OROXINE

What it is

Oroxine is levothyroxine sodium. It is available in four strengths containing levothyroxine sodium 50, 75, 100 or 200 micrograms as the active ingredient. The tablets are white and round, each strength debossed with its dose on one side and scored in the shape of a plus sign on the other side.

Approved indications

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

Dosing overview

Oroxine 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. The dose should be individualised on the basis of clinical response and biochemical tests. For adults, the initial dose is 50 to 100 micrograms daily, increased by 25 to 50 micrograms according to response at not less than 4-weekly intervals, up to 100 to 200 micrograms daily. In patients aged 60 years and over and in those with ischaemic heart disease, levothyroxine therapy should normally be initiated with low doses of 25 or 50 micrograms per day. The maintenance dose for adults is 100 to 200 micrograms per day.

Key safety warnings

Extreme caution is required in patients with a cardiovascular disorder, and in the event of cardiovascular effects, the dosage should be lowered. Corticosteroid replacement therapy must precede initiation of levothyroxine therapy to avoid Addisonian crisis in conditions such as hypopituitarism and adrenal insufficiency. 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 receiving suppressive doses. The increased bone resorption may be associated with increased serum levels and urinary excretion of calcium and phosphorus, elevations in bone alkaline phosphate and suppressed serum parathyroid hormone levels. It is recommended that patients be given the minimum dose necessary to achieve the desired clinical and biochemical response. Caution is required when levothyroxine is given to hypothyroid patients with diabetes mellitus or diabetes insipidus, as it may cause the required dosage of insulin and oral antidiabetic agents to be increased. Careful monitoring of diabetic control is recommended, especially when levothyroxine therapy is initiated, changed or discontinued. Levothyroxine should not be used for the treatment of obesity or weight loss. 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 anorectic effects.

Contraindications

Known hypersensitivity to thyroxine, untreated hyperthyroidism, uncorrected primary or secondary adrenal insufficiency, thyrotoxicosis, and acute myocardial infarction uncomplicated by hypothyroidism are contraindications. Acute myocarditis, acute pancarditis, and during pregnancy, combination of levothyroxine and antithyroid agents for the treatment of hyperthyroidism are also contraindicated.

PBS listing

Information regarding PBS listing, including strength, item count, restriction type, and ex-manufacturer price, is not provided in the source documents.

Regulatory history

Oroxine was first registered on the ARTG on 1 August 1991 with tablets in 50, 100 and 200 microgram strengths. A 75 microgram strength was added on 5 February 2008.