Chlorthalidone and Fosinopril Interaction
Drug interaction information between Chlorthalidone and Fosinopril.
Chlorthalidone and Fosinopril have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Chlorthalidone and Fosinopril. 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
Taking these medications together does not affect the amount of active medicine that enters your body.
What To Do
You can generally take these together without adjusting the dose, though your doctor will monitor your response.
FDA Label Information
In separate single or multiple dose pharmacokinetic interaction studies with chlorthalidone, nifedipine, propranolol, hydrochlorothiazide, cimetidine, metoclopramide, propantheline, digoxin, and warfarin, the bioavailability of fosinoprilat was not altered by coadministration of fosinopril with any one of these drugs.
Chlorthalidone Also Interacts With
- Azilsartan moderate
- Norepinephrine minor
Fosinopril Also Interacts With
- Aliskiren major
- Lithium moderate
- Hydrochlorothiazide minor
- Aspirin minor
- Propranolol minor
Frequently Asked Questions
Can I take Chlorthalidone and Fosinopril together?
This is a minor interaction. You can generally take these together without adjusting the dose, though your doctor will monitor your response.
How serious is the interaction between Chlorthalidone and Fosinopril?
This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.
Why do Chlorthalidone and Fosinopril interact?
Taking these medications together does not affect the amount of active medicine that enters your body.
Understanding the Chlorthalidone and Fosinopril Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Chlorthalidone belongs to the Thiazide-Like Diuretic class and Fosinopril belongs to the ACE Inhibitor class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Taking these medications together does not affect the amount of active medicine that enters your body. 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. Chlorthalidone has 3 total documented interactions on file in this dataset, and Fosinopril has 12. 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: You can generally take these together without adjusting the dose, though your doctor will monitor your response. 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 Chlorthalidone or Fosinopril 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.