Biomedical subjects

S C Boike

Publications and source records attributed to S C Boike.

6 recordsLinked to original sources

PubMed1990

Nephrotoxicity of vancomycin, alone and with an aminoglycoside.

The incidence of nephrotoxicity in patients receiving vancomycin alone or in combination with an aminoglycoside was prospectively evaluated. A total of 231 courses of antibiotic therapy in 224 patients were consecutively monitored over 28-month period. One hundred and sixty-eight patients received vancomycin alone, 63 patients received vancomycin with an aminoglycoside, and 103 patients received gentamicin. Nephrotoxicity was defined as an increase in serum creatinine of 0.5 mg/dl or a 50% increase above baseline, whichever was greater. Eight patients (5%) receiving vancomycin alone, 14 patients (22%) receiving vancomycin with an aminoglycoside, and 11 patients (11%) receiving gentamicin alone were found to have nephrotoxicity. Factors found to be associated with increased risk of nephrotoxicity in patients receiving vancomycin were concurrent therapy with an aminoglycoside, length of treatment with vancomycin (greater than 21 days), and vancomycin trough serum concentration (greater than 10 mg/l). Although the incidence of vancomycin nephrotoxicity is low, patients receiving vancomycin therapy with the above risk factors should be closely monitored.

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PubMed1988

Comparison of serum sampling methods for determining vancomycin dosage regimens.

The predictive ability of a four-point sampling method versus a two-point sampling method for vancomycin was assessed in 11 patients with various staphylococcal infections. All steady-state predictions were based on first-dose pharmacokinetic parameters. The mean vancomycin serum concentrations achieved at 4 and 8 h postinfusion were not significantly different from the predicted concentrations derived from either the four- or two-point method. Also, there was no significant difference between the two methods in predictive ability or accuracy. Both methods underpredicted the steady-state concentration to the same degree, 2.9 micrograms/ml at 4 h and 3.1 micrograms/ml at 8 h, which would appear to be clinically acceptable. A one-compartment pharmacokinetic model, which uses two serum concentrations, appears to be adequate for adjusting vancomycin regimens.

Adult↗

PubMed1986

Clinical use and toxicity of high-dose tobramycin in patients with pseudomonal endocarditis.

The effects and toxicity of tobramycin were assessed in 26 patients receiving high-dose (approximately 8 mg/kg/d) therapy for pseudomonal endocarditis or conventional-dose (approximately 3 mg/kg/d) therapy for various systemic Gram-negative infections. Patients in the high-dose group received an average of 29.5 g of drug over 49 days and the dosage was adjusted to maintain peak serum concentrations of 15-20 mg/l. In the conventional-dose group, patients received an average of 8.6 g of tobramycin over 26.7 days and the dosage was adjusted to achieve peak concentrations of 4-10 mg/l. Clinical evidence of acute renal failure was not apparent in any patient. Five of seven patients in the high-dose group, for whom audiologic data was available, exhibited loss of hearing sensitivity in the high frequency range, but no patients sustained significant reduction in hearing in the conversational frequency range. Patients receiving high-dose tobramycin do not appear to be at greater risk for development of nephrotoxicity than do patients receiving conventional-dose therapy.

Adult↗

PubMed1986

Individualized adjustment of vancomycin dosage: comparison with two dosage nomograms.

An individualized method of vancomycin dosage adjustment using steady-state serum concentrations was assessed in 50 patients (86 sets of vancomycin serum concentrations). The predictive accuracy of this method was compared with that of two published nomograms (Moellering, Matzke). Peak and trough serum concentrations predicted from previously drawn vancomycin serum concentrations (individualized method) using a one-compartment pharmacokinetic model were compared with measured steady-state peak and trough serum concentrations. Predicted peak and trough serum concentrations were also generated for both the Moellering and Matzke nomograms by using the elimination rate constant derived from each of the respective nomograms and the fixed volume of distribution (0.9 L/kg) assumed by the nomograms, and the actual administered vancomycin dose and dosage interval. These predicted concentrations were also compared with the measured peak and trough concentrations. Statistical measures of bias and precision indicated that the individualized method of dosage adjustment more closely predicted vancomycin serum concentrations following a dosage change than did either of the nomograms. Overall, the Moellering nomogram was the least accurate of the three methods in predicting vancomycin serum concentrations, and this nomogram should not be used to titrate vancomycin dosages in a clinical setting. Adjustment of vancomycin dosages should be individualized based on pharmacokinetic data derived from measured serum concentrations. In situations where quantitative analysis of vancomycin concentrations is not available, the Matzke nomogram appears to be a reasonable method of adjusting vancomycin dosages.

Adult↗

PubMed1986

Monitoring vancomycin therapy.

Vancomycin is an effective and widely used antistaphylococcal antibiotic. Despite several decades of use, however, our knowledge of the toxicologic and pharmacokinetic properties of vancomycin remains incomplete. This review summarizes current information regarding the adverse reactions and pharmacokinetics of vancomycin. Although there have been reports of side effects with vancomycin, these effects tend to be infrequent, easily managed, and reversible. Several methods for adjustment of vancomycin therapy have been recommended. The relationship between serum concentrations of vancomycin and the occurrence of ototoxicity or nephrotoxicity has not been well established. However, because of large interpatient variations in pharmacokinetic parameters, it seems preferable to individualize vancomycin therapy based on serum concentration data.

Adult↗

PubMedDate not supplied

Evaluation of the vancomycin-clearance:creatinine-clearance relationship for predicting vancomycin dosage.

Four methods of predicting vancomycin maintenance doses on the basis of the relationship between total-body or renal clearance of the drug and creatinine clearance were evaluated retrospectively using data from 24 patients who received vancomycin hydrochloride. Data for 18 men and 6 women with creatinine clearances of 10-130 mL/min were used; the mean (+/- S.D.) vancomycin maintenance dose was 22.0 +/- 11.2 mg/kg/day. The actual vancomycin maintenance dose needed to sustain an average steady-state vancomycin concentration of 15 mg/L was determined based on individual pharmacokinetic values. Predicted vancomycin maintenance doses were generated using the vancomycin-clearance:creatinine-clearance relationships derived separately by Nielsen, Moellering, Rotschafer, and Matzke. Orthogonal regression analysis was used to determine relationships between actual and predicted maintenance doses. Predictive ability of each method was assessed for bias (mean error) and precision (root mean squared error). Mean error and root mean squared error (+/- S.D.), respectively, for the four methods were as follows: Nielsen -262 +/- 451, 522 +/- 718; Moellering -91 +/- 439, 448 +/- 547; Rotschafer 192 +/- 602, 632 +/- 682; and Matzke -76 +/- 101, 408 +/- 517. Doses predicted by the Nielsen relationship were significantly lower than the actual vancomycin maintenance doses. Use of the Rotschafer relationship resulted in substantial overprediction, which increased as creatinine clearance declined. Doses predicted by the Moellering and Matzke relationships were slightly less than but not significantly different from the actual dose. The Matzke method demonstrated the least bias and was the most precise.(ABSTRACT TRUNCATED AT 250 WORDS)

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