Linezolid Injection and Cyclobenzaprine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cyclobenzaprine
Linezolid Injection
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.
What happens
Increased risk of serotonin syndrome and an increased risk of hyperpyretic crisis seizures
Interaction Deep Dive
Concurrent use of cyclobenzaprine and MAOIs, or administration of cyclobenzaprine within 14 days after discontinuation of an MAOI, is contraindicated due to the risk of serotonin syndrome, hyperpyretic crisis seizures, and death123. If serotonin syndrome symptoms occur with the use of other serotonergic drugs, immediately discontinue cyclobenzaprine, and initiate supportive symptomatic treatment. The development of a potentially life-threatening serotonin syndrome has been reported with cyclobenzaprine when used in combination with MAOIs. Serotonin syndrome symptoms may include mental status changes (eg, confusion, agitation, hallucinations), autonomic instability (eg, diaphoresis, tachycardia, labile blood pressure, hyperthermia), neuromuscular abnormalities (eg, tremor, ataxia, hyperreflexia, clonus, muscle rigidity), and/or gastrointestinal symptoms (eg, nausea, vomiting, diarrhea). If concomitant treatment with cyclobenzaprine and other serotonergic drugs is clinically warranted, careful observation is advised, particularly during treatment initiation or dosage increases 3.
Why it happens (mechanism)
Additive serotonergic effects
Literature reports
2 reports — tap to read
a) Serotonin syndrome, hyperpyretic crisis seizures, and deaths have occurred in patients receiving cyclobenzaprine or structurally related tricyclic antidepressants and MAOIs 123.
b) Postmarketing cases of serotonin syndrome have been reported with the concomitant use of oral cyclobenzaprine and other drugs, such as SSRIs, SNRIs, TCAs, traMADol, buPROPion, meperidine, verapamil, or MAO inhibitors 3.
Common questions
Can I take Linezolid Injection and Cyclobenzaprine together?
Increased risk of serotonin syndrome and an increased risk of hyperpyretic crisis seizures Always confirm with your pharmacist or prescriber before making any change.
How serious is the Linezolid Injection and Cyclobenzaprine interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
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 Linezolid Injection or Cyclobenzaprine 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: AMRIX(R) oral extended-release capsules, cyclobenzaprine HCl oral extended-release capsules. Teva Pharmaceuticals USA Inc (per FDA), Parsippany, NJ, 2024. DailyMed
- Product Information: FLEXERIL(R) oral tablets, cyclobenzaprine HCl oral tablets. McNeil Pediatrics (per FDA), Titusville, NJ, 2013. DailyMed
- Product Information: TONMYA(TM) sublingual tablets, cyclobenzaprine HCl sublingual tablets. Tonix Pharmaceuticals, Inc (per manufacturer), Chatham, NJ, 2025. DailyMed
Keep reading about Cyclobenzaprine
Keep reading about Linezolid Injection
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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