Hidden Dangers in Drugs' 'Inactive' Ingredients


When it comes to medications, “inactive” doesn’t always mean “safe.” Authors of a study just published in Science Translational Medicine found that more than 92 percent of oral meds sold in the United States contain at least one ingredient that can cause allergic reactions or side effects in people who are sensitive to them. These ingredients include lactose, peanut oil, gluten, and chemical dyes that are added to improve taste, shelf-life, absorption, or other characteristics of pills, capsules, or liquid medicines.

The study was conducted at Brigham and Women's Hospital in Boston and the Massachusetts Institute of Technology in Cambridge in response to an incident in which a person with celiac disease was prescribed a medication that contained gluten — which must be avoided by people with celiac. The researchers analyzed more than 42,000 oral meds containing more than 354,000 inactive ingredients that are not intended or expected to produce any effects.

They found 38 inactive ingredients that are known to cause reactions when taken by mouth. About 45 percent of the medicines contained lactose and 33 percent contained a chemical dye. If you take a new medication and experience an allergic reaction or side effect, talk to your health care provider, especially if you have a known allergy or sensitivity.