Phenytoin-Induced Reduction in Sirolimus Levels

Transplantation-Associated Thrombotic Microangiopathy in Patients Treated With Sirolimus and Cyclosporine as Salvage Therapy for Graft-Versus-Host Disease

“…42 A study in rats confirmed that concomitant administration of SIR and CsA produced an increase in CsA blood and tissue concentrations. 43 The second recommendation for those cases where both measures are unsuccessful is to administer an enzyme inducer such as phenytoin, which, as a strong inducer of cytochrome P450, may increase the hepatic metabolism of SIR 44 and CsA. 45 The role and value of plasmapheresis and rituximab are controversial in the management of TA-TMA.…”

Venous Thromboembolism Due to Suspected Interaction Between Nevirapine and Rivaroxaban

“…16 Metabolic induction dissipates slowly over a period of days to weeks, depending on the half-life of the inducer, the half-life of the CYP isozyme, the presence of hepatic disease, and the patient's age. 17 The patient described here had received nevirapine for years, so maximal enzyme induction of CYP3A4 was already present. The half-life of rivaroxaban is 5-13 h, so the patient's plasma rivaroxaban levels potentially reached steady state within 48 h of starting rivaroxaban therapy.…”

Phenytoin to expedite sirolimus and tacrolimus elimination

“…The interaction between phenytoin and sirolimus is reported in the context of seizure treatment, where a 4-fold sirolimus dose increase was needed to maintain sirolimus levels within the therapeutic range. 4 Strategic use of phenytoin to therapeutically clear sirolimus is not described. Herein we present a unique case leveraging phenytoin-inducing effects to expedite sirolimus and tacrolimus elimination while awaiting urgent thoracotomy for mucormycosis.…”