The short answer
Ephedrine-alkaloid supplements can raise blood pressure and cause serious stimulant-related harm, making them a poor choice during enalapril treatment. Evidence does not establish that enalapril specifically increases ephedra toxicity or causes an additional QT-prolongation interaction.
What this answer covers
Oral Ephedra sinica aerial-part preparations containing ephedrine alkaloids, including powdered ma-huang. Mixed supplements, alkaloid-free products, other Ephedra species and prescription ephedrine are not interchangeable.
- Supplement or preparation
- ephedra (ma-huang)
- Medication ingredient
- enalapril
Why can ephedra work against blood-pressure treatment?
Ephedra can deliver stimulant alkaloids, while enalapril is prescribed to lower blood pressure or treat heart disease. Their opposing effects are a reason for caution. A small study in healthy adults found increased heart rate in some participants and variable blood-pressure responses; it did not test enalapril or show a predictable size of interaction.
Is the heart-rhythm claim proven?
An enalapril-specific QT or arrhythmia interaction has not been established. One small trial tested a product containing more than 30 ingredients, including ephedra and caffeine. It found no average QT or blood-pressure difference from placebo, although one participant had a large QT change. That result cannot isolate ephedra or prove that enalapril adds to the risk.
Does the exact product matter?
The human ma-huang study used powdered Ephedra sinica with measured ephedrine, pseudoephedrine and methylephedrine. A different extract, a mixed weight-loss supplement and an alkaloid-free product can have very different contents. The safety warning here concerns ephedrine-alkaloid exposure; it does not apply equally to every product labeled ephedra.
Can I make co-use safer by separating the doses?
No effective spacing schedule was found for this combination. The concern is stimulant activity and cardiovascular harm, not a demonstrated absorption problem that a short gap solves. US dietary supplements containing ephedrine alkaloids were banned for serious safety risks. Avoid self-starting such products and have your pharmacist review any ma-huang preparation you already use.
Evidence and practical considerations
Side effects & toxicity
Ephedrine-alkaloid supplements pose established cardiovascular and stimulant risks that are relevant to an enalapril user, but the incremental pair-specific risk is unknown.
- Exact scope
- Oral Ephedra sinica aerial-part preparations containing ephedrine alkaloids, including powdered ma-huang. Mixed supplements, alkaloid-free products, other Ephedra species and prescription ephedrine are not interchangeable. with Enalapril, exact RxCUI 3827, inventory name enalapril, TTY IN. The inspected enalapril maleate label explicitly identifies the maleate salt of enalapril and its hydrolysis to enalaprilat. This is the salt-to-IN bridge for oral tablets and solution. The solution label also includes tablet clinical data. Do not transfer these conclusions to injected enalaprilat, combination products, or other ACE inhibitors without a separate rationale.
- Medication form and route
- oral
- Timing or duration
- Harm has been reported even with short exposure; no safe co-use interval established.
What remains uncertain
- Government safety information and a small herb-only study support the botanical hazard. Opposition to enalapril blood-pressure control is an explicit physiologic inference, not class-member transfer or measured pharmacokinetics.
Factors that may matter: ephedrine alkaloid content; caffeine or other stimulants; hypertension or heart disease.
Read the supporting source summaries
Source 1: government safety information
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of ephedra-containing products; government safety summary rather than a new cohort.
Describes serious cardiovascular and stimulant harms, including high blood pressure. Notes the 2004 US ban on dietary supplements containing ephedrine alkaloids, and limited subsequent human research.
How this applies: Supports a safety-based recommendation against ephedrine-alkaloid dietary supplements in an enalapril user. Blood-pressure opposition is physiologic inference, not a measured enalapril concentration change.
Does not establish an enalapril-specific interaction, quantify individual risk or show that an alkaloid-free product has the same effects.
Source 2: primary human pharmacokinetic and cardiovascular study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Twelve healthy, normotensive adults.
Six participants had a statistically significant heart-rate increase; blood-pressure effects varied. The herb delivered measurable ephedrine with slower absorption than historical immediate-release ephedrine tablets.
How this applies: Direct evidence about one E. sinica oral preparation, not proof of an enalapril interaction or every Herba Ephedrae product.
Small, short exposure study with no enalapril and no hypertensive cohort. Only the abstract was accessible; full methods and participant-level outcomes were not inspected.
Source 3: regulatory prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral enalapril for hypertension, heart failure or asymptomatic left ventricular dysfunction.
Warns that volume or salt depletion can produce excessive hypotension and renal consequences. Serum potassium should be monitored. Potassium supplements can cause hyperkalemia. Describes the maleate salt and conversion to enalaprilat.
How this applies: Applies to oral enalapril through the explicit maleate-to-enalapril bridge. Physiologic susceptibility is relevant when a botanical causes fluid loss or opposes blood-pressure control; this is an explicit clinical inference.
No named botanical interaction is measured. These medication-specific warnings establish susceptibility and monitoring context, not the incidence or magnitude of any botanical interaction.
Research assessment: · Open full citations ↗
Side effects & toxicity
The specific claim that enalapril plus Herba Ephedrae causes QT prolongation is not established by the inspected human evidence.
- Exact scope
- Oral Ephedra sinica aerial-part preparations containing ephedrine alkaloids, including powdered ma-huang. Mixed supplements, alkaloid-free products, other Ephedra species and prescription ephedrine are not interchangeable. with Enalapril, exact RxCUI 3827, inventory name enalapril, TTY IN. The inspected enalapril maleate label explicitly identifies the maleate salt of enalapril and its hydrolysis to enalaprilat. This is the salt-to-IN bridge for oral tablets and solution. The solution label also includes tablet clinical data. Do not transfer these conclusions to injected enalaprilat, combination products, or other ACE inhibitors without a separate rationale.
- Medication form and route
- oral
- Timing or duration
- Caron studied seven-day exposure only.
What remains uncertain
- The QT study used a multi-ingredient product without enalapril and showed no group effect, with one individual signal. It neither proves this exact interaction nor rules out rare harm.
Factors that may matter: mixed product composition; limited sample size.
Read the supporting source summaries
Source 1: primary randomized human crossover study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Thirteen healthy volunteers, eight men and five women.
No group difference in QTc or systolic blood pressure. One participant had a 96 millisecond QTc increase during the supplement phase; the authors called for further study.
How this applies: Indirect evidence used to reject an unqualified enalapril plus Herba Ephedrae QT-prolongation claim. It does not overturn the broader safety concerns about ephedrine alkaloids.
A multi-ingredient product cannot isolate ephedra. Small sample, short follow-up and abstract-only access. No enalapril was studied; an isolated QT change does not establish pair-induced arrhythmia.
Source 2: government safety information
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of ephedra-containing products; government safety summary rather than a new cohort.
Describes serious cardiovascular and stimulant harms, including high blood pressure. Notes the 2004 US ban on dietary supplements containing ephedrine alkaloids, and limited subsequent human research.
How this applies: Supports a safety-based recommendation against ephedrine-alkaloid dietary supplements in an enalapril user. Blood-pressure opposition is physiologic inference, not a measured enalapril concentration change.
Does not establish an enalapril-specific interaction, quantify individual risk or show that an alkaloid-free product has the same effects.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Original evidence and current official source documents inspected. Article distinguishes measured findings, preparation limits and remaining uncertainty. | |
| Research summary published |
Article revision: c0487f2c5dd77afd
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.