Lithium with Potassium Iodide Interaction Details
Brand Names Associated with Lithium
- Eskalith®
- Eskalith® CR
- Lithium
- Lithobid®
Brand Names Associated with Potassium Iodide
- Iosat®
- KI
- Potassium Iodide
- Thyrosafe®
- Thyroshield®

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 21, 2023
Interaction Effect
Increased hypothyroid effect
Interaction Summary
Concomitant potassium iodide and lithium therapy may result in hypothyroidism. This effect is related to a synergistic hypothyroid effect of both lithium and iodide.
Severity
Moderate
Onset
Delayed
Evidence
Theoretical
How To Manage Interaction
Concurrent therapy with lithium and potassium iodide should be avoided if possible. If deemed clinically appropriate, consider monitoring thyroid function tests periodically during therapy.
Mechanism Of Interaction
Additive hypothyroid effects
Lithium Overview
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Lithium is used to treat and prevent episodes of mania (frenzied, abnormally excited mood) in people with bipolar disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Lithium is in a class of medications called antimanic agents. It works by decreasing abnormal activity in the brain.
Potassium Iodide Overview
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Potassium iodide is used to protect the thyroid gland from taking in radioactive iodine that may be released during a nuclear radiation emergency. Radioactive iodine can damage the thyroid gland. You should only take potassium iodide if there is a nuclear radiation emergency and public officials tell you that you should take it. Potassium iodide is in a class of medications called anti-thyroid medications. It works by blocking radioactive iodine from entering the thyroid gland.
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Potassium iodide can protect you from the effects of radioactive iodine that may be released during a nuclear radiation emergency, but will not protect you from other dangerous substances that may be released during the emergency. Public officials may tell you to do other things to protect yourself during the emergency. Follow all of these directions carefully.
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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:
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.