G R Matzke

Virginia Commonwealth University Medical Center

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C E Halstenson

Prism Clinical Research

Reginald F. Frye

University of Florida Health Science Center

Walid M. Awni

AbbVie (United States)

W. F. Keane

University of Minnesota

David R.P. Guay

Université Laval

Juan F. Garcı́a

Hospital Juárez de México

William F. Keane

Merck & Co., Inc., Rahway, NJ, USA (United States)

J Mladenovic

St. Vincent's Medical Center

JA Opsahl

Hennepin County Medical Center

SE Steinberg

Hennepin County Medical Center

Cooperative Institutions

Hennepin County Medical Center

University of Minnesota

University of Pittsburgh

Twin Cities Orthopedics

University of Florida

Virginia Commonwealth University Medical Center

Virginia Commonwealth University

University of North Carolina at Chapel Hill

Merck & Co., Inc., Rahway, NJ, USA (United States)

Indiana University – Purdue University Indianapolis

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Improved liquid-chromatographic assay of labetalol in plasma.

Clinical Chemistry (1987)

David R. Luke G R Matzke J T Clarkson Walid M. Awni

This is an assay for labetalol in plasma by "high-performance" liquid chromatography, with 5-(2-[4-(4-chlorophenyl)ethyl]) salicylamide hemihydrate as the internal standard. Plasma samples (500 microL) are extracted with acetonitrile, evaporated under nitrogen, reconstituted in the mobile phase, and injected onto a PRP-1 (Hamilton) column packed with particles of poly(styrene-divinylbenzene) copolymer. Fluorescence, enhanced by post-column introduction of NH4OH, was measured in the effluent (excitation wavelength 340 nm, emission wavelength 418 nm). Retention times for labetalol and the internal standard were 1.99 and 3.32 min, respectively. Inter- and intraday CVs for high and low concentrations of the drug were less than 7.5%. The assay standard curve is linear from 1 to 250 micrograms/L. Some commonly co-administered drugs were tested and did not interfere.

Labetalol

10.1093/clinchem/33.8.1450

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Citations (8)

Cefsulodin pharmacokinetics in patients with various degrees of renal function

Antimicrobial Agents and Chemotherapy (1983)

G R Matzke W. F. Keane

The pharmacokinetics of cefsulodin were characterized in 19 patients with different degrees of renal function after a single 500-mg, 30-min intravenous infusion. Six subjects had a creatinine clearance (Clcr) of greater than 100 ml min-1 (group I), eight had a Clcr of between 12 and 42 ml min-1 (group II), and five had a Clcr of less than 10 ml min-1 (group III). Nine plasma and four urine samples were collected in the first 36 h. The plasma concentration-time data were fitted to a two-compartment open model. The mean beta-phase half-life was 1.77, 6.37, and 10.12 h in groups I, II, and III, respectively. A significant decline in plasma clearance (Clp) was also noted between the three groups: 136 to 49.6 to 27.2 ml min-1 in groups I, II, and III, respectively. Steady-state volume of distribution was 0.26 liter kg-1, regardless of renal function. The observed linear relationship between Clp and Clcr (Clp = 24.09 + 0.765 Clcr; r = 0.9566) can be utilized to revise dosage schedules for patients with any degree of renal impairment. The nonrenal clearance of cefsulodin was also noted to be significantly lower in groups II and III than in group I. Further investigations will be necessary to elucidate the mechanism(s) responsible for the decrease in the nonrenal clearance of cefsulodin.

Cefsulodin

Liter

Clearance

Half-life

Plasma clearance

10.1128/aac.23.3.369

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Citations (11)

Pharmacodynamic modeling of erythropoietin therapy

Pharmacotherapy The Journal of Human Pharmacology and Drug Therapy (1992)

G R Matzke Reginald F. Frye Samuel M. Poloyac

Pharmacodynamics

Epoetin alfa

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Citations (1)

Lack of pharmacodynamic interaction between pentoxifylline and warfarin in the rat.

PubMed (1986)

David R. Luke Michael P. O’Donnell W. F. Keane G R Matzke

Pentoxifylline is a new hemorrheologic agent which decreases platelet aggregation and reduces fibrinogen levels. Its ability to affect the coagulation cascade was studied in rats with and without the coadministration of warfarin. There was no significant difference between the prothrombin time ratio (PTR) of the warfarin group (1.51 +/- 0.38) and the combination drug group (1.47 +/- 0.30) at 6 hours. Likewise, there was no significant difference between the PTR of the control group (1.09 +/- 0.07) and the group administered pentoxifylline alone (1.05 +/- 0.06). Although the mechanisms of action of the two drugs may overlap, the pharmacodynamic activity of warfarin was not significantly altered when pentoxifylline was coadministered.

Pentoxifylline

Pharmacodynamics

Prothrombin time

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Citations (5)

Determinants of vancomycin clearance by continuous venovenous hemofiltration and continuous venovenous hemodialysis

American Journal of Kidney Diseases (1998)

MS Joy G R Matzke Reginald F. Frye Paul M. Palevsky

Hemofiltration

Renal replacement therapy

10.1053/ajkd.1998.v31.pm9631848

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Citations (100)

PUK16 ASSESSMENT OF ADHERENCE WITH IMMUNOSUPPRESSANT MEDICATIONS IN TRANSPLANT PATIENTS AND THE POTENTIAL COST SAVINGS ASSOCIATED WITH INCREASED ADHERENCE

Value in Health (2007)

SE Harpe G R Matzke C Osbon Daksha Ranade Thomas Barrett

Medication Adherence

10.1016/s1098-3015(10)68863-8

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Nephrology Pharmaceutical Care Preceptorship: A Programmatic and Clinical Outcomes Assessment

Annals of Pharmacotherapy (2007)

G R Matzke Wendy L. St. Peter Thomas J. Comstock Eric Foote

Objective:The University of Pittsburgh Nephrology Pharmaceutical Care Preceptorship (NPCP) program was conceived to acquaint health system pharmacists with the pharmacotherapeutic management of dialysis patients, enhance the delivery of pharmaceutical care, and improve clinical outcomes through the development of specialized professional skills. A survey designed to determine the impact of the NPCP program was sent to all 145 participants of the program.Methods:The survey, designed to collect demographic information and data about the participants’ practice sites, professional activities prior to and after the completion of the program, and markers of disease status, was mailed to all participants in September 1997. The 96 respondents (66.2%) were involved in a wide variety of clinical practices; inpatient management of peritoneal dialysis, hemodialysis, or renal transplant patients were most commonly reported.Results:Moro than 80% of the participants believed that the educational content of the NPCP prog...

Nephrology

Pharmaceutical Care

10.1345/aph.140070

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Analytical accuracy of determinations of aminoglycoside concentrations by enzyme multiplied immunoassay, fluorescence polarization immunoassay, and radioimmunoassay in the presence of heparin

Journal of Clinical Microbiology (1984)

Maile O'Connell K L Heim C E Halstenson G R Matzke

The accuracy of gentamicin, netilmicin, and tobramycin concentration determinations by enzyme multiplied immunoassay technique (EMIT; Syva Corp., Palo Alto, Calif.), fluorescence polarization immunoassay (TDx; Abbott Diagnostics, Irving, Tex.), and radioimmunoassay were compared in the presence of 0 to 3,000 USP units of porcine heparin per ml. Gentamicin, netilmicin, and tobramycin concentrations determined by EMIT decreased by 10 and 50% in the presence of 75 and 1,000 USP units/ml, 2 and 5 USP units/ml, and 2 and 7.5 USP units/ml, respectively. Accuracy of the TDx and radioimmunoassay determinations, however, were not affected by the presence of heparin. Blood samples for the determination of gentamicin, netilmicin, and tobramycin by EMIT should not be collected in evacuated heparinized tubes.

Netilmicin

Fluorescence polarization immunoassay

10.1128/jcm.20.6.1080-1082.1984

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Citations (16)

Erythropoietin kinetics in rats: generation and clearance

Blood (1986)

SE Steinberg Juan F. Garcı́a G R Matzke J Mladenovic

Clearance rate

Phlebotomy

Plasma clearance

Half-life