Quinidine and Metoclopramide Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Metoclopramide Injection
Quinidine
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 metoclopramide exposure and risk of increased adverse events
Interaction Deep Dive
Concomitant use of metoclopramide and a strong CYP2D6 inhibitor may result in increased metoclopramide exposure. In a study, coadministration resulted in increased metoclopramide Cmax, AUC, and t(1/2). If coadministered in patients with gastroesophageal reflux, decrease the metoclopramide dosage to 5 mg orally 4 times daily or 10 mg three times daily; maximum dose 30 mg/day. In patients with acute and recurrent diabetic gastroparesis, decrease the metoclopramide dosage to 5 mg orally 4 times daily; maximum dose 20 mg/day1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metoclopramide metabolism
Literature reports
1 report — tap to read
a) Coadministration of metoclopramide 20 mg and fluoxetine 60 mg orally for 8 days (a strong CYP2D6 inhibitor) in healthy subjects resulted in increases in metoclopramide Cmax of 40%, AUC(0 to infinity) by 90%, and t(1/2) from 5.5 to 8.5 hours compared with metoclopramide alone 1.
Common questions
Can I take Quinidine and Metoclopramide Injection together?
Increased metoclopramide exposure and risk of increased adverse events Always confirm with your pharmacist or prescriber before making any change.
How serious is the Quinidine and Metoclopramide Injection interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
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 Quinidine or Metoclopramide Injection 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)
- Product Information: REGLAN(R) oral tablets, metoclopramide oral tablets. ANI Pharmaceuticals, Inc. (per FDA), Baudette, MN, 2017. DailyMed
Keep reading about Metoclopramide Injection
Keep reading about Quinidine
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.
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