Evaluating Patients’ Warfarin Requirements

Jones, B.; Baran, Andrij; Reidenberg, Marcus M.

doi:10.1111/j.1532-5415.1980.tb00116.x

Cited by 17 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…INR response to an initial warfarin dose is largely reliant on the magnitude of the initial dose relative to the eventual maintenance dose (a proxy for warfarin sensitivity). 15 Initial INR response from the first 2 doses is not fully evident until days 3 and 4. These are the 2 days of the new protocol involving the majority of the dose adjustment.…”

Section: Discussionmentioning

confidence: 99%

Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement

2016

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement

2016

View full text Add to dashboard Cite

show abstract

“…5 A number of studies have suggested that the elderly exhibit increased sensitivity to the anticoagulant effects of warfarin. [6][7][8][9][10][11][12][13][14][15][16][17] In addition to age, some studies have shown contributing effects from other factors such as urea levels, 6 concomitant drug therapy, 7 albumin levels, 8 duration of treatment, 10 indication for anticoagulation, 12 weight, 12,14,16 gender, and interacting medications. 16 The pharmacologic response of drugs such as warfarin in minority populations has not been studied.…”

Section: Increased Sensitivity To Warfarin In Elderly Hispanicsmentioning

confidence: 99%

Increased Sensitivity to Warfarin in Elderly Hispanics

Casner

Sandoval

2002

The Journal of Clinical Pharma

View full text Add to dashboard Cite

It has been suggested that aging enhances the pharmacologic effect of warfarin, but there is little information about the effects of warfarin in aging minority populations. The authors examine the response of an aging Hispanic population to warfarin. Charts in their anticoagulation clinic were retrospectively examined for the following information: age, sex, weight, duration of anticoagulant therapy, number of medical problems, number of medications, number of minor or major bleeding episodes, prothrombin time, warfarin dose, and international normalized ratio (INR). The dose-adjusted prothrombin time ratio (PTR) and dose-adjusted INR were calculated by dividing the PTR and INR by the mean warfarin dose. Four groups were compared by age: < 50, 50 to 59, 60 to 69, and > or = 70. A total of 243 charts were reviewed: 113 female, 130 male; 90% were Hispanic. The most common indication for anticoagulation was atrial fibrillation. Elderly patients had more medical problems (3.1 vs. 2.4) and took more medications (3.4 vs. 2.4) than younger patients. The dose-adjusted PTR and dose-adjusted INR increased with aging (0.59 vs. 0.38 and 0.85 vs. 0.59, p < .05 ANOVA). In a multiple linear regression analysis, only age remained significantly associated with the anticoagulant effect. These results are consistent with previous reports on the effect of warfarin in aging patients and extend these data to the Hispanic population.

show abstract

“…For this reason, barbiturates probably have little role in geriatric therapy. However, there are actually relatively few objective data on this subject, and what data are available suggest different conclusions 77 . Traeger et al 78 showed that the half‐life of phenobarbital increases from 71 hours in a young age group to 107 hours in subjects over age 70.…”

Section: Review Of Literature and Current Researchmentioning

confidence: 99%

Pharmacology and Aging

Vestal

1982

J American Geriatrics Society

View full text Add to dashboard Cite

AgingThe elderly use more drugs than younger people, and often require multiple drugs, with the potential for drug interactions and adverse drug reactions. It is not known to what extent age per se may predispose to drug interactions. Furthermore, the toxicology of drugs in the elderly has received almost no systematic investigation. For example, are the elderly more susceptible than the young to the hepatotoxic effects of some drugs? Epidemiologic studies using standardized methodology, such as the Defined Daily Dose, are needed to compare drug utilization in both ambulatory and institutionalized elderly between countries and regions. This will provide the basis for the evaluation of the effects of educational programs aimed at promoting rational drug therapy in the elderly. Analysis of the differences on drug use and drug prescribing patterns in various countries may yield insight into the determinants of those patterns and suggest optimal educational approaches. Available evidence indicates that age-related alterations in the physiology of drug distribution, drug elimination, and drug action are the substrata upon which disease-related alterations in drug disposition and drug response are superimposed. Continued efforts to characterize these age-related and disease-related effects are needed. At present, generalizations are difficult because of conflicting data. Greater attention to subject selection, environmental factors, such as smoking and diet, and protocol design is necessary. As much as possible, research protocols should attempt to simulate the actual clinical use of the drug under study. This often means conducting studies at steady state after multiple dosing rather than only after a single dose. A longitudinal study using model compounds would be of great interest to help distinguish the effects of aging per se from those of disease. Wherever possible, pharmacodynamic studies should be combined with studies of pharmacokinetics. Gaps in our knowledge exist for all drug classes. Continued basic research in pharmacology and physiology is required to elucidate the mechanisms for the age differences observed in clinical studies. This research depends on the use of animal and in vitro model systems. Efforts to define the optimal animal or in vitro model(s) for human geriatric pharmacology are obviously important components of this basic research. Although compliance with therapeutic regimens is not necessarily worse in the elderly than in younger age groups, the consequences of errors in self medication may be more severe. Thus, further efforts are needed to develop ways of enhancing the comprehension and compliance of geriatric patients.The elderly are in many ways a more heterogeneous group than the young. Because of wide differences in the rates of deterioration of organs and enzyme systems with age, it is not possible to establish a guideline to allow for altered drug responses. Effective and safe use of drug therapy for old people is, therefore, a matter of individual prescribing and treatment.The ke...

show abstract

Evaluating Patients’ Warfarin Requirements

Cited by 17 publications

References 4 publications

Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement

Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement

Increased Sensitivity to Warfarin in Elderly Hispanics

Pharmacology and Aging

Contact Info

Product

Resources

About