Cyclopenthiazide 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
Cyclopenthiazide
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 (cyclopenthiazide) to help your body get rid of extra fluid and to help control blood pressure. You're also taking a pain medicine that contains codeine. The concern here is that codeine can trigger your body to hold onto more water. That could make your water pill work a little less well, so you might notice more swelling or a change in your blood pressure.
I want to reassure you that this is based mostly on theory, not strong real-world proof. Your care team can easily manage it by keeping an eye on your fluid and blood pressure and adjusting your water pill dose if needed. Please don't stop either medicine on your own. Just check in with your doctor or pharmacist.
Effect: Reduced diuretic (cyclopenthiazide) efficacy when combined with codeine.
Mechanism: Opioid-mediated stimulation of antidiuretic hormone (ADH) release promotes water retention, opposing the diuretic and antihypertensive action of the thiazide. This is a PD interaction, not CYP-based. Codeine is a prodrug (CYP2D6 to morphine), but that does not change the direction here.
- Direction: Diminished diuresis, possible blood pressure elevation.
- Onset: Unspecified.
- Evidence: Theoretical.
- Management: Monitor urine output, weight, edema, and BP; the diuretic dose may be adjusted and individualized as needed.
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
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction is theoretical, and it is very manageable.
- Your care team may watch you a bit more closely for signs the water pill is working less well, such as more swelling, weight gain, or changes in blood pressure.
- If needed, your diuretic dose may be adjusted and individualized by your care team.
- Tell your pharmacist or doctor if you notice new or worsening ankle swelling, sudden weight gain, or higher blood pressure readings.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Cyclopenthiazide and Acetaminophen And Codeine together?
Codeine may slightly weaken how well your water pill (cyclopenthiazide) works by making your body retain fluid, so watch for swelling or blood pressure changes and let your care team adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cyclopenthiazide 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 Cyclopenthiazide and Acetaminophen And Codeine interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction is theoretical, and it is very manageable. Your care team may watch you a bit more closely for signs the water pill is working less well, such as more swelling, weight gain, or changes in blood pressure. If needed, your diuretic dose may be adjusted and individualized by your care team. Tell your… 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 Cyclopenthiazide 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
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