Yes

Thyroid Product

Replacement or supplemental therapy in hypothyroidism, management of nontoxic goiter, chronic lymphocytic thyroiditis, as an adjunct in thyrotoxicosis and as a diagnostic aid; levothyroxine is recommended for chronic therapy; although previously thought to benefit cardiac patients with severely reduced fractions, liothyronine injection is no longer considered beneficial

A

Recent myocardial infarction or thyrotoxicosis, hypersensitivity to liothyronine sodium or any component, undocumented or uncorrected adrenal insufficiency

Ineffective for weight reduction; high doses may produce serious or even life-threatening toxic effects particularly when used with some anorectic drugs. Use with extreme caution in patients with angina pectoris or other cardiovascular disease (including hypertension) or coronary artery disease; use with caution in elderly patients since they may be more likely to have compromised cardiovascular function. Patients with adrenal insufficiency, myxedema, diabetes mellitus and insipidus may have symptoms exaggerated or aggravated; thyroid replacement requires periodic assessment of thyroid status. Chronic hypothyroidism predisposes patients to coronary artery disease.

<1%: Palpitations, tachycardia, cardiac arrhythmias, chest pain, nervousness, insomnia, fever, headache, ataxia, alopecia, changes in menstrual cycle, weight loss, increased appetite, diarrhea, abdominal cramps, constipation, myalgia, hand tremors, tremor, shortness of breath, diaphoresis

Chronic overdose may cause hyperthyroidism, weight loss, nervousness, sweating, tachycardia, insomnia, heat intolerance, menstrual irregularities, palpitations, psychosis, fever; acute overdose may cause fever, hypoglycemia, CHF, unrecognized adrenal insufficiency.

Reduce dose or temporarily discontinue therapy; normal hypothalamic-pituitary-thyroid axis will return to normal in 6-8 weeks; serum T₄ levels do not correlate well with toxicity

In massive acute ingestion, reduce GI absorption, administer general supportive care; treat congestive heart failure with digitalis glycosides; excessive adrenergic activity (tachycardia) requires propranolol 1-3 mg I.V. over 10 minutes or 80-160 mg orally/day; fever may be treated with acetaminophen.

Decreased effect:

Cholestyramine resin may decrease absorption

Antidiabetic drug requirements are increased

Estrogens may increase thyroid requirements

Increased effect: Increased oral anticoagulant effects

Vials must be stored under refrigeration at 2°C to 8°C (36°F to 46°F)

Primary active compound is T₃ (triiodothyronine), which may be converted from T₄ (thyroxine) and then circulates throughout the body to influence growth and maturation of various tissues; exact mechanism of action is unknown; however, it is believed the thyroid hormone exerts its many metabolic effects through control of DNA transcription and protein synthesis; involved in normal metabolism, growth, and development; promotes gluconeogenesis, increases utilization and mobilization of glycogen stores, and stimulates protein synthesis, increases basal metabolic rate

Onset of effect: Within 24-72 hours

Duration: Up to 72 hours

Absorption: Oral: Well absorbed (~85% to 90%)

Metabolism: In the liver to inactive compounds

Half-life: 16-49 hours

Elimination: In urine

Congenital hypothyroidism: Children: Oral: 5 mcg/day increase by 5 mcg every 3-4 days until the desired response is achieved. Usual maintenance dose: 20 mcg/day for infants, 50 mcg/day for children 1-3 years of age, and adult dose for children >3 years.

Hypothyroidism: Oral:

Adults: 25 mcg/day increase by increments of 12.5-25 mcg/day every 1-2 weeks to a maximum of 100 mcg/day; usual maintenance dose: 25-75 mcg/day

Elderly: Initial: 5 mcg/day, increase by 5 mcg/day every 1-2 weeks; usual maintenance dose: 25-75 mcg/day

T₃ suppression test: Oral: 75-100 mcg/day for 7 days; use lowest dose for elderly

Myxedema: Oral: Initial: 5 mcg/day; increase in increments of 5-10 mcg/day every 1-2 weeks. When 25 mcg/day is reached, dosage may be increased at intervals of 12.5-25 mcg/day every 1-2 weeks. Usual maintenance dose: 50-100 mcg/day.

Myxedema coma: I.V.: 25-50 mcg

Patients with known or suspected cardiovascular disease: 10-20 mcg

Note: Normally, at least 4 hours should be allowed between doses to adequately assess therapeutic response and no more than 12 hours should elapse between doses to avoid fluctuations in hormone levels. Oral therapy should be resumed as soon as the clinical situation has been stabilized and the patient is able to take oral medication. If levothyroxine rather than liothyronine sodium is used in initiating oral therapy, the physician should bear in mind that there is a delay of several days in the onset of levothyroxine activity and that I.V. therapy should be discontinued gradually.

Limit intake of goitrogenic foods (asparagus, cabbage, peas, turnip greens, broccoli, spinach, Brussels sprouts, lettuce, soybeans)

T₄, TSH, heart rate, blood pressure, clinical signs of hypo- and hyperthyroidism; TSH is the most reliable guide for evaluating adequacy of thyroid replacement dosage. TSH may be elevated during the first few months of thyroid replacement despite patients being clinically euthyroid. In cases where T₄ remains low and TSH is within normal limits, an evaluation of "free" (unbound) T₄ is needed to evaluate further increase in dosage.

Free T₃, serum: 250-390 pg/dL; TSH: 0.4 and up to 10 ( greater than or equal to 80 years of age) mIU/L; remains normal in pregnancy

Many drugs may have effects on thyroid function tests; para-aminosalicylic acid, aminoglutethimide, amiodarone, barbiturates, carbamazepine, chloral hydrate, clofibrate, colestipol, corticosteroids, danazol, diazepam, estrogens, ethionamide, fluorouracil, I.V. heparin, insulin, lithium, methadone, methimazole, mitotane, nitroprusside, oxyphenbutazone, phenylbutazone, PTU, perphenazine, phenytoin, propranolol, salicylates, sulfonylureas, and thiazides

May cause nervousness or insomnia

Used to augment antidepressants

No precautions with vasoconstrictor are necessary if patient is well controlled with liothyronine

No effects or complications reported

Take as directed; do not change brands of medication or discontinue without consulting prescriber. Do not change diet without consulting prescriber. Report chest pain, increased heartbeat, palpitations, excessive weight gain or loss, change in level of energy (increased or decreased), excessive sweating, or intolerance to heat.

I.V. form must be prepared immediately prior to administration; dilute 200 mcg/mL vial with 2 mL of 0.9% sodium chloride injection and shake well until a clear solution is obtained; should not be admixed with other solutions

Injection, as sodium: 10 mcg/mL (1 mL)

Tablet, as sodium: 5 mcg, 25 mcg, 50 mcg

Dahlberg PA, Karlsson FA, and Wide L, "Triiodothyronine Intoxication," Lancet, 1979, 2(8144):700.

Helfand M and Crapo LM, "Monitoring Therapy in Patients Taking Levothyroxine," Ann Intern Med, 1990, 113(6):450-4.

Sawin CT, Geller A, Hershman JM, et al, "The Aging Thyroid. The Use of Thyroid Hormone in Older Persons," JAMA, 1989, 261(18):2653-5.

Watts NB, "Use of a Sensitive Thyrotropin Assay for Monitoring Treatment With Levothyroxine," Arch Intern Med, 1989, 149(2):309-12.