The short answer
Do not self-start Scotch broom while taking isocarboxazid. Cytisus scoparius can contain tyramine, and Marplan warns that high-tyramine exposure can cause dangerous blood-pressure reactions. The evidence is indirect and does not quantify risk from a particular broom product.
What this answer covers
Oral Cytisus scoparius preparations containing tyramine. Plant part and extraction matter; other broom species and purified alkaloids are distinct exposures.
- Supplement or preparation
- Cytisus scoparius
- Medication ingredient
- isocarboxazid
Why the plant raises concern
An original chemistry study identified tyramine in Cytisus scoparius and found that alkaloid composition differed between plant parts. Marplan has caused hypertensive crises after high-tyramine food exposure; applying that warning to a tyramine-containing botanical is an indirect precaution.
What remains unknown
The available abstract does not establish how much tyramine a commercial capsule or tea delivers. No direct isocarboxazid and Scotch broom trial was identified. This uncertainty prevents a reliable safe-dose recommendation.
Before taking Scotch broom
Ask your prescriber or pharmacist to review the botanical species, plant part, extract and dose. Do not assume a product is safe because it is herbal or because it is taken several hours after Marplan.
Recognizing a serious reaction
Seek urgent medical attention for severe sudden headache, palpitations, chest pain, sweating or neck stiffness. Continue your prescribed Marplan food restrictions and do not change the medication without your prescriber.
Evidence and practical considerations
Side effects & toxicity
Do not self-start Scotch broom while taking isocarboxazid. Cytisus scoparius can contain tyramine, and Marplan warns that high-tyramine exposure can cause dangerous blood-pressure reactions. The evidence is indirect and does not quantify risk from a particular broom product.
- Exact scope
- Oral Cytisus scoparius preparations containing tyramine. Plant part and extraction matter; other broom species and purified alkaloids are distinct exposures. with isocarboxazid, RxCUI 6011 IN; oral MARPLAN tablets.
- Medication form and route
- Oral isocarboxazid; oral supplement
What remains uncertain
- Tyramine was identified in a plant chemistry study, but the abstract does not quantify commercial-product exposure. Applying Marplan's tyramine warning is an indirect precaution; an exact-pair clinical event and a safe botanical dose have not been established.
Factors that may matter: Exact product composition and dose; Other medicines and supplements.
Read the supporting source summaries
Source 1: Current U.S. prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral isocarboxazid tablets.
Phenylalanine is named among substances that may precipitate hypertension and headache. Sympathomimetics, some CNS depressants and excessive caffeine are contraindicated. The label describes high-tyramine hypertensive crises and warns about drowsiness, hypotension and impaired driving.
How this applies: Exact isocarboxazid authority. Botanical applicability must be assessed from the relevant constituent or sedating effect rather than a botanical name alone.
The label does not quantify these botanical pair risks or give a universally safe supplement dose.
Source 2: Original phytochemical study
sciencedirect.com · Source check Sep 10, 2026
Population: Plant samples, not human participants.
Tyramine was isolated with alkaloids; composition varied considerably between the examined plant parts.
How this applies: Constituent evidence for a conditional tyramine-based concern; not a statement that every broom preparation has the same amount.
Full paper inaccessible in this session. The abstract supplies neither a clinical dose nor a tested isocarboxazid interaction.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Sources checked and article drafted. | |
| Clarified the distinction between the original dataset statement and the narrower source-supported precaution, and edited evidence limitations for readers. | |
| Research summary published |
Article revision: 7661dc85fcb77b05
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.