Assessment of an Age-Adjusted Warfarin Initiation Protocol

2003 ◽  
Vol 37 (6) ◽  
pp. 799-803 ◽  
Author(s):  
Gregory W Roberts ◽  
Trine Helboe ◽  
Cathrine BM Nielsen ◽  
Alex S Gallus ◽  
Iwona Jensen ◽  
...  
Keyword(s):  
Warfarin Therapy ◽  
International Normalized Ratio ◽  
Albumin Level ◽  
Teaching Hospitals ◽  
Factors Affecting ◽  
Number Of Patients ◽  
Warfarin Dosing ◽  
Student’S T ◽  
Titration Protocol ◽  
Attending Physician

OBJECTIVE: To examine the time taken to reach a stable international normalized ratio (INR), as well as the incidence of overanticoagulation of an age-adjusted warfarin initiation protocol. METHODS: Inpatients and outpatients commencing warfarin therapy at 2 teaching hospitals were dosed according to the age-adjusted protocol. Data were collected prospectively. MAIN OUTCOME MEASURES: Time to reach a stable INR of 2–3 and the number of patients experiencing an INR ≥4 during the first week of warfarin therapy. RESULTS: Seventy-three patients were assessed; at the completion of the 4-day titration protocol, 63% had achieved a stable INR. After an additional 2 days of empiric dosage adjustment by the attending physician, 86% of the subjects demonstrated a stable INR. Five patients (7%) experienced an INR ≥4. These patients had a nonsignificant trend toward a lower plasma albumin level compared with other patients (p = 0.057, Student's t-test). The INR-driven dose adjustments on days 3 and 4 of this protocol coped with other variables that have been shown to affect maintenance warfarin dosing. These included weight, gender, pharmacologic factors affecting clearance, and the presence of certain predesignated risk factors. CONCLUSIONS: The age-adjusted dosing protocol rapidly achieved a stable INR with minimal overanticoagulation. Patients with low serum albumin levels (<3.0 g/dL) may be sensitive to the effects of warfarin during the loading phase.

A Protocol for the Rapid Normalization of INR in Trauma Patients with Intracranial Hemorrhage on Prescribed Warfarin Therapy

2008 ◽  
Vol 74 (9) ◽  
pp. 858-861 ◽  
Author(s):  
Michael Kalina ◽  
Glen Tinkoff ◽  
Adebayo Gbadebo ◽  
Paula Veneri ◽  
Gerard Fulda
Keyword(s):  
Intracranial Hemorrhage ◽  
Prothrombin Complex Concentrate ◽  
Warfarin Therapy ◽  
International Normalized Ratio ◽  
Fresh Frozen Plasma ◽  
Operative Intervention ◽  
Trauma Patients ◽  
Number Of Patients ◽  
Fresh Frozen ◽  
Factor Concentrate

Trauma patients on prescribed warfarin therapy sustaining intracranial hemorrhage can be difficult to manage. Rapid normalization of coagulopathy is imperative to operative intervention and may affect outcomes. To identify and expedite warfarin reversal, we designed a protocol to administer a prothrombin complex concentrate. A Proplex T protocol was instituted in May 2004. It dictated that trauma patients with an International Normalized Ratio (INR) greater than 1.5, history of prescribed warfarin therapy, and intracranial hemorrhage on CT scan receive a prothrombin complex concentrate for reversal of their coagulopathy. Neither the protocol nor the factor concentrate was validated for use in this subset of trauma patients; therefore, adherence to the protocol and use of the factor concentrate was not mandatory. Patients not administered the prothrombin complex concentrate received vitamin K and fresh-frozen plasma. The protocol resulted in an increased number of patients receiving Proplex T (54.3% vs 35.4%, P = 0.047). Protocol patients had improved times to normalization of INR (331.3 vs 737.8 minutes, P = 0.048), number of patients with reversal of coagulopathy (73.2% vs 50.9%, P = 0.026), and time to operative intervention (222.6 vs 351.3 minutes, P = 0.045) compared with control subjects. There were no differences in intensive care unit (ICU) days, hospital days, or mortality. The Proplex T protocol increased the number of patients who received prothrombin complex concentrate, provided rapid normalization of INR, and improved time to operative intervention.

Use of Venipuncture Blood Sample for INR Testing on a Point of Care Machine.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4159-4159
Author(s):  
Mandeep S. Dhami ◽  
Anca Bulgaru ◽  
K. Jagathambal ◽  
Dinesh Kapur ◽  
Francine Norris ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Blood Sample ◽  
Warfarin Therapy ◽  
Point Of Care ◽  
Test Strip ◽  
International Normalized Ratio ◽  
Blood Draw ◽  
Number Of Patients ◽  
Obtain Blood Sample ◽  
Oncology Practice

Abstract Point of care (POC) testing of International Normalized Ratio (INR) for monitoring warfarin therapy is rapidly becoming procedure of choice for patients requiring long term oral anticoagulation. This method allows for fingerstick blood sample to be used for INR testing at the point of service with immediate dose modification as needed. Most patients prefer a fingerstick method for blood draw to venipuncture. It is not known if venipuncture blood sample can be used for testing on POC machines. A significant number of patients in an oncology practice need additional laboratory testing on the same day as INR testing. These patients therefore get a fingerstick for POC INR testing and a venipuncture for other tests. We compared results of INR from venipuncture sample run on a POC machine (CoaguChek monitor) using CoaguChek test strips (ISI-2.0) with the INR performed on MDA analyzer (ISI-2.0). Blood samples from 24 patients on warfarin therapy were drawn from antecubital vein by a clean stick in a 10 cc plastic syringe. A drop of blood was immediately placed on the CoaguCheck test strip. Next the same blood sample was used to fill a 3.2% sodium citrate tube for testing on MDA analyzer. Results were analyzed using regression analysis; the correlation coefficient (r), slope and intercept were determined and following graph of the regression analysis was generated (see figure 1). Conclusions: These results show a good correlation (r-value&gt; 0.9) between the results of INR obtained on CoaguChek POC machine and the MDA analyzer using venipuncture blood sample. The preferred method to obtain blood sample for POC INR monitoring must remain fingerstick sample as per manufacturer’s recommendations. However, for those patients who need more than one blood sample done on the same day, a venipuncture sample as described above gives acceptable results when tested on CoaguCheck machine. Figure Figure

scholarly journals Does prophylactic antibiotic administration for tooth extraction affect PT-INR in patients taking warfarin?

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Eiji Iwata ◽  
Akira Tachibana ◽  
Junya Kusumoto ◽  
Naoki Takata ◽  
Takumi Hasegawa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Tooth Extraction ◽  
Warfarin Therapy ◽  
Prophylactic Antibiotic ◽  
International Normalized Ratio ◽  
Antibiotic Administration ◽  
Number Of Patients ◽  
Warfarin Treatment ◽  
Before And After

Abstract Background Various antibiotics and analgesics have been reported to interact with warfarin. Reports that investigate the effects of medication taken for just a few days during tooth extraction on the prothrombin time-international normalized ratio are rare. Methods A total of 110 patients receiving long-term stable warfarin therapy underwent tooth extraction without interruption of warfarin treatment. INR values were measured 1 month before the tooth extraction, the day of the extraction, and 1 week after the extraction. We investigated the changes in INR values between the day of extraction and 1 week after extraction, as well as the various risk factors for increases in INR values. Results Before and after tooth extraction, the number of patients taking cefcapene pivoxil, amoxicillin, and azithromycin was 57, 36, and 8, respectively. Nine patients were administered ampicillin before tooth extraction and received amoxicillin after their tooth extraction. One week after tooth extraction, the INR values increased beyond the therapeutic range in 3 out of 110 patients (2.7%). The INR values before tooth extraction in these three patients were close to 3.0. The INR value increased by more than twice as much in 1 out of 110 patients (0.9%). Conclusion Our results suggest that prophylactic antibiotic administration has little effect on INR values when patients on stable warfarin therapy undergo tooth extraction. Surgeons have to take attention if the patients whose INR values are close to 3.0 before their extraction.

Adherence to Anti-coagulant therapy in elderly patients with Atrial fibrillation in the Kyrgyzstan

Biomedicine ◽  
2021 ◽  
Vol 41 (3) ◽  
pp. 682-685
Author(s):  
Kanat kyzy Bazira ◽  
Nazgul Kinderbaeva ◽  
Gulnora Karataeva ◽  
Sabira Mamatova ◽  
Ulan Kundashev ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Elderly Patients ◽  
Warfarin Therapy ◽  
Anticoagulation Therapy ◽  
International Normalized Ratio ◽  
Adverse Outcomes ◽  
Drug Of Choice ◽  
Number Of Patients ◽  
Elderly Outpatients

Introduction: Anticoagulant therapy can prevent adverse outcomes of Atrial fibrillation (AF), reducing the risk of stroke by 64% and death by 25%. The present study aimed to assess treatment adherence in elderly patients with non-valvular atrial fibrillation (NVAF) who were prescribed the vitamin K antagonist warfarin.   Materials and methods: In the present retrospective study, we analyzed the medical records of 202 elderly outpatients with NVAF aged between 65 and 74 years (mean ± SD: 68.7 ± 10.2 years).    Results: Problems associated with warfarin arose throughout the follow-up period. After 1 month of treatment, the number of patients taking warfarin had decreased to 71.3% of all patients; less than half of the patients (46%) were still taking the drug. In subsequent periods, the number continued to decrease; of all patients who had been prescribed warfarin with periodic international normalized ratio (INR) control, only 19 (9.4%) remained after 1 year. Our study revealed inadequate anticoagulation therapy in elderly patients, probably because most patients refused warfarin therapy because they could not control their INR. Moreover, significantly more rural residents than urban residents refused therapy (48 vs. 22; p < 0.05). Doctors underprescribed anticoagulants because they feared hemorrhagic complications in their patients.   Conclusion: The results of the present study showed that anticoagulants were underprescribed at the outpatient stage in centers of family medicine in our country. The main drug of choice for specialists remains warfarin, which only provides adequate therapy in a small number of patients (9.4%).

A Review of Warfarin Dosing With Concurrent Acetaminophen Therapy

2013 ◽  
Vol 26 (5) ◽  
pp. 518-521 ◽  
Author(s):  
G. Michelle Pinson ◽  
Jennifer W. Beall ◽  
Jeffrey A. Kyle
Keyword(s):  
Drug Interaction ◽  
Drug Interactions ◽  
Warfarin Therapy ◽  
International Normalized Ratio ◽  
Over The Counter ◽  
Pain Medications ◽  
Concurrent Use ◽  
Prevention And Treatment ◽  
Drug Drug Interaction ◽  
Warfarin Dosing

Warfarin is frequently used for the prevention and treatment of thromboembolism, yet it is associated with numerous drug interactions. Regarding over-the-counter pain medications, the preferred analgesic for those patients who are taking warfarin is acetaminophen. There are, however, reports of elevation in the international normalized ratio (INR) in those patients taking concurrent warfarin and acetaminophen. For those practitioners who manage warfarin therapy, there is little guidance regarding management of the drug–drug interaction between warfarin and acetaminophen. This review seeks to evaluate the drug interaction between warfarin and acetaminophen and provides recommendations for concurrent use of these drugs.

scholarly journals Does prophylactic antibiotic administration for tooth extraction affect PT-INR in patients taking warfarin?

2020 ◽  
Author(s):  
Eiji Iwata ◽  
Akira Tachibana ◽  
Junya Kusumoto ◽  
Naoki Takata ◽  
Takumi Hasegawa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Tooth Extraction ◽  
Warfarin Therapy ◽  
Prophylactic Antibiotic ◽  
International Normalized Ratio ◽  
Antibiotic Administration ◽  
Number Of Patients ◽  
Warfarin Treatment ◽  
Before And After

Abstract Background: Various antibiotics and analgesics have been reported to interact with　warfarin. Reports that investigate the effects of medication taken for just a few days during tooth extraction on the prothrombin time-international normalized ratio (PT-INR) are rare.Methods: A total of 110 patients receiving long-term stable warfarin therapy underwent tooth extraction without interruption of warfarin treatment. INR values were measured one month before the tooth extraction, the day of the extraction, and one week after the extraction. We investigated the changes in INR values between the day of extraction and one week after extraction, as well as the various risk factors for increases in INR values.Results: Before and after tooth extraction, the number of patients taking cefcapene pivoxil, amoxicillin, and azithromycin was 57, 36, and 8, respectively. Nine patients were administered ampicillin before tooth extraction and received amoxicillin after their tooth extraction. One week after tooth extraction, the INR values increased beyond the therapeutic range in 3 out of 110 patients (2.7%). The INR values before tooth extraction in these three patients were close to 3.0. The INR value increased by more than twice as much in 1 out of 110 patients (0.9%).Conclusion: Our results suggest that prophylactic antibiotic administration has little effect on INR values when patients on stable warfarin therapy undergo tooth extraction. Surgeons have to take attention if the patients whose INR values are close to 3.0 before their extraction.

scholarly journals Does prophylactic antibiotic administration for tooth extraction affect PT-INR in patients taking warfarin?

2020 ◽  
Author(s):  
Eiji Iwata ◽  
Akira Tachibana ◽  
Junya Kusumoto ◽  
Naoki Takata ◽  
Takumi Hasegawa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Tooth Extraction ◽  
Warfarin Therapy ◽  
Prophylactic Antibiotic ◽  
International Normalized Ratio ◽  
Antibiotic Administration ◽  
Number Of Patients ◽  
Warfarin Treatment ◽  
Before And After

Abstract Background: Various antibiotics have been reported to interact with　warfarin. Reports to have investigated the effects of prophylactic antibiotic administration for tooth extraction in patients taking warfarin on the prothrombin time-international normalized ratio (PT-INR) are rare.Methods: A total of 110 patients receiving long-term stable warfarin therapy underwent tooth extraction without interruption of warfarin treatment. INR values were measured one month before the tooth extraction, the day of the extraction, and one week after the extraction. We investigated the changes of INR values between the day of extraction and one week after the extraction, as well as the various risk factors for increases in INR values.Results: Before and after tooth extraction, the number of patients taking cefcapene pivoxil, amoxicillin, and azithromycin was 57, 36, and 8, respectively. Nine patients were administered ampicillin before tooth extraction and received amoxicillin after their tooth extraction. One week after tooth extraction, the INR values increased beyond the therapeutic range in 3 out of 110 patients (2.7%). The INR values before tooth extraction in these three patients were close to 3.0. The INR value increased by more than twice as much in 1 of 110 patients (0.9%).Conclusion: Our results suggest that prophylactic antibiotic administration has little effect on their INR values when patients on stable warfarin therapy undergo tooth extraction. Surgeons have to take attention if the patients whose INR values are close to 3.0 before their extraction.

Evaluation of an Initiation Regimen of Warfarin for International Normalized Ratio Target 2.0 to 3.0

2021 ◽  
pp. 875512252110341
Author(s):  
Sahimi Mohamed ◽  
Chan Mei Fong ◽  
Yew Jie Ming ◽  
Ahlam Naila Kori ◽  
Sopian Abdul Wahab ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Warfarin Therapy ◽  
Warfarin Dose ◽  
Asian Population ◽  
International Normalized Ratio ◽  
Efficacy And Safety ◽  
Risk Of Bleeding ◽  
Number Of Patients ◽  
Inpatient Settings ◽  
The Mean

Background: he number of patients on warfarin therapy is rising steadily. Although warfarin is beneficial, it carries a high risk of bleeding, especially if the international normalized ratio (INR) values exceed 3.0. Currently, no warfarin initiation regimens have been developed for the Asian population, especially for Malaysians. Objective: This article describes the efficacy and safety of a new initiation regimen for warfarin among warfarin-naive patients. Method: Data were retrospectively collected from the ambulatory and inpatient settings. Results: A total of 165 patients who each had a target INR of 2.0 to 3.0 were included in the study. The mean age was 57.2 years and 94 patients were male. A total of 108 patients used Regimen 1 (5 mg/5 mg/3mg) and the rest of the patients used Regimen 2 (5 mg/3 mg/3 mg). Most patients used warfarin either for atrial fibrillation (52.1%) or for venous thromboembolism (29.7%). Overall, 88 of the patients had INR values above 50% from the baseline on Day 4. Additionally, 13 patients had INR values of >3.2, which required withholding and lower dose of warfarin. The predicted weekly maintenance warfarin dose (23 ± 0.5 mg/week) was found to have correlated closely with the actual maintenance dose (22.8 ± 0.5 mg/week; r2 = 0.75). Nearly two thirds (70.3%) of the patients achieved the target INR on Day 11. Conclusion: The warfarin initiation regimens in this study was simple, safe, and suitable to be used in both ambulatory and inpatient settings for managing warfarin therapy.

Abstract 9387: A Better Personalized Prediction for International Normalized Ratio Levels in Inpatients Receiving Warfarin

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yao Zhao ◽  
Nan Liu ◽  
Yijun Wang ◽  
Kathleen Hickey
Keyword(s):  
New York ◽  
Prediction Accuracy ◽  
Warfarin Therapy ◽  
Prediction Method ◽  
International Normalized Ratio ◽  
Adverse Outcomes ◽  
Prediction Errors ◽  
Rolling Horizon ◽  
Pkpd Model ◽  
Warfarin Dosing

Objectives: The objectives of this study were: 1) to test the effectiveness of a novel prediction method for International Normalized Ratio (INR) levels in inpatients receiving warfarin therapy; 2) to compare the prediction accuracy between this method and existing methods. Methods: We developed a novel personalized pharmaco-kinetic and pharmaco-dynamic (PKPD) model to predict the trajectory of INRs over time. We tested this model on 60 inpatient cases in New York Presbyterian Hospital from 2012 to 2013 using two different methods. The first method (fixed horizon) predicts future INR levels by the initial five observed INRs; the second method (rolling horizon) makes predictions based on the latest five observed INRs on a rolling basis. Prediction accuracy is evaluated by the Absolute Percentage Prediction Error (PAPE), which is |Predicted INR - Actual INR|/Actual INR. Results: A personalized INR prediction example: Summary statistics for prediction errors: Conclusions: The rolling horizon method continuously updates the PKPD model based on the individuals’ latest INR responses, and thus significantly improves the prediction accuracy as compared to the fixed horizon method (p<.001). The rolling horizon method provides accurate predictions for INR trajectory five days into the future, and can help clinicians improve warfarin dosing to reduce adverse outcomes due to INRs that are not within a therapeutic range.

scholarly journals Warfarin Interaction With Hepatic Cytochrome P-450 Enzyme-Inducing Anticonvulsants

2017 ◽  
Vol 24 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Nathan P. Clark ◽  
Kim Hoang ◽  
Thomas Delate ◽  
John R. Horn ◽  
Daniel M. Witt
Keyword(s):  
Warfarin Therapy ◽  
Therapeutic Response ◽  
Warfarin Dose ◽  
Clinical Information ◽  
International Normalized Ratio ◽  
The Mean ◽  
Warfarin Dosing ◽  
Meaningful Interaction ◽  
Cytochrome P 450 ◽  
Hepatic Cytochrome

Initiation of cytochrome P-450 (CYP)-inducing anticonvulsant medications during warfarin therapy may decrease anticoagulant effect and necessitate frequent warfarin dose adjustments to maintain therapeutic response measured by the international normalized ratio (INR). Clinical information regarding interactions between warfarin and these medications is limited. This study investigated warfarin dose and INR response following CYP-inducing anticonvulsant initiation among chronic warfarin users. This retrospective, pre-post study included patients ≥18 years who were receiving chronic warfarin therapy and who initiated carbamazepine, oxcarbazepine, phenobarbital, or phenytoin between January 1, 2006, and December 31, 2013. Mean weekly warfarin dose/INR ratio and mean weekly warfarin dose were compared in the 90 days pre- and days post-anticonvulsant initiation periods. Of the 57 included patients, 34 (60%), 15 (26%), 6 (11%), and 2 (3%) patients purchased a prescription for carbamazepine, phenytoin, oxcarbazepine, and phenobarbital, respectively. Mean age was 70 years, 59% were female, and the majority were receiving chronic warfarin therapy for atrial fibrillation (39%) or venous thromboembolism (26%). The ratio of mean warfarin dose and INR increased significantly between the pre- and post-anticonvulsant initiation periods (from 13 mg/INR to 18 mg/INR, respectively, P ≤ .001) as did the mean weekly warfarin dose (from 33 mg to 37 mg, P = <.001). Warfarin dose and dose/INR ratio significantly increased after carbamazepine initiation (both P < .001), while oxcarbazepine, phenobarbital, and phenytoin initiation did not significantly affect warfarin dosing. Our results support the presence of a clinically meaningful interaction between warfarin and carbamazepine. Frequent INR monitoring and warfarin dose escalation are recommended in this setting.

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