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S D Reich

Publications and source records attributed to S D Reich.

51 records · Page 3Linked to original sources
PubMed1979

Mathematical modeling -- guide to high-dose methotrexate infusion therapy.

A mathematical model that describes methotrexate pharmacokinetics has been refined for use as a guide to dose escalation during high-dose methotrexate infusion therapy. Parameters for the model are adjusted for a patients by the SAAM computer program of Berman and Weiss, on the basis of plasma concentrations obtained during the initial course of therapy. Various dose escalations can be simulated by the computer and a print-out of predicted plasma concentrations obtains. The model has been used successfully to predict plasma concentrations after high-dose infusions in patients, including those with abnormal creatinine clearances. The program is designed to allow comparisons among infusions of any duration. This can be helpful when a change from a 24-hour infusion to a 6-hour infusion is contemplated for a patient. Deviations of observed values from those predicted are used to warn of the possibility of delayed toxicity secondary to methotrexate and alert the physician that increased amounts of rescue agent may be required.

Carcinoma, Squamous Cell↗
PubMed1979

Mathematical model for adriamycin (doxorubicin) pharmacokinetics.

Adriamycin (doxorubicin), an active antineoplastic drug, is rapidly distributed across cell membranes and is concentrated within cells. Binding to protein and to tissue readily occurs. The drug is metabolized to both fluorescent and nonfluorescent compounds, the liver being the main organ of biotransformation and elimination. A multicompartment, open model that accounts for these processes has been derived. The model assumes an initial volume of distribution of 60% of body weight and includes two peripheral adriamycin compartments and a subsystem for adriamycinol, a major metabolite. Plasma and urine concentrations of adriamycin and adriamycinol were determined for four patients treated with adriamycin (60 mg/m2), and these concentrations were used to calculate rate constants for the model. Concentrations were measured by fluorescence assay after thin-layer chromatographic separation of parent compound and metabolites. Differential equations were solved by the SAAM computer program. Evaluation of adriamcinol pharmacokinetics suggests that the previously reported high concentrations of adriamycinol immediately after IV infusion of adriamycin are an artifact of the fluorescence method and that observed plasma concentrations of adriamycinol are the sum of adriamycinol concentrations and approximately 10% of the adriamycin concentrations. Corrected peak plasma concentrations of adriamycinol occur 2--12 h after infusion of adriamycin.

Doxorubicin↗
PubMed1979

Bleomycin.

Bleomycin was approved by the Food and Drug Administration in 1975 for therapy against squamous cell carcinomas, testicular cancers, and malignant lymphomas. An extensive bibliography on this drug indicates that there is little evidence of activity against other malignancies. Although initially used exclusively as a single agent, bleomycin has been considered recently for use in combination chemotherapy. Because of associated toxicity involving the lung and mucous membranes, bleomycin should be used cautiously by physicians, particularly in noninvestigational settings.

Bleomycin↗
PubMed1978

Hemoperfusion for methotrexate removal.

Removal of methotrexate by Amberlite XAD-4 hemoperfusion was determined in a patient with metastatic breast carcinoma. During 4 hr of hemoperfusion the plasma concentration of methotrexate fell from 5.5 x 10(-7) M TO 3.1 x 10(-7) M. After hemoperfusion methotrexate concentration increased as a consequence of multicompartmental pharmacokinetics to 5.5 x 10(-7) M and then slowly declined. Plasma methotrexate clearance decreased from 79 ml/min 30 min into hemoperfusion to 28 ml/min at the conclusion. In vitro clearance of methotrexate by 17 artificial kidneys, Amberlite XAD-4, and uncoated charcoal was determined. Uncoated charcoal had the greatest clearance of methotrexate of all the devices tested. We conclude that: (1) Amberlite XAD-4 transiently reduces plasma methotrexate concentration; (2) in vitro, charcoal hemoperfusion is more effective than XAD-4 in removing methotrexate; (3) as a consequence of the multicompartmental pharmacokinetics of methotrexate a postperfusion rebound in plasma methotrexate concentration is to be expected.

Charcoal↗
PubMed1976

Von Recklinghausen neurofibromatosis and acute leukemia.

The leukemias are neoplastic processes that have been associated with a variety of genetic disorders. A case of an adolescent with both acute myelomonocytic leukemia and von Recklinghausen disease is presented, and the literature reviewed to show that these two diseases are associated. Although the number of cases in the literature suggests that in children with von Recklinghausen disease there is a greater risk of leukemia developing, prospective studies are needed to prove this point.

Adolescent↗
PubMed1976

Alterations in adriamycin efficacy by phenobarbital.

Adriamycin dosage should be reduced in patients with impaired liver function, since adriamycin disposition is influenced by liver metabolism and biliary excretion. It follows that drugs that increase the metabolism or excretory capacity of the liver may decrease adriamycin concentrations to suboptimal values. Adriamycin metabolism was therefore studied in mice pretreated with phenobarbital (75 mg/kg i.v.) by injection. After an i.v. dose of adriamycin (30 mg/kg i.v.), plasma fluorescence due to drug and metabolites was less and disappeared at a greater rate in phenobarbital-pretreated mice than control animals. When extracted with chloroform: isoprophyl alcohol (1:1), the livers from the phenobarbital-pretreated group yielded a greater concentration of glycones. Experiments with liver microsomes confirmed that aglycone production occurred at a more rapid initial rate in phenobarbital-induced livers. No increase in aldoketo reductase (daunorubicin reductase) activity was noted. Phenobarbital-pretreated mice, inoculated i.p. with 1 million L1210 cells and then treated with adriamycin (6 mg/kg i.v.), had significantly lower survival than did controls (p less than 0.01). These findings show that phenobarbital affects the disposition of adriamycin by microsomal enzyme induction and suggest that drugs that induce microsomal enzymes should not be used concurrently with adriamycin if optimal drug efficacy is desired.

Alcohol Oxidoreductases↗