PubMed Health⌕ Search

Biomedical subjects

H I Bussey

Publications and source records attributed to H I Bussey.

At least 19 recordsLinked to original sources
PubMed1992

Potential warfarin-ciprofloxacin interaction in patients receiving long-term anticoagulation.

This study prospectively evaluated the potential interaction between the oral anticoagulant warfarin and the quinolone antimicrobial agent ciprofloxacin. After a 10-day placebo lead-in phase, 16 patients stabilized with long-term warfarin therapy were randomized to receive ciprofloxacin 500 mg or a matching placebo twice/day for 10 days. International normalized ratios (INRs) measured by both standard laboratory analysis and by Coumatrak (finger-stick) methods were evaluated at 3- to 5-day intervals. No patient experienced a significant increase in INR. No patient experienced a bleeding event. These data support the fact that a warfarin-ciprofloxacin interaction does not routinely occur at this dosage and duration of ciprofloxacin therapy.

Adult↗
PubMed1992

Reliance on prothrombin time ratios causes significant errors in anticoagulation therapy.

BACKGROUND: The intensity of warfarin anticoagulation in the United States may be inappropriate if the international normalized ratio (INR) is not used, or if the international sensitivity index (ISI) of the thromboplastin is outside the range of 2.2 to 2.6. METHODS: Fifty-three hospital laboratories provided data on the sensitivity of their thromboplastin and whether they reported INR values. Additional data on thromboplastin sensitivity were obtained from 140 laboratories involved in the Stroke Prevention in Atrial Fibrillation study. The three major manufacturers of thromboplastin confirmed the range of thromboplastin sensitivity reported by the laboratories. RESULTS: Of 53 laboratories surveyed, 16 (30%) could not provide ISI data and only 11 (21%) reported INR results. Unlabeled thromboplastin was being used by 20% to 24% of laboratories, and only 8% to 20% were using thromboplastins with an ISI of 2.2 to 2.6. At the time the three manufacturers were contacted, they reported marketing thromboplastins with ISI values from 1.2 to 2.8, but none of the thromboplastins at that time had ISI values between 2.2 and 2.6. CONCLUSION: Warfarin therapy in the United States is managed inappropriately because most laboratories do not report INRs and the variability in thromboplastin sensitivity produces misleading prothrombin time ratio results. Additionally, recent research may require reexamination if INR or ISI data were not provided.

Data Collection↗
PubMed1989

Evaluation of factors associated with stability of anticoagulation therapy.

Eighty-two patients receiving long-term warfarin therapy provided 199.34 patient-years of data that were evaluated to determine if certain variables could identify those who might be monitored safely at less frequent intervals. Most patient demographics, social habits, medical histories, indications for anticoagulation, and concurrent therapy were not useful in discriminating between patients with stable (n = 67) and unstable (n = 15) anticoagulation. A few trends were noted, but they failed to achieve statistical significance. Patients who never achieved stability (the unstable group) tended to be younger than those who did (p 0.13). Among the stable patients, those with a diagnosis of deep vein thrombosis or pulmonary embolus, or with elevated alanine aminotransferase values, were significantly more likely to require a dosage change. The probability of requiring a dosage change at monthly visits did not correlate with the time required to become stable, but it did correlate inversely with the duration of stable anticoagulation. This probability declined from almost 16% when monitoring frequency was first extended to monthly intervals to less than 8% at 2 months of stable anticoagulation, and tended to decline further with longer periods of stable therapy. Of the 67 patients who became stable, 23 did not require a dosage change during an average of 526 days of follow-up. Among the 44 stable patients who required a dosage change, the mean time to the change was 250 days after becoming stable. Few complications occurred, almost all of them early in therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The safety and effectiveness of long-term warfarin therapy in an anticoagulation clinic.

Whenever long-term anticoagulation is prescribed, the risks of such therapy must be evaluated accurately. Whether these risks are influenced by the duration of therapy, the indication for therapy, patient demographics and social habits, or the use of an anticoagulation clinic is controversial. This study examined the occurrence rates of major hemorrhage, minor hemorrhage, and thromboembolic events among an inception cohort of 82 patients receiving long term-warfarin therapy in an anticoagulation clinic. During 199.34 patient-years of observation, there were 4 major hemorrhages (0.0201/patient-year), 31 minor hemorrhages (0.1555/patient-year), and 7 thromboembolic events (0.0351/patient-year). Although each type of event tended to occur during the first 6 months of therapy, this trend was not statistically significant. Failure to demonstrate statistically significant influence of any of the evaluated variables may have been due to the unusually low rate of complications, a finding that may reflect the safety of anticoagulant therapy when managed by a specialized clinic.

Adult↗
PubMed1988

A comparative trial of digoxin and digitoxin in the treatment of congestive heart failure.

A randomized, crossover, single-blind study compared the efficacy and dosing accuracy of digoxin and digitoxin in 15 ambulatory patients wth congestive heart failure. Loading doses and maintenance doses were calculated according to published equations that adjust for sex, height, and lean body weight (for digitoxin), plus estimated creatinine clearance (for digoxin). At each 2-week visit, serum drug concentrations were measured and compliance with the prescribed regimen was assessed by tablet count. At the end of each study period, a congestive heart failure (CHF) score was determined in a blinded fashion by the same physician. Patient compliance was unusually high (greater than or equal to 80%) at every visit. Therapeutic concentrations were achieved with digoxin and digitoxin in 5 and 14 patients, respectively (p less than 0.05). During digitoxin therapy, CHF scores were lower than pretreatment values (p less than 0.05). The difference between CHF scores during the digoxin and digitoxin periods did not achieve significance (0.05 less than p less than 0.06). Therapeutic serum concentrations can be achieved more easily and frequently with digitoxin than digoxin without compromising the patient's CHF status.

Adult↗
PubMed1988

Effect of influenza vaccine on chronic warfarin therapy.

Whether influenza vaccination causes a prolongation in the prothrombin time (PT) and produces bleeding complications in patients receiving chronic warfarin therapy is a clinically important controversy. The degree of anticoagulation during chronic warfarin therapy of 33 patients was assessed before and after vaccination with trivalent types A and B influenza vaccine. Three patients were excluded because of inadequate PT data before vaccination and one patient was unavailable for follow-up after vaccination. Data from five additional patients were excluded from statistical analysis because the warfarin dose was changed within one week of vaccination. PT values obtained at zero to two weeks, three to four weeks, and two, three, and four months after vaccination were compared with each patient's prevaccination baseline value. PT values following vaccination were unchanged except for a decrease that occurred during the first two weeks (p less than 0.05). Complications did not require dosage adjustments and were limited to minor nose bleeds or bruises occurring in two patients before and three patients after vaccination. These data suggest a decrease rather than an increase in PT values following vaccination, and do not support the existence of a serious warfarin-vaccine interaction. The possibility that an occasional patient may experience such an interaction cannot be excluded, but none was seen in these patients.

Adult↗
PubMed1988

Clinically significant diuretic-induced glucose intolerance.

Diuretic-induced glucose intolerance is cited frequently as a problem of only limited clinical significance. In certain populations, such as Mexican-Americans, this effect may be much more dramatic. A 50-year-old obese Mexican-American woman presented with a three-month history of increased thirst and frequent urination. A fasting blood glucose concentration of 365 mg/dL prompted initiation of chlorpropamide therapy. A review of her medical history revealed that a thiazide diuretic was started six months previously. A reduction in thiazide dose and potassium supplementation together with chlorpropamide therapy controlled the patient's blood glucose. Subsequently, all three medications were discontinued, and the patient remained normoglycemic during a full year of follow-up. The temporal relationship between symptomatic diabetes and hydrochlorothiazide therapy incriminates the diuretic as the most probable cause.

Benzothiadiazines↗
PubMed1988

Lack of endogenous crossreactivity with three digitoxin radioimmunoassays in adults with renal insufficiency.

The possibility of interference by apparent digitoxin-like immunoreactive substance (DTLIS) with three radioimmunoassays was studied in patients with renal insufficiency. From each of 25 adult patients with renal insufficiency and 25 age-matched and sex-matched control subjects with normal renal function, a single serum sample was obtained and assayed for digitoxin content by three commercially available radioimmunoassays (GammaCoat, Coat-A-Count, and the Wien assay). Although two of the three assays found measurable concentrations, the difference in apparent digitoxin concentrations between the control subjects and those with renal insufficiency was not significant. Assay interference could not be explained on the basis of differences in age, serum creatinine concentration, or weight. The magnitude of DTLIS interference in relation to the digitoxin therapeutic range appears to be small with the radioimmunoassays used in this study.

Acute Kidney Injury↗
PubMed1986

Practical value of a new serum digitoxin assay.

The purpose of this study was to evaluate a new fluorescence polarization immunoassay, TDx, for digitoxin by comparing the results of this assay with those of a radioimmunoassay (RIA). Thirty-three serum samples were obtained from 15 patients during, and for 4 weeks after, a 4-week course of digitoxin therapy. Each sample was separated by centrifugation, coded, and frozen until analysis. At the time of analysis, each sample was divided and analyzed simultaneously by TDx and RIA. Nine samples yielded results less than 2 ng/ml (limit of assay sensitivity) by one or both methods and were excluded from further data analysis. Linear regression analysis of the results of the remaining 24 paired samples (x = TDx, y = RIA) revealed a strong correlation coefficient of r2 = 0.95, slope = 0.95, and a y intercept of -0.99 (y = -0.99 + 0.95x). Additionally, the TDx results were lower than the RIA values in only five of 33 paired samples; and these occurred in four patients who had a significantly lower mean estimated creatinine clearance than that of the other 11 patients (39.0 +/- 9.1 ml/min/1.73 m2 vs. 63.3 +/- 11.8 ml/min/1.73 m2, p less than 0.01). The TDx system is a comparable alternative to the RIA method, but differences in specificity and sensitivity may exist and should be evaluated more thoroughly.

Aged↗
PubMed1984

Digoxin.

Explore the source record for details and available documents.

Digoxin↗
PubMed1984

The influence of rifampin on quinidine and digoxin.

Serum drug concentration data from the first of the two patients described herein suggest that rifampin may directly increase the metabolism of quinidine and thereby negate the influence of quinidine on the serum digoxin concentration (SDC). Data on the second patient suggest that rifampin may directly increase the metabolism of digoxin producing lower SDC values. In both cases, the discontinuation of rifampin therapy appears to have allowed reversion toward prerifampin metabolism of both quinidine and digoxin.

Aged↗
PubMed1983

A prospective evaluation of therapeutic drug monitoring.

Since therapeutic drug monitoring is rapidly becoming a widely used tool in clinical medicine, we prospectively assessed 390 serum drug assays over a 4-week period to determine the appropriateness of serum sample collection. The results of appropriately collected samples were used to evaluate the ability of the physician to interpret and apply this information. Of the 244 samples evaluated in the study, 104 (43%) were inappropriately collected. The physician apparently misapplied the results in 40 of 101 (40%) instances. When combined, this represented a misuse of therapeutic drug monitoring 70% of the time and documented an unjustifiable expense of $3,600 for the 4 weeks. The magnitude of misuse of this tool warrants the implementation of measures to assure appropriate serum sampling and application of therapeutic drug monitoring.

Costs and Cost Analysis↗