Letters7 December 2010Standard-Dose Tegafur Combined With Uracil Is Not Safe Treatment After Severe Toxicity From 5-Fluorouracil or CapecitabineMaarten J. Deenen, PharmD, Wim E. Terpstra, MD, PhD, Annemieke Cats, MD, PhD, Henk Boot, MD, PhD, and Jan H.M. Schellens, MD, PhDMaarten J. Deenen, PharmDFrom The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands; Onze Lieve Vrouwe Gasthuis, 1091 AC, Amsterdam, The Netherlands; and The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands.Search for more papers by this author, Wim E. Terpstra, MD, PhDFrom The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands; Onze Lieve Vrouwe Gasthuis, 1091 AC, Amsterdam, The Netherlands; and The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands.Search for more papers by this author, Annemieke Cats, MD, PhDFrom The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands; Onze Lieve Vrouwe Gasthuis, 1091 AC, Amsterdam, The Netherlands; and The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands.Search for more papers by this author, Henk Boot, MD, PhDFrom The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands; Onze Lieve Vrouwe Gasthuis, 1091 AC, Amsterdam, The Netherlands; and The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands.Search for more papers by this author, and Jan H.M. Schellens, MD, PhDFrom The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands; Onze Lieve Vrouwe Gasthuis, 1091 AC, Amsterdam, The Netherlands; and The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-153-11-201012070-00023 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail Background: The most frequently prescribed anticancer drugs are the fluoropyrimidines, which include 5-fluorouracil (5-FU). Most patients tolerate fluoropyrimidines well, but about 10% develop severe, potentially life-threatening complications. The most important cause of these complications is a deficiency of dihydropyrimidine dehydrogenase (DPD), the primary enzyme that detoxifies fluoropyrimidines. Fluoropyrimidines are often combined with a compound that inhibits DPD and creates an artificial DPD deficiency, which reduces interpatient variability in tolerance of the fluoropyrimidines and should allow uniform dosing for all patients. Most clinicians who prescribe chemotherapy believe that this practice is safe for DPD-deficient patients.Objective: To describe 4 cases in ...