Ma Huang 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
Ma Huang
No brand names on record
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 for excessive monoamine activity including headache, hyperpyrexia, arrhythmias, and hypertensive crisis
Interaction Deep Dive
Ephedrine and pseudoephedrine are the main alkaloids in Ma Huang (ephedra). The German Commission E Monograph recommends avoiding combining Ma Huang and monoamine oxidase inhibitors (MAOIs)5. Coadministration of indirect-acting sympathomimetics such as pseudoephedrine and phenylpropanolamine with MAOIs has resulted in severe hypertension 124 and one case has been reported of severe agitation, tachycardia, hypotension, and fever with concomitant use of ephedrine and a MAOI 3. Sympathomimetics with indirect/mixed activity such as ephedrine cause the release of norepinephrine. MAOIs cause more norepinephrine to be available at nerve receptor sites through inhibition of catecholamine degradation. Concurrent use of ephedrine and MAOIs leads to greater amounts of norepinephrine, which increases sympathetic activity. Patients who take MAOIs with Ma Huang may be predisposed to hypertensive crisis and other symptoms consistent with excessive sympathomimetic amine activity. Other potential reactions include cardiac arrhythmias, chest pain, hyperpyrexia, and death. Concomitant use should be avoided.
Why it happens (mechanism)
Additive sympathomimetic effect
Literature reports
3 reports — tap to read
a) A 28-year-old female ingested a Do-Do tablet containing ephedrine 18.31 milligrams (mg), caffeine 30 mg, and theophylline 100 mg for a "wheezy cough" 24 hours after discontinuing 4 weeks' treatment with phenelzine 60 mg/day. Symptoms on presentation 8 hours later were flushing, collapse, severe agitation, dilated pupils, increased muscle tone and hyperreflexia, pulse 150 beats per minute, and blood pressure 90/60 mmHg. Medical history included asthma treated with inhaled salbutamol. Diazepam was given intravenously for agitation which led to visual hallucinations and loss of coherency. Non-depolarizing muscle relaxants and mechanical ventilation were then used to control agitation and neuromuscular irritability. Fever of 39 degrees Celsius developed over the next 4 hours. Creatine kinase was elevated and myoglobin was present in urine, considered a result of rhabdomyolysis. Treatment consisted of intravenous fluids. Complications of lobar pneumonia and adult respiratory distress syndrome necessitated mechanical ventilation for 17 days; during which the patient became colonized with methicillin-resistant Staphylococcus aureus. Total hospital stay was 3 weeks 3.
b) A 24 year-old female presented with palpitations and irregular pulse which on admission was characterized as atrioventricular Wenckebach phenomenon with pulse rate 40 beats/minute. She had been taking phenelzine 45 mg/day for one year for depression. She then took one Sinutab(R) tablet (containing pseudoephedrine and acetaminophen) for sinusitis. Over 6 hours, her heart rate spontaneously reverted to sinus bradycardia (50 beats/minute), then to normal sinus rhythm 2.
c) One healthy male volunteer experienced significantly increased blood pressure following ingestion of single doses of phenylpropanolamine and tranylcypromine. Phenylpropanolamine 50 mg given after tranylcypromine 10 mg led to blood pressure of 210/140 mmHg within 2 hours, with bradycardia and an intense throbbing headache. Phentolamine 5 mg was given intramuscularly to control blood pressure. In 3 healthy male subjects with normal blood pressure (approximately 120/80 mmHg), phenylpropanolamine 50 mg given alone increased systolic blood pressure by 18 mmHg to 26 mmHg with maximum not exceeding 142 mmHg; diastolic blood pressure was unaffected. Phenylpropanolamine 100 mg given alone increased blood pressure to 157/123 mmHg, 134/123 mmHg, and 177/109 mmHg in each subject 4.
Common questions
Can I take Ma Huang and Linezolid Injection together?
Increased risk for excessive monoamine activity including headache, hyperpyrexia, arrhythmias, and hypertensive crisis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ma Huang 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 Ma Huang 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)
- Smookler S & Bermudez AJ: Hypertensive crisis resulting from an MAO inhibitor and an over-the-counter appetite suppressant. Ann Emerg Med 1982; 11:482-484. PubMed
- Terry R, Kaye AH, & McDonald M: Sinutab (letter). Med J Aust 1975; 1:763.
- Dawson JK, Earnshaw SM, & Graham CS: Dangerous monoamine oxidase interactions are still occurring in the 1990s. J Accid Emerg Med 1995; 12(1):49-51.
- Cuthbert MF, Greenberg MP, & Morley SW: Cough and cold remedies: a potential danger to patients on monoamine oxidase inhibitors. Br Med J 1969; 1(641):404-406. PubMed
- Blumenthal M, Busse WR, Goldberg A, et alBlumenthal M, Busse WR, Goldberg A, et al (Eds): The Complete German Commission E Monographs, 1st. American Botanical Council, Austin, TX, 1998, pp 125-26, 477.
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