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# FDA OKs Canine Levothyroxine, Warns 6 Firms
- URL: https://www.fdaweb.com/fda-oks-canine-levothyroxine-warns-6-firms/
- Published: 2016-01-29T12:00:00.000Z
- Updated: 2026-09-15T02:32:04.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5134608

> FDA’s Center for Veterinary Medicine 1/29 simultaneously announced the [approval of the first animal drug (levothyroxine)](http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm482116.htm?ref=fdaweb.com) to treat canine hypothyroidism and its [issuance of Warning Letters](http://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm482928.htm?ref=fdaweb.com) to six manufacturers of unapproved veterinary levothyroxine products for this condition. The newly approved product, Thyro Tabs Canine, is made by Shenandoah, IA-based Lloyd, Inc.  
>  
> Warning Letters were sent to Intervet/Merck Animal Health, Madison, NJ; Neogen Corp., Lansing, MI; Quality Care Mfg., Lincoln, NE; Verbac Animal Health, Fort Worth, TX; Dechra Veterinary Products, Overland Park, KS; and Diamond Animal Health, De Moines, IA. FDA told the companies their levothyroxine products for dogs are unsafe and adulterated, and gave them 15 days to respond stating “the steps you have taken to bring your firm into compliance with the law.”