s-1-(combination) and alpha-fluoro-beta-alanine

Topics: 2-Pyridinylmethylsulfinylbenzimidazoles; Administration, Oral; Anti-Ulcer Agents; Antimetabolites, Antineoplastic; Area Under Curve; beta-Alanine; Biological Availability; Clinical Trials as Topic; Dihydrouracil Dehydrogenase (NADP); Drug Combinations; Fasting; Fluorouracil; Food; Gastric Acidity Determination; Half-Life; Humans; Hydrogen-Ion Concentration; Oxonic Acid; Pantoprazole; Pyridines; Tegafur; Triazines; Uracil

We studied whether total gastrectomy for gastric cancer would affect the pharmacokinetics of 5-fluorouracil (5-FU) and its degradation products, such as dihydrouracil (FUH(2)) and alpha-fluoro-beta-alanine (FBAL), after oral administration of the fluorouracil derivative S-1, composed of tegafur, 5-chloro-2,4-dihydroxypyridine (CDHP; a dihydropyrimidine dehydrogenase inhibitor) and potassium oxonate. Blood and urine samples were obtained, both preoperatively and at least 2 weeks postoperatively, from six patients with advanced gastric cancers who were undergoing total gastrectomy. Plasma levels of tegafur, 5-FU, CDHP, potassium oxonate, FUH(2) and FBAL were measured prior to and at 1, 2, 4, 6 and 10 h after oral administration of 40 mg/m(2) S-1. The total amounts of 5-FU, FUH(2) and FBAL excreted into urine during the 24-h period after S-1 administration were also measured. Total gastrectomy significantly increased the maximum concentration and the area under the curve until 10 h after administration (AUC(1-10h)) of plasma 5-FU. The plasma AUC(1-10h) of CDHP was significantly higher than the preoperative value. In terms of clinical efficacy, the higher AUC(1-10h) of 5-FU after total gastrectomy may be beneficial to S-1 administered as adjuvant chemotherapy, and might be caused by the higher postoperative AUC(1-10h) of CDHP relative to preoperative values. However, the dose of S-1 for patients who have undergone total gastrectomy might be diminished to avoid severe adverse events and to continue the treatment for a long period.

Topics: Administration, Oral; Adult; Aged; Area Under Curve; beta-Alanine; Drug Combinations; Fluorouracil; Gastrectomy; Humans; Middle Aged; Oxonic Acid; Stomach Neoplasms; Tegafur

The pharmacokinetics and pharmacodynamics of oral S-1, a dihydropyrimidine dehydrogenase (DPD) inhibitory fluoropyrimidine, were compared with those of protracted venous infusion (PVI) of 5-fluorouracil (5-FU). In all, 10 patients with gastric cancer received PVI of 5-FU at a dose of 250 mg/m2/day for 5 days. After a washout period of 9 days, the 10 patients received two divided doses daily for 28 days. S-1 was administered orally at about 9 a.m. and 7 p.m. Plasma concentrations of 5-FU and F-beta-alanine (FBAL) were measured for pharmacokinetic analysis, and the plasma uracil concentration was monitored as a surrogate marker of DPD inhibition in the same 10 patients on days 1-5 of PVI of 5-FU and on days 1-5 of oral S-1. The area under the curve (AUC0-10h) of 5-FU on day 5 was 728 +/- 113 ng x hr/ml for PVI of 5-FU and 1,364 +/- 374 ng x hr/ml for S-1. The median 5-FU PVI: S-1 ratio of the AUC0-10h of 5-FU was 1.9. The AUC0-10h of FBAL on day 5 of PVI of 5-FU was 9,465 +/- 3,225 ng x hr/ml, AUC0-10h, as compared with 1,725 +/- 605 ng x hr/ml on day 5 of S-1 treatment. The AUC0-10h of uracil on day 5 was 252 +/- 60 ng x hr/ml with PVI of 5-FU and 12,582 +/- 3,060 ng x hr/ml with S-1. The AUC0-10h of FBAL was markedly lower and plasma uracil concentrations were significantly higher for S-1 than for PVI of 5-FU, clearly demonstrating the effect of DPD inhibition.

Topics: beta-Alanine; Dihydrouracil Dehydrogenase (NADP); Drug Combinations; Fluorouracil; Humans; Infusions, Intravenous; Kidney; Oxonic Acid; Stomach Neoplasms; Tegafur; Uracil

Cardiotoxicity is a rare complication occurring during 5-fluorouracil (5-FU) treatment for malignancies. We herein report the case of a 70-year-old man with 5-FU-induced cardiotoxicity, in whom a high serum level of alpha-fluoro-beta-alanine (FBAL) was observed. The patient, who had unresectable colon cancer metastases to the liver and lung, was referred to us for chemotherapy from an affiliated hospital; he had no cardiac history. After admission, the patient received a continuous intravenous infusion of 5-FU (1000 mg/day), during which precordial pain with right bundle branch block occurred concomitantly with a high serum FBAL concentration of 1955 ng/ml. Both the precordial pain and the electrocardiographic changes disappeared spontaneously after the discontinuation of 5-FU. As the precordial pain in this patient was considered to have been due to 5-FU-induced cardiotoxicity, the administration of 5-FU was abandoned. Instead, oral administration of S-1 (a derivative of 5-FU), at 200 mg/day twice a week, was instituted, because S-1 has a strong inhibitory effect on dihydropyrimidine dehydrogenase, which catalyzes the degradative of 5-FU into FBAL. The serum FBAL concentration subsequently decreased to 352 ng/ml, the same as the value measured on the first day of S-1 administration. Thereafter, no cardiac symptoms were observed. The patient achieved a partial response 6 months after the initiation of the S-1 treatment. The experience of this case, together with a review of the literature, suggests that FBAL is related to 5-FU-induced cardiotoxicity. S-1 may be administered safely to patients with 5-FU-induced cardiotoxicity.

Topics: Aged; Antimetabolites, Antineoplastic; beta-Alanine; Cardiovascular Diseases; Colonic Neoplasms; Drug Combinations; Electrocardiography; Fluorouracil; Heart; Humans; Liver Neoplasms; Lung Neoplasms; Male; Oxonic Acid; Tegafur