levothyroxine absorption may depend on gastric acidity
Preliminary evidence suggests that levothyroxine absorption may depend on gastric acidity.
Goiter patients are sometimes given levothyroxine to limit goiter growth or reduce its size.
Patients with goiters who also have low gastric acid levels seem to need about 25% higher dose of levothyroxine to suppress their TSH. This could include patients taking omeprazole or patients with H. pylori.