Carbidopa and Linezolid Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Carbidopa
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
Hypertensive crisis
Interaction Deep Dive
Coadministration of carbidopa/levodopa and a nonselective MAOI, such as linezolid, is contraindicated2345 as hypertensive crisis may occur. Serotonin toxicity has also been reported with concurrent use 1. Discontinue linezolid at least 2 weeks prior to initiating treatment with carbidopa/levodopa 2345.
Why it happens (mechanism)
Increased dopamine and norepinephrine levels
Literature reports
1 report — tap to read
a) In a review of postmarketing data, 2 cases of serotonin toxicity were reported in the concurrent use of carbidopa/levodopa and linezolid. Postmarketing adverse events reported to the US Food and Drug Administration's Adverse Event Reporting System (AERS) database between November 1997 and September 2003 regarding serotonin toxicity with linezolid use were reviewed. A serotonin toxicity case was defined as having: (a) linezolid as the primary suspect drug, (b) concomitant administration of 1 or more secondary suspect drugs with CNS serotonergic activity, and (c) serotonin toxicity, as defined by the modified Hunter Serotonin Toxicity Criteria or by the reporter of the adverse event. A total of 29 cases were identified (age range 17 to 83 years) where linezolid was coadministered with 1 drug (n=20), with 2 drugs (n=6), and with 3 or more drugs (n=3). While SSRIs were the most common class of drugs received concomitantly with linezolid (n=26), other drug classes included tricyclic antidepressants (n=6) and atypical antidepressants (n=4). Additionally, other concurrent drugs included carbidopa/levodopa (n=2), dextromethorphan (n=1), lithium (n=1), metoclopramide (n=1), risperidone (n=1), and traMADol (n=1). Intervention including hospitalization was required in 13 patients, and 3 deaths were reported with concurrent SSRI use 1.
Common questions
Can I take Carbidopa and Linezolid Injection together?
Hypertensive crisis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Carbidopa and Linezolid Injection 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 Carbidopa 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 (5)
- Lawrence KR, Adra M, & Gillman PK: Serotonin toxicity associated with the use of linezolid: a review of postmarketing data. Clin Infect Dis 2006; 42(11):1578-1583. PubMed
- Product Information: LODOSYN(R) oral tablets, carbidopa oral tablets. Valeant Pharmaceuticals North America LLC (per FDA), Bridgewater, NJ, 2014. DailyMed
- Product Information: SINEMET(R) CR oral sustained release tablets, carbidopa levodopa oral sustained release tablets. Merck Sharp & Dohme Corp. (per DailyMed), Whitehouse Station, NJ, 2013.
- Product Information: SINEMET(R) oral tablets, carbidopa levodopa oral tablets. Merck Sharp & Dohme Corp. (per DailyMed), Whitehouse Station, NJ, 2013. DailyMed
- Product Information: PARCOPA(R) oral disintegrating tablets, carbidopa levodopa oral disintegrating tablets. Azur Pharma, Inc. (per manufacturer), Philadelphia, PA, 2011. DailyMed
Keep reading about Carbidopa
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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