Concurrent administration with iron salts, antacids, calcium carbonate (including milk sucralfate, cholestyramine and soy-based formulas may therefore decrease absorption of thyroxine. Administration Patients should be instructed to take thyroxine 3060 minutes before breakfast in order to maximise absorption.
Jul 21, 2014. Levothyroxine Tablets BP 50 micrograms - Summary of Product. 6.3 Shelf life; 6.4 Special precautions for storage; 6.5 Nature and contents of container. by 50 micrograms every 3-4 weeks until thyroxine levels are correct.
If this is too difficult or threatens compliance, the patient may try taking the thyroxine last thing at night on an empty stomach. Patients who still decide to take their tablets with, rather than before, breakfast need to do this consistently, to avoid fluctuating thyroxine concentrations.
2. Thomas J, editor. Australian Prescription Products Guide 2003. 32nd ed. Hawthorn: Australian Pharmaceutical Publishing Company Limited; 2003. 3. Grebe SK, Cooke RR, Ford HC, Fagerstrom JN, Cordwell DP, Lever NA, et al.
In the USA, the Food and Drug Administration has determined that stability and potency problems with oral thyroxine preparations could potentially have adverse effects on health. It is therefore very important that thyroxine tablets should be kept in their original container and stored out of sunlight in a cool dry place.
Drug interactions Most drug interactions are seen during shifts to and from the euthyroid state and rarely have any clinical significance during periods of thyroid stability. The hyperthyroid state increases clearance of some hepatically cleared drugs, notably propranolol, metoprolol and theophylline.
The two Australian brands are marketed by Sigma and one of its subsidiaries. They are identical products so patients can swap them safely, but this assumption should not be extended to overseas brands.
Onset and duration of action The half-life of thyroxine in euthyroidism is 67 days. This is reduced to 34 days in hyperthyroidism and prolonged to 910 days in hypothyroidism. Thyroxine has a full therapeutic effect 34 weeks after starting treatment and will continue to have a therapeutic action for 13 weeks after treatment stops.
If the patient is a child or if you cannot swallow the tablet whole, you may crush the. Brief storage at temperatures between 59 and 86 degrees F (15 and 30 ).
Jun 20, 2005. Should thyroxine tablets be refrigerated? Have we. tablets can be stored at room temperature. storage was recommended in Australia, pre.
Stability Thyroxine is stable in dry air, but unstable in the presence of light, heat and humidity. In some cases overseas, thyroxine tablets have been unstable even at room temperature, and storage temperatures of 8C to 15C were required to maintain potency.
Depending on the fibre and milk content of the meal, taking thyroxine with food may require a larger dose to maintain euthyroidism, because of the decreased bioavailability. While most patients take a daily dose, the long half-life of thyroxine lends itself to longer dosing intervals, such as alternate daily dosing.
In view of the long half-life, dose changes should only be made every 34 weeks. Despite undergoing both hepatic and renal clearance, there is no evidence that dose adjustment is required for patients with liver or kidney disease.
Jun 30, 2014. Each tablet contains 100 micrograms Levothyroxine sodium anhydrous BP. 3. Beta Blockers: levothyroxine (thyroxine) accelerates metabolism of propranolol, atenolol and sotalol. 6.4 Special precautions for storage.
Once-weekly dosing is also possible although a slightly larger dose than seven times the normal daily dose may be required. This regimen may be suitable for poorly compliant patients who require supervised dosing.
3 For patients, particularly children, who cannot swallow tablets, the tablets may be crushed in 1020 mL of water, breast milk or non-soybean formula. The resulting mixture should be used immediately and any remainder discarded.
The stability of thyroxine tablets is limited and they may reach the expiry date before the bottle is finished. Administration should preferably be on an empty stomach and be consistent with respect to food and other drugs.
Aust Prescr 2004; Gregory W. Roberts, Clinical Pharmacist, Repatriation General Hospital, Daw Park, South Australia. Summary Some of the pharmaceutical properties of thyroxine have important implications for the quality use of medicines.
Key words: hypothyroidism, hyperthyroidism, pharmacokinetics. Introduction Thyroxine tablets are important in managing hypothyroidism, but treatment may be sub-optimal if they are used incorrectly. The tablets have pharmaceutical properties which can impair the patients management.