In our last blog about What is medication adherence? Why does it matter? we took a closer look at medication adherence and how the community understands the term. In this blog we take it one step further as we explore medication non-adherence and find that it’s more than forgetting to take medication.

Medication non-adherence is broken down into two categories: Primary (PNA) and Secondary non-adherence (SNA). Primary non-adherence occurs when a new medication is prescribed for a patient but the patient fails to obtain the medication (or its appropriate alternative) within an acceptable period of time after it was initially prescribed.1 Secondary non-adherence is defined as a patient filling a prescription but not taking the medication as it was intended and/or prescribed. Within this type of non-adherence, there are two sub-types the literature describes as non-persistance and non-conforming. 1

In addition, general non-adherence may also be categorized based upon the patients’ intent to consume medication; known as intentional and unintentional. These types of non-adherences must be treated differently due to the variety of underlying factors.

Intentional non-adherence refers to a deliberate patient action (typically associated with the patient’s motivation) whereas unintentional non-adherence is driven by a lack of patient capacity or available resources to take their prescribed medications. 3

Poor medication adherence results in worse health outcomes, increased hospitalizations, and increased health care cost.4-6 Statistics suggest overall medication non-adherence equates to 10-30%  taking an unplanned trip to the hospital7-8

To tackle such an issue, the first step is to identify the underlying cause or problem for medication non-adherence for each patient, then medical professionals subsequently can provide individual strategies to improve their outcomes. By first understanding why a patient is not adherent to medications, only then can we find strategies to change behavior, improve patient health, and continue to keep one independent in their daily living.


1 Adams, A. J., & Stolpe, S. F. (2016). Defining and Measuring Primary Medication Nonadherence: Development of a Quality Measure. Journal of Managed Care & Specialty Pharmacy, 22(5), 516–523. doi: 10.18553/jmcp.2016.22.5.516

2 Erie Niagara AHEC . (2018, July 18). Types of Non-Adherence. Retrieved March 2020, from

3 Molloy, G. J., Messerli-Bürgy, N., Hutton, G., Wikman, A., Perkins-Porras, L., & Steptoe, A. (2014). Intentional and unintentional non-adherence to medications following an acute coronary syndrome: A longitudinal study. Journal of Psychosomatic Research, 76(5), 430–432. doi: 10.1016/j.jpsychores.2014.02.007

4 Cutler, D. M., Long, G., Berndt, E. R., Royer, J., Fournier, A.-A., Sasser, A., & Cremieux, P. (2007). The Value Of Antihypertensive Drugs: A Perspective On Medical Innovation. Health Affairs, 26(1), 97–110. doi: 10.1377/hlthaff.26.1.97

5 Congressional Budget Office. Offsetting effects of prescription drug use on Medicare’s spending for medical services. November 2012. Available at: Accessed March, 2020. Google Scholar

6 Commissioner, O. of the. (n.d.). Are You Taking Medication as Prescribed? Retrieved March 2020, from

Nair, N. P., Chalmers, L., Peterson, G. M., Bereznicki, B., Castelino, R. L., & Bereznicki, L. (2016). Hospitalization in older patients due to adverse drug reactions – the need for a prediction tool. Clinical Interventions in Aging, 497. doi: 10.2147/cia.s99097

8 Thomas, R., Huntley, A. L., Mann, M., Huws, D., Elwyn, G., Paranjothy, S., & Purdy, S. (2013). Pharmacist-led interventions to reduce unplanned admissions for older people: a systematic review and meta-analysis of randomised controlled trials. Age and Ageing, 43(2), 174–187. doi: 10.1093/ageing/aft169