Non-heme<unk>  forms an insoluble complex with several other drugs, resulting in decreased absorption of both<unk>  and the other drug. Examples include tetracycline, penicillamine, methyldopa, levodopa, bisphosphonates and quinolones. The same can occur with elements in food, such as calcium. Absorption of<unk>  is better at a low pH (i.e. an acidic environment), and absorption is decreased if there is a simultaneous intake of antacids. Many other substances decrease the rate of non-heme<unk>  absorption. Examples are tannins from foods, such as tea and saw palmetto, phytic acid, and roughage. Because<unk>  from plant sources is less easily absorbed than the heme-bound<unk>  of animal sources, vegetarians and vegans should have a somewhat higher total daily<unk>  intake than those who eat meat, fish or poultry. Taken after a meal, there are fewer side effects but there is also less absorption because of interaction and pH alteration. Generally, an interval of 2–3 hours between the<unk>  intake and that of other drugs seems advisable, but is less convenient for patients and can impact on compliance.
Iron supplement
Iron preparation
Protein supplement
Phosphate supplement
Calcium supplement
Deferoxamine
Electrocution
Zinc sulfate 