PlainMeds provides educational information only. This is not medical advice. Always consult your doctor or pharmacist.

Buspirone and Diltiazem Interaction

Drug interaction information between Buspirone and Diltiazem.

Buspirone and Diltiazem have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Buspirone and Diltiazem. 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.

Drug A

Buspirone

Azapirone Anxiolytic

Drug B

Diltiazem

Calcium Channel Blocker

How They Interact

Diltiazem prevents the body from breaking down buspirone properly, which causes buspirone levels to rise significantly.

What To Do

Your doctor may need to lower your buspirone dose to prevent increased side effects.

FDA Label Information

Buspirone : In nine healthy subjects, diltiazem significantly increased the mean buspirone AUC 5.5-fold and C max 4.1-fold compared to placebo. The T 1/2 and T max of buspirone were not significantly affected by diltiazem. Enhanced effects and increased toxicity of buspirone may be possible during concomitant administration with diltiazem.

Frequently Asked Questions

Can I take Buspirone and Diltiazem together?

This is a minor interaction. Your doctor may need to lower your buspirone dose to prevent increased side effects.

How serious is the interaction between Buspirone and Diltiazem?

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 Buspirone and Diltiazem interact?

Diltiazem prevents the body from breaking down buspirone properly, which causes buspirone levels to rise significantly.

Understanding the Buspirone and Diltiazem Interaction

FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Buspirone belongs to the Azapirone Anxiolytic class and Diltiazem belongs to the Calcium Channel Blocker class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Diltiazem prevents the body from breaking down buspirone properly, which causes buspirone levels to rise significantly. 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. Buspirone has 17 total documented interactions on file in this dataset, and Diltiazem has 46. 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 may need to lower your buspirone dose to prevent increased side effects. 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 Buspirone or Diltiazem 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.