Amitriptyline and Nefopam: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amitriptyline
Nefopam
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.
Taking these two together can make seizures more likely. Amitriptyline (Elavil) is a tricyclic antidepressant, and one of its known effects is that it can lower your brain's "seizure threshold," meaning it takes a little less to trigger a seizure. Nefopam, a pain reliever, can do the same thing. When you combine them, those effects add up.
This matters most if you have ever had a seizure or a convulsive disorder. The good news is your care team can manage this. Please don't stop either medicine on your own. Talk with your pharmacist or doctor, who may choose a different pain reliever or watch you more closely.
Interaction: Additive lowering of the seizure threshold, raising seizure risk. Onset is rapid; evidence is rated probable; severity major.
- Mechanism: Nefopam inhibits neuronal reuptake of norepinephrine and serotonin and independently lowers seizure threshold; amitriptyline, a TCA, also lowers seizure threshold. Effect is pharmacodynamic and additive (not a metabolic/PK interaction). Neither agent's activity depends on prodrug conversion.
- Risk group: Greatest in patients with a history of a convulsive disorder.
- Management: Exercise extreme caution with concurrent use. Consider an alternative analgesic to nefopam. If used together, monitor closely for CNS excitation and seizure activity.
What happens
An increased risk of seizures
Interaction Deep Dive
By blocking the neuronal reuptake of both norepinephrine and serotonin, nefopam raises the likelihood of seizures, particularly among patients who have previously experienced a convulsive disorder. Because tricyclic antidepressants likewise reduce the seizure threshold, the maker of nefopam recommends caution when it is given together with tricyclic antidepressant therapy1.
Why it happens (mechanism)
Additive lowering of seizure threshold
How to manage this interaction
This is manageable with the right plan from your care team. Keep taking both medicines exactly as prescribed unless your prescriber or pharmacist tells you otherwise.
- Your care team may choose a different pain reliever instead of nefopam, especially if you have a history of seizures.
- If both are used together, they may watch you more closely for warning signs.
- Tell your prescriber or pharmacist if you have ever had a seizure or convulsive disorder.
- Seek urgent care right away if you experience twitching, muscle jerks, confusion, or a seizure.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Nefopam together?
Combining amitriptyline and nefopam adds up to a higher seizure risk, so talk with your pharmacist or doctor; they may pick a different pain reliever or monitor you more closely, especially if you have a seizure history. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Nefopam interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Amitriptyline and Nefopam interaction managed?
This is manageable with the right plan from your care team. Keep taking both medicines exactly as prescribed unless your prescriber or pharmacist tells you otherwise. Your care team may choose a different pain reliever instead of nefopam, especially if you have a history of seizures. If both are used together, they may watch you more closely for warning signs. Tell your prescriber or pharmacist if… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Amitriptyline or Nefopam 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)
- Pillans PI & Woods DJ: Adverse reactions associated with nefopam. NZ Med J 1995; 108:832-834.
Keep reading about Amitriptyline
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