from 90% at therapeutic concentrations to 50% when it reaches 800 mg/l which is a level where significant symptoms might occur, and extracorporeal purification may be beneficial . Some poisons show little to no saturable binding in overdose conditions, such as carbamazepine (PB = 75%) and phenytoin (PB = 90%). Despite this, reports show that they are relatively well eliminated by diffusive and convective techniques, especially with newer high‐flux/high‐efficiency filters . These observations suggest that the free (unbound) poison is continuously removed by ECTR, and it is also in rapid equilibrium with bound poison that quickly dissociates from albumin into the free form. New dialyzers and hemofilters with higher MW cut‐offs developed for specific clinical conditions, such as multiple myeloma, can remove poison‐protein complexes.…”