Fosinopril and Lithium Interaction
Drug interaction information between Fosinopril and Lithium.
Fosinopril and Lithium have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Fosinopril 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
Fosinopril can make it harder for your body to get rid of lithium, causing it to build up to toxic levels in your blood.
What To Do
Your doctor should frequently monitor your lithium blood levels if you take these medications together.
FDA Label Information
Lithium Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors during therapy with lithium. These drugs should be coadministered with caution, and frequent monitoring of serum lithium levels is recommended. If a diuretic is also used, the risk of lithium toxicity may be increased.
Fosinopril Also Interacts With
- Aliskiren major
- Hydrochlorothiazide minor
- Aspirin minor
- Propranolol minor
- Warfarin minor
Lithium Also Interacts With
- Amlodipine/Benazepril major
- Risperidone major
- Amiloride moderate
- Amiodarone moderate
- Amlodipine/Valsartan moderate
Frequently Asked Questions
Can I take Fosinopril and Lithium together?
This is a moderate interaction. Your doctor should frequently monitor your lithium blood levels if you take these medications together.
How serious is the interaction between Fosinopril 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 Fosinopril and Lithium interact?
Fosinopril can make it harder for your body to get rid of lithium, causing it to build up to toxic levels in your blood.
Understanding the Fosinopril and Lithium Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Fosinopril belongs to the ACE Inhibitor class and Lithium belongs to the Mood Stabilizer class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Fosinopril can make it harder for your body to get rid of lithium, causing it to build up to toxic levels in your blood. 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. Fosinopril has 12 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: Your doctor should frequently monitor your lithium blood levels if you take these 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 Fosinopril 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.