Many foods and other substances can interfere with absorption of thyroxine. Substances that reduce absorption are aluminium- and magnesium-containing antacids, simethicone, sucralfate, cholestyramine, colestipol, and polystyrene sulfonate. Sevelamer with calcium carbonate may decrease the bioavailability of<unk> . Grapefruit juice may delay the absorption of<unk> , but based on a study of 10 healthy people aged 20–30 (eight men, two women), it may not have a significant effect on bioavailability in young adults. A study of eight women suggested that coffee may interfere with the intestinal absorption of<unk> , though at a level less than eating bran. Certain other substances can cause adverse effects that may be severe. Combination of<unk>  with ketamine may cause hypertension and tachycardia; and tricyclic and tetracyclic antidepressants increase its toxicity. Lithium, though, can cause hyperthyroidism (but most often hypothyroidism) by affecting iodine metabolism of the thyroid itself, thus inhibiting synthetic<unk> , as well. Soy, walnuts, fiber, calcium supplements, and iron supplements can also adversely affect absorption. A study found that cow's milk reduces<unk>  absorption. To minimize interactions, a manufacturer of<unk>  recommends after taking it, waiting 30 minutes to one hour before eating or drinking anything that is not water. They further recommend to take it in the morning on an empty stomach.
Levothyroxine
Cortisone acetate
Cortisone
Fludrocortisone
Calcipotriol
Potassium iodide
Liothyronine
Hypophysectomy