CYTOMEL® Warnings and Precautions

(liothyronine sodium)

5 WARNINGS AND PRECAUTIONS

5.1 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease

Overtreatment with thyroid hormone may cause an increase in heart rate, cardiac wall thickness, and cardiac contractility and may precipitate angina or arrhythmias, particularly in patients with cardiovascular disease and in elderly patients. Initiate CYTOMEL therapy in this population at lower doses than those recommended in younger individuals or in patients without cardiac disease [see Dosage and Administration (2.3) and Use in Specific Populations (8.5)].

Monitor for cardiac arrhythmias during surgical procedures in patients with coronary artery disease receiving suppressive CYTOMEL therapy. Monitor patients receiving concomitant CYTOMEL and sympathomimetic agents for signs and symptoms of coronary insufficiency. If cardiovascular symptoms develop or worsen, reduce or withhold the CYTOMEL dose for one week and restart at a lower dose.

5.2 Myxedema Coma

Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism, and may result in unpredictable absorption of thyroid hormone from the gastrointestinal tract. Use of oral thyroid hormone drug products is not recommended to treat myxedema coma. Administer thyroid hormone products formulated for intravenous administration to treat myxedema coma.

5.3 Acute Adrenal Crisis in Patients with Concomitant Adrenal Insufficiency

Thyroid hormone increases metabolic clearance of glucocorticoids. Initiation of thyroid hormone therapy prior to initiating glucocorticoid therapy may precipitate an acute adrenal crisis in patients with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with CYTOMEL [see Contraindications (4)].

5.4 Prevention of Hyperthyroidism or Incomplete Treatment of Hypothyroidism

CYTOMEL has a narrow therapeutic index. Over- or undertreatment with CYTOMEL may have negative effects on growth and development, cardiovascular function, bone metabolism, reproductive function, cognitive function, emotional state, gastrointestinal function, and on glucose and lipid metabolism. Titrate the dose of CYTOMEL carefully and monitor response to titration to avoid these effects [see Dosage and Administration (2.4)]. Monitor for the presence of drug or food interactions when using CYTOMEL and adjust the dose as necessary [see Drug Interactions (7) and Clinical Pharmacology (12.3)].

5.5 Worsening of Diabetic Control

Addition of thyroid hormone therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing CYTOMEL [see Drug Interactions (7.2)].

5.6 Decreased Bone Mineral Density Associated with Thyroid Hormone Over-Replacement

Increased bone resorption and decreased bone mineral density may occur as a result of thyroid hormone over-replacement, particularly in post-menopausal women. The increased bone resorption may be associated with increased serum levels and urinary excretion of calcium and phosphorous, elevations in bone alkaline phosphatase, and suppressed serum parathyroid hormone levels. Administer the minimum dose of CYTOMEL that achieves the desired clinical and biochemical response to mitigate against this risk.

Find CYTOMEL® medical information:

Find CYTOMEL® medical information:

Our scientific content is evidence-based, scientifically balanced and non-promotional. It undergoes rigorous internal medical review and is updated regularly to reflect new information.

CYTOMEL® Quick Finder

Medication Guide

Health Professional Information

Warnings and Precautions

5 WARNINGS AND PRECAUTIONS

5.1 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease

Overtreatment with thyroid hormone may cause an increase in heart rate, cardiac wall thickness, and cardiac contractility and may precipitate angina or arrhythmias, particularly in patients with cardiovascular disease and in elderly patients. Initiate CYTOMEL therapy in this population at lower doses than those recommended in younger individuals or in patients without cardiac disease [see Dosage and Administration (2.3) and Use in Specific Populations (8.5)].

Monitor for cardiac arrhythmias during surgical procedures in patients with coronary artery disease receiving suppressive CYTOMEL therapy. Monitor patients receiving concomitant CYTOMEL and sympathomimetic agents for signs and symptoms of coronary insufficiency. If cardiovascular symptoms develop or worsen, reduce or withhold the CYTOMEL dose for one week and restart at a lower dose.

5.2 Myxedema Coma

Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism, and may result in unpredictable absorption of thyroid hormone from the gastrointestinal tract. Use of oral thyroid hormone drug products is not recommended to treat myxedema coma. Administer thyroid hormone products formulated for intravenous administration to treat myxedema coma.

5.3 Acute Adrenal Crisis in Patients with Concomitant Adrenal Insufficiency

Thyroid hormone increases metabolic clearance of glucocorticoids. Initiation of thyroid hormone therapy prior to initiating glucocorticoid therapy may precipitate an acute adrenal crisis in patients with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with CYTOMEL [see Contraindications (4)].

5.4 Prevention of Hyperthyroidism or Incomplete Treatment of Hypothyroidism

CYTOMEL has a narrow therapeutic index. Over- or undertreatment with CYTOMEL may have negative effects on growth and development, cardiovascular function, bone metabolism, reproductive function, cognitive function, emotional state, gastrointestinal function, and on glucose and lipid metabolism. Titrate the dose of CYTOMEL carefully and monitor response to titration to avoid these effects [see Dosage and Administration (2.4)]. Monitor for the presence of drug or food interactions when using CYTOMEL and adjust the dose as necessary [see Drug Interactions (7) and Clinical Pharmacology (12.3)].

5.5 Worsening of Diabetic Control

Addition of thyroid hormone therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing CYTOMEL [see Drug Interactions (7.2)].

5.6 Decreased Bone Mineral Density Associated with Thyroid Hormone Over-Replacement

Increased bone resorption and decreased bone mineral density may occur as a result of thyroid hormone over-replacement, particularly in post-menopausal women. The increased bone resorption may be associated with increased serum levels and urinary excretion of calcium and phosphorous, elevations in bone alkaline phosphatase, and suppressed serum parathyroid hormone levels. Administer the minimum dose of CYTOMEL that achieves the desired clinical and biochemical response to mitigate against this risk.

Prescribing Information
Download Prescribing Information

Health Professional Information

Warnings and Precautions

5 WARNINGS AND PRECAUTIONS

5.1 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease

Overtreatment with thyroid hormone may cause an increase in heart rate, cardiac wall thickness, and cardiac contractility and may precipitate angina or arrhythmias, particularly in patients with cardiovascular disease and in elderly patients. Initiate CYTOMEL therapy in this population at lower doses than those recommended in younger individuals or in patients without cardiac disease [see Dosage and Administration (2.3) and Use in Specific Populations (8.5)].

Monitor for cardiac arrhythmias during surgical procedures in patients with coronary artery disease receiving suppressive CYTOMEL therapy. Monitor patients receiving concomitant CYTOMEL and sympathomimetic agents for signs and symptoms of coronary insufficiency. If cardiovascular symptoms develop or worsen, reduce or withhold the CYTOMEL dose for one week and restart at a lower dose.

5.2 Myxedema Coma

Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism, and may result in unpredictable absorption of thyroid hormone from the gastrointestinal tract. Use of oral thyroid hormone drug products is not recommended to treat myxedema coma. Administer thyroid hormone products formulated for intravenous administration to treat myxedema coma.

5.3 Acute Adrenal Crisis in Patients with Concomitant Adrenal Insufficiency

Thyroid hormone increases metabolic clearance of glucocorticoids. Initiation of thyroid hormone therapy prior to initiating glucocorticoid therapy may precipitate an acute adrenal crisis in patients with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with CYTOMEL [see Contraindications (4)].

5.4 Prevention of Hyperthyroidism or Incomplete Treatment of Hypothyroidism

CYTOMEL has a narrow therapeutic index. Over- or undertreatment with CYTOMEL may have negative effects on growth and development, cardiovascular function, bone metabolism, reproductive function, cognitive function, emotional state, gastrointestinal function, and on glucose and lipid metabolism. Titrate the dose of CYTOMEL carefully and monitor response to titration to avoid these effects [see Dosage and Administration (2.4)]. Monitor for the presence of drug or food interactions when using CYTOMEL and adjust the dose as necessary [see Drug Interactions (7) and Clinical Pharmacology (12.3)].

5.5 Worsening of Diabetic Control

Addition of thyroid hormone therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing CYTOMEL [see Drug Interactions (7.2)].

5.6 Decreased Bone Mineral Density Associated with Thyroid Hormone Over-Replacement

Increased bone resorption and decreased bone mineral density may occur as a result of thyroid hormone over-replacement, particularly in post-menopausal women. The increased bone resorption may be associated with increased serum levels and urinary excretion of calcium and phosphorous, elevations in bone alkaline phosphatase, and suppressed serum parathyroid hormone levels. Administer the minimum dose of CYTOMEL that achieves the desired clinical and biochemical response to mitigate against this risk.

Resources

Didn’t find what you were looking for? Contact us.

MI Digital Assistant

Chat online with Pfizer Medical Information regarding your inquiry on a Pfizer medicine.

Call 800-438-1985*

*Contact Medical Information.9AM-5PM ET Monday to Friday; excluding holidays.

Report Adverse Event

Pfizer Safety

To report an adverse event related to the Pfizer-BioNTech COVID-19 Vaccine, and you are not part of a clinical trial* for this product, click the link below to submit your information:

Pfizer Safety Reporting Site

*If you are involved in a clinical trial for this product, adverse events should be reported to your coordinating study site.

If you cannot use the above website, or would like to report an adverse event related to a different Pfizer product, please call Pfizer Safety at (800) 438-1985.

FDA Medwatch

You may also contact the U.S. Food and Drug Administration (FDA) directly to report adverse events or product quality concerns either online at www.fda.gov/medwatch or call (800) 822-7967.