Bendroflumethiazide and Acetaminophen And Codeine: 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
Bendroflumethiazide
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 a pain medicine that contains codeine (along with acetaminophen) plus a water pill called bendroflumethiazide. Water pills help your body get rid of extra fluid and can help control blood pressure. The concern here is mostly theoretical, but codeine may cause your body to hold onto more water by triggering a hormone that keeps fluid in. That could make your water pill work a little less well, so you might notice more swelling or a change in your blood pressure.
The good news is this is easy for your care team to keep an eye on. Keep taking both medicines as prescribed, and let your pharmacist or doctor know if you notice more puffiness or changes in your blood pressure.
Effect: Codeine may reduce the diuretic/antihypertensive efficacy of bendroflumethiazide, a thiazide diuretic.
Mechanism: Opioid-mediated release of antidiuretic hormone (ADH) promotes water retention, opposing the diuretic effect. Codeine here is an active opioid (also a CYP2D6 prodrug for morphine, but the ADH effect is opioid-class mediated, so directionality is unchanged).
- Direction: reduced diuretic effect (PD antagonism)
- Onset: unspecified
- Evidence: theoretical
- Severity on file: major
Management: Monitor for diminished diuresis, edema, and blood pressure changes; the diuretic dose may be adjusted and individualized as needed by the care team.
What happens
Reduced diuretic efficacy
Interaction Deep Dive
Concomitant use of codeine with diuretics may reduce the efficacy of diuretics by inducing the release of anti-diuretic hormone. Monitor patients for signs of diminished diuresis and/or effects on blood pressure and increase the dosage of the diuretic as needed1.
Why it happens (mechanism)
Increased opioid-mediated release of antidiuretic hormone
How to manage this interaction
This interaction can be managed with monitoring and dose tailoring. Both medicines can still be used together.
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Your care team may monitor you more closely for signs the water pill is working less well, such as new or worse swelling, weight gain from fluid, or higher blood pressure.
- If needed, your diuretic dose may be adjusted and individualized by your care team.
- Tell your pharmacist or doctor if you notice increased puffiness in your legs or feet, sudden fluid weight gain, or blood pressure readings higher than usual.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Bendroflumethiazide and Acetaminophen And Codeine together?
Codeine may slightly reduce how well your water pill (bendroflumethiazide) works by causing fluid retention, though this is a theoretical concern. Keep taking both as prescribed and let your care team monitor your swelling and blood pressure so they can adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Bendroflumethiazide and Acetaminophen And Codeine 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 Bendroflumethiazide and Acetaminophen And Codeine interaction managed?
This interaction can be managed with monitoring and dose tailoring. Both medicines can still be used together. Keep taking both as prescribed unless your prescriber tells you otherwise. Your care team may monitor you more closely for signs the water pill is working less well, such as new or worse swelling, weight gain from fluid, or higher blood pressure. If needed, your diuretic dose may be adjus… 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 Bendroflumethiazide or Acetaminophen And Codeine 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 Bendroflumethiazide
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