Proton pump inhibitor and Levothyroxine: interaction, severity and spacing
Proton pump inhibitor and Levothyroxine interact because levothyroxine requires gastric acid for dissolution. Acid suppression reduces dissolution and absorption. Take them with care. Moderate risk.
The interaction in detail
| Pair | Proton pump inhibitor and Levothyroxine |
|---|---|
| Type | Nutrient–drug interaction |
| Severity | Moderate |
| Required spacing | None specified |
| Onset | At the time of dosing |
Mechanism
Levothyroxine requires gastric acid for dissolution. Acid suppression reduces dissolution and absorption.
What to do
Take levothyroxine on an empty stomach while fasting, and ask about dosage review if starting a PPI.
How to fit both into one day
PPIs must be taken 30-60 minutes before the first meal to inhibit actively secreting proton pumps. Acid-dependent nutrients will absorb worse.
Levothyroxine needs an empty stomach and gastric acid for full absorption. Take it 30-60 minutes before breakfast with plain water, and keep calcium, iron and coffee at least 4 hours away.
Putting Proton pump inhibitor in the morning and Levothyroxine in the morning satisfies the 0-hour separation without disrupting either one's absorption window.