Loxapine and Amitriptyline: 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
Loxapine
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.
Amitriptyline (Elavil) and loxapine (Adasuve) both calm down the nervous system. When you take them together, those calming effects can stack up. That can leave you feeling very drowsy, foggy, or dizzy, and it may slow your breathing, drop your blood pressure, or make you feel faint (especially when you stand up).
The good news is that your care team knows about this combination and can manage it, often by adjusting a dose and keeping a closer eye on how you feel. Please keep taking both exactly as prescribed, and let your doctor or pharmacist know if you feel unusually sleepy, dizzy, or short of breath.
Mechanism: additive CNS depression. Amitriptyline (a sedating tricyclic with antihistaminic and anticholinergic properties) plus loxapine (an antipsychotic with sedative effects) produce overlapping pharmacodynamic depression. Neither is a prodrug relevant to this PD interaction.
- Effect: potentiated cognitive/motor impairment, profound sedation, respiratory depression, hypotension, syncope
- Direction: additive/increased CNS and cardiovascular depressant effect
- Severity: major; evidence: theoretical; onset: unspecified
- Management: if coadministration is necessary, consider dose reduction of the CNS depressant; monitor sedation, respiratory status, and orthostatic blood pressure
What happens
Potentiation of impaired cognitive function and motor skills and an increased risk of respiratory depression, hypotension, profound sedation, and syncope
Interaction Deep Dive
Taking loxapine together with other agents that depress the CNS can heighten deficits in cognition and motor performance while raising the likelihood of hypotension, respiratory depression, syncope, and profound sedation. The substances involved include benzodiazepines, opioid analgesics, alcohol, general anesthetics, tricyclic antidepressants, sedative/hypnotics, phenothiazines, muscle relaxants, and illicit CNS depressants. When these must be given together, a reduction in the dose of the CNS depressant should be considered1.
Why it happens (mechanism)
Additive CNS depression
How to manage this interaction
This combination is manageable with the right precautions. Your care team may:
- Adjust and individualize the dose of one of these medicines to limit the additive sedation
- Monitor you more closely for drowsiness, breathing changes, low blood pressure, or fainting
What you can do:
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise
- Be cautious with driving or activities that need alertness until you know how you feel
- Avoid alcohol and other sedating substances, which add to the effect
- Tell your pharmacist or doctor promptly about heavy sedation, dizziness on standing, or slowed breathing
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Loxapine and Amitriptyline together?
Taking amitriptyline and loxapine together can stack up sedation and raise the risk of slowed breathing, low blood pressure, and fainting; keep taking both as prescribed and tell your care team if you feel very drowsy or dizzy so they can adjust the dose and monitor you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Loxapine and Amitriptyline 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 Loxapine and Amitriptyline interaction managed?
This combination is manageable with the right precautions. Your care team may: Adjust and individualize the dose of one of these medicines to limit the additive sedation Monitor you more closely for drowsiness, breathing changes, low blood pressure, or fainting What you can do: Keep taking both exactly as prescribed unless your prescriber tells you otherwise Be cautious with driving or activities… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Loxapine or Amitriptyline 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: ADASUVE(R) oral inhalation powder, loxapine oral inhalation powder. Alexza Pharmaceuticals Inc (per FDA), Mountain View, CA, 2017. DailyMed
Keep reading about Amitriptyline
Keep reading about Loxapine
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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