Displaying publications 1 - 20 of 23 in total

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  1. Sapapsap B, Srisawat C, Suthumpoung P, Luengrungkiat O, Leelakanok N, Saokaew S, et al.
    Medicine (Baltimore), 2022 Sep 09;101(36):e30388.
    PMID: 36086772 DOI: 10.1097/MD.0000000000030388
    BACKGROUND: Patients who had mechanical heart valves and an international normalized ratio (INR) of >5.0 should be managed by temporary cessation of vitamin K antagonist. This study aimed to investigate the safety of low-dose vitamin K1 in patients with mechanical heart valves who have supratherapeutic INR.

    METHODS: CINAHL, Cochran Library, Clinical trial.gov, OpenGrey, PubMed, ScienceDirect, and Scopus were systematically searched from the inception up to October 2021 without language restriction. Studies comparing the safety of low-dose vitamin K1 treatment in patients with placebo or other anticoagulant reversal agents were included. We used a random-effect model for the meta-analysis. Publication bias was determined by a funnel plot with subsequent Begg's test and Egger's test.

    RESULTS: From 7529 retrieved studies, 3 randomized control trials were included in the meta-analysis. Pooled data demonstrated that low-dose vitamin K was not associated with thromboembolism rate (risk ratio [RR] = 0.94; 95% CI: 0.19-4.55) major bleeding rate (RR = 0.58; 95% CI: 0.07-4.82), and minor bleeding rate (RR = 0.60; 95% CI: 0.07-5.09). Subgroup and sensitivity analysis demonstrated the nonsignificant effect of low-dose vitamin K on the risk of thromboembolism. Publication bias was not apparent, according to Begg's test and Egger's test (P = .090 and 0.134, respectively).

    CONCLUSION: The current evidence does not support the role of low-dose vitamin K as a trigger of thromboembolism in supratherapeutic INR patients with mechanical heart valves. Nevertheless, more well-designed studies with larger sample sizes are required to justify this research question.

    Matched MeSH terms: International Normalized Ratio
  2. Mohd Tarmizi Mohamad Mahyedin, Afifah Hassan, Abdul Rahim Hussein
    MyJurnal
    The fresh frozen plasma (FFP) is frequently prescribed either for therapeutic or prophylactic transfusion. The international normalised ratio (INR) value of 1.50 and above is frequently reported to be a transfusion trigger for FFP prior to interventional procedure. This study aimed to evaluate the efficacy of prophylactic FFP transfusion in normalising the INR and to determine the post-transfusion outcomes. Methods: A prospective cross-sectional study involved 81 patients who received prophylactic FFP transfusion over a period of three months. All demographic, clinical data and outcomes of FFP transfusion were captured and filled in the research proforma. Results: The proportion of patients achieved posttransfusion INR below 1.51 was 30.30% (n=27). The majority of patients underwent the interventional procedures with posttransfusion INR > 1.50 (n=52) without experiencing any bleeding episodes. Overall, FFP transfusion resulted in significant median INR difference from 1.89 (IQR, 0.53) to 1.60 (IQR, 0.25); p< 0.001. The greater median INR difference was observed in group with pretransfusion INR > 2.00 and who received FFP doses between 10.00 to 20.00 ml kg-1 (p < 0.001). The INR difference showed the significant, positive correlation with pretransfusion INR values (rs= 0.83, p < 0.001) and FFP doses (rs= 0.72, p< 0.001). Conclusions: The interventional procedures were safely carried out despite abnormal posttransfusion INR. The prophylactic FFP transfusions could be avoided in patients with mild coagulopathy (INR 1.50 - 2.00) prior interventional procedures.
    Matched MeSH terms: International Normalized Ratio
  3. Islam MA, Wong KK, Sasongko TH, Gan SH, Wong JS
    Eur J Rheumatol, 2016 Sep;3(3):139-141.
    PMID: 27733946 DOI: 10.5152/eurjrheum.2015.0068
    Here we present a case report of three familial primary antiphospholipid syndrome (PAPS) patients from Malaysia. The three familial patients comprised two females and one male with a mean age of 26.3 years. The first diagnosis was made between 2005 and 2009, and all patients demonstrated deep vein thrombosis, high levels of IgM and IgG anticardiolipin antibodies, and received warfarin treatment international normalized ratio (INR) 2.0-3.0. The patients ceased to show clinical symptoms after treatment. Recently (August 2014), we investigated whether the levels of antiphospholipid antibodies remained elevated, and we found that seronegativity occurred in the patients. We suspect that prolonged anticoagulant treatment might be one of the causes of reduced levels of antiphospholipid antibodies in these familial PAPS patients.
    Matched MeSH terms: International Normalized Ratio
  4. Hasan SS, Shamala R, Syed IA, Basariah N, Chong DW, Mei TK, et al.
    J Pharm Pract, 2011 Oct;24(5):485-93.
    PMID: 21844213 DOI: 10.1177/0897190011415684
    OBJECTIVES: To assess the anticoagulation knowledge and international normalized ratio (INR) control among patients on warfarin.
    METHODS: A cross-sectional study with 156 randomly sampled patients from physician- (non-medication therapy adherence clinic [non-MTAC]) and pharmacist (MTAC)-run anticoagulation clinics using a validated interviewer-administered questionnaire. Patients' INR readings from 2008 to 2010 were recorded.
    RESULTS: Patients on warfarin scored an average of 66.5% ± 36.0% for their knowledge on how warfarin works, 42.9% ± 44.9% for interaction between warfarin and alcohol, and 49.2% ± 21.1% for adverse effects. No significant differences were found between MTAC and non-MTAC patients on their knowledge. There was a negative correlation between patients' knowledge and age (P = .001, r (s) = -.293) and a positive correlation between patients' knowledge and education level (P = .001, r (s) = .365). MTAC patients were found to have better INR control than non-MTAC when compared for mean percentage days in range (63.4% ± 18.9% vs 52.5% ± 18.2%; P = .006) and mean percentage visits in range (58.8% ± 17.9% vs 46.8% ± 18.6%; P = .001).
    CONCLUSIONS: MTAC patients were found to have better INR control compared to non-MTAC patients. A joint cooperation between physicians, pharmacists, and nurses should exist to achieve desired therapeutic outcomes.

    Study site: warfarin patients
    attending the anticoagulation clinics
    Matched MeSH terms: International Normalized Ratio*
  5. Hasan SS, Teh KM, Ahmed SI, Chong DW, Ong HC, Naina B
    Public Health, 2015 Jul;129(7):954-62.
    PMID: 26138018 DOI: 10.1016/j.puhe.2015.05.014
    OBJECTIVES: To investigate association between quality of life (QoL) and International Normalized Ratio (INR) control, with the secondary aim of assessing QoL using generic and anticoagulation-specific, the Short Form Health Survey (SF-12) and the Duke Anticoagulation Satisfaction Scale (DASS).
    STUDY DESIGN: This study assessed anticoagulation related QoL at three time intervals in two groups of patients on long-term warfarin therapy.
    METHODS: Data of 326 randomly sampled patients (163 patients each in DASS and SF-12 groups) who had been on warfarin therapy for at least one year at anticoagulation clinics were analysed. QoL was assessed at three time intervals: at the start, six months and one year of warfarin therapy. Indications and target INR ranges and subjects INR values were recorded. Time in Therapeutic Range (TTR) was estimated for four subject subgroups, based on target ranges of INR for clustered indications.
    RESULTS: Of the total, 43% of the subjects were aged between 50 and 64 years, and 51% were female. DASS assessed subjects older than 35 years perceived significant decrease in overall mean scores of anticoagulation related QoL, whilst all SF-12 assessed subjects perceived an increase in QoL. The mean percentage days in range for all INR target range subgroups did not exceed more than 60% but there was only a weak correlation (Rs = 0.104, P > 0.05) between INR control and overall QoL.
    CONCLUSION: Malaysian urban outpatients on warfarin treatment longer than one year report a significant overall decrease in QoL, as measured using a validated condition-specific instrument. These patients appeared to adapt well to lifestyle limitations imposed by long-term anticoagulation.
    KEYWORDS: Anticoagulation therapy; International Normalized Ratio; Quality of life

    Study site: anticoagulation clinics at a
    suburban tertiary Ministry of Health hospital in Peninsular
    Malaysia
    Matched MeSH terms: International Normalized Ratio*
  6. Hassan Y, Awaisu A, Aziz NA, Ismail O
    Pharm World Sci, 2005 Feb;27(1):16-9.
    PMID: 15861930
    Phenytoin has been reported to have major interactions with warfarin. Phenytoin induces warfarin's metabolism. However, there are many case reports which provide conflicting conclusions. Here, we report a case of a 65-year-old man with mechanical heart valve on chronic warfarin therapy who experienced persistent fluctuations of INR and bleeding secondary to probable warfarin-phenytoin interactions. The patient's anticoagulation clinic visits prior to hospitalization were thoroughly evaluated and we continued to follow-up the case for 3 months post-hospitalization. The reported interaction could be reasonably explained from the chronology of events and the pattern of INR fluctuations whenever phenytoin was either added or discontinued from his drug regimen.
    Matched MeSH terms: International Normalized Ratio
  7. Gan GG, Teh A, Goh KY, Chong HT, Pang KW
    Int J Hematol, 2003 Jul;78(1):84-6.
    PMID: 12894858
    Warfarin is a drug commonly used in the prevention of thromboembolic events. There have been reports suggesting that racial background may influence warfarin dose requirements. Malaysia is a multiracial country in which there are 3 major races, Malay, Chinese, and Indian. We examined 100 patients from our hospital on stable maintenance doses of warfarin, with international normalized ratio (INR) of 2.0 to 3.5. We found that the mean warfarin dose for Indian patients (n = 19) was 6.9 mg, for Chinese patients (n = 55) was 3.6 mg, and for Malay patients (n = 26) was 3.2 mg. The results showed that the Indian patients required a statistically significantly higher warfarin dose than did patients of the other 2 races (P < .0005). Age was also found to affect the daily warfarin maintenance dose.
    Matched MeSH terms: International Normalized Ratio
  8. Shivanna MM, Ganesh S, Khanagar SB, Naik S, Divakar DD, Al-Kheraif AA, et al.
    World J Clin Cases, 2020 Sep 26;8(18):3999-4009.
    PMID: 33024756 DOI: 10.12998/wjcc.v8.i18.3999
    BACKGROUND: Atraumatic restorative treatment (ART) may be appropriate for populations without accessibility and affordability. More data are required regarding the success rate of ART in anterior teeth.

    AIM: To evaluate the clinical performance of restoring class III cavities in anterior teeth of permanent dentition using the ART approach.

    METHODS: A longitudinal interventional field study was carried out at two rural primary health centers, Tumkur district, India. A total of 54 teeth in 39 patients were evaluated for the survival rate of class III restorations in permanent anterior teeth using the ART approach in children and adult populations. Evaluation of ART restoration was carried out using Frencken J criteria, the mean procedure time, patient acceptance and reported pain severity during the ART approach were evaluated using a visual analog scale. Calculation of the cost of ART was also performed.

    RESULTS: The mean time taken to perform the ART procedure was 14.79 ± 5.8 min with the majority of patients reporting only mild pain. At 6 mo follow-up, 72.2% remained in a good state, but this reduced to 27% at 12 mo. The cumulative survival rate of the restorations was 94.4% at 6 mo and 80.9% at 12 mo follow-up. Estimation of the direct cost for a single class III restoration was 186.50 INR (2.64 USD).

    CONCLUSION: ART may be a good comprehensive option for basic oral health care for underserved or inaccessible populations, and preventive care for patients.

    Matched MeSH terms: International Normalized Ratio
  9. Wan Mohamad WM, Mohd Ashari NS, Wan AbHamid WZ
    Objective: We presented a case report, systemic lupus erythematosus (SLE) in a Malay boy. Interestingly, this case occurs in a boy, which is not so common because autoimmune disease usually occurs in female. Design: Case report. Methods: We highlighted a case of a boy with SLE who presented with clinical symptoms suggestive of SLE and fulfilled the criteria for SLE diagnosis. Results: The patient was successfully managed with antihypertensive, intravenous cyclophosphamide and oral prednisolone and respond well to the therapy. Conclusion: Systemic lupus erythematosus is a chronic autoimmune disease which rarely occurs in male. However we reported one such case which fulfilled the criteria for SLE. © 2017 Japan Health Sciences University & Japan International Cultural Exchange Foundation.
    Matched MeSH terms: International Normalized Ratio
  10. Ooi PC, Ramayah G, Omar SR, Rajadorai V, Nadarajah T, Ting CH, et al.
    Malays Fam Physician, 2021 Mar 25;16(1):39-49.
    PMID: 33948141 DOI: 10.51866/oa0002
    Introduction: Atrial fibrillation (AF) is known to lead to stroke and thromboembolism, causing a five-fold increase in the risk of stroke and almost doubling the mortality rate. Optimal anticoagulant therapy is effective in reducing AF-related death. However, prescription of anticoagulants in AF in East Asian countries has been low, ranging from 0.5% to 28%. This study aimed to determine whether vocational training in family medicine improves primary care physicians' knowledge, attitude, and practice in the management of AF.

    Method: This investigation was a cross-sectional study carried out during centralized workshops for two groups of trainees using a validated questionnaire: (i) junior trainees were newly enrolled postgraduate trainees in the Graduate Certificate in Family Medicine (GCFM) program, and (ii) senior trainees were postgraduate trainees in Advance Training in Family Medicine (ATFM) programs of the Academy of Family Physicians of Malaysia (AFPM).

    Results: A total of 223 trainees (127 junior and 96 senior) participated in this study. Only 55.2% of the trainees passed the knowledge test; senior trainees were more likely to pass the knowledge test compared to junior trainees (69.8% vs. 44.1%, p < 0.001). Female trainees were significantly more likely to pass the knowledge test than male trainees. While the attitude of senior and junior trainees was similar, more of the latter group worked in public clinic that provide better support where there is better support for outpatient anticoagulation treatment (e.g., same-day INR test, direct access echocardiogram, and warfarin in in-house pharmacy).

    Conclusion: Vocational training in family medicine appears to improve primary care physicians' knowledge regarding the management of AF. Better knowledge will help vocationally trained primary care physicians to provide anticoagulation treatment for AF within primary care clinics. More optimal AF management within primary care can take place if the identified barriers are addressed and a shared care plan can be implemented.

    Matched MeSH terms: International Normalized Ratio
  11. Ng Tsai HO, Goh JJN, Aw JWX, Lin Y, Fong AYY, Tiong LL, et al.
    J Thromb Thrombolysis, 2018 Nov;46(4):541-548.
    PMID: 30155672 DOI: 10.1007/s11239-018-1726-y
    The objectives of this study are to compare steady-state trough (Cmin,ss) and peak (Cmax,ss) concentrations of rivaroxaban between Asians and Caucasians and to evaluate the relationship between rivaroxaban concentrations and prothrombin time/international normalized ratio (PT/INR). Recruited patients were advised on the time to take rivaroxaban. Cmin,ss and PT/INR were taken when patients arrived. Cmax,ss and PT/INR were drawn between 2 and 4 h later after the patient took rivaroxaban with food. Thirty patients were included in the analyses: 57% (n = 17) males and 43% (n = 13) females, 77% (n = 23) on 20 mg and 23% (n = 7) on 15 mg. Median PTtrough and PTpeak are moderately correlated with Cmin,ss (r2 = 0.43) and Cmax,ss (r2 = 0.49), respectively. Patients on 15 mg have lower Cmin,ss and Cmax,ss versus Caucasians [12 ng/ml vs. 57 ng/ml (Cmin,ss); 87 ng/ml vs. 229 ng/ml (Cmax,ss), p 
    Matched MeSH terms: International Normalized Ratio
  12. Doris G, Devaraj NK, Shakirin SR, Sahimi M, Noraini M
    Med J Malaysia, 2019 Oct;74(5):425-430.
    PMID: 31649220
    BACKGROUND: Direct oral anticoagulants (DOACs) especially dabigatran, have gain popularity for their efficacy, fixed dosing and favourable safety profile. A dabigatran prescribing checklist has been prepared by the Ministry of Health, Malaysia (MOH) to ensure rational and safe prescribing of dabigatran. This study therefore aimed to audit the utilization and documentation of this checklist and use of dabigatran in the government healthcare facilities.

    METHODS: This is a nationwide retrospective audit on the documentation of Dabigatran Prescribing and Dispensing Checklist for a period of two years from January 2013 till December 2014. Data from these Dabigatran Checklists (indication, dose, duration, renal function and adverse drug reactions encountered) were extracted by the pharmacist at MOH healthcare facilities.

    RESULTS: A total of 52 out of 56 (92.9%) of MOH facilities complied to usage of checklist at their centres involving a total of 582 patients of which 569 (97.7%) patients were initiated on dabigatran for the approved indications. The recommended dose of dabigatran was used correctly in 501 (99.6%) of patients. Reason for switching to DOACs use was only documented in 76.7% (131/171) of patients. The most common reason for switching from warfarin was poor INR control (n=39), history of bleeding/overwarfarinisation (n=22) and unable to attend regular INR clinic (n=21). There were 75 cases of adverse events reported. The most common adverse event reported were abdominal discomfort (n=10) followed by gum bleeding (n=9) and dizziness (n=5).

    CONCLUSIONS: Compliance to the dabigatran check list was high with 70% of patients prescribed the appropriate dosing.

    Matched MeSH terms: International Normalized Ratio
  13. Zulkifly H, Cheli P, Lutchman I, Bai Y, Lip GYH, Lane DA
    Thromb Res, 2020 08;192:12-20.
    PMID: 32416364 DOI: 10.1016/j.thromres.2020.04.001
    BACKGROUND: Efficacy and safety of vitamin K antagonists (VKAs) is optimised in atrial fibrillation (AF) patients when the International Normalised Ratio (INR) is 2.0-3.0. Anticoagulation control comparing different ethnic groups is limited, although epidemiological studies suggest poorer INR control in non-white cohorts.

    METHODS: VKA control was assessed retrospectively by time-in-the-therapeutic range (TTR) (Rosendaal method) and percentage INR-in-range (PINRR) in 991 White, Afro-Caribbean and South-Asian AF patients [overall mean (SD) age 71.6 (9.4) years; 55% male; mean (SD) CHA2DS2-VASc score 3.4 (1.6)] over a median (IQR) follow-up of 5.2 (3.2-7.0) years.

    RESULTS: Compared to Whites, mean (SD) TTR and PINRR were significantly lower in South-Asians [TTR 67.9% vs. 60.5%; PINRR 58.8% vs. 51.6%, respectively] and Afro-Caribbeans [TTR 67.9% vs. 61.3%; PINRR 58.8% vs. 53.1%, respectively], despite similar INR monitoring intensity. Logistic regression revealed non-white ethnicity [OR 2.62; 95% Confidence Interval [CI] (1.67-4.10) and OR 3.47 (1.44-8.34)] and anaemia [OR 1.65 (1.00-2.70) and OR 6.27 (1.89-20.94)] as independent predictors of both TTR and PINRR 

    Matched MeSH terms: International Normalized Ratio
  14. Bawadikji AA, Teh CH, Sheikh Abdul Kader MAB, Abdul Wahab MJB, Syed Sulaiman SA, Ibrahim B
    Am J Cardiovasc Drugs, 2020 Apr;20(2):169-177.
    PMID: 31435902 DOI: 10.1007/s40256-019-00364-2
    BACKGROUND: Warfarin is prescribed as an oral anticoagulant to treat/prevent thromboembolism in conditions such as atrial fibrillation. As there is a narrow therapeutic window, treatment with warfarin is challenging. Pharmacometabonomics using nuclear magnetic resonance (NMR) spectroscopy may provide novel techniques for the identification of novel biomarkers of warfarin.

    PURPOSE: The aim was to determine the metabolic fingerprint that predicts warfarin response based on the international normalized ratio (INR) in patients who are already receiving warfarin (phase I: identification) and to ascertain the metabolic fingerprint that discriminates stable from unstable INR in patients starting treatment with warfarin (phase II: validation).

    EXPERIMENTAL APPROACH: A total of 94 blood samples were collected for phase I: 44 patients with stable INR and 50 with unstable INR. Meanwhile, 23 samples were collected for phase II: nine patients with stable INR and 14 with unstable INR. Data analysis was performed using multivariate analysis including principal component analysis and partial least square-discriminate analysis (PLS-DA), followed by univariate and multivariate logistic regression (MVLR) to develop a model to identify unstable INR biomarkers.

    KEY RESULTS: For phase I, the PLS-DA model showed the following results: sensitivity 93.18%, specificity 91.49% and accuracy 92.31%. In the MVLR analysis of phase I, ten regions were associated with unstable INR. For phase II, the PLS-DA model showed the following results: sensitivity 66.67%, specificity 61.54% and accuracy 63.64%.

    CONCLUSIONS AND IMPLICATIONS: We have shown that the pharmacometabonomics technique was able to differentiate between unstable and stable INR with good accuracy. NMR-based pharmacometabonomics has the potential to identify novel biomarkers in plasma, which can be useful in individualizing treatment and controlling warfarin side effects, thus, minimizing undesirable effects in the future.

    Matched MeSH terms: International Normalized Ratio*
  15. Yew KL, Lee WC
    Med J Malaysia, 2012 Aug;67(4):420-1.
    PMID: 23082454 MyJurnal
    Matched MeSH terms: International Normalized Ratio
  16. Ng DL, Malik NMBA, Chai CS, Goh GM, Tan SB, Bee PC, et al.
    Health Qual Life Outcomes, 2020 Oct 20;18(1):347.
    PMID: 33081816 DOI: 10.1186/s12955-020-01600-z
    BACKGROUND: The use of warfarin in patients with non-valvular atrial fibrillation (NVAF) can be challenging. In this study, we evaluate the time in therapeutic range (TTR), health-related quality of life (HRQoL) and treatment satisfaction of patients on long-term warfarin for NVAF. The HRQoL and treatment satisfaction were compared based on the TTR.

    METHODS: A cross-sectional study was conducted among patients on warfarin for NVAF who attended the anticoagulant clinic of a tertiary cardiology referral center in Sarawak from 1st June 2018 to 31st May 2019. Patients' TTR was calculated by using Rosendaal technique, while their HRQoL and treatment satisfaction were assessed by using Short Form 12 Health Survey version 2 (SF12v2) and Duke Anticoagulant Satisfaction Scale (DASS), respectively.

    RESULTS: A total of 300 patients were included, with mean TTR score of 47.0 ± 17.3%. The physical component summary (PCS) and mental component summary (MCS) score of SF-12v2 were 47.0 ± 9.0 and 53.5 ± 9.6, respectively. The total score for DASS was 55.2 ± 21.3, while the score for limitations (L), hassles and burdens (H&B) and positive psychological impacts (PPI) were 18.0 ± 10.0, 15.6 ± 9.1 and 21.6 ± 5.9, respectively. Seventy-three (24.3%) patients had good TTR (≥ 60%), with mean of 70.2 ± 8.7%; while 227 (75.5%) patients with poor TTR had significantly lower mean of 39.5 ± 11.9% (p = 0.006). There was no significant difference in the score of PCS (p = 0.150), MCS (p = 0.919) and each domain of SF-12v2 (p = 0.184-0.684) between good and poor TTR, except for social functioning (p = 0.019). The total DASS score was also not significantly different between group (p = 0.779). Similar non-significant difference was also reported in all the DASS sub dimensions (p = 0.502-0.699).

    CONCLUSIONS: Majority of the patients on long-term warfarin for NVAF in the current study have poor TTR. Their HRQoL and treatment satisfaction are independent of their TTR. Achieving a good TTR do not compromise the HRQoL and treatment satisfaction. Therefore, appropriate measures should be taken to optimise INR control, failing which direct oral anticoagulant therapy should be considered.

    Matched MeSH terms: International Normalized Ratio
  17. Saffian SM, Wright DF, Roberts RL, Duffull SB
    Ther Drug Monit, 2015 Aug;37(4):531-8.
    PMID: 25549208 DOI: 10.1097/FTD.0000000000000177
    The aim of this study was to compare the predictive performance of different warfarin dosing methods.
    Matched MeSH terms: International Normalized Ratio
  18. Chua YA, Abdullah WZ, Yusof Z, Gan SH
    Turk J Med Sci, 2015;45(4):913-8.
    PMID: 26422867
    BACKGROUND/AIM: VKORC1 and CYP2C9 genetic polymorphisms may not accurately predict warfarin dose requirements. We evaluated an existing warfarin dosing algorithm developed for Malaysian patients that was based only on VKORC1 and CYP2C9 genes.

    MATERIALS AND METHODS: Five Malay patients receiving warfarin maintenance therapy were investigated for their CYP2C9*2, CYP2C9*3, and VKORC1-1639G>A genotypes and their vitamin K-dependent (VKD) clotting factor activities. The records of their daily warfarin doses and international normalized ratio (INR) 2 years prior to and after the measurement of VKD clotting factors activities were acquired. The mean warfarin doses were compared with predicted warfarin doses calculated from a genotypic-based dosing model developed for Asians.

    RESULTS: A patient with the VKORC1-1639 GA genotype, who was supposed to have higher dose requirements, had a lower mean warfarin dose similar to those having the VKORC1-1639 AA genotype. This discrepancy may be due to the coadministration of celecoxib, which has the potential to decrease warfarins metabolism. Not all patients' predicted mean warfarin doses based on a previously developed dosing algorithm for Asians were similar to the actual mean warfarin dose, with the worst predicted dose being 54.34% higher than the required warfarin dose.

    CONCLUSION: Multiple clinical factors can significantly change the actual required dose from the predicted dose from time to time. The additions of other dynamic variables, especially INR, VKD clotting factors, and concomitant drug use, into the dosing model are important in order to improve its accuracy.

    Matched MeSH terms: International Normalized Ratio
  19. Bawadikji AA, Teh CH, Kader MABSA, Sulaiman SAS, Ibrahim B
    Curr Pharm Biotechnol, 2017;18(9):740-747.
    PMID: 29110602 DOI: 10.2174/1389201018666171103141828
    BACKGROUND: Warfarin, an anticoagulant medication, is prescribed regularly despite of its bleeding tendency for the prevention and/or treatment of various thromboembolic conditions, such as deep vein thrombosis, and complications associated with atrial fibrillation, and myocardial infarction, but because of its narrow therapeutic window, it has a lot of interactions with drugs and diet.

    METHODS: Warfarin relies on regular monitoring of International Normalized Ratio which is a standardized test to measure prothrombin time and appropriate dose adjustment. Pharmacometabonomics is a novel scientific field which deals with identification and quantification of the metabolites present in the metabolome using spectroscopic techniques such as Nuclear Magnetic Resonance (NMR). Pharmacometabonomics helps to indicate perturbation in the levels of metabolites in the cells and tissues due to drug or ingestion of any substance. NMR is one of the most widely-used spectroscopic techniques in metabolomics because of its reproducibility and speed.

    RESULTS: There are many factors that influence the metabolism of warfarin, making changes in drug dosage common, and clinical factors like drug-drug interactions, dietary interactions and age explain for the most part the variability in warfarin dosing. Some studies have showed that pharmacogenetic testing for warfarin dosing does not improve health outcomes, and around 26% of the variation in warfarin dose requirements remains unexplained yet.

    CONCLUSION: Many recent pharmacometabonomics studies have been conducted to identify novel biomarkers of drug therapies such as paracetamol, aspirin and simvastatin. Thus, a technique such as NMR based pharmacometabonomics to find novel biomarkers in plasma and urine might be useful to predict warfarin outcome.

    Matched MeSH terms: International Normalized Ratio
  20. Edwards F, Arkell P, Fong, Roberts LM, Gendy D, Wong CS, et al.
    J Thromb Thrombolysis, 2014;38(2):226-34.
    PMID: 24233388
    Evidence is emerging that rates of adverse events in patients taking warfarin may vary with ethnicity. This study investigated the rates of bleeds and thromboembolic events, the international normalised ratio (INR) status and the relationship between INR and bleeding events in Malaysia. Patients attending INR clinic at the Heart Centre, Sarawak General Hospital were enrolled on an ad hoc basis from May 2010 and followed up for 1 year. At each routine visit, INR was recorded and screening for bleeding or thromboembolism occurred. Variables relating to INR control were used as predictors of bleeds in logistic regression models. 125 patients contributed to 140 person-years of follow-up. The rates of major bleed, thromboembolic event and minor bleed per 100 person-years of follow-up were 1.4, 0.75 and 34.3. The median time at target range calculated using the Rosendaal method was 61.6% (IQR 44.6–74.1%). Of the out-of-range readings, 30.0% were below range and 15.4% were above. INR variability, (standard deviation of individuals’ mean INR), was the best predictor of bleeding events, with an odds ratio of 3.21 (95% CI 1.10–9.38). Low rates of both major bleeds and thromboembolic events were recorded, in addition to a substantial number of INR readings under the recommended target range. This may suggest that the recommended INR ranges may not represent the optimal warfarin intensity for this population and that a lower intensity of therapy, as observed in this cohort, could be beneficial in preventing adverse events.

    Study site: INR clinic at the Heart Centre, Sarawak General Hospital
    Matched MeSH terms: International Normalized Ratio
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