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Black Box Warning
WARNING:
See full prescribing information for complete Boxed Warning.
* NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including Levothyroxine Sodium for Injection , should not be used for the treatment of obesity or for weight loss.
Larger doses may produce serious or even life threatening manifestations of toxicity.
Levothyroxine Sodium for Injection is indicated for the treatment of myxedema coma. Important Limitations of Use: The relative bioavailability between Levothyroxine Sodium for Injection and oral levothyroxine products has not been established. Caution should be used when switching patients from oral levothyroxine products to Levothyroxine Sodium for Injection as accurate dosing conversion has not been studied.
Dosage
An initial intravenous loading dose of Levothyroxine Sodium for Injection between 300 to 500 mcg, followed by once daily intravenous maintenance doses between 50 and 100 mcg, should be administered, as clinically indicated, until the patient can tolerate oral therapy. The age, general physical condition, cardiac risk factors, and clinical severity of myxedema and duration of myxedema symptoms should be considered when determining the starting and maintenance dosages of Levothyroxine Sodium for Injection.
Levothyroxine Sodium for Injection produces a gradual increase in the circulating concentrations of the hormone with an approximate half-life of 9 to 10 days in hypothyroid patients. Daily administration of Levothyroxine Sodium for Injection should be maintained until the patient is capable of tolerating an oral dose and is clinically stable. For chronic treatment of hypothyroidism, an oral dosage form of levothyroxine should be used to maintain a euthyroid state. Relative bioavailability between Levothyroxine Sodium for Injection and oral levothyroxine products has not been established. Based on medical practice, the relative bioavailability between oral and intravenous administration of Levothyroxine Sodium for Injection is estimated to be from 48 to 74%. Due to differences in absorption characteristics of patients and the oral levothyroxine product formulations, TSH and thyroid hormone levels should be measured a few weeks after initiating oral levothyroxine and dose adjusted accordingly.
Dosing in the Elderly and in Patients with Cardiovascular Disease
Intravenous levothyroxine may be associated with cardiac toxicity—including arrhythmias, tachycardia, myocardial ischemia and infarction, or worsening of congestive heart failure and death—in the elderly and in those with underlying cardiovascular disease. Therefore, cautious use, including doses in the lower end of the recommended range, may be warranted in these populations.
Reconstitution Directions
Reconstitute the lyophilized Levothyroxine Sodium for Injection by aseptically adding 5 mL of 0.9% Sodium Chloride Injection, USP only. Shake vial to ensure complete mixing. The resultant solution will have a final concentration of approximately 20 mcg per mL, 40 mcg per mL and and 100 mcg per mL for the 100 mcg, 200 mcg and 500 mcg vials, respectively. Reconstituted drug product is preservative free and is stable for 4 hours. Discard any unused portion. DO NOT ADD LEVOTHYROXINE SODIUM FOR INJECTION TO OTHER IV FLUIDS. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
Off-Label Use and Dosage (Adult)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Levothyroxine (injection) in adult patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Levothyroxine (injection) in adult patients.
Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Levothyroxine (injection) in pediatric patients.
Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Levothyroxine (injection) in pediatric patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Levothyroxine (injection) in pediatric patients.
Contraindications
There is limited information regarding Levothyroxine (injection) Contraindications in the drug label.
Warnings
WARNING:
See full prescribing information for complete Boxed Warning.
* NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including Levothyroxine Sodium for Injection , should not be used for the treatment of obesity or for weight loss.
Larger doses may produce serious or even life threatening manifestations of toxicity.
There is limited information regarding Levothyroxine (injection) Warnings' in the drug label.
Adverse Reactions
Clinical Trials Experience
There is limited information regarding Clinical Trial Experience of Levothyroxine (injection) in the drug label.
Body as a Whole
Cardiovascular
Digestive
Endocrine
Hematologic and Lymphatic
Metabolic and Nutritional
Musculoskeletal
Neurologic
Respiratory
Skin and Hypersensitivy Reactions
Special Senses
Urogenital
Miscellaneous
Postmarketing Experience
There is limited information regarding Postmarketing Experience of Levothyroxine (injection) in the drug label.
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