The short answer
Do not take ephedra (ma huang) with linezolid. Linezolid enhances the blood pressure effect of ephedrine-type stimulants, and a reversible MAO inhibitor of the same type roughly tripled ephedrine's blood pressure effect in healthy volunteers. The documented risk is a dangerous rise in blood pressure and heart symptoms; serotonin syndrome from this pair has not been shown.
What this answer covers
Ephedra herb (Herba Ephedrae, ma huang) preparations that contain ephedrine alkaloids, with linezolid by any route. Such supplements are banned in the United States, but imported or traditional preparations may still contain them.
- Supplement or preparation
- ephedra (ma huang)
- Medication ingredient
- linezolid
What the label establishes
Linezolid reversibly enhanced the blood pressure response to pseudoephedrine and phenylpropanolamine, two indirect-acting stimulants, in healthy volunteers. The label says linezolid should not be given to people using sympathomimetic agents unless blood pressure is monitored. Ephedrine, the main alkaloid in ephedra, acts the same way.
How large the effect can be
With moclobemide, a reversible MAO inhibitor that the linezolid label uses as its comparator, ephedrine raised systolic pressure about three times as much and diastolic pressure almost four times as much as ephedrine alone, with more palpitations and headache. Ephedra herb delivers ephedrine alkaloids in amounts that vary by product.
Ephedra carries its own risk
The FDA banned ephedrine-alkaloid supplements in 2004 because of high blood pressure, heart attack, stroke, seizure and psychosis reports, some at low doses. Adding an MAO inhibitor removes a safety margin that is already thin.
Serotonin syndrome was not demonstrated
The imported statement also mentions serotonin syndrome. None of the inspected sources reports serotonin syndrome from ephedra with an MAO inhibitor; the established hazard is a pressor crisis. Seek urgent care for severe headache, chest pain, pounding heartbeat or a very high blood pressure reading.
Evidence and practical considerations
Side effects & toxicity
Ephedrine alkaloids in ephedra are indirect sympathomimetics whose pressor effect linezolid-type MAO inhibition enhances; co-use risks a hypertensive reaction. Serotonin syndrome is not established by the inspected sources.
- Exact scope
- Ephedra herb preparations containing ephedrine alkaloids; ephedrine-free products are outside this finding. with Linezolid tablets, oral suspension and intravenous injection (ZYVOX and generics); the reversible, nonselective MAO inhibition is a property of the drug at all routes.
- Medication form and route
- oral medication; intravenous medication; oral supplement
What remains uncertain
- No ephedra or ephedrine study with linezolid itself; the quantitative interaction comes from moclobemide; alkaloid content of herb products varies.
Factors that may matter: Ephedrine alkaloid content; Existing high blood pressure or heart disease; Other stimulants or decongestants; Dose.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 22, 2026
Population: People prescribed linezolid
Linezolid reversibly enhanced the pressor response to pseudoephedrine and phenylpropanolamine in normotensive volunteers; the label says linezolid should not be given with sympathomimetic agents, uncontrolled hypertension, pheochromocytoma or thyrotoxicosis unless blood pressure is monitored. No similar study was done in hypertensive patients.
How this applies: Exact linezolid (RxCUI 190376) at every marketed route; the label names tyramine, pseudoephedrine, phenylpropanolamine and serotonergic agents, not the supplements assessed here.
Ephedrine and ephedra are not named; the studied agents are the closest labelled comparators. The label does not describe serotonin syndrome with stimulants.
Source 2: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 22, 2026
Population: Twelve healthy adults aged 19 to 36.
Moclobemide, a reversible MAO-A inhibitor, potentiated ephedrine's systolic pressure effect by a median factor of 3.2 and diastolic by 3.8, and increased palpitations and headache; no subject withdrew.
How this applies: Shows the size of the pressor interaction between purified ephedrine and a reversible MAO inhibitor of the same type; ephedra herb contains ephedrine alkaloids in variable amounts.
Moclobemide is not linezolid, although the linezolid label compares its MAO inhibition to moclobemide; small volunteer study read as an abstract.
Source 3: federal supplement safety guidance
nccih.nih.gov · Source check Sep 22, 2026
Population: General consumer population; no medication co-use data
The FDA banned dietary supplements containing ephedrine alkaloids in 2004; ephedra has been linked to high blood pressure, heart attack, seizure, stroke and psychosis even at low doses, and there are theoretical reasons to suspect interaction with other stimulants.
How this applies: Establishes identity (ephedrine alkaloids from Ephedra sinica and related plants), the US ban and the herb's intrinsic cardiovascular risk.
Consumer summary; it does not address linezolid or MAO inhibitors and reports no serotonin syndrome cases.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Article prepared | |
| Prepared exact linezolid and Herba Ephedrae article from inspected current labeling and original sources, with uncertainty stated. |
Article revision: 825e442f175a9e75
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.