Felodipine and Mibefradil: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Felodipine
Mibefradil
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Severe bradycardia and hypotension
Interaction Deep Dive
One case report describes severe hypotension and bradycardia in a patient who took felodipine and mibefradil concurrently. Mibefradil has a half-life of 17 to 25 hours. Therefore, a washout period of 14 days should elapse after the discontinuation of mibefradil before therapy with felodipine should be considered. In addition, since mibefradil blocks both T (transient) and L (long) calcium channels, other available calcium channel blockers which only block L-type calcium channels are unlikely to be more effective at controlling hypertension1.
Why it happens (mechanism)
Additive calcium channel blockade
Literature reports
1 report — tap to read
a) The blood pressure of a 55-year-old female taking mibefradil 100 mg and nadolol 80 mg daily continued to be inadequately controlled. Her physician added felodipine 5 mg and enalapril 5 mg to her drug regimen. She ingested her first dose of felodipine and enalapril at bedtime with her mibefradil, and five hours later she was in acute distress with altered mental status and substernal chest pain. Upon arrival to the emergency department she had a heart rate of 48 beats per minute and her blood pressure was 112/77 mm Hg. Soon after arrival, she collapsed into cardiogenic shock and her heart rate fell into the 30s while her systolic blood pressure was 80 mm Hg. Intensive care treatment followed, and she recovered and was discharged from the hospital without residual effects 1.
Common questions
Can I take Felodipine and Mibefradil together?
Severe bradycardia and hypotension Always confirm with your pharmacist or prescriber before making any change.
How serious is the Felodipine and Mibefradil interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Felodipine or Mibefradil need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Mullins ME, Horowitz BZ, Linden DHJ, et al: Life-threatening interaction of mibefradil and beta-blockers with dihydropyridine calcium channel blockers. JAMA 1998; 280:157-158.
Keep reading about Felodipine
Keep reading about Mibefradil
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