Journal of General Internal Medicine

, Volume 21, Issue 8, pp 847–851 | Cite as

Low literacy impairs comprehension of prescription drug warning labels

  • Terry C. DavisEmail author
  • Michael S. Wolf
  • Pat F. Bass
  • Mark Middlebrooks
  • Estela Kennen
  • David W. Baker
  • Charles L. Bennett
  • Ramon Durazo-Arvizu
  • Anna Bocchini
  • Stephanie Savory
  • Ruth M. Parker
Original Articles


BACKGROUND: Adverse events resulting from medication error are a serious concern. Patients’ literacy and their ability to understand medication information are increasingly seen as a safety issue.

OBJECTIVE: To examine whether adult patients receiving primary care services at a public hospital clinic were able to correctly interpret commonly used prescription medication warning labels.

DESIGN: In-person structured interviews with literacy assessment.

SETTING: Public hospital, primary care clinic.

PARTICIPANTS: A total of 251 adult patients waiting for an appointment at the Louisiana State University Health Sciences Center in Shreveport (LSUHSC-S) Primary Care Clinic.

MEASUREMENTS: Correct interpretation, as determined by expert panel review of patients’ verbatim responses, for each of 8 commonly used prescription medication warning labels.

RESULTS: Approximately one-third of patients (n=74) were reading at or below the 6th-grade level (low literacy). Patient comprehension of warning labels was associated with one’s literacy level. Multistep instructions proved difficult for patients across all literacy levels. After controlling for relevant potential confounding variables, patients with low literacy were 3.4 times less likely to interpret prescription medication warning labels correctly (95% confidence interval: 2.3 to 4.9).

CONCLUSIONS: Patients with low literacy had difficulty understanding prescription medication warning labels. Patients of all literacy levels had better understanding of warning labels that contained single-step versus multiple-step instructions. Warning labels should be developed with consumer participation, especially with lower literate populations, to ensure comprehension of short, concise messages created with familiar words and recognizable icons.

Key words

literacy warning labels prescription drug labels medication error patient comprehension lexile 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Institute of Medicine. To Err is Human: Building a Safer Health System. In: Kohn L, Corrigan J, Donaldson M, eds. Washington, DC: National Academy Press; 2000.Google Scholar
  2. 2.
    Williams CM. Using medications appropriately in older adults. Am Fam Physician. 2002;66:1917–24.Google Scholar
  3. 3.
    Rollins G. Adverse drug events among elderly outpatients are common and preventable. Rep MedGuidelines Outcomes Res. 2003;14:6–7.Google Scholar
  4. 4.
    Georgetown University. Prescription drugs: a vital component of health care. Challenges for the 21st Century: Chronic and Disabling Conditions, Center on an Aging Society, Data Profile Series II 2002; 5: 1–6.Google Scholar
  5. 5.
    Institute of Medicine. Health Literacy: A Prescription to End Confusion. In: Nielsen-Bohlman L, Panzer A, Kindig DA, eds. Washington, DC: National Academy Press; 2004.Google Scholar
  6. 6.
    Nichols-English G, Poirier S. Optimizing adherence to pharmaceutical care plans. J Am Pharm Assoc. 2004;40:475–85.Google Scholar
  7. 7.
    Kutner M, Greenberg E, Baer J. A First Look at the Literacy of America’s Adults in the 21st Century. National Center for Education Statistics: U.S. Department of Education; 2005.Google Scholar
  8. 8.
    Pharmex-Pharmacy Excellence, 1531 Airway Circle, New Smyrna Beach, FL 32168-5900, URL: Scholar
  9. 9.
    Davis TC, Kennen EM, Gazmararian JA, Williams MV. Literacy testing in health care research. In: Schwartzberg JG, VanGeest JB, Wang CC, eds. Understanding Health Literacy: Implications for Medicine and Public Health. Chicago, IL: AMA Press; 2004: 157–79.Google Scholar
  10. 10.
    Davis TC, Long SW, Jackson RH, et al. Rapid estimate of adult literacy in medicine: a shortened screening instrument. Fam Med. 1993;25:391–5.PubMedGoogle Scholar
  11. 11.
    Parker RM, Baker DW, Williams MV, Nurss JR. The test of functional health literacy in adults: a new instrument for measuring patients’ literacy skills. J Gen Intern Med. 1995;10:537–41.PubMedCrossRefGoogle Scholar
  12. 12.
    MetaMetrics Inc. 1000 Park Forty Plaza Drive, Suite 120, Durham, North Carolina 27713. Lexile Analyzer: Scholar
  13. 13.
    Stenner AJ, Horabin I, Smith DR, Smith M. The Lexile Framework. Durham, NC: Metametrics; 1998.Google Scholar
  14. 14.
    Stenner AJ. Measuring reading comprehension with the Lexile framework. Paper presented at the 4th North American Conference on Adolescent/Adult Literacy; February 1996; Washington, D.C.Google Scholar
  15. 15.
    White S, Clement J. Assessing the Lexile Framework: Results of a panel meeting. NCES Working Paper Series, Working Paper No. 2001-08. Washington, DC: U.S. Department of Education, Office of Educational Research and Improvement; 2001.Google Scholar
  16. 16.
    Zeger SL, Liang KY, Albert PS. Models for longitudinal data: a generalized estimating equation approach. Biometrics. 1988;44:1049–60.PubMedCrossRefGoogle Scholar
  17. 17.
    Davis CS. Statistical Methods for the Analysis of Repeated Measurements. New York: Springer; 2002.Google Scholar
  18. 18.
    McGee J. Writing and Designing Print Materials for Beneficiaries: A Guide for State Medicaid Agencies. HFCA Publication Number 10145. Baltimore, MD: US Department of Health and Human Services, Health Care Financing Administration, Center for Medicaid and State Operations; 1999.Google Scholar
  19. 19.
    Weiss BD. Health Literacy: A Manual for Clinicians. Chicago: American Medical Association; American Medical Association Foundation; 2003.Google Scholar
  20. 20.
    Doak CC, Doak LG, Root JH. Teaching Patients with Low-Literacy Skills. 2nd edn. Philadelphia, PA: JB Lippincott; 1996.Google Scholar
  21. 21.
    Schillinger D, Grumbach K, Piette J, et al. Association of health literacy with diabetes outcomes. JAMA. 2002;288:475–82.PubMedCrossRefGoogle Scholar
  22. 22.
    Rudd RE, Comings JP, Hyde JN. Leave no one behind: improving health and risk communication through attention to literacy. J Health Commun. 2003;8(Suppl 1):104–15.PubMedGoogle Scholar
  23. 23.
    Baker DW, Gazmararian JA, Williams MV, et al. Functional health literacy and the risk of hospital admission among Medicare managed care enrollees. Am J Public Health. 2002;92:1278–83.PubMedCrossRefGoogle Scholar
  24. 24.
    Baker DW, Parker RM, Williams MV, Clark WS. Health literacy and the risk of hospital admission. J Gen Intern Med. 1998;13:791–8.PubMedCrossRefGoogle Scholar
  25. 25.
    Williams MV, Baker DW, Parker RM, Nurss JR. Relationship of functional health literacy to patients’ knowledge of their chronic disease: a study of patients with hypertension and diabetes. Arch Intern Med. 1998;158:166–72.PubMedCrossRefGoogle Scholar
  26. 26.
    Wolf MS, Davis TC, Cross JT, Marin E, Green KM, Bennett CL. Health literacy and patient knowledge in a Southern US HIV clinic. Int J STD AIDS. 2004;15:1144–50.CrossRefGoogle Scholar
  27. 27.
    Dewalt DA, Berkman ND, Sheridan S, Lohr KN, Pignone MP. Literacy and health outcomes: a systematic review of the literature. J Gen Intern Med. 2004;19:1228–39.PubMedCrossRefGoogle Scholar
  28. 28.
    Kalichman SC, Ramachandran B, Catz S. Adherence to combination antiretroviral therapies in HIV patients of low health literacy. J Gen Intern Med. 1999;14:267–73.PubMedCrossRefGoogle Scholar
  29. 29.
    Wolf MS, Gazmararian JA, Baker DW. Health literacy and functional health status among older adults. Arch Intern Med. 2005;165:1946–52.PubMedCrossRefGoogle Scholar
  30. 30.
    Einarson TR. Drug-related hospital admissions. Ann Pharm. 1993;27:832–40.Google Scholar
  31. 31.
    Morrell RW, Park DC, Poon LW. Quality of instruction on prescription drug labels: effects on memory and comprehension in young and old adults. Gerontologist. 1989;29:345–53.PubMedCrossRefGoogle Scholar
  32. 32.
    Cline CM, Bjorck-Linne AK, Israelsson BY, et al. Non-compliance and knowledge of prescribed medication in elderly patients with heart failure. Eur J Heart Failure. 1999;1:145–9.CrossRefGoogle Scholar
  33. 33.
    Moisan J, Gaudet M, Gregoire JP, Bouchard R. Non-compliance with drug treatment and reading difficulties with regard to prescription labeling among seniors. Gerontology. 2002;48:44–51.PubMedCrossRefGoogle Scholar
  34. 34.
    Beard K. Adverse reactions as a cause of hospital admission in the aged. Drugs Agency. 1992;2:336–7.Google Scholar
  35. 35.
    US Department of Health and Human Services. Health Communication. In: Healthy People 2010. With Understanding and Improving Health and Objectives for Improving Health. 2nd edn. Washington, DC: US Government Printing Office; 2000.Google Scholar
  36. 36.
    Farley D. FDA’s Rx for better medication information. FDA Consum. 1995;29:5–10.PubMedGoogle Scholar
  37. 37.
    Medication Guides for Prescription Drug Products. Code of Federal Regulations 2004 ed. Title 21; Pt 208: 111–114.Google Scholar
  38. 38.
    Status of Useful Written Prescription Drug Information for Patients; Docket No 00N-0352. Federal Register 65 (April 28, 2000): 7022.Google Scholar
  39. 39.
    Over-The-Counter Human Drugs: Labeling Requirements. Federal Register 64 (March 17, 1999): 13253–13303.Google Scholar
  40. 40.
    Svarsted BL, Bultman DC, Mount JK, Tabak ER. Evaluation of written prescription information provided in community pharmacies: a study in eight states. J Am Pharm Assoc. 2003;43:383–93.CrossRefGoogle Scholar
  41. 41.
    American Pharmaceutical Association. Committee Policy Report on Health Literacy 2001–2002.Google Scholar
  42. 42.
    American Society of Health-System Pharmacists. ASHP Guidelines on Pharmacist-Conducted Patient Education and Counseling. Medication Therapy and Patient Care: Organization and Delivery of Services-Guidelines 1997;192–4.Google Scholar
  43. 43.
    Wogalter MS, Vigilante WJ Jr. Effects of label format on knowledge acquisition and perceived readability by younger and older adults. Ergonomics. 2003;46:327–44.PubMedCrossRefGoogle Scholar
  44. 44.
    Sansgiry SS, Cady PS, Patil S. Readability of over-the-counter medication labels. J Am Pharm Assoc. 1997;NS37:522–8.Google Scholar
  45. 45.
    Dickinson D, Raynor DK, Duman M. Patient information leaflets for medicines: using consumer testing to determine the most effective design. Patient Educ Couns. 2001;43:147–59.PubMedCrossRefGoogle Scholar

Copyright information

© Society of General Internal Medicine 2006

Authors and Affiliations

  • Terry C. Davis
    • 1
    Email author
  • Michael S. Wolf
    • 2
  • Pat F. Bass
    • 1
  • Mark Middlebrooks
    • 1
  • Estela Kennen
    • 1
  • David W. Baker
    • 2
  • Charles L. Bennett
    • 2
  • Ramon Durazo-Arvizu
    • 2
  • Anna Bocchini
    • 1
  • Stephanie Savory
    • 1
  • Ruth M. Parker
    • 3
  1. 1.Departments of Medicine, Pediatrics, and PharmacyLouisiana State University Health Sciences CenterShreveportUSA
  2. 2.Institute for Healthcare Studies, Division of General Internal Medicine, and Robert H. Lurie Comprehensive Cancer CenterFeinberg School of Medicine at Northwestern UniversityChicagoUSA
  3. 3.Emory University School of MedicineAtlantaUSA

Personalised recommendations