Prenat Drug Interactions

Iron salts are not well absorbed by mouth, and administration with food may further impair their absorption. Compounds containing calcium and magnesium, including antacids and mineral supplements, and bicarbonates, carbonates, oxalates, or phosphates, may also impair the absorption of iron by the formation of the insoluble complexes. Similarly the absorption of both iron salts and tetracyclines is diminished when they are taken concomitantly by mouth. If treatment with both drugs is required, a time interval of about 2 to 3 hours should be allowed between them. A suitable interval is also advised if an iron supplement is required in patients receiving trientine. Zinc salts may decrease the absorption of iron. Some agents, such as ascorbic acid and citric acid may increase the absorption of iron. The response to iron may be delayed in patients receiving systemic chloramphenicol. Folate deficiency states may be produced by a number of drugs including antiepileptics, oral contraceptives, antituberculous drugs, alcohol, and folic acid antagonists such as aminopterin, methotrexate, pyrimethamine, trimethoprim and sulfonamides. In some instances, such as during methotrexate or antiepileptic therapy, replacement therapy with folinic acid or folic acid may become necessary in order to prevent megaloblastic anemia developing, folate supplementation has reportedly decreased serum-phenytoin concentrations in a few cases and there is a possibility that such an effect could also occur with barbiturate antiepileptics.