Quinidine and Nifedipine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Quinidine
Nifedipine
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 NIFEdipine exposure and reduced quiNIDine exposure
Interaction Deep Dive
Concomitant use of NIFEdipine, a CYP3A4 substrate, with a CYP3A4 inhibitor such as quiNIDine may increase NIFEdipine exposure and increase hypotensive effects1. Additionally, quiNIDine exposure may be reduced by coadministration of NIFEdipine, although this is very rare and the mechanism is not understood 4. If coadministration is required, NIFEdipine dose adjustment and monitoring may be necessary 1. Monitor heart rate when quiNIDine is added to a treatment with NIFEdipine 2. Initiate NIFEdipine at the lowest dose available if given concomitantly with quiNIDine 32.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of NIFEdipine; unknown
Literature reports
4 reports — tap to read
a) The AUC for NIFEdipine almost doubled for 7 healthy volunteers when quiNIDine was added to the regimen 5. Oral NIFEdipine 5 mg was given alone or 15 minutes after a dose of quiNIDine 200 mg. Alternatively, several patients have experienced elevated quiNIDine levels when NIFEdipine was discontinued; 2 patients had a doubling of the level 678.
b) In a randomized cross-over study of 10 healthy volunteers, the concurrent use of quiNIDine and NIFEdipine demonstrated a 37% increase in NIFEdipine AUC, compared with NIFEdipine alone. Heart rate was significantly increased during the first 2 hours of coadministration, and the initial increase was significantly correlated with NIFEdipine serum concentration. QuiNIDine pharmacokinetics appeared to be unchanged 9.
c) The interaction between NIFEdipine and quiNIDine was studied in 12 patients who were being treated with quiNIDine for ventricular or supraventricular arrhythmias. Overall, concurrent NIFEdipine did not significantly alter quiNIDine's total body clearance or AUC compared to quiNIDine alone. However, 1 patient with a 70% ejection fraction experienced a 41% decrease in mean steady-state quinidine concentration and AUC and a 68% increase in clearance. The mechanism of the interaction did not appear to be a hemodynamic alteration since nitroprusside plus quiNIDine did not alter quiNIDine's pharmacokinetics in the same patient. The interaction may be related to enhanced quiNIDine metabolism as a result of enzyme induction or protein binding displacement 10.
d) Pharmacokinetic and pharmacodynamic effects of concurrent administration of either NIFEdipine or felodipine and quiNIDine were evaluated in 12 healthy volunteers. Subjects were pretreated for 3 days with prolonged action NIFEdipine 20 mg twice daily or felodipine extended release 10 mg daily, followed by quiNIDine 400 mg. Pharmacokinetic parameters of quiNIDine were unchanged by either NIFEdipine or felodipine. However, 3-hydroxyquinidine (an active metabolite of quiNIDine) AUC and 3-hydroxyquinidine/quiNIDine AUC ratio were both was decreased by felodipine, suggesting reduced metabolite formation. The authors concluded that the changes induced in quiNIDine disposition by either NIFEdipine or felodipine were not clinically significant 11.
Common questions
Can I take Quinidine and Nifedipine together?
Increased NIFEdipine exposure and reduced quiNIDine exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Quinidine and Nifedipine interaction?
It is rated major. Potentially serious — often needs a change or close 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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Quinidine or Nifedipine 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 (11)
- Product Information: ADALAT(R) XL(R) oral extended-release tablets, nifedipine oral extended-release tablets. Bayer Inc (per Health Canada), Mississauga, Ontario, Canada, 2016. DailyMed
- Product Information: NIFEDIPINE oral tablet, extended-release, nifedipine oral tablet, extended-release. Aurobindo Pharma Limited (per DailyMed), East Windsor, NJ, 2024. DailyMed
- Product Information: PROCARDIA XL(R) oral extended-release tablets, nifedipine oral extended-release tablets. Pfizer Labs (per Dailymed), New York, NY, 2023. DailyMed
- Product Information: Quinidine gluconate oral extended-release tablets, quinidine gluconate oral extended-release tablets. Wes Pharma Inc (per DailyMed), Westminster, MD, 2021. DailyMed
- Oates NS, Feher MD, Perry HE, et al: Influence of quinidine on nifedipine plasma pharmacokinetics (abstract). Br J Clin Pharmacol 1988; 25:675P.
- Green JA, Clementi WA, Porter C, et al: Nifedipine-quinidine interaction. Clin Pharm 1983; 2:461-465.
- Van Lith RM & Appleby DH: Quinidine - nifedipine interaction. Drug Intell Clin Pharm 1985; 19:829-831. PubMed
- Farringer JA, Green JA, O'Rourke RA, et al: Nifedipine-induced alterations in serum quinidine concentrations. Am Heart J 1984; 108:1570-1572.
- Bowles SK, Reeves RA, Cardozo L, et al: Evaluation of the pharmacokinetic and pharmacodynamic interaction between quinidine and nifedipine. J Clin Pharmacol 1993; 33:727-731. PubMed
- Munger MA, Jarvis RC, Nair R, et al: Elucidation of the nifedipine-quinidine interaction. Clin Pharmacol Ther 1989; 45:411-416. PubMed
- Bailey DG, Freeman DJ, Melendez LJ, et al: Quinidine interaction with nifedipine and felodipine: pharmacokinetic and pharmacodynamic evaluation. Clin Pharmacol Ther 1993; 53:354-359. PubMed
Keep reading about Quinidine
Keep reading about Nifedipine
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