Levothyroxine is taken on an empty stomach approximately half an hour to an hour before meals.
There are also foods and other substances that can interfere with absorption of thyroxine replacement. Patients under treatment ought to avoid taking calcium and iron supplements within 4 hours, as well as soy products within 3 hours of the medication, as these can reduce absorption of the drug. Grapefruit juice may delay the absorption of levothyroxine, but it is not believed to have a significant effect on bioavailability. Other substances that reduce absorption are aluminium and magnesium containing antacids, simethicone or sucralfate, cholestyramine, colestipol, Kayexalate. A study of eight women suggested that coffee may interfere with the intestinal absorption of levothyroxine, though at a level less than eating bran. Different substances cause other adverse effects that may be severe. Ketamine may cause hypertension and tachycardia and tricyclic and tetracyclic antidepressants increase its toxicity. On the other hand Lithium can cause hyperthyroidism (but most often hypothyroidism) by affecting iodine metabolism of the thyroid itself and thus inhibits synthetic levothyroxine as well.
For real.... endocrenologist or script does not say how to take? You ask bro's here for advice on the governing hormone of the body? This is not where I be asking for medical advice for a prescription thyroid med. What are ya on .0125 Synthroid? I will help ya if ya have zero other resources..So whats the deal since ya asked? Details if ya want details.