Vet Q & AMy dog has hypothyroidism. Should I start Eltroxin slowly?
Hello there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. Based on Bismarck's weight you provided me with, the starting Eltroxin dose is typically 20 micrograms / kg (0.02mg/kg) by mouth twice daily. This would put Bismarck at about 1.6mg twice daily. However, it should be noted that we typically do not exceed 0.8mg twice daily. For cases like this, I would generally start with the 0.6mg Levothyroxine and then recheck the thyroid level in 3-4 weeks to see if an adjustment needs to be made. I keep doing this until the thyroid level has been corrected. Also keep in mind that if Bismarck is sick, the thyroid level could be falsely decreased, a condition known as euthyroid sick syndrome. I would confirm that he is indeed hypothyroid by sending out a free-T4. I hope this helps! Please let me know if you have any other questions or concerns and I would be more than happy to help you further!
Updated on September 24th, 2025