Acetaminophen And Codeine and Capivasertib: 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
Capivasertib
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.
Your pain medicine contains codeine, which is a bit unusual. Codeine itself does not do much for pain until your body converts it into morphine, using an enzyme called CYP2D6. That is where capivasertib (Truqap) comes in. It can slow that enzyme down, so your body makes less morphine. The likely result is that your codeine may not relieve pain as well, and you could even feel mild withdrawal.
This concern is based on theory rather than strong studies, so please do not panic or stop anything on your own. Your care team can manage it by watching how well your pain is controlled and adjusting your dose if needed.
Effect: Codeine is a prodrug requiring CYP2D6-mediated O-demethylation to morphine for analgesia. Capivasertib inhibits CYP2D6, increasing parent codeine exposure while reducing formation of the active metabolite morphine.
- Direction: Reduced analgesic efficacy; possible opioid withdrawal in dependent patients.
- Evidence: Theoretical; magnitude not quantified.
- Onset: Unspecified.
- Management: If co-use is necessary, monitor for inadequate analgesia and withdrawal; the codeine dose may be increased and individualized. When capivasertib is stopped, anticipate increased morphine formation, consider reducing codeine, and monitor for sedation and respiratory depression.
What happens
Increased codeine exposure and reduced active metabolite (morphine) exposure
Interaction Deep Dive
Concomitant use of codeine and a CYP2D6 inhibitor may reduce plasma concentrations of morphine, the active metabolite of codeine, thus potentially leading to reduced efficacy and withdrawal symptoms. If concomitant use is necessary, monitor patients for withdrawal symptoms and consider increasing the codeine dose. Once the CYP2D6 inhibitor is discontinued, consider reducing the codeine dose and monitor for signs and symptoms of respiratory depression and sedation312.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated codeine metabolism
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Because this combination may make codeine work less well, here is what typically happens:
- Your team may monitor how well your pain is controlled and watch for withdrawal-type symptoms.
- Your codeine dose may be adjusted and individualized if needed while you are on capivasertib.
- When capivasertib is stopped, your team may lower the codeine dose again and watch for excess drowsiness or slowed breathing.
Tell your pharmacist or prescriber if your pain is not controlled, or if you feel restless, achy, or unwell.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Capivasertib together?
Capivasertib can blunt how well codeine relieves pain by reducing its conversion to morphine, so tell your care team if your pain worsens; they can adjust and monitor your dose safely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Capivasertib 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 Capivasertib interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Because this combination may make codeine work less well, here is what typically happens: Your team may monitor how well your pain is controlled and watch for withdrawal-type symptoms. Your codeine dose may be adjusted and individualized if needed while you are on capivasertib. When capivasertib is stopped,… 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 Capivasertib 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 (3)
- Product Information: Codeine sulfate oral solution, codeine sulfate oral solution. Hikma Pharmaceuticals USA Inc(per FDA), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: Codeine sulfate oral tablets, codeine sulfate oral tablets. Hikma Pharmaceuticals USA Inc. (per FDA), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: codeine sulfate oral tablets, codeine sulfate oral tablets. West-Ward Pharmaceuticals Corp. (per FDA), Eatontown, NJ, 2017. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Capivasertib
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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