Furosemide and Lithium Interaction
Drug interaction information between Furosemide and Lithium.
Furosemide and Lithium have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Furosemide and Lithium. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Furosemide prevents the kidneys from clearing lithium out of the body properly. This causes lithium to build up to dangerous levels, which can lead to toxicity.
What To Do
Avoid taking these two medications together. If they must be used, your doctor will need to monitor your lithium blood levels very closely.
FDA Label Information
Lithium generally should not be given with diuretics because they reduce lithium's renal clearance and add a high risk of lithium toxicity.
Furosemide Also Interacts With
- Dutasteride major
- Dutasteride/Tamsulosin major
- Tamsulosin major
- Cyclosporine moderate
- Oxaprozin moderate
Lithium Also Interacts With
- Amlodipine/Benazepril major
- Risperidone major
- Amiloride moderate
- Amiodarone moderate
- Amlodipine/Valsartan moderate
Frequently Asked Questions
Can I take Furosemide and Lithium together?
This is a moderate interaction. Avoid taking these two medications together. If they must be used, your doctor will need to monitor your lithium blood levels very closely.
How serious is the interaction between Furosemide and Lithium?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Furosemide and Lithium interact?
Furosemide prevents the kidneys from clearing lithium out of the body properly. This causes lithium to build up to dangerous levels, which can lead to toxicity.
Understanding the Furosemide and Lithium Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Furosemide belongs to the Loop Diuretic class and Lithium belongs to the Mood Stabilizer class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Furosemide prevents the kidneys from clearing lithium out of the body properly. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Furosemide has 36 total documented interactions on file in this dataset, and Lithium has 90. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Avoid taking these two medications together. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Furosemide or Lithium based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.