The U.S. Food and Drug Administration is investigating serious adverse events involving Limbrel, a product in capsule form currently being marketed as a medical food to manage the metabolic processes associated with osteoarthritis. While a range of adverse events have been reported, two serious and potentially life-threatening medical conditions are among them: drug-induced liver injury and hypersensitivity pneumonitis.

In total, the FDA has received 194 adverse event reports regarding Limbrel, of those, 57 of the cases contained sufficient information to analyze in detail whether Limbrel was associated with an adverse event; 30 of these contained sufficient information to use the Council for International Organizations of Medical Sciences (CIOMS) causality assessment method to determine the likelihood that an association between the consumption of Limbrel and the adverse events reported exists.

Limbrel is marketed by Primus Pharmaceuticals Inc., Scottsdale, AZ. Limbrel is available in capsule form in two dosages: Limbrel250 and Limbrel500. The labeling states that the products contain two types of flavonoids: baicalin (from Scutellaria baicalensis) and catechin (from Acacia catechu). Both dosages also contain zinc. Claims made on the product label and in labeling indicate that Limbrel is intended to manage the metabolic processes associated with osteoarthritis.

On November 8, 2017, the FDA contacted Primus Pharmaceuticals regarding the adverse events and requested information about the formula for Limbrel. The formula is being reviewed by the FDA. In the interim, the agency is alerting consumers and health care providers about the potential impact to health and advising consumers not to use Limbrel.