Acetaminophen And Codeine and Quinethazone: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jun 30, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Quinethazone
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.
You've been prescribed acetaminophen with codeine for pain, along with quinethazone, a water pill (diuretic) that helps your body get rid of extra fluid. The concern here is that codeine may cause your body to release a hormone that makes you hold onto water. In theory, this could make your water pill work a little less well, so you may not lose as much fluid or your blood pressure may not drop as much as expected.
The good news is this is only a possible effect based on theory, not something proven to happen often. Your care team can easily keep an eye on things and adjust your water pill if needed. Please don't stop either medicine on your own.
Effect: Codeine may reduce the diuretic efficacy of quinethazone (a thiazide-like diuretic).
Mechanism: Opioid-mediated increase in antidiuretic hormone (ADH/vasopressin) release, promoting water retention and opposing diuresis. Neither agent is metabolically dependent on the other; this is a pharmacodynamic, not PK, interaction.
Direction/magnitude: Reduced diuretic response; magnitude undefined. Onset: unspecified. Evidence: theoretical.
- Monitor urine output, fluid status, edema, and blood pressure.
- The diuretic dose may need to be individualized and titrated upward if diminished diuresis is observed.
- Reassess if opioid is discontinued.
What happens
Reduced diuretic efficacy
Interaction Deep Dive
When codeine is taken together with diuretics, the diuretic's effectiveness may be lessened because codeine can trigger the release of anti-diuretic hormone. Watch for indications of reduced diuresis and/or changes in blood pressure, and raise the diuretic dose as required1.
Why it happens (mechanism)
Increased opioid-mediated release of antidiuretic hormone
How to manage this interaction
Keep taking both medications exactly as prescribed. This is a theoretical concern, and it is very manageable with routine follow-up.
- Your care team may watch for signs your water pill isn't working as well, such as more swelling, less urination, or higher blood pressure.
- Your diuretic dose may need to be adjusted and individualized by your team if needed.
- Tell your pharmacist or doctor if you notice new or worsening swelling, weight gain, or blood pressure changes.
Do not start, stop, or change either medicine on your own. Check with your care team first.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Quinethazone together?
Codeine may slightly weaken quinethazone's water-pill effect by causing fluid retention, but this is only theoretical. Keep taking both and let your care team monitor and adjust the diuretic dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Quinethazone 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 is the Acetaminophen And Codeine and Quinethazone interaction managed?
Keep taking both medications exactly as prescribed. This is a theoretical concern, and it is very manageable with routine follow-up. Your care team may watch for signs your water pill isn't working as well, such as more swelling, less urination, or higher blood pressure. Your diuretic dose may need to be adjusted and individualized by your team if needed. Tell your pharmacist or doctor if you noti… Management is individual — always follow your own care team's guidance.
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 Acetaminophen And Codeine or Quinethazone 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: CARISOPRODOL, ASPIRIN, CODEINE PHOSPHATE oral tablets, carisoprodol, aspirin, codeine phosphate oral tablets. Ingenus Pharmaceuticals LLC (per DailyMed), Orlando, FL, 2021. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Quinethazone
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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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