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Risk of Potential Drug-Drug Interactions among Brazilian Elderly

A Population-Based, Cross-Sectional Study

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Abstract

Background Drug-drug interactions (DDIs) are one of the main causes of adverse reactions related to medications, being responsible for up to 23% of hospital admissions. However, only a few studies have evaluated this problem in elderly Brazilians.

Objectives To determine the prevalence of potential DDIs (PDDIs) in community-dwelling elderly people in Brazil, analyse these interactions with regard to severity and clinical implications, and identify associated factors.

Methods A population-based cross-sectional study was carried out involving 2143 elderly (aged ≥60 years) residents of the metropolitan area of Sao Paulo, Brazil. Data were obtained from the SABE (Saúde, Bem estar e Envelhecimento [Health, Well-Being, and Aging]) survey, which is a multicentre study carried out in seven countries of Latin America and the Caribbean, coordinated by the Pan-American Health Organization. PDDIs were analysed using a computerized program and categorized according to level of severity, onset, mechanism and documentation in the literature. The STATA software statistical package was used for data analysis, and logistic regression was conducted to determine whether variables were associated with PDDIs.

Results Analysis revealed that 568 (26.5%) of the elderly population included in the study were taking medications that could lead to a DDI. Almost two-thirds (64.4%) of the elderly population exposed to PDDIs were women, 50.7% were aged ≥75 years, 71.7% reported having fair or poor health and 65.8% took 2–5 medications. A total of 125 different PDDIs were identified; the treatment combination of an ACE inhibitor with a thiazide or loop diuretic (associated with hypotension) was the most frequent cause of PDDIs (n=322 patients; 56.7% of individuals with PDDIs). Analysis of the PDDIs revealed that 70.4% were of moderate severity, 64.8% were supported by good quality evidence and 56.8% were considered of delayed onset. The multivariate analysis showed that the risk of a PDDI was significantly increased among elderly individuals using six or more medications (odds ratio [OR] 3.37) and in patients with hypertension (OR 2.56), diabetes mellitus (OR 1.73) or heart problems (OR 3.36).

Conclusions Approximately one-quarter of the elderly population living in Sao Paulo could be taking two or more potentially interacting medicines. Polypharmacy predisposes elderly individuals to PDDIs. More than half of these drug combinations (57.6%, n=72) were part of commonly employed treatment regimens and may be responsible for adverse reactions that compromise the safety of elderly individuals, especially at home. Educational initiatives are needed to avoid unnecessary risks.

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References

  1. Einarson TR. Drug-related hospital admissions. Ann Pharmacother 1993; 27: 832–9

    PubMed  CAS  Google Scholar 

  2. Classen DC, Pestotnik SL, Evans RS, et al. Adverse drug events in hospitalized patients. JAMA 1997; 277: 301–6

    Article  PubMed  CAS  Google Scholar 

  3. Hohl CM, Dankoff J, Colacone A, et al. Polypharmacy, adverse drug-related events, and potential adverse drug interactions in elderly patients presenting to an emergency department. Ann Emerg Med 2001; 38: 666–71

    Article  PubMed  CAS  Google Scholar 

  4. Lazarou J, Pomeranz BH, Corey PN. Incidence of adverse drug reactions in hospitalized patients: a meta-analysis of prospective studies. JAMA 1998; 279: 200–5

    Article  Google Scholar 

  5. Tato DS. Drug interactions facts. Saint Louis (MO): Facts and Comparisons, 2002

    Google Scholar 

  6. Bachmann KA. Drug interactions handbook. Hudson (OH): Lexi, 2003

    Google Scholar 

  7. Grahame-Smith DG, Aronson JK. Drug interactions. In: Grahame-Smith DG, Aronson JK. Oxford textbook of clinical pharmacology and drug therapy. Oxford: Oxford University Press, 2002: 105–18

    Google Scholar 

  8. Secoli SR. Drug interactions: fundamental aspects for clinical practice nursing. Rev Esc Enferm USP 2001; 35: 28–34

    Article  Google Scholar 

  9. Fonseca RB, Secoli SR. Drugs used in bone marrow transplantation: a study about combinations of antimicrobial potentially interactives. Rev Esc Enferm USP 2008; 42: 706–14

    Article  PubMed  Google Scholar 

  10. Spitzer WO. Drug as determinants of health and disease in the population: an orientation to the bridge of pharmacoepidemiology. J Clin Epidemiol 1991; 44: 823–30

    Article  PubMed  CAS  Google Scholar 

  11. Prybys KM, Melville K, Hanna J, et al. Polypharmacy in the elderly — clinical challenges in emergency practice: part 1. Overview, etiology, and drug interactions. Emerg Med Rep 2002; 23: 145–53

    Google Scholar 

  12. Bjorkman IK, Fastbom J, Schmidt IK, et al., The Pharmaceutical Care of the Elderly in Europe Research (PEER) Group. Drug-drug interactions in the elderly. Ann Pharmacother 2002; 36: 1675–81

    Article  PubMed  CAS  Google Scholar 

  13. Passarelli MC, Jacob-Filho W, Figueras A. Adverse drug reactions in an elderly hospitalised population: inappropriate prescription is a leading cause. Drugs Aging 2005; 22: 767–77

    Article  PubMed  Google Scholar 

  14. Egger SS, Jurgen D, Schlienger RG. Potential drug-drug interactions in the medication of medical patients at hospital discharge. Eur J Clin Pharmacol 2004; 58: 773–8

    Google Scholar 

  15. Schneider JK, Mion LC, Frengley JD. Adverse drug reactions in an elderly outpatient population. Am J Hosp Pharm 1992; 49: 90–6

    PubMed  CAS  Google Scholar 

  16. McDonnell PJ, Jacobs MR. Hospital admissions resulting from preventable adverse drug reactions. Ann Pharmacother 2002; 36: 1331–6

    Article  PubMed  Google Scholar 

  17. Langdorf M, Fox J, Marwah R, et al. Physician versus computer knowledge of potential drug interactions in the emergency department. Acad Emerg Med 2000; 7: 1321–9

    Article  PubMed  CAS  Google Scholar 

  18. Gaddi G, Holt T, Woods M. Drug interactions in at risk emergency department patients. Acad Emerg Med 2002; 9: 1162–7

    Article  Google Scholar 

  19. Doucet J, Chassagne P, Trivalle C, et al. Drug-drug interactions related to hospital admissions in older adults: a prospective study of 1000 patients. J Am Geriatric Soc 1996; 44: 944–8

    CAS  Google Scholar 

  20. Bootman JL, Harrison DL, Cox E. The health care cost of drug-related morbidity and mortality in nursing facilities. Arch Intern Med 1997; 157: 2089–96

    Article  PubMed  CAS  Google Scholar 

  21. Lebrão ML, Laurenti R. Health, well-being and aging: the SABE study in São Paulo, Brazil. Rev Bras Epidemiol 2005; 8: 127–41

    Article  Google Scholar 

  22. World Health Organization. Anatomical therapeutic chemical (ATC) classification index with defined daily doses (DDDs); Geneva, 2007 (updated on 2006 Dec 16) [online]. Available from URL: http://www.whocc.no/atcddd/index [Accessed 2007 Mar 16]

    Google Scholar 

  23. Micromedex® Healthcare Series. Greenwood Village (CO): Thomson Reuters (Healthcare) Inc., 2007 [online]. Available from URL: http://www.thomsonhc.com [Accessed 2005 Sep 5]

  24. Costa AJ. Potential drug interactions in an ambulatory geriatric population. Fam Pract 1991; 8: 234–6

    Article  PubMed  CAS  Google Scholar 

  25. Bergendal L, Friberg A, Schaffrath AM. Potential drug-drug interactions in 5,125 mostly elderly out-patients in Gothenburg, Sweden. Pharm World Sci 1995; 17: 152–7

    Article  PubMed  CAS  Google Scholar 

  26. Gaeta TJ, Fiorini M, Ender K, et al. Potential drug-drug interactions in elderly patients presenting with syncope. J Emerg Med 2002; 22: 159–62

    Article  PubMed  Google Scholar 

  27. Aparasu R, Baer R, Aparasu A. Clinically important potential drug-drug interactions in outpatient settings. Res Soc Administrat Pharm 2007; 3: 426–37

    Article  Google Scholar 

  28. Delafuente JC. Understanding and preventing drug interactions in elderly patients. Crit Rev Oncol Hematol 2003; 48: 133–43

    Article  PubMed  Google Scholar 

  29. Karas Jr S. The potential for drug interactions. Ann Emerg Med 1981; 10: 627–30

    Article  PubMed  Google Scholar 

  30. Johnson JA, Bootman JL. Drug-related morbidity and mortality: a cost-of-illness model. Arch Intern Med 1995; 155: 1949–56

    Article  PubMed  CAS  Google Scholar 

  31. Thomas A, Routledge PA. Drug interaction in clinical practice. Focus Pharmacovigilance Bull 2003: 1–7

    Google Scholar 

  32. Seymour RM, Routledge PA. Important drug-drug interactions the elderly. Drugs Aging 1998; 12: 485–94

    Article  PubMed  CAS  Google Scholar 

  33. Anderson JR, Nawarskas JJ. Cardiovascular drug-drug interactions. Cardiol Clin 2001; 19: 215–34

    Article  PubMed  CAS  Google Scholar 

  34. Ament PW, Bertolino JG, Liszewski JL. Clinically significant drug interactions. Am Fam Physician 2000; 61: 1745–54

    PubMed  CAS  Google Scholar 

  35. Oscanoa T. Interaction medicamentosa em geriatría. An Facultad Medic 2006; 2: 119–26

    Google Scholar 

  36. Romero R, Castellote E, Ocon J, et al. Controlled multi-center study with quinapril, hydrochlorothiazide, and combination in patients with moderate to severe hypertension. J Cardiovasc Pharmacol 1995; 26: 114–8

    Article  PubMed  CAS  Google Scholar 

  37. Mahe I, Meune C, Diemer M, et al. Interaction between aspirin and ACE inhibitors in patients with heart failure. Drug Saf 2001; 24: 167–82

    Article  PubMed  CAS  Google Scholar 

  38. Malone DC, Hutchins DS, Haupert H, et al. Assessment of potential drug-drug interactions with a prescription claims database. Am J Health Syst Pharm 2005; 62: 1983–91

    Article  PubMed  CAS  Google Scholar 

  39. Holbrook AM, Pereira JA, Labiris R, et al. Systematic overview of warfarin and its drug and food interactions. Arch Intern Med 2005; 165: 1095–106

    Article  PubMed  CAS  Google Scholar 

  40. Chung L, Chakravarty EF, Kearns P, et al. Bleeding complications in patients on celecoxib and warfarin. J Clin Pharm Ther 2005; 30: 471–7

    Article  PubMed  CAS  Google Scholar 

  41. Juurlink DN, Mamdani M, Kopp A, et al. Drug-drug interactions among elderly patients hospitalized for drug toxicity. JAMA 2003; 289: 1652–8

    Article  PubMed  CAS  Google Scholar 

  42. Mallet L, Spinewine A, Huang A. The challenge of managing drug interactions in elderly people. Lancet 2007; 370: 185–91

    Article  PubMed  CAS  Google Scholar 

Download references

Acknowledgements

This study was supported by the Fundação de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP; Sao Paulo, Brazil). FAPESP provided a research scholarship for Silvia-Regina Secoli. The Conselho Nacional de Pesquisas (CNPq; Brasilia, Brazil) provided a research productivity grant to Jair Licio Ferreira Santos. The authors have no conflicts of interest that are directly relevant to the content of this study.

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Authors and Affiliations

  1. Nursing College, University of São Paulo, São Paulo, Brazil

    Silvia-Regina Secoli

  2. Fundació Institut Català de Farmacologia, Universitat Autònoma de Barcelona, Hospital Universitari Vall d’Hebron, Barcelona, Spain

    Albert Figueras

  3. Faculty of Public Health, University of São Paulo, São Paulo, Brazil

    Maria Lúcia Lebrão & Fernão Dias de Lima

  4. Faculty of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil

    Jair Licio Ferreira Santos

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  1. Silvia-Regina Secoli
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  2. Albert Figueras
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  3. Maria Lúcia Lebrão
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  4. Fernão Dias de Lima
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  5. Jair Licio Ferreira Santos
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Correspondence to Albert Figueras.

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Secoli, SR., Figueras, A., Lebrão, M.L. et al. Risk of Potential Drug-Drug Interactions among Brazilian Elderly. Drugs Aging 27, 759–770 (2010). https://doi.org/10.2165/11538460-000000000-00000

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