How Calcium interacts with levothyroxine

Interaction type: Interactions

Interaction rating: Study Supported

Calcium carbonate can decrease the absorption of levothyroxine, which may alter the effects of these medications and possibly the dose needed for treatment. Use with caution. (1)


  1. View Abstract: Singh N, Singh PN, Hershman JM. Effect of calcium carbonate on the absorption of levothyroxine. JAMA. Jun2000;283(21):2822-5.