Drug interactions in users of tablet vs. oral liquid levothyroxine formulations: a real-world evidence study in primary care

Purpose Several medications may interact with levothyroxine(LT4) intestinal absorption or metabolism, thus reducing its bioavailability. We investigated the variability of thyroid stimulating hormone(TSH) levels and prescribed daily dosages (PDDs) of LT4 before and during potential drug–drug interactions(DDIs) in users of tablets vs. oral liquid LT4 formulations.