Medication Adherence


An increasing number of cancer patients are now able to take oral anti-cancer medications from the comforts of home. While this is more convenient for patients going through treatment, the convenience comes with more responsibility. Taking your medication correctly might not seem like a difficult task, but even the most motivated and organized patient can have difficulties at some point —which can be dangerous. Studies show that nearly 25 percent of all cancer patients take one or more oral medications as a part of their comprehensive cancer care. This guide will explain some of the common reasons patients get off schedule and provide solutions to help you stay on track.

What does medication adherence mean?

The word “adherence” refers to taking the right dose of the right drug at the right time. It's non-adherence when patients don’t follow their scheduled regimen exactly as prescribed. Some patients may simply forget to take their medications, while others may stop taking them in general because they start feeling better or because of financial reasons. There are two types of non-adherence:

  • Primary non-adherence – The patient doesn’t fill a new prescription.
  • Secondary non-adherence – The patient doesn’t take the medication as prescribed or doesn’t refill their prescription.

Why is it important?

Taking your medication exactly as prescribed by your doctor is important in the fight against cancer because it can influence the effectiveness of your medication during treatment. Most anti-cancer drug regimens are designed to maintain a specific level of drugs in your system for a specific duration of time, based on your cancer type, stage, previous treatments and several other factors. Non-adherence can lead to unnecessary side effects, physician visits, hospitalizations and even cancer progression.

Figure 1. Medication adherence statistics

What are common causes for non-adherence?

Research shows that of all the patients taking medications for chronic illnesses, approximately half aren't taking them exactly as prescribed by their doctor. In a national survey, one-third of cancer patients admitted they didn’t always follow the regimen exactly, with more than half admitting they occasionally forget to take a dose. Other known reasons for non-adherence include skipping doses to avoid side effects; splitting doses to save money; not filling (or refilling) prescriptions because of high copays or lack of insurance; complex and confusing treatment regimens; a lack of understanding of the actual purpose of the drug; or a belief that the treatment is unnecessary (especially in patients without symptoms).

A different form of non-adherence occurs when patients take too much of their medication. This may happen as a result of the misconception that if a treatment works well, two doses will work twice as well, or as a result of taking doses too close together (possibly after missing a dose). This type of medication non-adherence has the potential to be extremely dangerous and can even lead to an increased risk of death.

Most patients start their treatments with the best of intentions, but rates of adherence tend to taper off over time. For example, medication adherence for women taking tamoxifen for breast cancer is generally high during the first year but gradually decreases over the five years of recommended therapy—even though it’s proven to reduce the rate of recurrence and extend lives when taken as prescribed.

Many physicians believe that treatment fatigue (the feeling of wanting to escape the confines of cancer treatment) may contribute to reduced medication adherence in individuals with long-term treatment plans. Treatment fatigue may also occur in patients who are not yet willing to accept cancer as a part of their lives.

In the following content, you will learn more about the importance of sticking to your prescribed treatment plan and how proper medication adherence can benefit your health, well-being and chance of survival.

Six factors for medication adherence

  1. The right drug
  2. At the right dose
  3. At the right time
  4. On the right schedule
  5. Under the right conditions
  6. With the right precautions