# FDA Approves Chattem's XYZAL ALLERGY 24HR for Over-the-Counter Use The FDA has approved Chattem, Inc.'s levocetirizine dihydrochloride formulation under the brand XYZAL ALLERGY 24HR, expanding the company's footprint in the highly competitive over-the-counter antihistamine market. The approval positions Chattem to capture additional market share in the $6+ billion U.S. allergy relief category, where extended-release formulations continue to drive consumer demand.