Antimicrobial Agents Used in Eye Drops Might Inhibit Mitochondrial Function, Scientists Warn

Researchers have found that quaternary ammonium compounds, or “quats,” used as antimicrobial agents in common household and pharmaceuticals products, inhibited mitochondrial function in human cells grown in the laboratory. One of them, benzalkonium chloride (BAK), is often used in eye drops.

The researchers tested over 1,600 compounds for their effects on mitochondria, the energy-producing machinery in cells of the body, including BAK and another kind of quat, cetylpyridinium chloride (CPC).

“Quats such as CPC and BAK are antimicrobial agents that occur in toothpaste, mouthwash, lozenges, throat and nasal sprays, shampoos, hand lotions, creams, eye drops, biocides, intravaginal sponges, consumer antiseptic rubs, and other products that come into contact with epithelial [skin] cells,” the authors stated.

The study, “In Vitro Evaluation of Mitochondrial Function and Estrogen Signaling in Cell Lines Exposed to the Antiseptic Cetylpyridinium Chloride,” was published in the journal Environmental Health Perspectives.

They found that quats as a class inhibited mitochondrial function and estrogen signaling.

This is a concern because mitochondrial dysfunction potentially plays a role contributing to several medical conditions, including cardiac diseases, diabetes, obesity, Alzheimer’s and Parkinson’s disease, and cancer.

A previous study found that repeated use of the BAK chemical can cause damage to the eye. “Although this study was done in animals the same thing could be happening in humans who use eye drops containing BAK for a long time,” study author Sandipan Datta said to Optometry Today.

“Further clinical studies are needed in order to assess the effect of these quats in humans, but caution should be exercised while using or prescribing quat-containing eye drops,” he said.

A recent FDA ruling canceled  the generally recognized as safe (GRAS) status of CPC in certain products. The FDA called for more evidence to support GRAS status for BAK due to potential safety issues and possible hormonal effects. However, they are still used in many formulations in healthcare, food, and in pharmaceutical and cleaning products.

“Mitochondrial inhibition in vitro occurred at a CPC concentration that may be relevant to human exposures. The antiestrogenic activity of CPC, BAK, rotenone, and triclosan may be related to their mitochondrial inhibitory activity. Our findings support the need for additional research on the mitochondrial inhibitory and antiestrogenic effects of QUATS, including CPC and BAK,” the study concluded.