Levothyroxine with Pantoprazole Interaction Details

Brand Names Associated with Levothyroxine

Brand Names Associated with Pantoprazole

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 09, 2023

Interaction Effect

Decreased levothyroxine effectiveness

Interaction Summary

Although some pharmacokinetic studies have not shown any interaction, other studies have shown that concomitant use of levothyroxine and proton pump inhibitors may cause clinically significant increases in TSH levels in patients with hypothyroidism . Administer levothyroxine 4 hours before or after drugs that are known to decrease absorption . Monitor TSH levels closely and adjust levothyroxine doses as necessary during concomitant use .

Severity

Moderate

Onset

Unspecified

Evidence

Probable

How To Manage Interaction

Concomitant use of levothyroxine and a proton pump inhibitor may cause clinically significant increases in TSH levels. Proton pump inhibitors may cause low stomach acid, decrease levothyroxine absorption, and affect intragastirc pH. Administer levothyroxine 4 hours before or after drugs that are known to decrease absorption and monitor patients appropriately .

Mechanism Of Interaction

Decreased levothyroxine absorption

Literature Reports

A) Two small pharmacokinetic studies using young, healthy volunteers found that concomitant use of levothyroxine with pantoprazole 40 mg daily or esomeprazole 40 mg daily for 1 week did not significantly affect TSH or T4 AUCs or T4 peak level . However, retrospective studies of hypothyroid patients have found significant increases in TSH with concomitant use in patients with hypothyroidism . One study found that patients receiving lansoprazole in addition to levothyroxine for 2 to 6 months had a significant mean TSH increase of 0.69 +/- 1.9 microinternational Units/mL from baseline, and 19% (7 of 37) required a levothyroxine dose increase (mean dose increase, 20 mcg) . In another study, median TSH significantly increased by 0.22 milliunits/L in patients taking levothyroxine and a proton pump inhibitor for 6 months. Of 887 patients who had been on a stable levothyroxine dose for at least 2 years prior to initiation of a proton pump inhibitor, 5.6% had a 5 milliunit/L or greater increase in TSH .

Levothyroxine Overview

• Levothyroxine is used to treat hypothyroidism (condition where the thyroid gland does not produce enough thyroid hormone). It is also used with surgery and radioactive iodine therapy to treat thyroid cancer. Levothyroxine is in a class of medications called hormones. It works by replacing thyroid hormone that is normally produced by the body.

• Without thyroid hormone, your body cannot function properly, which may result in poor growth, slow speech, lack of energy, excessive tiredness, constipation, weight gain, hair loss, dry, thick skin, increased sensitivity to cold, joint and muscle pain, heavy or irregular menstrual periods, and depression. When taken correctly, levothyroxine reverses these symptoms.

Pantoprazole Overview

• Pantoprazole is used to treat damage from gastroesophageal reflux disease (GERD), a condition in which backward flow of acid from the stomach causes heartburn and possible injury of the esophagus (the tube between the throat and stomach) in adults and children 5 years of age and older. Pantoprazole is used to allow the esophagus to heal and prevent further damage to the esophagus in adults with GERD. It is also used to treat conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome in adults. Pantoprazole is in a class of medications called proton-pump inhibitors. It works by decreasing the amount of acid made in the stomach.

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.