Acetaminophen And Codeine and Polythiazide: 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
Polythiazide
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're taking a water pill (polythiazide) to help your body get rid of extra fluid and to help control blood pressure. The codeine in your pain medicine may make your body hold onto a little more water by nudging up a hormone that tells your kidneys to keep fluid in. In theory, that could make your water pill work a bit less well.
The good news is this is a possible effect, not a sure thing, and it's easy for your care team to keep an eye on. If you notice more swelling, weight gain, or your blood pressure creeping up, let your pharmacist or doctor know. Don't stop either medicine on your own, your team can adjust things if needed.
Effect: Codeine may blunt the diuretic and antihypertensive efficacy of polythiazide (a thiazide diuretic).
Mechanism: Opioid-mediated stimulation of antidiuretic hormone (ADH) release promotes water retention, opposing the diuretic's action. This is a pharmacodynamic interaction; codeine is a CYP2D6 prodrug, but that is not the relevant pathway here.
- Direction: Reduced diuretic effect.
- Onset: Unspecified.
- Evidence: Theoretical; rated major on file.
- Management: Monitor diuresis, weight/edema, and blood pressure. The diuretic dose may be adjusted and individualized by the care team as needed.
What happens
Reduced diuretic efficacy
Interaction Deep Dive
When codeine is taken together with diuretics, the diuretic effect may be lessened because codeine can trigger the release of anti-diuretic hormone. Watch patients 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 medicines exactly as prescribed. Because this is a theoretical interaction, your care team simply keeps an eye out for signs the water pill isn't working as well.
- Watch for new or worsening swelling (ankles, legs), unexpected weight gain, or a rise in your blood pressure.
- Report these to your pharmacist or prescriber if they happen.
- Your polythiazide dose may be adjusted and individualized by your care team, and they may check your blood pressure more closely.
Don't start, stop, or change either medication on your own.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Polythiazide together?
Codeine may slightly reduce how well your polythiazide water pill works by causing fluid retention, so watch for swelling or higher blood pressure and tell your care team, who can adjust your dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Polythiazide 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 Polythiazide interaction managed?
Keep taking both medicines exactly as prescribed. Because this is a theoretical interaction, your care team simply keeps an eye out for signs the water pill isn't working as well. Watch for new or worsening swelling (ankles, legs), unexpected weight gain, or a rise in your blood pressure. Report these to your pharmacist or prescriber if they happen. Your polythiazide dose may be adjusted and indiv… 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 Polythiazide 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 Polythiazide
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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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