Possible Interaction: Thyroxine and Ferrous Sulfate

“Moreover, concomitant ingestion of calcium supplements, ferrous sulfate , proton-pump inhibitors, bile acid sequestrants, and sucralfate might influence LT4 absorption and/or metabolism.”

“Many commonly used drugs, such as bile acid sequestrants, ferrous sulphate , sucralfate, calcium carbonate, aluminium-containing antacids, phosphate binders, raloxifene and proton-pump inhibitors, have also been shown to interfere with the absorption of levothyroxine.”

“Drugs like ferrous sulfate , bile acid sequestrants and aluminum hydroxide decrease the absorption of levothyroxine [1–3].”

“A decrease in the absorption of LT4 is established and clinically significant when administered concomitantly with cholestyramine, colesevelam, lanthanum, calcium carbonate, calcium citrate, calcium acetate, iron sulfate , ciprofloxacin, aluminum hydroxide, sevelamer, or proton pump inhibitors.”

“Furthermore, soy products and several drugs, such as calcium carbonate, bile acid sequestrants, proton pump inhibitors, and ferrous sulfate , may alter L-T4 absorption [7].”

“We report a case of drug-drug interaction between ferrous sulfate and l-thyroxin.”

“Recent studies have shown that under experimental conditions ferrous sulfate may reduce the gastrointestinal absorption of orally administered levothyroxine sodium in patients with primary hypothyroidism.”

“Since both hypothyroidism and iron deficiency anemia may coexist, additional thyroid function testing is recommended in patients treated concurrently with ferrous sulfate and L-thyroxine.”