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Benzalkonium Chloride

Medically reviewed by Last updated on Apr 17, 2023.

Excipient (pharmacologically inactive substance)

What is it?

Benzalkonium chloride is quaternary ammonium compound used in the pharmaceutical industry as an antimicrobial preservative, antiseptic, disinfectant, solubilizing agent, and wetting agent. It is a widely used preservative often found in ophthalmic solutions and contact lens solutions.

It may be used in combination with other preservatives or excipients to enhance its antimicrobial activity against strains of other bacteria. In nasal and ear formulations it may be combined with the preservative thimerosol. It is also used as a preservative in cosmetics.[1]

Benzalkonium chloride is a common bactericidal preservative in albuterol and metaproterenol nebulizer solutions in the U.S. Benzalkonium chloride has been implicated in causing paradoxical broncospasms in children after the use of inhaled antiasthmatic medications. The bronchospasm may be accompanied by a cough, burning sensation, facial flushing and pruritus.[2]


  1. Medicines Complete. Pharmaceutical Excipients. Monographs. Benzalkonium chloride. Accessed April 8, 2012.
  2. Inactive Ingredients in Pharmaceutical Products: Update. Committee on Drugs Pediatrics 1997;99;268

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.