Capsaicin and Theophylline: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Theophylline
Capsaicin
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 theophylline absorption, and increased risk of theophylline toxicity
Interaction Deep Dive
An animal study suggests increased absorption of theophylline may occur if coadministered with, or given prior to, capsaicin1. It is unknown if the amount of capsaicin absorbed from common topical preparations is significant enough to interact with theophylline. Large amounts of dietary red pepper may potentially lead to an interaction. Concomitant use of capsaicin and theophylline should be undertaken with caution. Theophylline levels and signs and symptoms of theophylline toxicity should be monitored closely if these agents are administered concomitantly.
Why it happens (mechanism)
Active ingredient of capsaicin (8-methyl-N-vanillyl-6-nonenamide) may increase mesenteric blood flow due to cholinergic action and thereby increase bioavailability of theophylline
Literature reports
1 report — tap to read
a) In 10 male rabbits administered oral theophylline 20 mg/kg with and without a 10 percent capsicum fruit suspension of equal volume (5 mL/kg volume of water), theophylline pharmacokinetics were altered. Area under the curve (AUC) increased from 86.06 +/- 9.78 mg x hour/L to 138.32 +/- 17.26 mg x hour/L (p less than 0.001) when capsicum fruit suspension was administered. Similarly, peak plasma levels increased from 6.65 +/- 0.76 to 8.78 +/- 0.98 mg/L (p less than 0.01) and mean residence time increased from 14.94 +/- 2.97 hours to 20.98 +/- 5.75 hours (p less than 0.001). When a second dose of capsicum suspension was given 11 hours after theophylline, plasma theophylline levels were again increased. The authors attribute this finding to increased mesenteric blood flow secondary to the active ingredient of capsaicin (8-methyl-N-vanillyl-6-noneamide) 1.
Common questions
Can I take Capsaicin and Theophylline together?
Increased theophylline absorption, and increased risk of theophylline toxicity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Capsaicin and Theophylline interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
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 Capsaicin or Theophylline 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 anything you'd monitor while I'm on both?
References (1)
- Bouraoui A, Toumi A, Mustapha HG, et al: Effects of capsicum fruit on theophylline absorption and bioavailability in rabbits. Drug Nutrient Interactions 1988; 5(4):345-350.
Keep reading about Theophylline
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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