Acetaminophen And Codeine and Lacosamide: 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
Lacosamide
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.
These two medicines can add up to make you very sleepy. The codeine in your pain medicine is an opioid, and it can slow down your brain and breathing. Lacosamide (Vimpat), used for seizures, can also cause drowsiness, dizziness, and trouble thinking clearly. When you take them together, those effects can stack on top of each other.
You might feel more tired, foggy, or unsteady than usual. This is based on how the drugs work rather than lots of real-world reports, but it is worth taking seriously. Please don't stop either medicine on your own. Talk with your pharmacist or doctor, who can adjust doses and keep a closer eye on you.
Additive CNS depression between acetaminophen/codeine (opioid analgesic) and lacosamide.
- Mechanism: pharmacodynamic, additive CNS and respiratory depression; both agents are independently sedating. No prodrug reversal here (codeine is a CYP2D6 prodrug, but that does not alter this PD interaction).
- Direction/magnitude: increased sedation, dizziness, cognitive/neuropsychiatric effects; magnitude not quantified.
- Onset: unspecified.
- Evidence: theoretical, but severity rated major.
- Management: use combination with extreme caution; monitor sedation, respiratory status, and neurocognitive function; individualize and consider dose reduction of one or both agents.
What happens
An increased risk of CNS depression
Interaction Deep Dive
When lacosamide is given together with CNS depressants, exercise extreme caution because of the risk of CNS depression, along with other neuropsychiatric and/or cognitive adverse effects1.
Why it happens (mechanism)
Additive CNS depression
How to manage this interaction
If both medicines are prescribed, that can be appropriate, but your care team will watch you carefully for extra drowsiness or dizziness.
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Doses may need to be adjusted and individualized by your care team, and they may monitor you more closely.
- Watch for heavy sedation, confusion, slowed or shallow breathing, or feeling unsteady, and report these promptly.
- Avoid alcohol and other sedating substances, and be careful driving until you know how you feel.
Raise any new or worsening symptoms with your pharmacist or doctor.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Lacosamide together?
Taking acetaminophen/codeine with lacosamide can add up to cause more drowsiness, dizziness, and slowed breathing, so use them together only under your care team's guidance and watch for heavy sedation. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Lacosamide 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 Lacosamide interaction managed?
If both medicines are prescribed, that can be appropriate, but your care team will watch you carefully for extra drowsiness or dizziness. Keep taking both as prescribed unless your prescriber tells you otherwise. Doses may need to be adjusted and individualized by your care team, and they may monitor you more closely. Watch for heavy sedation, confusion, slowed or shallow breathing, or feeling uns… 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 Lacosamide 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: Motpoly XR oral extended-release capsules, lacosamide oral extended-release capsules. Aucta Pharmaceuticals, Inc, Piscataway, NJ, 2023. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Lacosamide
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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