A new study led by a team at Brigham and Women's Hospital and the Massachusetts Institute of Technology found that the vast majority of the most commonly prescribed drugs in the United States contain at least one component that causes an adverse reaction. These substances, called "inactive ingredients", can improve the taste, shelf life, absorption and other properties of the oral cavity. However, the authors found that more than 90% of all oral medications tested contained at least one component that caused allergies or allergies. These ingredients include lactose, peanut oil, gluten and chemical dyes. The team's findings are published online in the journal Science Translational Medicine.

The authors and colleagues analyzed data on 354,597 inactive ingredients contained in 42,052 oral drugs. Inactive ingredients are defined as substances that are added to a pill formulation but are not intended or intended to have a direct biological or therapeutic effect. Although these ingredients have been tested for safety at the population level, disaggregated case reports indicate that inactive ingredients may adversely affect individuals with allergies or intolerance.

“What really makes this data set really compelling is its complexity,” Reker said. “There are hundreds of different versions of pills or capsules that use the same combination of different inactive ingredients to provide the same drug. This highlights the complexity of the choice of inactive ingredients, but it also shows that there is an untapped opportunity today for specific choices for people with The most appropriate drug version for patients with abnormal sensitivity."

The team found that a total of 38 inactive ingredients were described in the literature as causing allergic symptoms after oral exposure. The authors report that 92.8% of the drugs they analyzed contained at least one of these inactive ingredients. Specifically, they report that approximately 45% of drugs contain lactose; approximately 33% of drugs contain food dyes;
Although only 0.08% of the drugs contain peanut oil, for some drugs - such as progesterone - there are few alternatives that do not contain this inactive ingredient.

The authors point out that inactive ingredients may cause adverse reactions through allergies (a histamine-related reaction that can cause urticaria, dyspnea and/or allergic reactions) or intolerance, where difficulty in absorbing a substance can cause the gastrointestinal tract. symptom. It is unclear what the amount of ingredients needed to initiate a reaction in a sensitive individual. For example, the lactose content of a drug may be too low to cause a response in many patients.


Daniel Reker, Steven M. Blum, Christoph Steiger, Kevin E. Anger, Jamie M. Sommer, John Fanikos and Giovanni Traverso. Inactive” ingredients in oral medications. Science Translational Medicine, 2019 DOI: 10.1126/scitranslmed.aau6753