Tolcapone and Linezolid Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Linezolid Injection
Tolcapone
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
Decreased catecholamine metabolism and increased risk of hypertensive crisis
Interaction Deep Dive
Catechol-O-methyltransferase (COMT) and MAO enzymes are the 2 major enzyme systems involved in the metabolism of catecholamines. In theory, the coadministration of tolcapone, which inhibits COMT, and a non-selective MAOI could result in the inhibition of catecholamine metabolism2and an increase in the risk of hypertensive reaction or crisis. Consider medication-free intervals in between discontinuing and initiating either drug. If concomitant use is necessary, use at the lowest appropriate dosage, monitor for adverse events, and discontinue if hypertensive crisis is suspected 1.
Why it happens (mechanism)
Inhibition of catechol-O-methyltransferase (COMT) and MAO
Common questions
Can I take Tolcapone and Linezolid Injection together?
Decreased catecholamine metabolism and increased risk of hypertensive crisis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tolcapone and Linezolid Injection 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 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 Tolcapone or Linezolid Injection 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 (2)
- Product Information: PARNATE(R) oral tablets, tranylcypromine oral tablets. Concordia Pharmaceuticals, Inc. (per FDA), Kansas City, MO, 2018. DailyMed
- Product Information: TASMAR(R) oral tablets, tolcapone oral tablets. Valeant Pharmaceuticals North America LLC (per FDA), Bridgewater, NJ, 2013. DailyMed
Keep reading about Linezolid Injection
Keep reading about Tolcapone
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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