Inactive ingredients in medications flagged as potential problem for some patients

  • Most prescription drugs contain at least one inactive ingrediant capable of causing adverse reactions, according to a new study.
  • Researchers from Brigham and Women's Hospital at Harvard and Massachusetts Institute of Technology found these medications to contain lactose, peanut oil, gluten or chemical dyes.
Medication In Pill Bottle And Hand
Craig F. Walker | Boston Globe | Getty Images

Five years ago, Dr. Giovanni Traverso was perplexed when a patient began to have negative reactions to a common medication he prescribed.

The assistant professor in MIT's department of mechanical engineering, who was also gastroenterologist at Harvard-affiliated Brigham Women's Hospital, was treating the patient's celiac disease. He didn't realize the acid suppressant contained ingredients derived from wheat gluten, the one thing celiac patients can't eat.

"That really brought it home to me as far as how little we know about tablets and the potential adverse effects
they might have," Traverso said. "I think there's a tremendous underappreciation of the potential impact that inactive ingredients may have."

So he and a team began looking into the inactive compounds used to make medications. The results were published Wednesday in the Science Translational Medicine journal.

The team analyzed 42,052 different oral medications and found that nearly 93 percent of them contained at least one inactive ingredient that could cause adverse reactions in certain conditions, such as peanut oil, lactose or dyes. And other medications included ingredients that people were sensitive to, including gluten and some kinds of sugar compounds.

According to the study, over half of the medications included sugars that were known to trigger digestive problems in some people suffering from irritable bowel syndrome.

The researchers wanted to know how much of the medications were made up by inactive ingredients and enlisted a team to weigh each one. They found that about 75 percent of each medication was made up of these ingredients.

While a person may not react to the amount of lactose in one pill, for example, they may react to the amount of lactose when they're on five different medications.

"How much is too much?" Traverso asked in a phone interview. "They may add up particularly for someone taking more pills or capsules. Someone is on 10 prescriptions as opposed to one."

But that's not to say inactive ingredients need to be cut out or avoided completely. "They are helpful and they are critical," he said.

Inactive ingredients help extend shelf-life, absorption, improve taste and more. Right now, researchers are just trying to increase the awareness of these potential adverse physical reactions.

And a problem arises when prescribers try to avoid certain ingredients. Common medications can come in a dozen different formulations, according to the research, and the specific combinations varies on the person's insurance, pharmacy and the pharmacy's manufacturer.

Whether it's through more transparent labeling or an app that helps a patient break down the ingredients, Traverso said it could help.The team is now polling health care providers to study how many people have reported negative reactions to these compounds as a follow up.

"There need to be more clinical trials and more data out there so that we can really dive deep into how many
patients are affected and how we can help them," Daniel Reker, a lead author on the study and researcher at MIT's Koch Institute for Integrative Cancer Research, said in a statement.