Glad to hear the fits have stopped now, that must have been scary for both of you!!

You wouldn't by chance know what your dog's T3/T4 levels were when she was diagnosed do you?

At work dogs are typically dosed on a twice a day schedule and the size of the dose is based on the T3/T4 levels and the dog's size. Then we retest the levels once the dog has been on the medication 4 weeks and adjust the dose accordingly.

I looked up the label for Thyro-Tabs. Since it's a human product it's hard for me to tell how much of the warnings apply to dogs, however I did find a couple things that might apply. Now bear in mind that they are required to put ANY reaction or side effect on the label even if it's one person out of 10 million that had a problem with it so don't get too frightened over some of it.

thyro-tabs Due to the long half-life of levothyroxine, the peak therapeutic effect at a given dose of levothyroxine sodium may not be attained for 4-6 weeks.

The signs and symptoms of overdosage are those of hyperthyroidism (see PRECAUTIONS and ADVERSE REACTIONS). In addition, confusion and disorientation may occur. Cerebral embolism, shock, coma, and death have been reported. Seizures have occurred in a child ingesting 18 mg of levothyroxine. Symptoms may not necessarily be evident or may not appear until several days after ingestion of levothyroxine sodium.

Treatment of Overdosage

Levothyroxine sodium should be reduced in dose or temporarily discontinued if signs or symptoms of overdosage occur.

Acute Massive Overdosage This may be a life-threatening emergency, therefore, symptomatic and supportive therapy should be instituted immediately. If not contraindicated (e.g., by seizures, coma, or loss of the gag reflex), the stomach should be emptied by emesis or gastric lavage to decrease gastrointestinal absorption. Activated charcoal or cholestyramine may also be used to decrease absorption.


If it were my dog; I'd have her stay at the vet another night and let them give her the medication there. If there's a reaction they will be there to witness it which may tell them something. Or possibly have the T3/T4 levels retested. If your vet doesn't want to do either then I'd be looking for a second opinion.