They were frequently unable to grasp four out of five label instructions. But even people with a high-school education and higher had problems. “We came at this from a health literacy perspective, but we found it was a problem with many people in general,” said Michael Wolf, director of Northwestern´s new Health Literacy and Learning Program. “It was surprising how prevalent mistakes were regardless of an individual´s literacy level.”

The study showed that the more medications a patient takes, the more likely he or she will misunderstand the labels. The most common mistake made by patients in the study was misinterpreting dosage instructions (a tablespoon versus a teaspoon) followed by misunderstanding the dose frequency.

“Just being able to read the label doesn´t mean you´ll be able to interpret it. Patients reading at a sixth-grade level or below could read it back. But if you ask them what it means to take two tablets twice daily, only one-third of the patients with limited literacy skills got that correct,” Wolf said. “The most common misinterpretation was to take two pills a day. It´s not that they couldn´t figure out two plus two equals four. Rather, it´s the way the instructions were written. It´s awkward wording,” Wolf said, noting the wording is chosen by the individual pharmacist filling the prescription.

The more numbers included in the dosage, the more likely patients in the study got it wrong. The hardest label to understand: Take 1 teaspoon 3 times a day for 7 days. “It´s possible people read this quickly because they perceive it as simple. They get the numbers flipped. They confuse and misread them,” Wolf said.

Addressing medication error is a high priority within the health care system. In July, the Institute of Medicine reported 1.5 million patients are injured each year by medication errors, of which more than one-third occur at home.; Source: Northwestern University