MODERATE — Monitor Closely
FDA-documented interaction. PPIs may reduce levothyroxine absorption. TSH monitoring recommended when PPI is started or stopped.
Evidence level: STRONG
Omeprazole (Prilosec) reduces stomach acid, which may decrease how well your thyroid medication is absorbed. You may need a higher dose of levothyroxine if you take a proton pump inhibitor regularly.
Proton pump inhibitors increase gastric pH, which may reduce levothyroxine absorption (levothyroxine is better absorbed in acidic environment). FDA levothyroxine label warns about drugs that affect gastric acidity.
If you start or stop a proton pump inhibitor, get your thyroid levels (TSH) rechecked in 8-12 weeks. Your levothyroxine dose may need adjustment.
Take levothyroxine on an empty stomach, 30-60 minutes before breakfast. Take supplements at least 4 hours later to be safe.
Risk may increase with: older age, liver or kidney impairment, taking multiple medications, and higher doses of either substance.
Symptoms of underactive thyroid: fatigue, weight gain, cold intolerance, constipation, brain fog
Check TSH 8-12 weeks after starting or stopping PPI. May need levothyroxine dose increase with PPI therapy.
Thyroid medications are sensitive to absorption interference. Take levothyroxine on an empty stomach, 30-60 minutes before food or other supplements. Space calcium, iron, and antacids at least 4 hours away. Selenium and zinc are generally safe thyroid-supporting nutrients.
Omeprazole (Prilosec) reduces stomach acid, which may decrease how well your thyroid medication is absorbed. You may need a higher dose of levothyroxine if you take a proton pump inhibitor regularly.
Take levothyroxine on an empty stomach, 30-60 minutes before breakfast. Take supplements at least 4 hours later to be safe.
Symptoms of underactive thyroid: fatigue, weight gain, cold intolerance, constipation, brain fog
Thyroid medications are sensitive to absorption interference. Take levothyroxine on an empty stomach, 30-60 minutes before food or other supplements. Space calcium, iron, and antacids at least 4 hours away. Selenium and zinc are generally safe thyroid-supporting nutrients.
Check TSH 8-12 weeks after starting or stopping PPI. May need levothyroxine dose increase with PPI therapy.
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