Spacing Between Synthroid and Nexium Administration
Levothyroxine (Synthroid) should be taken at least 4-6 hours before or after taking esomeprazole (Nexium) to minimize drug interactions and ensure optimal absorption of the thyroid medication.
Understanding the Interaction
- Proton pump inhibitors (PPIs) like esomeprazole (Nexium) can interfere with the absorption of levothyroxine (Synthroid) by altering gastric pH 1
- This interaction can lead to elevated TSH levels and suboptimal control of hypothyroidism, even after just 6 weeks of concomitant use 2
- The interaction occurs regardless of whether the PPI is taken in the morning or evening 2
Recommended Spacing Protocol
- Health Canada recommends that when a drug interaction cannot be excluded, patients should take other drugs at least 1 hour before or 4-6 hours after bile acid sequestrants 1
- This same principle applies to spacing levothyroxine and PPIs like esomeprazole
- For optimal absorption of levothyroxine:
Alternative Administration Options
- Consider bedtime administration of levothyroxine as an alternative strategy:
- Taking levothyroxine at bedtime (at least 2 hours after the last meal) has been shown to improve thyroid hormone levels compared to morning intake 3
- This may help minimize interference with PPIs taken during the day 4
- Bedtime administration resulted in lower TSH and higher free T4 and T3 levels in studies 4, 3
Special Considerations
- PPIs can significantly elevate serum TSH in levothyroxine-treated patients who were previously biochemically euthyroid 2
- If you must take both medications and cannot adequately space them, monitor thyroid function tests more frequently to ensure proper thyroid hormone levels 2
- Some formulations of levothyroxine (soft gel capsules) may be less affected by changes in gastric pH compared to tablet formulations 5
Monitoring Recommendations
- Monitor TSH levels 6-8 weeks after starting concomitant therapy with levothyroxine and esomeprazole 6
- If TSH levels rise despite proper spacing, your healthcare provider may need to adjust your levothyroxine dose 6
- Once stabilized, continue monitoring TSH every 6-12 months 6
Common Pitfalls to Avoid
- Taking levothyroxine and esomeprazole simultaneously, which significantly reduces levothyroxine absorption 2
- Inconsistent timing of medication administration, which can lead to variable thyroid hormone levels 6
- Failing to inform healthcare providers about all medications being taken, including over-the-counter drugs 6