Federal law restricts this drug to use by or on the order of a licensed veterinarian.
Each tablet, Pala-Tech™ Canine Thyroid Chewable Tablets (Levothyroxine Sodium, USP), provides synthetic crystalline levothyroxine sodium (L-thyroxine).
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.
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). Each tablet, Pala-Tech™ Canine Thyroid 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 the 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 are clinical signs of hypothyroidism in dogs:
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
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)
Shortening or absence of estrus, lack of libido
Dry feces, occasional diarrhea
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.
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 dosage is established.
Each tablet, Pala-Tech™ Canine Thyroid 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.
Pala-Tech™ Canine Thyroid 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, 0.8 mg, 0.9 mg and 1.0 mg strength chewable tablets. Tablets are bilaterally scored for all dosage strengths, except for the 1.0 mg strength chewable tablets. 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.
Feldman EC, Nelson RW. Canine and Feline Endocrinology and Reproduction. W.B. Saunders, Co., Philadelphia, PA 1996: 68-117.
Nelson RW. Current Veterinary Therapy X. R.W. Kirk (ed), W.B. Saunders, Co., Philadelphia, PA 1989: 993-997.
Evinger JV, Nelson RW. J Am Vet Med Assoc 1984; 185(3): 314-316.
KEEP OUT OF REACH OF CHILDREN
Manufactured for: Pala-Tech™ Laboratories, Inc., The Science of Palatability™, Lakeville, MN 55044 USA
© Pala-Tech™ Laboratories, Inc.
Made in the U.S.A.
NAC No.: 10680051