Dosage Flexibility
Initial Dosing1
The starting dose of RenThyroid depends on various factors, including the patient's age, weight, cardiovascular status, and the severity and duration of hypothyroidism.
Typically, the initial dose is 30 mg daily. The dose can be increased by 15 mg every 2 to 3 weeks until the desired response is achieved. In patients who are older or who have myxedema or underlying cardiovascular disease, the initial dose should be lower, 15 mg daily, with gradual increases.
Maintenance Dosing1
The maintenance dose of RenThyroid is usually in the range of 60 to 120 mg daily. Adjustments should be based on the patient's clinical response and periodic laboratory evaluations, including serum levels of T4 (bound and free) and TSH.
Regular Monitoring
Thyroid function tests should be performed periodically to ensure the dosage remains appropriate and to adjust as needed.
Ensure Patients Receive
RenThyroid as Prescribed
If you and your patient decide that RenThyroid is appropriate, write “Dispense as Written” (or similar language depending on your state) to help ensure that RenThyroid is dispensed.
[1] RenThyroid [prescribing information]. Allentown, PA: Genus Lifesciences, Inc.; 2025
INDICATIONS:
RenThyroid™ (Thyroid Tablets, USP) is a prescription oral medication indicated as
replacement or supplemental therapy in patients with hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis.
Note: RenThyroid has not been approved by the FDA.
IMPORTANT SAFETY INFORMATION
Drugs with thyroid hormone activity, alone or together with other therapeutic agents, have been used for the treatment of obesity. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
CONTRAINDICATIONS:
RenThyroid is contraindicated in patients with uncorrected adrenal cortical insufficiency, untreated thyrotoxicosis, and/or hypersensitivity to any of component of the product.
WARNINGS AND PRECAUTIONS:
Cardiovascular System. Thyroid hormones should be used with caution in the presence of cardiovascular risks, and particularly coronary artery risks. Patients with angina pectoris and elderly patients present increased risks. Initiate treatment with low doses (15-30 mg). Worsening cardiovascular disease may require reduced dose or discontinuation.
Diabetes and Adrenal Disorders. In patients with concomitant diabetes mellitus, diabetes insipidus, or adrenal cortical insufficiency, thyroid hormones aggravate symptoms of these conditions. Adjust treatment for these concomitant endocrine diseases as appropriate. Treatment of myxedema coma requires simultaneous administration of glucocorticoids.
Oral Anticoagulants. Hypothyroidism decreases and hyperthyroidism increases sensitivity to oral anticoagulants. For patients taking thyroid hormones and oral anticoagulants, prothrombin time and dose should be closely monitored and adjusted based on frequent prothrombin time determinations.
Infant Craniosynostosis. In infants, excessive doses of thyroid hormones may produce craniosynostosis.
ADVERSE REACTIONS:
Adverse reactions other than those indicative of hyperthyroidism because of therapeutic overdosage, either initially or during the maintenance period, are rare. Excessive doses of thyroid result in a hypermetabolic state. In case of overdosage, temporarily discontinue treatment. Treatment may be reinstituted at a lower dosage.
DRUG INTERACTIONS:
Oral Anticoagulants. Concomitant use of thyroid hormones with oral anticoagulants alters the sensitivity of oral anticoagulants.
Insulin or Oral Hypoglycemics. Initiating thyroid replacement therapy may cause increases in insulin or oral hypoglycemic requirements. Patients receiving insulin or oral hypoglycemics should be closely monitored during initiation of thyroid replacement therapy.
Cholestyramine or Colestipol. Cholestyramine or colestipol binds both levothyroxine (T4) and liothyronine (T3) in the intestine, impairing their absorption. Allow 4 to 5 hours between the administration of cholestyramine or colestipol and thyroid hormones.
Estrogen, Oral Contraceptives. Estrogens tend to increase serum thyroxine-binding globulin (TBg), decreasing free levothyroxine (T4). Patients without a functioning thyroid gland who are on thyroid replacement therapy may need to increase their thyroid dose if taking estrogen or estrogen-containing oral contraceptives.
Drug/Laboratory Test Interactions. Certain drugs or moieties interfere with laboratory tests performed in patients on thyroid hormone therapy: androgens, corticosteroids, estrogens, oral contraceptives containing estrogens, iodine-containing preparations, biotin, and preparations containing salicylates.
For complete safety information, please see the full Prescribing Information.
To report suspected adverse reactions, contact Genus Lifesciences at 1-610-782-9780 or Info@GenusLifesciences.com or the FDA at www.fda.gov/medwatch or call 1-800-FDA-1088.