Proton Pump Inhibitors Do Not Affect the Bioavailability of a Novel Liquid Formulation of Levothyroxine
Authors' conclusion
This study demonstrated that Tirosint-SOL bioavailability is unaffected by coadministration of a representative PPI, given simultaneously or staggered by about 12 hours, compared to administration of LT4 solution alone. For hypothyroid patients on PPI therapy, administration of LT4 solution may reduce variations in thyroid stimulating hormone levels related to intermittent use of acid-reducing drugs and consequently the need for dose adjustments.
Study context
- Population
- Healthy adultscrossover
- Participants
- 36 adults
- Comparison
- Omeprazole in the morning (simultaneous) or evening (staggered) vs no omeprazole, with levothyroxine (LT4) solution (Tirosint-SOL) 600 mcg
- Outcome
- Total serum thyroxine Cmax and AUC0-48 (baseline-corrected); geometric mean ratios with 90% CI, equivalence boundaries 80%-125%
- Follow-up
- 0 to 48 hours post-LT4
Methodological detailsrandomized, 3-way crossover, fasting conditions
- Randomized
- 3-way crossover
- Fasting conditions
Main finding
As reported in the abstract
Total serum T4 bioavailability (AUC0-48, Cmax), baseline-corrected
- A vs C · A: omeprazole mornings; C: no omeprazole; within equivalence boundaries (80%-125%)
- geometric mean ratio, AUC0-48 98.98% (90% CI 94%–104%)
- A vs C · within equivalence boundaries (80%-125%)
- geometric mean ratio, Cmax 91.68% (90% CI 87%–97%)
- B vs C · B: omeprazole evenings; within equivalence boundaries (80%-125%)
- geometric mean ratio, AUC0-48 98.94% (90% CI 95%–103%)
- B vs C · within equivalence boundaries (80%-125%)
- geometric mean ratio, Cmax 94.90% (90% CI 90%–100%)
Further findings
- Median Tmax was similar across treatments
Original publication
Proton Pump Inhibitors Do Not Affect the Bioavailability of a Novel Liquid Formulation of Levothyroxine. Endocr Pract. Published 28 March 2024. doi:10.
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