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Ahmed H, Reeve N, Farewell D, Hamilton F, Ponsford M, Hippisley-Cox J, Noble S. Risk of bleeding amongst warfarin and direct oral anticoagulant users prescribed immediate antibiotics for respiratory tract infection: Cohort study. Pharmacoepidemiol Drug Saf 2024; 33:e5794. [PMID: 38680080 DOI: 10.1002/pds.5794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 02/20/2024] [Accepted: 04/01/2024] [Indexed: 05/01/2024]
Abstract
PURPOSE Incidence of bleeding amongst warfarin and direct oral anticoagulant (DOAC) users is greater following a respiratory tract infection (RTI). It is unclear whether immediate antibiotics modify this association. We estimated the risk of bleeding amongst warfarin and DOAC users with RTI by antibiotic treatment. METHODS This retrospective cohort study used data from the Clinical Practice Research Datalink (CPRD) GOLD for adults in England prescribed warfarin or a DOAC, who sought primary care for an RTI between 1st January 2011 and 31st December 2019. Outcomes were major bleeding (hospital admission for intracranial or gastrointestinal bleeding), and non-major bleeding (hospital admission or General Practice consult for epistaxis, haemoptysis, or haematuria). Cox models derived hazard ratios (HRs) and 95% confidence intervals (CIs) for each outcome, adjusting for confounders using inverse probability of treatment weighting. RESULTS Of 14 817 warfarin and DOAC users consulting for an RTI, 8768 (59%) were prescribed immediate antibiotics and 6049 (41%) were not. Approximately 49% were female, and median age was 76 years. Antibiotics were associated with reduced risk of major bleeding (adjusted HR 0.38, 95% CI 0.25 to 0.58). This was consistent across several sensitivity analyses. Antibiotics were also associated with a reduced risk of non-major bleeding (adjusted HR 0.78, 95% CI 0.61 to 0.99). CONCLUSIONS Immediate antibiotics were associated with reduced risk of bleeding amongst warfarin and DOAC users with an RTI. Further work is needed to understand mechanisms and confirm whether a lower threshold for antibiotic use for RTI in this population may be beneficial.
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Affiliation(s)
- Haroon Ahmed
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
| | - Nicola Reeve
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
| | - Daniel Farewell
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
| | - Fergus Hamilton
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Mark Ponsford
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, UK
| | - Julia Hippisley-Cox
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - Simon Noble
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
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2
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Mar PL, Gopinathannair R, Gengler BE, Chung MK, Perez A, Dukes J, Ezekowitz MD, Lakkireddy D, Lip GYH, Miletello M, Noseworthy PA, Reiffel J, Tisdale JE, Olshansky B. Drug Interactions Affecting Oral Anticoagulant Use. Circ Arrhythm Electrophysiol 2022; 15:e007956. [PMID: 35622425 PMCID: PMC9308105 DOI: 10.1161/circep.121.007956] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Oral anticoagulants (OACs) are medications commonly used in patients with atrial fibrillation and other cardiovascular conditions. Both warfarin and direct oral anticoagulants are susceptible to drug-drug interactions (DDIs). DDIs are an important cause of adverse drug reactions and exact a large toll on the health care system. DDI for warfarin mainly involve moderate to strong inhibitors/inducers of cytochrome P450 (CYP) 2C9, which is responsible for the elimination of the more potent S-isomer of warfarin. However, inhibitor/inducers of CYP3A4 and CYP1A2 may also cause DDI with warfarin. Recognition of these precipitating agents along with increased frequency of monitoring when these agents are initiated or discontinued will minimize the impact of warfarin DDI. Direct oral anticoagulants are mainly affected by medications strongly affecting the permeability glycoprotein (P-gp), and to a lesser extent, strong CYP3A4 inhibitors/inducers. Dabigatran and edoxaban are affected by P-gp modulation. Strong inducers of CYP3A4 or P-gp should be avoided in all patients taking direct oral anticoagulant unless previously proven to be otherwise safe. Simultaneous strong CYP3A4 and P-gp inhibitors should be avoided in patients taking apixaban and rivaroxaban. Concomitant antiplatelet/anticoagulant use confers additive risk for bleeding, but their combination is unavoidable in many cases. Minimizing duration of concomitant anticoagulant/antiplatelet therapy as indicated by evidence-based clinical guidelines is the best way to reduce the risk of bleeding.
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Affiliation(s)
- Philip L Mar
- Division of Cardiology, Department of Medicine, St. Louis University, MO (P.L.M., A.P.)
| | | | - Brooke E Gengler
- Department of Pharmacy, Saint Louis University Hospital, MO (B.E.G.)
| | - Mina K Chung
- Department of Cardiovascular Medicine, Heart, Vascular & Thoracic Institute (M.K.C.)
| | - Arturo Perez
- Division of Cardiology, Department of Medicine, St. Louis University, MO (P.L.M., A.P.)
| | | | - Michael D Ezekowitz
- Lankenau Heart Institute, Bryn Mawr Hospital & Sidney Kimmel Medical College, Wynnewood, PA (M.D.E.)
| | | | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool & Liverpool Heart & Chest Hospital, United Kingdom (G.Y.H.L.).,Department of Clinical Medicine, Aalborg, Denmark (G.Y.H.L.)
| | | | - Peter A Noseworthy
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (P.A.N.)
| | - James Reiffel
- Division of Cardiology, Department of Medicine, Columbia University, New York (J.R.)
| | - James E Tisdale
- College of Pharmacy, Purdue University (J.E.T.).,School of Medicine, Indiana University, Indianapolis (J.E.T.)
| | - Brian Olshansky
- Division of Cardiology, Department of Medicine, University of Iowa, Iowa City (B.O.)
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Scuteri D, Contrada M, Loria T, Tonin P, Sandrini G, Tamburin S, Nicotera P, Bagetta G, Corasaniti MT. Pharmacological Treatment of Pain and Agitation in Severe Dementia and Responsiveness to Change of the Italian Mobilization–Observation–Behavior–Intensity–Dementia (I-MOBID2) Pain Scale: Study Protocol. Brain Sci 2022; 12:brainsci12050573. [PMID: 35624960 PMCID: PMC9139373 DOI: 10.3390/brainsci12050573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 02/04/2023] Open
Abstract
Up to 80% of Alzheimer’s disease (AD) patients in nursing homes experiences chronic pain and 97% develops fluctuant neuropsychiatric symptoms (NPS). Agitation, associated with unrelieved pain, is managed through antipsychotics and may increase the risk of death. Evidence is accumulating in favor of analgesia for a safer, effective therapy of agitation. The Italian version of Mobilization–Observation–Behavior–Intensity–Dementia, I-MOBID2, recently validated in the Italian setting, shows: good scale content validity index (0.89), high construct validity (Spearman rank-order correlation Rho = 0.748), reliable internal consistency (Cronbach’s α coefficient = 0.751), good-excellent inter-rater (intraclass correlation coefficient, ICC = 0.778) and test-retest (ICC = 0.902) reliability, and good inter-rater and test-retest agreement (Cohen’s K = 0.744) with 5.8 min completion time. This study intends to identify the responsiveness of the I-MOBID2 based on COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) recommendations, assessing the a priori hypotheses of (1) the efficacy of painkillers administered to severe AD patients after proper pain assessment and (2) the effect of reduction of the Cohen-Mansfield Agitation Inventory (CMAI) score and of agitation rescue medications. This protocol is approved by Calabria Region Ethics Committee protocol No. 31/2017 and follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines.
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Affiliation(s)
- Damiana Scuteri
- Pharmacotechnology Documentation and Transfer Unit, Preclinical and Translational Pharmacology, Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy;
- Regional Center for Serious Brain Injuries, S. Anna Institute, 88900 Crotone, Italy; (M.C.); (P.T.)
- Correspondence:
| | - Marianna Contrada
- Regional Center for Serious Brain Injuries, S. Anna Institute, 88900 Crotone, Italy; (M.C.); (P.T.)
| | | | - Paolo Tonin
- Regional Center for Serious Brain Injuries, S. Anna Institute, 88900 Crotone, Italy; (M.C.); (P.T.)
| | - Giorgio Sandrini
- Department of Brain and Behavioral Sciences, IRCCS C. Mondino Foundation Neurologic Institute, University of Pavia, 27100 Pavia, Italy;
| | - Stefano Tamburin
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37100 Verona, Italy;
| | - Pierluigi Nicotera
- German Center for Neurodegenerative Diseases (DZNE), 53111 Bonn, Germany;
| | - Giacinto Bagetta
- Pharmacotechnology Documentation and Transfer Unit, Preclinical and Translational Pharmacology, Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy;
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4
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Ahmed H, Whitaker H, Farewell D, Hippisley-Cox J, Noble S. Respiratory tract infection and risk of bleeding in oral anticoagulant users: self-controlled case series. BMJ 2021; 375:e068037. [PMID: 34933893 PMCID: PMC8689396 DOI: 10.1136/bmj-2021-068037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To estimate the association between untreated, community acquired, respiratory tract infections and bleeding in oral anticoagulant users. DESIGN Self-controlled case series. SETTING General practices in England contributing data to the Clinical Practice Research Datalink GOLD. PARTICIPANTS 1208 adult users of warfarin or direct oral anticoagulants with a general practice or hospital admission record of a bleeding event between January 2010 and December 2019, and a general practice record of a consultation for a community acquired respiratory tract infection for which immediate antibiotics were not prescribed (that is, untreated). MAIN OUTCOME MEASURES Relative incidence of major bleeding and clinically relevant non-major bleeding in the 0-14 days after an untreated respiratory tract infection, compared to unexposed time periods. RESULTS Of 1208 study participants, 58% (n=701) were male, median age at time of first bleed was 79 years (interquartile range 72-85), with a median observation period of 2.4 years (interquartile range 1.3-3.8). 292 major bleeds occurred during unexposed time periods and 41 in the 0-14 days after consultation for a respiratory tract infection. 1003 clinically relevant non-major bleeds occurred during unexposed time periods and 81 in the 0-14 days after consultation for a respiratory tract infection. After adjustment for age, season, and calendar year, the relative incidence of major bleeding (incidence rate ratio 2.68, 95% confidence interval 1.83 to 3.93) and clinically relevant non-major bleeding (2.32, 1.82 to 2.94) increased in the 0-14 days after an untreated respiratory tract infection. Findings were robust to several sensitivity analyses and did not differ by sex or type of oral anticoagulant. CONCLUSIONS This study observed a greater than twofold increase in the risk of bleeding during the 0-14 days after an untreated respiratory tract infection. These findings have potential implications for how patients and clinicians manage oral anticoagulant use during an acute intercurrent illness and warrant further investigation into the potential risks and how they might be mitigated.
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Affiliation(s)
- Haroon Ahmed
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
| | | | - Daniel Farewell
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
| | - Julia Hippisley-Cox
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - Simon Noble
- Division of Population Medicine, Cardiff University School of Medicine, Cardiff, UK
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5
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Tam KW, Chan CK, Liu S. Anticoagulant rodenticide ingestion: Who will develop coagulopathy? HONG KONG J EMERG ME 2021. [DOI: 10.1177/10249079211049939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Introduction: Development of coagulopathy after anticoagulant rodenticide ingestion varies among patients. This study aimed to identify factors that were associated with coagulopathy after anticoagulant rodenticide ingestion. Methods: This was a retrospective cohort study, conducted in the Hong Kong Poison Information Centre. All patients who reported rodenticide exposure and presented to the Accident and Emergency Department from 1 January 2010 to 31 December 2019 were recruited. Coagulopathy was defined as International Normalized Ratio of 1.3 or above. Results: One hundred sixty-nine patients were included in the final analysis. The median age was 44 years old. Forty-nine patients developed coagulopathy (International Normalized Ratio ⩾1.3). Univariate analysis (at p < 0.05) showed that age (p = 0.003), ingestion of first-generation anticoagulant rodenticide (p = 0.017), ingestion of more than one pack (p < 0.001), intentional ingestion (p = 0.002), hypoalbuminemia (p < 0.001), elevated alanine aminotransferase level (p = 0.041) and abnormal estimated glomerular filtration rate (p = 0.005) on presentation, and co-ingestion with paracetamol (p = 0.018) were associated with coagulopathy after anticoagulant rodenticide ingestion. Among these, ingestion of more than one pack (p < 0.001; odds ratio = 19.8; 95% confidence interval = 6.78–65.7), ingestion of first-generation anticoagulant rodenticide (p = 0.006; odds ratio = 5.2; 95% confidence interval = 1.96–15.2), hypoalbuminemia (p < 0.001; odds ratio = 22.4; 95% confidence interval = 6.17–99.0) and elevated alanine aminotransferase level on presentation (p = 0.039; odds ratio = 7.11; 95% confidence interval = 1.58–33.1) were statistically significant in the multivariate analysis. Conclusion: Ingestion of more than one pack and ingestion of first-generation anticoagulant rodenticides were significantly associated with the development of coagulopathy after anticoagulant rodenticide ingestion. Patients who developed hypoalbuminemia or elevated alanine aminotransferase level as a result of anticoagulant rodenticide ingestion were also significantly associated with the development of coagulopathy.
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Affiliation(s)
- Ka Wing Tam
- Department of Accident & Emergency, Queen Elizabeth Hospital, Kowloon, Hong Kong
| | - Chi Keung Chan
- Hong Kong Poison Information Centre and Department of Clinical Toxicology, United Christian Hospital, Kwun Tong, Hong Kong
| | - Shan Liu
- Department of Accident & Emergency, Queen Elizabeth Hospital, Kowloon, Hong Kong
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6
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Kow CS, Sunter W, Hasan SS. Management of Comedication in Hospitalized COVID-19 Patients With Atrial Fibrillation. Hosp Pharm 2021; 56:629-632. [PMID: 34732912 DOI: 10.1177/0018578720947354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Chia Siang Kow
- International Medical University, Kuala Lumpur, Malaysia
| | - Wendy Sunter
- Calderdale and Huddersfield NHS Foundation Trust, Huddersfield, UK
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7
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Hauta-Aho M, Teperi S, Korhonen MJ, Bell JS, Farinola N, Johns S, Shakib S, Huupponen R. Frailty and Co-Prescribing of Potentially Interacting Drugs in New Users of Warfarin. Drugs Aging 2020; 37:373-382. [PMID: 32147805 PMCID: PMC7190596 DOI: 10.1007/s40266-020-00755-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background Warfarin is underutilised in frail older people because of the fear of bleeding complications. Drug interactions are an independent bleeding risk factor. However, the extent to which potential drug interactions are taken into account at warfarin therapy initiation in frail patients is not known. Objective The objective of this study was to investigate the use of potentially interacting drugs increasing the bleeding risk before and after warfarin initiation in frail and non-frail patients. Methods We conducted an observational study including inpatients aged ≥ 60 years initiated on warfarin in a tertiary hospital in Adelaide, South Australia. Frailty status was assessed with the Reported Edmonton Frail Scale. Medication charts were reviewed before and after warfarin initiation. Results In total, 151 patients (102 non-frail and 49 frail) were included. Before warfarin initiation, the use of clopidogrel and acetaminophen was more common in frail patients compared with non-frail patients (25.5% vs 10.2%, p = 0.0135, 63.8% vs 35.7% p = 0.0014, respectively). The use of non-steroidal anti-inflammatory drugs, 9.2% in non-frail patients and 6.4% in frail patients before warfarin initiation, was completely stopped after warfarin initiation in both groups. The use of antiplatelet drugs decreased from 56.1% in non-frail patients and 66.0 % in frail patients to 12.2% and 14.9%, respectively. Instead, the use of drugs affecting the metabolism of warfarin or vitamin K increased in both groups. No statistically significant difference was seen in the exposure to interacting drugs between study groups after warfarin initiation. Acetaminophen, senna glycosides and cytochrome P450 2C9 inhibiting drugs were the most common interacting drugs at discharge used in 49.0%, 18.4% and 20.4% of non-frail patients and 53.2%, 29.8% and 19.1% of frail patients, respectively. Conclusions The overall frequency of potential drug interactions was moderate and frail patients were not exposed to warfarin drug interactions more often than non-frail patients. Further studies in larger study populations are required to verify these results. Electronic supplementary material The online version of this article (10.1007/s40266-020-00755-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Milka Hauta-Aho
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, 20014, Turku, Finland. .,Clinical Pharmacology Unit, Turku University Hospital, Turku, Finland. .,Department of Clinical Pharmacology, Royal Adelaide Hospital, Adelaide, SA, Australia.
| | - Simo Teperi
- Department of Biostatistics, University of Turku, Turku, Finland
| | - Maarit J Korhonen
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, 20014, Turku, Finland.,Faculty of Pharmacy and Pharmaceutical Sciences, Centre for Medicine Use and Safety, Monash University, Melbourne, VIC, Australia
| | - J Simon Bell
- Faculty of Pharmacy and Pharmaceutical Sciences, Centre for Medicine Use and Safety, Monash University, Melbourne, VIC, Australia.,NHMRC Centre of Research Excellence in Frailty and Healthy Ageing, Adelaide, SA, Australia
| | - Nicholas Farinola
- Department of Clinical Pharmacology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Sally Johns
- Department of Clinical Pharmacology, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Sepehr Shakib
- Department of Clinical Pharmacology, Royal Adelaide Hospital, Adelaide, SA, Australia.,Department of Clinical Pharmacology, Faculty of Health Science, University of Adelaide, Adelaide, SA, Australia
| | - Risto Huupponen
- Institute of Biomedicine, Research Centre for Integrative Physiology and Pharmacology, University of Turku, Kiinamyllynkatu 10, 20014, Turku, Finland.,Clinical Pharmacology Unit, Turku University Hospital, Turku, Finland
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8
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Kow CS, Thiruchelvam K, Hasan SS. Pharmacotherapeutic considerations for the management of cardiovascular diseases among hospitalized COVID-19 patients. Expert Rev Cardiovasc Ther 2020; 18:475-485. [PMID: 32700573 DOI: 10.1080/14779072.2020.1797492] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Cardiovascular diseases (CVDs) are among the most frequently identified comorbidities in hospitalized patients with COVID-19. Patients with CV comorbidities are typically prescribed with long-term medications. We reviewed the management of co-medications prescribed for CVDs among hospitalized COVID-19 patients. AREAS COVERED There is no specific contraindication or caution related to COVID-19 on the use of antihypertensives unless patients develop severe hypotension from septic shock where all antihypertensives should be discontinued or severe hyperkalemia in which continuation of renin-angiotensin system inhibitors is not desired. The continuation of antiplatelet or statin is not desired when severe thrombocytopenia or severe transminitis develop, respectively. Patients with atrial fibrillation receiving oral anticoagulants, particularly those who are critically ill, should be considered for substitution to parenteral anticoagulants. EXPERT OPINION An individualized approach to medication management among hospitalized COVID-19 patients with concurrent CVDs would seem prudent with attention paid to changes in clinical conditions and medications intended for COVID-19. The decision to modify prescribed long-term CV medications should be entailed by close follow-up to check if a revision on the decision is needed, with resumption of any long-term CV medication before discharge if it is discontinued during hospitalization for COVID-19, to ensure continuity of care.
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Affiliation(s)
- Chia Siang Kow
- School of Postgraduate Studies, International Medical University , Kuala Lumpur, Malaysia
| | | | - Syed Shahzad Hasan
- School of Biomedical Sciences & Pharmacy, University of Newcastle , Callaghan, Australia.,Department of Pharmacy, University of Huddersfield , Huddersfield, UK
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The Risk of Drug-Drug Interactions with Paracetamol in a Population of Hospitalized Geriatric Patients. JOURNAL OF PHARMACEUTICS 2020; 2020:1354209. [PMID: 32099714 PMCID: PMC6995317 DOI: 10.1155/2020/1354209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 11/17/2022]
Abstract
Aims This study investigates the consumption of paracetamol and the risk of potential drug-drug interactions and assesses the clinical impact hereof in patients admitted to a department of geriatric medicine. Methods A retrospective and longitudinal study was conducted in patients who had been receiving paracetamol upon or during hospitalization. The hospital files of the included patients were reviewed, including documentation of concomitant medications, diagnoses, biochemical values, and adverse incidents during admission. These parameters were used as a clinical follow-up when assessing a clinical probability impact of the identified drug-drug interactions. Results In total, 104 patients were admitted during the study period. 91 (87.5%) of these (mean age 86 years) received a prescription or were treated with paracetamol. Of these, 10% were evaluated as being at risk of potential drug-drug interactions with paracetamol. Seven of the potential drug-drug interactions were related to treatments with warfarin, one with valsartan and one with phenytoin. Of the nine patients at risk, six did experience either abnormal biochemical values or potential related clinical incidents. Four patients experienced increased INR (range 3.2–4.6), of which one patient suffered from anaemia and one with hematemesis. Two patients experienced increased ALAT/ASAT (55/42 U/I and 87/51 U/I, both females). One experienced hypertension. Conclusion A large majority of the patients in this study received treatment with paracetamol. Six patients were evaluated as having abnormal biochemical values or were experiencing clinical incidents during their hospitalization potentially related to the identified potential drug-drug interactions.
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10
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Saksena D, Mishra YK, Muralidharan S, Kanhere V, Srivastava P, Srivastava CP. Follow-up and management of valvular heart disease patients with prosthetic valve: a clinical practice guideline for Indian scenario. Indian J Thorac Cardiovasc Surg 2019; 35:3-44. [PMID: 33061064 PMCID: PMC7525528 DOI: 10.1007/s12055-019-00789-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Valvular heart disease (VHD) patients after prosthetic valve implantation are at risk of thromboembolic events. Follow-up care of patients with prosthetic valve has a paramount role in reducing the morbidity and mortality. Currently, in India, there is quintessential need to stream line the follow-up care of prosthetic valve patients. This mandates the development of a consensus guideline for the antithrombotic therapy in VHD patients post prosthetic valve implantation. METHODS A national level panel was constituted comprising 13 leading cardio care experts in India who thoroughly reviewed the up to date literature, formulated the recommendations, and developed the consensus document. Later on, extensive discussions were held on this draft and the recommendations in 8 regional meetings involving 79 additional experts from the cardio care in India, to arrive at a consensus. The final consensus document is developed relying on the available evidence and/or majority consensus from all the meetings. RESULTS The panel recommended vitamin K antagonist (VKA) therapy with individualized target international normalized ratio (INR) in VHD patients after prosthetic valve implantation. The panel opined that management of prosthetic valve complications should be personalized on the basis of type of complications. In addition, the panel recommends to distinguish individuals with various co-morbidities and attend them appropriately. CONCLUSIONS Anticoagulant therapy with VKA seems to be an effective option post prosthetic valve implantation in VHD patients. However, the role for non-VKA oral therapy in prosthetic valve patients and the safety and efficacy of novel oral anticoagulants in patients with bioprosthetic valve need to be studied extensively.
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11
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Oshikoya KA, Oreagba IA, Godman B, Oguntayo FS, Fadare J, Orubu S, Massele A, Senbanjo IO. Potential drug-drug interactions in paediatric outpatient prescriptions in Nigeria and implications for the future. Expert Rev Clin Pharmacol 2016; 9:1505-1515. [PMID: 27592636 DOI: 10.1080/17512433.2016.1232619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Information regarding the incidence of drug-drug interactions (DDIs) and adverse drug events (ADEs) among paediatric patients in Nigeria is limited. METHODS Prospective clinical audit among paediatric outpatients in four general hospitals in Nigeria over a 3-month period. Details of ADEs documented in case files was extracted. RESULTS Among 1233 eligible patients, 208 (16.9%) received prescriptions with at least one potential DDI. Seven drug classes were implicated with antimalarial combination therapies predominating. Exposure mostly to a single potential DDI, commonly involved promethazine, artemether/lumefantrine, ciprofloxacin and artemether/lumefantrine. Exposure mostly to major and serious, and moderate and clinically significant, potential DDIs. Overall exposure similar across all age groups and across genders. A significant association was seen between severity of potential DDIs and age. Only 48 (23.1%) of these patients presented at follow-up clinics with only 15 reporting ADEs. CONCLUSION There was exposure to potential DDIs in this population. However, potential DDIs were associated with only a few reported ADEs.
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Affiliation(s)
- Kazeem Adeola Oshikoya
- a Pharmacology Department , Lagos State University College of Medicine , Ikeja , Nigeria
| | - Ibrahim Adekunle Oreagba
- b Pharmacology, Therapeutic and Toxicology Department , College of Medicine, University of Lagos , Idiaraba , Nigeria
| | - Brian Godman
- c Division of Clinical Pharmacology , Karolinska Institute , Stockholm , Sweden.,d Strathclyde Institute of Pharmacy and Biomedical Sciences , University of Strathclyde , Glasgow , United Kingdom
| | - Fisayo Solomon Oguntayo
- b Pharmacology, Therapeutic and Toxicology Department , College of Medicine, University of Lagos , Idiaraba , Nigeria
| | - Joseph Fadare
- e Department of Pharmacology , Ekiti State University , Ado-Ekiti , Nigeria
| | - Samuel Orubu
- f Faculty of Pharmacy , Niger Delta University , Wilberforce Island , Nigeria
| | - Amos Massele
- g Department of Clinical Pharmacology , School of Medicine, University of Botswana , Gaborone , Botswana
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12
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Levine M, O'Connor AD, Padilla-Jones A, Gerkin RD. Comparison of Prothrombin Time and Aspartate Aminotransferase in Predicting Hepatotoxicity After Acetaminophen Overdose. J Med Toxicol 2016; 12:100-6. [PMID: 26341088 PMCID: PMC4781795 DOI: 10.1007/s13181-015-0504-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Despite decades of experience with acetaminophen (APAP) overdoses, it remains unclear whether elevated hepatic transaminases or coagulopathy develop first. Furthermore, comparison of the predictive value of these two variables in determining hepatic toxicity following APAP overdoses has been poorly elucidated. The primary objective of this study is to determine the test characteristics of the aspartate aminotransferase (AST) and the prothrombin time (PT) in patients with APAP toxicity. A retrospective chart review of APAP overdoses treated with IV N-acetylcysteine at a tertiary care referral center was performed. Of the 304 subjects included in the study, 246 with an initial AST less than 1000 were analyzed to determine predictors of hepatic injury, defined as an AST exceeding 1000 IU/L. The initial AST >50 was 79.5 % sensitive and 82.6 % specific for predicting hepatic injury. The corresponding negative and positive predictive values were 95.5 and 46.3 %, respectively. In contrast, an initial abnormal PT had a sensitivity of 82.1 % and a specificity of 63.6 %. The negative and positive predictive values for initial PT were 94.9 and 30.2 %, respectively. Although the two tests performed similarly for predicting a composite endpoint of death or liver transplant, neither was a useful predictor. Initial AST performed better than the initial PT for predicting hepatic injury in this series of patients with APAP overdose.
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Affiliation(s)
- Michael Levine
- Department of Emergency Medicine, Division of Medical Toxicology, University of Southern California, Los Angeles, CA, USA.
- Department of Medical Toxicology, Banner Good Samaritan Medical Center, Phoenix, AZ, USA.
| | - Ayrn D O'Connor
- Department of Medical Toxicology, Banner Good Samaritan Medical Center, Phoenix, AZ, USA
- Center for Toxicology and Pharmacology, Education, and Research, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | | | - Richard D Gerkin
- Center for Toxicology and Pharmacology, Education, and Research, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
- Banner Research Institute, Phoenix, AZ, USA
- Department of Internal Medicine, Banner Good Samaritan Medical Center, Phoenix, AZ, USA
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13
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Moore N, Pollack C, Butkerait P. Adverse drug reactions and drug-drug interactions with over-the-counter NSAIDs. Ther Clin Risk Manag 2015. [PMID: 26203254 PMCID: PMC4508078 DOI: 10.2147/tcrm.s79135] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen have a long history of safe and effective use as both prescription and over-the-counter (OTC) analgesics/antipyretics. The mechanism of action of all NSAIDs is through reversible inhibition of cyclooxygenase enzymes. Adverse drug reactions (ADRs) including gastrointestinal bleeding as well as cardiovascular and renal effects have been reported with NSAID use. In many cases, ADRs may occur because of drug-drug interactions (DDIs) between the NSAID and a concomitant medication. For example, DDIs have been reported when NSAIDs are coadministered with aspirin, alcohol, some antihypertensives, antidepressants, and other commonly used medications. Because of the pharmacologic nature of these interactions, there is a continuum of risk in that the potential for an ADR is dependent on total drug exposure. Therefore, consideration of dose and duration of NSAID use, as well as the type or class of comedication administered, is important when assessing potential risk for ADRs. Safety findings from clinical studies evaluating prescription-strength NSAIDs may not be directly applicable to OTC dosing. Health care providers can be instrumental in educating patients that using OTC NSAIDs at the lowest effective dose for the shortest required duration is vital to balancing efficacy and safety. This review discusses some of the most clinically relevant DDIs reported with NSAIDs based on major sites of ADRs and classes of medication, with a focus on OTC ibuprofen, for which the most data are available.
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Affiliation(s)
- Nicholas Moore
- Department of Pharmacology, Université de Bordeaux, Bordeaux, France
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14
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Analgesic use before and after oral anticoagulant initiation—a population-based study in Finland. Eur J Clin Pharmacol 2015; 71:723-732. [DOI: 10.1007/s00228-015-1836-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 03/17/2015] [Indexed: 01/02/2023]
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15
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Abstract
Polypharmacy, specifically the overuse and misuse of medications, is associated with adverse health events, increased disability, hospitalizations, and mortality. Mechanisms through which polypharmacy may increase adverse health outcomes include decreased adherence, increased drug side effects, higher use of potentially inappropriate medications, and more frequent drug-drug interactions. This article reviews clinical problems associated with polypharmacy and presents a framework to optimize prescribing for older adults.
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Affiliation(s)
- Jeffrey Wallace
- Division of Geriatric Medicine, Department of Internal Medicine, University of Colorado School of Medicine, 12631 East 17th Avenue, B-179, Aurora, CO 80045, USA.
| | - Douglas S Paauw
- Division of General Internal Medicine, Department of Medicine, University of Washington, 4245 Roosevelt way NE, #MC354760, Seattle, WA 98105, USA
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16
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Rikala M, Hauta-Aho M, Helin-Salmivaara A, Lassila R, Korhonen MJ, Huupponen R. Co-Prescribing of Potentially Interacting Drugs during Warfarin Therapy - A Population-Based Register Study. Basic Clin Pharmacol Toxicol 2015; 117:126-32. [PMID: 25537751 DOI: 10.1111/bcpt.12373] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/16/2014] [Indexed: 11/29/2022]
Abstract
We analysed the occurrence of co-prescribing of potentially interacting drugs during warfarin therapy in the community-dwelling population of Finland. We identified drugs having interaction potential with warfarin using the Swedish Finnish INteraction X-referencing drug-drug interaction database (SFINX) and obtained data on drug purchases from the nationwide Prescription Register. We defined warfarin users as persons purchasing warfarin in 2010 (n = 148,536) and followed them from their first prescription in 2010 until the end of the calendar year. Co-prescribing was defined as at least 1-day overlap between warfarin and interacting drug episodes. In addition, we identified persons who initiated warfarin therapy between 1 January 2007 and 30 September 2010 (n = 110,299) and followed these incident users for a 3-month period since warfarin initiation. Overall, 74.4% of warfarin users were co-prescribed interacting drugs. Co-prescribing covered 46.4% of the total person-years of warfarin exposure. Interacting drugs that should be avoided with warfarin were co-prescribed for 13.4% of warfarin users. The majority of the co-prescriptions were for drugs that are not contraindicated during warfarin therapy but require special consideration. Among incident users, 57.1% purchased potentially interacting drugs during the 3-month period after initiation, while 9.0% purchased interacting drugs that should be avoided with warfarin. To conclude, the occurrence of co-prescribing of potentially interacting drugs was high during warfarin therapy. Our findings highlight the importance of close monitoring of warfarin therapy and the need for further studies on the clinical consequences of co-prescribing of interacting drugs with warfarin.
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Affiliation(s)
- Maria Rikala
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Milka Hauta-Aho
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
| | - Arja Helin-Salmivaara
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Unit of Primary Health Care, Hospital District of Helsinki and Uusimaa, Helsinki, Finland
| | - Riitta Lassila
- Coagulation Disorders Unit, Hematology, Cancer Center and Laboratory Services HUSLAB, Helsinki University Central Hospital, Helsinki, Finland
| | - Maarit Jaana Korhonen
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Department of Public Health, University of Turku, Turku, Finland
| | - Risto Huupponen
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland.,Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
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17
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How safe is acetaminophen use in patients treated with vitamin K antagonists? A systematic review and meta-analysis. Thromb Res 2015; 135:58-61. [DOI: 10.1016/j.thromres.2014.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/18/2014] [Accepted: 10/14/2014] [Indexed: 11/22/2022]
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18
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Choi DJ, Cho WK, Kim MK. An analysis of the interactions between warfarin and Korean traditional herbal medicine in a Korean oriental hospital. Eur J Integr Med 2014. [DOI: 10.1016/j.eujim.2013.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Abstract
The WHO analgesic ladder for the treatment of cancer pain provides a three-step sequential approach for analgesic administration based on pain severity that has global applicability. Nonopioids were recommended for mild pain, with the addition of mild opioids for moderate pain and strong opioids for severe pain. Here, we review the evidence for the use of nonopioid analgesic agents in patients with cancer and describe the mode of action of the main drug classes. Evidence supports the use of anti-inflammatory drugs such as acetaminophen/paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) for mild cancer pain. Adding an NSAID to an opioid for stronger cancer pain is efficacious, but the risk of long-term adverse effects has not been quantified. There is limited evidence to support using acetaminophen with stronger opioids. Corticosteroids have a specific role in spinal cord compression and brain metastases, where improved analgesia is a secondary benefit. There is limited evidence for adding corticosteroids to stronger opioids when pain control is the primary objective. Systematic reviews suggest a role for antidepressant and anticonvulsant medications for neuropathic pain, but there are methodologic issues with the available studies. Bisphosphonates improve pain in patients with bony metastases in some tumor types. Denosumab may delay worsening of pain compared with bisphosphonates. Larger studies of longer duration are required to address outstanding questions concerning the use of nonopioid analgesia for stronger cancer pain.
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Affiliation(s)
- Janette Vardy
- Janette Vardy, Sydney Medical School, University of Sydney, Sydney, and Concord Cancer Centre, Concord; Meera Agar, Braeside Hospital, Hammond Care, Prairiewood, and South West Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia
| | - Meera Agar
- Janette Vardy, Sydney Medical School, University of Sydney, Sydney, and Concord Cancer Centre, Concord; Meera Agar, Braeside Hospital, Hammond Care, Prairiewood, and South West Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia
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20
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Quantifying four-probe metabolites in a single UPLC–MS/MS run to explore the effects of cooked rhubarb on cytochrome P450 isozymes. Bioanalysis 2012; 4:2693-703. [DOI: 10.4155/bio.12.236] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Background: Cytochrome P450 (CYP) enzymes primarily account for the oxidation of xenobiotics. A single run UPLC–MS/MS method was developed to simultaneously detect four metabolites from a probe cocktail to investigate four CYP isozymes. Paracetamol was detected to investigate CYP1A2, 4-hydroxytolbutamide for CYP2C6, 6-hydroxychlorzoxazone for CYP2E1 and dehydronifedipine for CYP3A1. 6-hydroxychlorzoxazone was detected in ESI-negative mode, while the other three were detected in ESI-positive mode. Results: The method was rapid (2.5 min) and validated to be specific, accurate and precise. It was successfully applied to evaluate the effects of cooked rhubarb on the activities of the four isozymes in rat microsomes. Cooked rhubarb inhibited the activity of CYP2C6 but induced both CYP2E1 and CYP3A1. Conclusion: This convenient UPLC–MS/MS method was applicable. It could improve the efficiency of future studies estimating the influence of herbs, herbal products or drug entities on the activities of CYP1A2, CYP2C6, CYP2E1 and CYP3A1.
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21
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Geller AI, Nopkhun W, Dows-Martinez MN, Strasser DC. Polypharmacy and the role of physical medicine and rehabilitation. PM R 2012; 4:198-219. [PMID: 22443958 DOI: 10.1016/j.pmrj.2012.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/08/2012] [Accepted: 02/10/2012] [Indexed: 02/07/2023]
Abstract
Polypharmacy and inappropriate prescribing practices lead to higher rates of mortality and morbidity, particularly in vulnerable populations, such as the elderly and those with complex medical conditions. Physical medicine and physiatrists face particular challenges given the array of symptoms treated across a spectrum of conditions. This clinical review focuses on polypharmacy and the associated issue of potentially inappropriate prescribing. The article begins with a review of polypharmacy along with relevant aspects of pharmacokinetics and pharmacodynamics in the elderly. The adverse effects and potential hazards of selected medications commonly initiated and managed by rehabilitation specialists are then discussed with specific attention to pain medications, neurostimulants, antipsychotics, antidepressants, antispasmodics, sleep medications, and antiepileptics. Of particular concern is the notion that an adverse effect of one medication can mimic an indication for another and lead to a prescribing cascade and further adverse medication events. Appropriate prescribing practices mandate an accurate, current medication list, yet errors and inaccuracies often plague such lists. The evidence to support explicit (medications to avoid) and implicit (how to evaluate) criteria is presented along with the role of physicians and patients in prescribing medications. A brief discussion of "medication debridement" or de-prescribing strategies follows. In the last section, we draw on the essence of physiatry as a team-based endeavor to discuss the potential benefits of collaboration. In working to optimize medication prescribing, efforts should be made to collaborate not only with pharmacists and other medical specialties but with members of inpatient rehabilitation teams as well.
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Affiliation(s)
- Andrew I Geller
- Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
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22
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Concurrent use of tramadol and oral vitamin K antagonists and the risk of excessive anticoagulation: a register-based nested case-control study. Eur J Clin Pharmacol 2012; 69:641-6. [PMID: 22847619 DOI: 10.1007/s00228-012-1363-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/15/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVES The objective was to assess whether the concurrent use of tramadol and vitamin K antagonists (VKAs) leads to an increased risk of excessive anticoagulation. DESIGN The study was designed as a case-control study, nested within users of VKA and with tramadol use as our main exposure. We used conditional logistic regression to control for potential confounders. SETTING Prescription data from primary care were obtained from Odense Pharmacoepidemiological Database (OPED). Information about hospital admissions was obtained from the patient administrative system of Funen County (FPAS). SUBJECTS Both cases and controls were selected from users of VKA. Cases were defined by being hospitalised with a main diagnosis indicating excessive anticoagulation. For each case, we selected 15 controls among VKA users, matched by age and sex. MAIN OUTCOME MEASURE Odds ratio for experiencing excessive anticoagulation attributable to the use of tramadol. RESULTS A total of 178 patients were included, 30 of which were exposed to tramadol, along with 2643 controls, 114 of which were exposed to tramadol. The adjusted odds-ratio for experiencing excessive anticoagulation during use of tramadol was 3.1 (1.9-5.2). This corresponds to, on average, one excess case per 250 treatment years (CI 125-584). The result is potentially confounded by concomitant paracetamol use and the presence of acute illness. CONCLUSION Caution is advised when using tramadol in patients using VKA, and if possible, an alternative pain-medication should be used.
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Firriolo FJ, Hupp WS. Beyond warfarin: the new generation of oral anticoagulants and their implications for the management of dental patients. Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 113:431-41. [DOI: 10.1016/j.oooo.2011.10.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/17/2011] [Accepted: 10/13/2011] [Indexed: 01/19/2023]
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Duong S, Chang F. A Practical Approach to the Management of Chronic Non-Cancer Nociceptive Pain in the Elderly. Can Pharm J (Ott) 2011. [DOI: 10.3821/1913-701x-144.6.270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Silvia Duong
- Department of Pharmacy, Herzl Family Medicine Centre and Herzl CRIU Walk-in Centre (Duong), Jewish General Hospital, Montréal, Québec; and the School of Pharmacy (Chang), University of Waterloo, Waterloo, Ontario. Contact
| | - Feng Chang
- Department of Pharmacy, Herzl Family Medicine Centre and Herzl CRIU Walk-in Centre (Duong), Jewish General Hospital, Montréal, Québec; and the School of Pharmacy (Chang), University of Waterloo, Waterloo, Ontario. Contact
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25
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Warfarin and acetaminophen interaction: a summary of the evidence and biologic plausibility. Blood 2011; 118:6269-73. [PMID: 21911832 DOI: 10.1182/blood-2011-08-335612] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ms TS is a 66-year-old woman who receives warfarin for prevention of systemic embolization in the setting of hypertension, diabetes, and atrial fibrillation. She had a transient ischemic attack about 4 years ago when she was receiving aspirin. Her INR control was excellent; however, over the past few months it has become erratic, and her average dose required to maintain an INR of 2.0 to 3.0 appears to have decreased. She has had back pain over this same period and has been taking acetaminophen at doses at large as 650 mg four times daily, with her dose varying based on her symptoms. You recall a potential interaction and wonder if (1) her acetaminophen use is contributing to her loss of INR control, and (2) does this interaction place her at increased risk of warfarin-related complications?
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26
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Zhang Q, Bal-dit-Sollier C, Drouet L, Simoneau G, Alvarez JC, Pruvot S, Aubourg R, Berge N, Bergmann JF, Mouly S, Mahé I. Interaction between acetaminophen and warfarin in adults receiving long-term oral anticoagulants: a randomized controlled trial. Eur J Clin Pharmacol 2010; 67:309-14. [PMID: 21191575 DOI: 10.1007/s00228-010-0975-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Accepted: 12/06/2010] [Indexed: 11/24/2022]
Abstract
PURPOSE We investigated whether acetaminophen, given at 2 g/day and 3 g/day might potentiate the anticoagulant effect of warfarin. METHODS Forty-five patients on stable warfarin therapy, enrolled in this prospective, randomized, parallel (three arms), placebo-controlled study, received a 10-day regimen of acetaminophen (2 g/day or 3 g/day) or placebo. RESULTS The mean maximal INR increase was 0.70 ± 0.49 and 0.67 ± 0.62 in patients receiving acetaminophen at 2 g/day and 3 g/day, respectively (P=0.01 for the respective comparisons versus placebo). The INR increase became significant on day 3 and was independently and significantly predicted by a maximal decrease in factor II (R(2)=0.36, P<0.0001), factor VII (R (2)=0.46, P<0.0001) and a maximal increase in acetaminophen plasma concentrations (R(2)=0.563, P<0.0001). CONCLUSION Acetaminophen, at 2 g/day or 3 g/day, enhanced the anticoagulant effect of warfarin in stable patients, thus requiring close INR monitoring in the clinical setting.
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Affiliation(s)
- Qian Zhang
- Unité de Recherches Thérapeutiques-Service de Médecine Interne A, Hôpital Lariboisière, 2 rue Ambroise Paré, 75010, Paris, France
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