AmTech Levothyroxine Sodium Tablets

Description

Each Levothyroxine Sodium Tablet provides synthetic crystalline levothyroxine sodium (L-Thyroxine).

Action

Levothyroxine sodium acts as does endogenous thyroxine, to stimulate metabolism, growth, development and differentiation on 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.

AmTech Levothyroxine Sodium 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). Levothyroxine sodium 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, ie., 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 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 front feet

Head tilt, disturbed balance, unilateral facial paralysis

Atrophy of epidermis, thickening of dermis

Surface and follicular hyperkeratosis, pigmentation

Puffy face, blepharoptosis, tragic expression

Dry, coarse, sparse coat, slow regrowth after clipping

Retarded turnover of hair (carpet coat of boxers)

Shortening or absence of estrus, lack of libido

Dry feces, occasional diarrhea

Hypercholesterolemia

Normochromic, normocytic anemia

Elevated serum creatinine phosphokinase

Contraindications

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

Precautions

The effects of levothyroxine sodium therapy are slow in being manifested. 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.

Adverse Reactions

There are no particular adverse reactions connected with L-Thyroxine therapy at the recommended dosage levels. Overdose will result in the signs of thyrotoxicosis listed above under precautions.

Dosage

The initial recommended daily dose is 0.1 mg/10 lb body weight. Dosage is then adjusted according to patient's response by monitoring T4 blood levels at time intervals of four weeks.

Administration

Thyroxine tablets may be administered orally or placed in the food.

Dosage Forms Available

0.2 mg - pink

0.5 mg - white

0.8 mg - light blue

Tablets in bottles of 180 and 1000.

AmTech Levothyroxine Sodium Tablets Caution

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

Storage

Store Between 15°c And 30°c (59°f And 86°f).

Tightly close this container after each use.

For Animal Use Only

Keep Out Of Reach Of Children

AmTech^® is a registered trademark of IVX Animal Health, Inc.

Manufactured by IVX Animal Health, Inc., St. Joseph, MO 64503

Rev1105

Nac No.