Can I Take Omeprazole with Levothyroxine? A Guide to Managing the Interaction

October 12, 2025 •

4 min read

Omeprazole and levothyroxine are two of the most commonly prescribed medications in the United States, so it's no surprise that many people need to take them both. However, the concurrent use of these drugs can lead to an important interaction that affects the absorption of levothyroxine.

Quick Summary

Concurrent use of omeprazole and levothyroxine is possible with proper management. The former decreases stomach acidity, which reduces thyroid hormone absorption. This requires careful monitoring of TSH levels to ensure the levothyroxine dose remains effective. Alternative formulations exist to mitigate this interaction.

Key Points

Drug Interaction: Omeprazole, a PPI, reduces stomach acid, which can decrease the absorption of levothyroxine tablets.
Monitoring is Crucial: Regular monitoring of TSH levels is necessary when starting or stopping omeprazole to ensure the levothyroxine dose remains effective.
Timing May Not Be Enough: Separating the administration times of the two medications may not prevent the interaction because omeprazole's acid-reducing effects last for over 24 hours.
Alternative Formulations Exist: Liquid or soft gel capsule versions of levothyroxine have been shown to be less affected by PPIs and may be a better option for some patients.
Report Symptoms: Be vigilant for signs of hypothyroidism, such as fatigue or weight gain, which could indicate poor absorption of your thyroid medication.
Always Consult a Doctor: Never change your medication dosage or schedule without consulting your healthcare provider, who can adjust your treatment plan accordingly.

The Interaction Between Omeprazole and Levothyroxine Explained

For many patients, managing multiple health conditions means navigating complex medication regimens. Omeprazole, a proton pump inhibitor (PPI) used to treat acid reflux and stomach ulcers, is one such medication. Levothyroxine, a synthetic thyroid hormone, is the standard treatment for hypothyroidism. When taken together, an important drug interaction occurs because omeprazole significantly reduces the amount of acid in the stomach.

Why Acidity is Critical for Levothyroxine Absorption

Oral levothyroxine tablets require a certain level of stomach acid (a low pH) for proper dissolution and absorption into the bloodstream. Omeprazole works by blocking the enzyme system that produces gastric acid, effectively raising the stomach's pH level. This creates an environment that can hinder the body's ability to absorb the thyroid hormone, potentially leading to inadequate hormone levels. A review of studies found that patients taking a PPI along with their levothyroxine often had higher Thyroid-Stimulating Hormone (TSH) levels, indicating that their thyroid hormone levels were lower than desired.

The Timing Problem

While separating the dose of omeprazole and levothyroxine seems like a logical solution, it's not always effective. Omeprazole's acid-reducing effects are long-lasting, often extending for 24 hours or more. This means that taking the medications at different times of day does not completely eliminate the interaction. Some studies suggest that the timing might not matter significantly due to the sustained effect of PPIs. Therefore, a different strategy is required to ensure consistent thyroid hormone levels.

Management Strategies for Taking Omeprazole and Levothyroxine

If you require both medications, your healthcare provider will create a plan to minimize the effects of the interaction. The core of this strategy revolves around careful monitoring and potential dose adjustments.

Key Management Approaches

Consistent Timing: Maintain a consistent schedule for taking both medications to avoid large fluctuations in hormone levels. A common practice is to take levothyroxine on an empty stomach first thing in the morning, 30-60 minutes before any food, coffee, or other medications, including omeprazole.
Frequent Monitoring: Your doctor will likely need to monitor your TSH levels more frequently, especially when you start or stop omeprazole therapy. A TSH blood test every four to six weeks is typical during dosage changes until a stable dose is achieved.
Levothyroxine Dose Adjustment: Based on the TSH monitoring results, your healthcare provider may need to increase your levothyroxine dose to compensate for the reduced absorption. It is crucial not to adjust your dose without medical supervision.
Consider Alternative Formulations: Certain levothyroxine formulations are designed to be less affected by changes in stomach acidity. Discuss these options with your doctor if the tablet form proves problematic.

Alternative Formulations of Levothyroxine

If maintaining stable TSH levels is difficult while taking omeprazole, your doctor may suggest an alternative formulation. These options do not rely as heavily on a low gastric pH for absorption.

Soft Gel Capsules: Soft gel formulations, such as Tirosint®, have shown better absorption in patients also taking PPIs. In a 2014 study, patients who switched from tablets to soft gel capsules while taking a PPI showed improved TSH levels.
Liquid Formulations: Newer liquid formulations (e.g., Tirosint-SOL®) have also demonstrated better absorption. A 2024 study suggests these may not be significantly affected by concurrent PPI administration.

Comparison: Tablet vs. Alternative Levothyroxine with Omeprazole


Feature	Levothyroxine Tablets	Alternative Formulations (Soft Gel/Liquid)
Absorption Mechanism	Relies on an acidic stomach environment for dissolution.	Do not rely on gastric acidity for dissolution and absorption.
Impact of Omeprazole	Reduced absorption due to decreased stomach acid.	Minimal or no impact on absorption.
Monitoring Frequency	Frequent TSH monitoring (every 4-6 weeks) often required when starting or stopping PPIs.	Standard TSH monitoring may be sufficient, but still requires physician oversight.
Typical Cost	Often more affordable, especially generics.	Potentially higher cost, may depend on insurance coverage.
Administration Timing	Requires strict, consistent timing on an empty stomach, typically 30-60 minutes before food/other meds.	Allows for more flexible timing with fewer concerns about food or PPI interference.

Recognizing Symptoms and When to See a Doctor

If the interaction between omeprazole and your levothyroxine leads to inadequate hormone levels, you may experience symptoms of hypothyroidism. It is essential to be aware of these signs and to contact your healthcare provider if they occur or worsen. Prompt action allows for proper dosage adjustment and prevents complications.

Symptoms to Watch For

Fatigue and sluggishness
Unexplained weight gain
Increased sensitivity to cold
Dry skin and hair loss
Constipation
Depression or other mood changes
Muscle aches, weakness, or tenderness
Hoarseness

Conclusion

While you can take omeprazole with levothyroxine, it is crucial to do so under strict medical supervision. The interaction between these two common medications can significantly impact the effectiveness of your thyroid replacement therapy by reducing absorption. Adhering to a consistent dosing schedule, undergoing regular TSH monitoring, and communicating any new or worsening symptoms to your healthcare provider are vital steps. In some cases, switching to a different levothyroxine formulation, such as a liquid or soft gel capsule, may be the most effective solution to ensure optimal thyroid function while simultaneously managing acid reflux. Always consult with your doctor before making any changes to your medication regimen. For further reading on managing interactions, you may find the official FDA drug label information useful, though specific guidance should come from a healthcare professional.

Frequently Asked Questions

While some recommendations suggest waiting 4 hours, omeprazole's effects on stomach acid can last for over 24 hours, so simple timing separation might not be enough. The most important factor is consistent timing and close monitoring by your doctor, who can adjust your levothyroxine dose if needed.

For a short course of over-the-counter omeprazole, the interaction is less likely to be clinically significant. However, it is still best to inform your doctor, who may opt for a TSH check to be safe.

You may experience symptoms of an underactive thyroid (hypothyroidism), such as fatigue, unexplained weight gain, constipation, depression, or increased sensitivity to cold.

Yes, for patients taking PPIs, liquid or soft gel capsule formulations of levothyroxine (like Tirosint® or Tirosint-SOL®) have been shown to be less affected by reduced stomach acid. Discuss this option with your doctor.

Yes, other PPIs, such as esomeprazole (Nexium), lansoprazole (Prevacid), and pantoprazole (Protonix), have the same acid-reducing effect and interact with levothyroxine similarly to omeprazole.

Your healthcare provider will likely order more frequent TSH blood tests, especially after starting, changing, or stopping omeprazole. Based on these results, they can adjust your levothyroxine dosage to maintain stable thyroid hormone levels.

If you are on levothyroxine and have started taking omeprazole, especially long-term, it is important to inform your doctor immediately. This allows them to monitor your TSH and adjust your dose if necessary, preventing symptoms of hypothyroidism.

Not necessarily. In most cases, you can continue taking both medications. The key is proper medical management, which may include dose adjustments and switching to a different formulation of levothyroxine.