LEVOXINE

What it is

LEVOXINE is a tablet containing levothyroxine sodium, available in strengths of 25, 50, 75, 100, 125, 150 or 200 micrograms. Levothyroxine sodium is the monosodium salt of the levo isomer of thyroxine, the principal secretion of the thyroid gland.

Approved indications

— Management of demonstrated thyroid hormone deficiency. — Suppression of thyrotropin (TSH) for the management of TSH-responsive tumours of the thyroid.

Dosing overview

LEVOXINE is best taken as a single daily dose first thing in the morning, with water and on an empty stomach, at least 30 minutes and preferably 60 minutes before the intake of any food or other medications. For adults, commence with 50 to 100 micrograms daily, increasing the daily dose by 25 to 50 micrograms according to response at intervals of not less than 4 weeks, up to 100 to 200 micrograms daily. In patients aged 60 years and over and in those with ischaemic heart disease, therapy should normally be initiated with low doses of 25 or 50 micrograms per day. The usual maintenance dose for adults is 100 to 200 micrograms per day.

Key safety warnings

LEVOXINE is not bioequivalent on a same-dose basis with ELTROXIN. If a decision is made to switch a patient from ELTROXIN to LEVOXINE, prescribers should have a plan for monitoring TSH, and dose adjustment may be required. Extreme caution is required in patients with a cardiovascular disorder, and in the event of cardiovascular effects, the dosage of levothyroxine sodium should be lowered. Corticosteroid replacement therapy must precede initiation of levothyroxine therapy to avoid Addisonian crisis in conditions such as hypopituitarism and adrenal insufficiency. In women, long-term levothyroxine sodium therapy has been associated with increased bone resorption, thereby decreasing bone mineral density, especially in post-menopausal women on greater than replacement doses or in women receiving suppressive doses of levothyroxine sodium. Patients receiving levothyroxine sodium should be given the minimum dose necessary to achieve the desired clinical and biochemical response. Caution is required when levothyroxine sodium is given to hypothyroid patients with diabetes mellitus or diabetes insipidus, as it may increase the required dosage of insulin and oral antidiabetic agents, and careful monitoring of diabetic control is recommended.

Contraindications

LEVOXINE is contraindicated in known hypersensitivity to thyroxine, untreated hyperthyroidism, uncorrected primary or secondary adrenal insufficiency, thyrotoxicosis, and acute myocardial infarction uncomplicated by hypothyroidism. It is also contraindicated in acute myocarditis and acute pancarditis, and during pregnancy, combination of levothyroxine and antithyroid agents for the treatment of hyperthyroidism is contraindicated.

PBS listing

LEVOXINE tablets are listed on the PBS in strengths of 50, 75, 100 and 200 micrograms, with one item per strength under restricted access, at ex-manufacturer prices of A$8.03 (50 micrograms), A$8.17 (75 micrograms), A$8.32 (100 micrograms) and A$9.76 (200 micrograms).

Regulatory history

LEVOXINE levothyroxine sodium tablets in strengths of 50, 75, 100 and 200 micrograms were first listed on the ARTG on 29 July 2021.