Skip to Content

The originating document has been archived. We cannot confirm the completeness, accuracy and currency of the content.

HESKA ThyroMed Chewable Tablets

This page contains information on HESKA ThyroMed Chewable Tablets for veterinary use.
The information provided typically includes the following:
  • HESKA ThyroMed Chewable Tablets Indications
  • Warnings and cautions for HESKA ThyroMed Chewable Tablets
  • Direction and dosage information for HESKA ThyroMed Chewable Tablets

HESKA ThyroMed Chewable Tablets

This treatment applies to the following species:
Manufacturer: Heska

(Levothyroxine Sodium, USP)

HESKA ThyroMed Chewable Tablets Caution:

Federal law restricts this drug to use by or on the order of a licensed veterinarian.


Each ThyroMed® Chewable Tablet (Levothyroxine Sodium, USP) provides synthetic crystalline levothyroxine sodium (L-thyroxine).

The structural formula for levothyroxine sodium is:

Levothyroxine Sodium Action:

Levothyroxine sodium acts, as does endogenous thyroxine, to stimulate metabolism, growth, development and differentiation of tissues. It increases the rate of energy exchange and increases the maturation rate of the epiphyses. Levothyroxine sodium is absorbed rapidly from the gastrointestinal tract after oral administration. Following absorption, the compound becomes bound to the serum alpha globulin fraction. For purposes of comparison, 0.1 mg of levothyroxine sodium elicits a clinical response approximately equal to that produced by one grain (65 mg) of desiccated thyroid.

HESKA ThyroMed Chewable Tablets Indications:

Provides thyroid replacement therapy in all conditions of inadequate production of thyroid hormones. Hypothyroidism is the generalized metabolic disease resulting from deficiency of the thyroid hormones levothyroxine (T4) and liothyronine (T3). ThyroMed® Chewable Tablets (Levothyroxine Sodium, USP) will provide levothyroxine (T4) as a substrate for the physiologic deiodination to liothyronine (T3). Administration of levothyroxine sodium alone will result in complete physiologic thyroid replacement.

Canine hypothyroidism is usually primary, i.e. due to atrophy of the thyroid gland. In the majority of cases the atrophy is associated with lymphocytic thyroiditis and in the remainder it is non-inflammatory and as of yet unknown etiology. Less than 10 percent of cases of hypothyroidism are secondary, i.e. due to deficiency of thyroid stimulating hormone (TSH). TSH deficiency may occur as a component of congenital hypopituitarism or as an acquired disorder in adult dogs, in which case it is invariably due to the growth of a pituitary tumor.

Hypothyroidism In The Dog:

Hypothyroidism usually occurs in middle-aged and older dogs although the condition will sometimes be seen in younger dogs of the larger breeds. Neutered animals of either sex are also frequently affected, regardless of age. The following may be clinical manifestations of hypothyroidism in dogs:


Atrophy of the epidermis, thickening of the dermis; Surface and follicular hyperkeratosis, pigmentation; Puffy face, blepharoptosis, tragic expression; Dry, coarse, sparse haircoat, slow regrowth after clipping; Retarded turnover of hair (carpet coat of boxers)


Lethargy, lack of endurance, increased sleeping; Reduced interest, alertness and excitability; Slow heart rate, weak apex beat and pulse, low voltage on ECG; Preference for warmth, low body temperature, cool skin; Increased body weight


Stiff and slow movements, dragging of the front feet; Head tilt, disturbed balance, unilateral facial paralysis


Shortening or absence of estrus, lack of libido


Dry feces, occasional diarrhea

Clinical pathological

Hypercholesterolemia; Normochromic, normocytic anemia; Elevated serum creatinine phosphokinase


Levothyroxine sodium therapy is contraindicated in thyrotoxicosis, acute myocardial infarction and uncorrected adrenal insufficiency. Use in pregnant bitches has not been evaluated.


The effects of levothyroxine sodium therapy are slow to manifest. Overdosage of any thyroid drug may produce the signs and symptoms of thyrotoxicosis including, but not limited to: polydipsia, polyuria, polyphagia, reduced heat tolerance and hyperactivity or personality change. Administer with caution to animals with clinically significant heart disease, hypertension, or other complications for which a sharply increased metabolic rate might prove hazardous.

The material safety data sheet (MSDS) contains more detailed occupational safety information. For technical service, to report an adverse event or to obtain a copy of the MSDS, call 1-888-437-5287.

Adverse Reactions:

There are no particular adverse reactions associated with levothyroxine sodium therapy at the recommended dosage levels. Overdosage will result in the signs of thyrotoxicosis listed above under precautions.


The initial recommended dose of levothyroxine is 0.1 mg/10 lb (4.5 kg) body weight twice daily. Dosage is then adjusted by monitoring the post-pill blood level of thyroid hormone in the dog every four weeks until an adequate maintenance dose is established. The usual maintenance dose is 0.1 mg/10 lb (4.5 kg) once daily.


ThyroMed® Chewable Tablets may be given orally to dogs as a treat, or crumbled over their food at the veterinarian-prescribed dose. If crumbled over food, consumption should be monitored.

How Supplied:

ThyroMed® Chewable Tablets are available in 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg and 0.8 mg strength chewable tablets. Tablets are bilaterally scored. The tablets are packaged in bottles of 180 tablets (with childproof caps) and 1,000 tablets.


Store at controlled room temperature; 15°C to 30°C (59°F to 86°F) and protect from light.


1. Feldman EC, Nelson RW. Canine and Feline Endocrinology and Reproduction. W.B. Saunders, Co., Philadelphia, PA 1996: 68-117.

2. Scott DW, Miller WH, Griffen CE. Small Animal Dermatology. W.B. Saunders, Co., Philadelphia, PA 1995: 237-8, 894-5.

3. Nelson RW. Current Veterinary Therapy X. R.W. Kirk (ed), W.B. Saunders, Co., Philadelphia, PA 1989: 993-997.

4. Evinger JV, Nelson RW. J Am Vet Med Assoc 1984; 185(3): 314-316.

Manufactured for: Heska Corporation, 1613 Prospect Parkway, Fort Collins, CO 80525 USA

©2004 Heska Corporation

918110, 918111, 918120, 918121, 918130, 918131, 918140, 918141, 918150, 918151, 918160, 918161, 918170, 918171, 918180, 918181

NAC No.: 14820132

Telephone:   970-493-7272
Fax:   970-619-3008
Information/Order Desk:   800-GO-HESKA
Every effort has been made to ensure the accuracy of the HESKA ThyroMed Chewable Tablets information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2017 North American Compendiums. Updated: 2017-11-28