Delavirdine and Isradipine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Delavirdine
Isradipine
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
Increased serum isradipine concentrations
Interaction Deep Dive
No data are currently available on the effects of coadministered isradipine and delavirdine. Delavirdine exhibits inhibitory action on the cytochrome P450 3A family of isozymes, the primary enzymes involved in the metabolism of many dihydropyridine calcium channel blockers. It is possible that the concurrent use of isradipine and delavirdine could result in reduced isradipine metabolism, thereby leading to increased isradipine serum concentrations. Use caution when these agents are coadministered and monitor patients for excessive adverse effects related to isradipine toxicity1. A downward dosage adjustment of isradipine may be required.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated isradipine metabolism
Common questions
Can I take Delavirdine and Isradipine together?
Increased serum isradipine concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Delavirdine and Isradipine interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Delavirdine or Isradipine 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 anything you'd monitor while I'm on both?
References (1)
- Product Information: RESCRIPTOR(R) oral tablets, delavirdine mesylate oral tablets. Pfizer,Inc, New York, NY, 2006.
Keep reading about Delavirdine
Keep reading about Isradipine
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist