One Third of Diabetics Taking Metformin Don’t Adhere to Medication Schedule Due to Side Effects

According to a recent article in the journal Diabetes, Obesity and Metabolism, around 30 percent of patients with diabetes who are given metformin stop taking the drug as prescribed due to its side effects. Since metformin is the most commonly prescribed diabetes drug, the findings paint a concerning picture of the current state of medication adherence in this patient population.

“The importance of diabetes patients taking their prescribed medication cannot be underestimated,” said Dr. Andy McGovern, Clinical Researcher at the University of Surrey. “A failure to do so can lead to complications in their condition including eye disease and kidney damage. Medication which is not taken does no good for the patient but still costs the NHS money so this is an important issue.”

The study analyzed the results of 48 clinical trials and included data from observational studies on medication adherence rates among diabetic patients taking the oral and injectable forms of diabetes drugs. Patients who were prescribed metformin were the least likely to take the recommended dosages, compared to those taking other drugs to manage their type 2 diabetes.

The analysis found that 30 percent of all metformin doses are not taken by patients. This is compared to 23 percent of sulfonylureas and 20 percent for pioglitazone, two other types of diabetes disease management medications. When the researchers looked at newer classes of diabetes drugs, such as DPP4 inhibitors (gliptins), rates on non-adherence were between 10 and 20 percent, suggesting that these modern drugs are easier for patients to keep taking.

“We have known for a long time that a lot of medication prescribed for chronic diseases never actually get taken,” said McGovern. “What this latest research suggests is that patients find some of these medication classes much easier to take than others.”

According to the research team, side effects and complex dosing regimens could be the reason behind poorer medication adherence among patients taking metformin. Diarrhea and flatulence are common side effects of metformin and while an extended-release version of the diabetes drug exists, many people with diabetes must take multiple doses of metformin per day in order to control their blood sugar.

“I urge anyone who is struggling to take their medication as prescribed, whether this is because of side effects or because the schedule is too complicated, to discuss this openly with their doctor or nurse,” said McGovern. “Fortunately for type 2 diabetes we have lots of treatment options and switching to a different medication class which is easier to take could provide an easy way to improve adherence. I would also encourage doctors and nurses to actively ask their patients about medication adherence.”