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Biomedical subjects

T E Lackner

Publications and source records attributed to T E Lackner.

At least 19 recordsLinked to original sources
PubMed1995

Use of warfarin for nonvalvular atrial fibrillation in nursing home patients.

OBJECTIVE: To assess warfarin sodium use and anticoagulant monitoring in nursing home patients with nonvalvular atrial fibrillation (NVAF), according to American College of Chest Physicians Consensus Conference guidelines. DESIGN: Retrospective, multicenter, point-prevalence study. SETTING: Nursing homes in Minneapolis-St Paul, Minn. PATIENTS: Nine-hundred two patients 60 years and older, from whom 69 with a diagnosis of NVAF and 16 with valvular atrial fibrillation (VAF) (control group) were identified. DATA COLLECTED: Patient demographics and diseases, diagnostic tests for atrial fibrillation (AF), antithrombotic drugs and dosage, anticoagulant activity test results, other drugs, and drug allergies were determined by chart review and attending physician response to written communication from the nursing home's medical director and consultant pharmacist. MAIN OUTCOME MEASURES: Prevalence of NVAF, VAF, and risk factors for thromboembolism and major bleeding, use of warfarin and other antithrombotic drugs for AF, anticoagulation control, and the relationship of warfarin dose with the recommended international normalized ratio (INR) and prothrombin time (PT). RESULTS: Nonvalvular AF was documented in 7.6% of the patients. Most patients with NVAF were at an increased risk for stroke, yet only 20% without a conventional contraindication to warfarin use experienced anticoagulation; a greater proportion of patients with VAF experienced anticoagulation. The INR was within the recommended range for NVAF over a 6-month period 37% of the time and recommended PT, 52% of the time. An equal percentage of warfarin dose changes occurred in response to a PT ratio outside the recommended range as occurred with an INR outside the recommended range. CONCLUSIONS: Many nursing home patients have NVAF with comorbid conditions that subject them to a greater than average risk for thromboembolic stroke. Warfarin is underused for stroke prophylaxis and often is not used according to the American College of Chest Physician guidelines. Physicians, nurses, and consultant pharmacists must be better informed about (1) known risk factors for thromboembolism and major bleeding to identify patients with AF who will most likely benefit from warfarin therapy, (2) maintaining an INR of 2 to 3, and (3) the need for small warfarin dose adjustments in elderly patients.

Aged↗
PubMed1994

Antiepileptics in the elderly. Pharmacoepidemiology and pharmacokinetics.

OBJECTIVE: To evaluate antiepileptic (AE) use by nursing home residents. DATA SOURCES: Medical records for 996 residents from six Minnesota nursing homes (5% of the nursing home residents in the Minneapolis-St Paul area) compared with medication records of 45,405 nursing home residents nationwide serviced by Pharmacy Corporation of America, Boulder, Colo. STUDY SELECTION: Reports comparing pharmacokinetics in younger adults and elderly volunteers or patients with epilepsy who were given AEs. DATA SYNTHESIS: Among Minnesota nursing home residents, 7.7% were taking AEs. Usage in a national survey was 10.1%. A review of published studies involving small numbers of elderly subjects or patients given phenytoin sodium, valproic acid, or carbamazepine demonstrates decreased protein binding and intrinsic clearance and increased half-life with advancing age. Concomitant drugs, especially those with central nervous system effects, can lower the concentration at which AEs cause dose-related side effects, thereby narrowing therapeutic ranges. CONCLUSION: Approximately 10% of nursing home residents receive AEs, usually with other maintenance medications. In 82% of residents receiving an AE, the indication was treatment of a seizure disorder. Other indications included aggressive behavior, essential tremors, and neurologic pain. Age-related alterations in AE pharmacokinetics result in protein-binding changes and decreases in drug elimination. Measurement of unbound drug concentrations may be helpful when altered binding is suspected or clinical response does not correlate with total AE concentration. Concomitant drugs pose the risk for significant drug interactions and adverse reactions. An understanding of the underlying pharmacokinetic processes, including the need of most elderly patients for lower doses and longer dosing intervals, permits more effective management of therapy and reduces the risk for adverse reactions.

Age Factors↗
PubMed1992

A simple method to estimate the initial dose of gentamicin.

A simple equation to estimate the initial dosing interval of gentamicin was compared with the "rule of eights" equation in 81 adult patients with stable renal function. The Sawchuk-Zaske method was employed as the standard with which dosing intervals estimated by the simple equation and the rule of eights method were compared. The actual mean peak gentamicin concentration was not significantly different from that predicted by the Sawchuk-Zaske method. The actual mean trough concentration was significantly higher than the predicted concentration, but trough concentrations within the usual therapeutic range of 0.5-2 microgram/ml were achieved in more than 90% of patients. The mean dosing interval calculated by Sawchuk-Zaske was not significantly different from that calculated by the equation, but was longer than the one calculated by the rule of eights. A peak gentamicin concentration within the usual therapeutic range was generally achieved with a total daily dose of 3-5 mg/kg of actual body weight. Until gentamicin concentrations are known, an easily remembered equation can be used to estimate the initial dosing interval for gentamicin. When used together with a standard total daily dose of 3-5 mg/kg total body weight, usual therapeutic concentrations are achieved in the majority of patients.

Adolescent↗
PubMed1991

Consistency of evaluators assessing inhaler technique.

Since correct inhaler technique is vital for maximum efficacy, the evaluation of technique in patients or health care professionals involved in education programs or research projects is essential. Inconsistency could lead to confused patients and inaccurate research findings. This study is the first to determine interrater consistency with assessing recitation and demonstration of inhaler technique and, if needed, was designed to improve consistency until 95% agreement was achieved. A checklist for correct inhaler technique was constructed by consolidating information from the literature and package inserts. Initially three evaluators were used, however, a fourth evaluator was added for the last two trials to create teams to improve consistency. Percent agreement, probability and kappa scores were calculated. Six trials evaluating inhaler technique of 56 health care professionals at five different sites, revisions of the checklist, and evaluator teams were required to increase overall percent agreement from 81% to 98%. Agreement increased substantially on the verbal component because of specific changes made in the checklist and the objective nature. Demonstration steps consistently had lower agreement than verbal steps. Agreement on the demonstration component was more difficult because of subjectivity involved in observing a subject actuate the inhaler at the correct time, inhale or exhale slowly, and hold one's breath. The relative rankings of percent agreement and kappa scores were the same, however, kappa scores allowed differentiation of agreement due to chance and ability. To achieve interrater consistency, training and practice are required. Interrater consistency should be achieved to ensure accurate reporting of research results on inhaler technique and education of patients.

Clinical Trials as Topic↗
PubMed1991

Interaction of dexamethasone with phenytoin.

Phenytoin and dexamethasone are frequently administered concurrently to prevent consequences of central nervous system pathology. Limited and conflicting data are available regarding an interaction between the agents. A patient receiving dexamethasone required a daily phenytoin dose of greater than 10 mg/kg to maintain the phenytoin serum concentration within the usual therapeutic range. The concentration increased by nearly 300% after dexamethasone was discontinued.

Adenocarcinoma↗
PubMed1990

Accuracy of pharmacokinetic dose determination of gentamicin in geriatric patients.

Gentamicin pharmacokinetics and the predictive performance of the Sawchuk-Zaske dosing method for gentamicin were compared in elderly and young patients with stable normal serum creatinine concentrations. The predicted peak gentamicin concentrations in both young and elderly patients were not significantly different from the actual measured concentrations. The predicted trough concentrations for both the young and elderly were significantly different from the measured trough concentrations. However, the magnitude of this difference (0.2 micrograms/mL) is not considered to be clinically significant. A trend toward greater underprediction of trough gentamicin concentrations in elderly patients was evident. The mean increase of 15 percent in the gentamicin half-life at steady-state compared with the initial pharmacokinetics analysis in elderly patients was significantly larger than the increase in half-life in the young patients. The Sawchuk-Zaske method was equally accurate in determining the gentamicin dosing regimen in young elderly patients with normal serum creatinine concentrations.

Adolescent↗
PubMed1989

Bifonazole. A review of its antimicrobial activity and therapeutic use in superficial mycoses.

Bifonazole is a substituted imidazole antifungal agent structurally related to other drugs in this group. It possesses a broad spectrum of activity in vitro against dermatophytes, moulds, yeasts, dimorphic fungi and some Gram-positive bacteria. Both non-comparative and comparative clinical trials have clearly demonstrated the efficacy and safety of various formulations of bifonazole 1% (cream, gel, solution and powder) applied once daily in the treatment of superficial fungal infections of the skin such as dermatophytoses, cutaneous candidiasis and pityriasis versicolor. In comparative studies bifonazole was significantly superior to placebo and at least as effective as alternative imidazole antifungal drugs including clotrimazole, econazole, miconazole, oxiconazole and sulconazole. Preliminary studies in other superficial skin and nail infections/dermatoses suggest that bifonazole may be useful for treating onychomycoses (in a combination cream; bifonazole 1% plus urea 40%), otomycoses, erythrasma, sebopsoriasis, seborrhoeic dermatitis and rosacea. However, controlled trials are needed in each of these clinical settings to assess accurately its relative place in therapy. Thus, bifonazole is an effective and well-tolerated treatment for superficial fungal infections of the skin. Compared with the majority of topical antifungal drugs, which need to be applied at least twice daily, bifonazole offers the convenience of once daily administration, which may improve patient compliance.

Antifungal Agents↗
PubMed1988

Endogenous digoxin-like immunoreactivity in elderly patients with normal serum creatinine concentrations.

The effect of digoxin-like immunoreactive substance (DLIS) on serum digoxin determinations in elderly patients with normal serum creatinine concentrations was studied. Patients in the study group were over 70 years of age; the control population was under 55 years of age. All patients had serum creatinine concentrations of less than or equal to 1.5 mg/dL. Apparent digoxin content of serum samples from patients receiving digoxin and from patients in each age group who were not receiving digoxin was determined in duplicate by each of two radioimmunoassays: RIANEN (New England Nuclear), which detects DLIS, and Immophase (Corning Medical and Scientific), which is far less cross-reactive with DLIS. Results from the patients under 55 years of age were analyzed for inherent bias between the assay methods. In patients over 70 years of age, concentrations of DLIS (differences between serum digoxin concentrations measured by RIANEN and Immophase) were compared with creatinine clearance values. No DLIS was detected in sera of patients who had not received digoxin. For patients who received digoxin, nearly all apparent digoxin concentrations were within the usual therapeutic range. For patients without liver or renal failure who received digoxin, no significant difference in digoxin concentrations was observed between the RIANEN and Immophase assays in either the young (n = 17) or elderly (n = 26) patients. There was no significant increase in the difference between the RIANEN and Immophase results with decreasing creatinine clearance. In the elderly patients with normal serum creatinine concentrations, there was no evidence that measurement of serum digoxin concentration using the RIANEN and Immophase assays was compromised by DLIS.

Adult↗
PubMed1987

Ceforanide. A review of its antibacterial activity, pharmacokinetic properties and clinical efficacy.

Ceforanide is a 'second generation' cephalosporin administered intravenously or intramuscularly. It is similar to cefamandole and cefonicid in its in vitro superiority to 'first generation' cephalosporins against several species of Enterobacteriaceae as well as its activity against Haemophilus influenzae, including beta-lactamase-producing strains. Its activity against Staphylococcus aureus is less than that of cefamandole, cefuroxime and first generation cephalosporins. The in vitro activity against Neisseria gonorrhoeae is excellent. Pseudomonas, Acinetobacter and Serratia species, and Bacteroides fragilis are resistant, as are many strains of Proteus and Providencia species. The elimination half-life is relatively long, although shorter than that of cefonicid, and in most clinical trials ceforanide has been administered twice daily. It appeared to be comparable in therapeutic efficacy to procaine penicillin and cephazolin in the treatment of patients with community-acquired pneumonia, to cephazolin in the treatment of skin and soft tissue infections due to S. aureus or beta-haemolytic streptococci and to cefapirin in S. aureus endocarditis in parenteral drug abusers. Also, it was comparable in efficacy to cephalothin in the prophylaxis of infection in patients undergoing open heart surgery or vaginal hysterectomy, and to cephazolin in patients undergoing cholecystectomy. Thus, ceforanide is an alternative to first and certain other second generation cephalosporins in several important therapeutic and prophylactic situations. It has no advantage over other cephalosporins with regard to spectrum of antibacterial activity, but has a longer half-life than other second generation cephalosporins, except cefonicid, and can be administered according to a twice daily dosage schedule.

Bacteria↗
PubMed1983

Lidocaine stability in cardioplegic solution stored in glass bottles and polyvinyl chloride bags.

The stability of lidocaine hydrochloride in buffered cardioplegic solutions stored in glass and polyvinyl chloride bags was studied. Concentrations of lidocaine (incorporated as the hydrochloride salt) were measured in buffered cardioplegic solutions containing potassium chloride, sodium bicarbonate, dextrose, and sodium chloride. Solutions were stored at 22 +/- 2 degrees C and 4 degrees C in glass bottles and 500-ml and 250-ml polyvinyl chloride (PVC) containers; some 250-ml PVC bags were underfilled to study the effects of varying surface area-volume ratios. Lidocaine concentrations were measured using a homogeneous enzyme immunoassay (EMIT, Syva Corporation) on days 0, 1, 2, 7, and 21. Lidocaine concentrations decreased significantly in all PVC bags stored at 22 degrees C and in underfilled PVC bags stored at 4 degrees C. Lidocaine loss in PVC bags appeared to result from sorption. It is concluded that lidocaine is stable in cardioplegic solutions when these are refrigerated and stored in glass containers or filled large-volume PVC bags for 21 days.

Drug Combinations↗