The short answer
There is not enough human evidence to say Capsicum annuum extract raises theophylline levels. Animal results should not be used to change your dose.
What this answer covers
Capsicum annuum extract; ground capsicum fruit, isolated capsaicin and black pepper piperine are not equivalent.
- Supplement or preparation
- Capsicum Annuum Extract
- Medication ingredient
- theophylline
Where the claim comes from
In rabbits, ground capsicum fruit increased exposure to an oral sustained-release theophylline capsule. This was not a study of people taking the extract listed here.
The contrary findings matter
Capsaicin pretreatment did not significantly change intravenous theophylline pharmacokinetics in rats. Another rabbit study found no significant overall exposure change with intravenous drug. These different experiments cannot settle the human oral question.
Keep pepper identities distinct
Capsicum fruit and its capsaicin are different from black pepper and isolated piperine. Results from one should not be used as dosing instructions for the other. Bring the botanical name and extract ingredients to a pharmacist.
Use a monitored plan
Keep theophylline dosing and formulation consistent with your prescription. Tell the prescriber about supplement starts, stops and dose changes. Separating products by a few hours has not been shown to prevent changes in drug clearance, and a study dose is not a recommended supplement dose.
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
Absorption & effectiveness
The current claim of increased human absorption or exposure is not established. An oral rabbit experiment found increased exposure, while intravenous rat and rabbit studies had largely null overall pharmacokinetic findings.
- Exact scope
- Capsicum annuum extract; ground capsicum fruit, isolated capsaicin and black pepper piperine are not equivalent. 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 exact human extract study identified. Species, preparation and administration route prevent direct translation.
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 animal study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Ten male rabbits.
Higher AUC and peak concentrations; a second fruit suspension dose caused another concentration rise.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
Animal study and ground fruit, not human Capsicum annuum extract; cannot establish human absorption interaction.
Source 4: original animal study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Rats.
No significant effect on theophylline pharmacokinetics, although antipyrine clearance changed.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
Different species, isolated capsaicin and intravenous route; cannot disprove an oral extract interaction in people.
Source 5: original animal study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Male rabbits in three groups.
No significant AUC, clearance or half-life change; some elimination/metabolite measures changed.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
Different route and animal preparation; urinary metabolite changes do not prove raised human oral drug exposure.
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: 9e475fe29b382deb
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.