The short answer
Avoid self-starting an ephedrine-containing Ephedra product with theophylline. Pharmaceutical ephedrine combinations caused more unwanted effects in a clinical trial.
What this answer covers
Ephedra sinica; ephedrine alkaloid content and plant preparation must be verified. Pharmaceutical ephedrine is indirect botanical evidence.
- Supplement or preparation
- Ephedra sinica
- Medication ingredient
- theophylline
What was actually tested
Children taking individualized theophylline doses had more insomnia, nervousness and stomach complaints when pharmaceutical ephedrine was added. The combination did not provide significant extra asthma control. This was not a trial of whole Ephedra sinica.
Why the herb needs extra caution
Ephedra products containing ephedrine alkaloids have been linked to serious cardiovascular and nervous system events. Reports cannot tell us how often these events occur with theophylline, but they strengthen the reason to avoid unsupervised combination use.
A clock gap is not protection
The theophylline label describes overlapping central nervous system effects with ephedrine. It does not provide a supplement separation interval that makes this combination safe.
Recognize possible toxicity
Contact the prescriber promptly for repeated nausea or vomiting, new insomnia or tremor after a product change. A seizure, fainting or a sustained rapid or irregular heartbeat needs urgent assessment. A blood theophylline measurement may be needed; symptoms alone cannot determine the level.
Evidence and practical considerations
Side effects & toxicity
The labeled ephedrine interaction and original trial support caution for ephedrine-containing Ephedra, especially stimulation and gastrointestinal effects. Botanical reports support independent cardiovascular/seizure concern, but no exact-pair QT, arrhythmia or seizure rate is established.
- Exact scope
- Ephedra sinica; ephedrine alkaloid content and plant preparation must be verified. Pharmaceutical ephedrine is indirect botanical evidence. with Exact theophylline anhydrous extended-release tablets and oral solution. Exact RxNorm IN10438. Oral anhydrous theophylline formulations distinguished; intravenous and aminophylline study exposures are identified separately.
- Medication form and route
- oral
- Timing or duration
- Source-specific single-dose, repeated-dose and observational exposures distinguished.
What remains uncertain
- No validated timing interval. Whole-herb alkaloid amounts are uncertain; ephedrine-free products cannot automatically be treated as equivalent.
Factors that may matter: preparation and plant part; clinical indication; dose; other medicines; baseline alertness.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed theophylline.
Variable clearance, narrow therapeutic range and serum concentration monitoring; toxicity can include arrhythmias and seizures; label specifically warns about St John’s wort and ephedrine.
How this applies: Exact RxNorm IN10438. Oral anhydrous theophylline formulations distinguished; intravenous and aminophylline study exposures are identified separately.
No universal supplement dose, interval, event rate or untested formulation equivalence.
Source 2: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed theophylline.
Variable clearance, narrow therapeutic range and serum concentration monitoring; toxicity can include arrhythmias and seizures; label specifically warns about St John’s wort and ephedrine.
How this applies: Exact RxNorm IN10438. Oral anhydrous theophylline formulations distinguished; intravenous and aminophylline study exposures are identified separately.
No universal supplement dose, interval, event rate or untested formulation equivalence.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Twenty-three children with chronic asthma in double-blind randomized treatment periods.
Combination periods caused insomnia, nervousness and gastrointestinal complaints without significant extra efficacy.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
Ephedrine medicine, not whole Ephedra sinica; no precise botanical alkaloid dose, QT prolongation or seizure risk estimate.
Source 4: official botanical guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: People considering Ephedra sinica products.
Serious cardiovascular and psychiatric adverse effects reported, including with low-dose or short-term exposure; US ephedrine-alkaloid dietary supplements banned.
How this applies: Only the studied preparation, route and measured endpoints apply; no untested respiratory medication transfer.
Not an theophylline co-use study or a population-specific incidence estimate.
Source 5: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 140 adverse-event reports submitted to FDA.
Reports judged related or possibly related included cardiovascular and CNS events, some fatal or disabling.
How this applies: Only the studied preparation, route and measured endpoints apply; no untested respiratory medication transfer.
Selected reports without an exposed-user denominator cannot establish frequency; no theophylline coexposure.
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 | |
| Current exact available claims adjudicated using original captures and explicit identity and comparator limits. |
Article revision: a0a82b4aca73d8c9
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.