Soloxine is manufacturer discontinued. We recommend the equivalent Thyro-tab. Click here to purchase Thyro-tab.
(Soloxine, Thyrozine, ThyroTabs, Synthroid, Leventa, Nutrived T4 Chewable, Levocrine)
Common Drug Name
Common Brand Names
Soloxine, Thyrozine, ThyroTabs,
Leventa, Nutrived T4 Chewable, Levocrine (veterinary forms)
Synthroid (human form)
Tablets: Store at room temperature in a tight, light resistant, childproof container. Liquid: Store refrigerated at 37-46 degrees F (28 degrees C), protect from light. After first opening, store in refrigerator (37-46 degrees F) and use the product within 6 months.
Levothyroxine is a synthetic thyroid hormone. It usually needs to be given for the life of the animal when the animal is not producing enough thyroid hormone.
Dogs and Cats: Levothyroxine is used for the treatment of hypothyroidism, a condition in which the body does not produce enough thyroid hormone.
Birds: Levothyroxine is used for the treatment of respiratory clicking, vomiting, obesity, and thyroid responsive diseases.
Turtles: It is used for the treatment of hypothyroidism and to stimulate eating in debilitated turtles.
Dose and Administration
Always follow the dosage instructions provided by your veterinarian. If you have difficulty giving the medication, contact your veterinarian.
Dogs and Cats: Give by mouth. If approved by your veterinarian, it may be given with food.
Birds: Levothyroxine is usually administered in the drinking water.
Your veterinarian may monitor thyroid hormone levels in the blood every 24 weeks while adjusting the dose.
If you miss a dose, give it as soon as you remember. If it is almost time for the next dose, skip the one you missed and go back to the regular schedule. Do not give 2 doses at once.
This medication should only be given to the pet for whom it was prescribed.
Possible Side Effects
None if given at correct dosage.
Some species of redfeathered birds may start growing yellow feathers.
If your pet experiences an allergic reaction to the medication, signs may include facial swelling, hives, scratching, sudden onset of diarrhea, vomiting, shock, seizures, pale gums, cold limbs, or coma. If you observe any of these signs, contact your veterinarian immediately.
Differences exist between brands. Do not change brands if possible. If there is a need to change, your veterinarian may need to recheck thyroid hormone levels and adjust dose if indicated.
Not for use in animals hypersensitive (allergic) to it.
Use with extreme caution in older or debilitated animals, or those with heart disease, high blood pressure, Addison's disease (hypoadrenocorticism), or diabetes.
Do not use in animals with hyperthyroidism, a condition in which the body produces too much thyroid hormone.
The safety of this medication in pregnant and lactating animals (female animals nursing their young) has not been determined.
Consult with your veterinarian regarding the physical examinations and laboratory testing necessary prior to and during treatment with levothyroxine.
Drug, Food, and Test Interactions
Consult with your veterinarian before using levothyroxine with any other medications, including vitamins and supplements, epinephrine, norepinephrine, insulin, estrogens, warfarin, or digoxin, since interactions may occur.
No known food interactions.
Levothyroxine can alter the results of many laboratory tests. Tell your veterinarian your pet is on levothyroxine before any tests are performed.
Signs of Toxicity/Overdose
With chronic overdosing (taking a slightly higher dose over a long period of time), expect to see signs of hyperthyroidism such as an increase in drinking, urinating, eating, activity; seeking cool areas; increased heart rate; panting; restlessness; and behavior changes. May also see vomiting.
If you know or suspect your pet has had an overdose, or if you observe any of these signs in your pet, contact your veterinarian immediately.
Keep this and all other medications out of the reach of children and pets.
This information may not cover all possible uses, directions, side effects, precautions, allergic reactions, drug interactions, or withdrawal times. Always consult your own veterinarian for specific advice concerning the treatment of your pet.