Warning issued to makers of unapproved canine levothyroxine drugs

The U.S. Food and Drug Administration (FDA) gave six manufacturers of unapproved levothyroxine sodium drugs marketed and labeled as treatment for hypothyroidism in dogs 15 working days to come into compliance with the law.

The FDA letters warned the manufacturers of the following unapproved drugs:

• Thyrosyn (Vedco)

• Soloxine (Virbac)

• Levocrine (Dechra)

• ThyroMed (Heska)

• Thyroid Chewable Tablets (Pala-Tech)

• ThyroKare (Neogen)

• Thyroxine L (Henry Schein)

• ThyroVet (VetOne)

• Leventa (Merck Animal Health)

Animal drugs that have not been reviewed and approved by FDA may not meet the legal standards for safety and effectiveness, or they may be improperly manufactured or labeled, the agency states in a release. As such, if the manufacturers do not come into compliance, they may be subject to enforcement action, including seizure of offending products or an injunction.

Currently there is only one FDA-approved drug for replacement therapy for diminished thyroid function: Thyro-Tabs Canine (Lloyd). Dog owners and veterinarians can report to the FDA any adverse events, including ineffectiveness, in dogs that have received approved or unapproved hypothyroidism products at fda.gov.