The short answer
Do not add St John's wort to methamphetamine treatment without your prescriber's review. The current methamphetamine label specifically warns about serotonin syndrome with St John's wort. Taking them at different times has not been shown to prevent it.
What this answer covers
Oral Hypericum perforatum supplements with prescribed oral methamphetamine hydrochloride; product-specific risk size is unknown.
- Supplement or preparation
- Hypericum perforatum
- Medication ingredient
- methamphetamine
This herb is named in the medication warning
The methamphetamine label specifically includes St John's wort among products that can increase serotonin-syndrome risk when combined with the medicine. This is stronger support than a general assumption about herbal products.
Have the prescriber review starting or stopping
Tell the prescriber why you want St John's wort, the product strength and your other medicines. If combined treatment is clinically necessary, the label calls for prescriber-led dosing and monitoring, especially when treatment starts or doses increase.
Spacing is not a substitute for review
The label does not provide an interval that makes the combination safe. Its separate fourteen-day rule concerns MAOI medicines and should not be automatically applied to this herb.
Recognize a potentially urgent reaction
Seek urgent medical care for a combination of agitation or confusion, fever or heavy sweating, rapid heartbeat, and tremor or muscle stiffness. These can be signs of serotonin syndrome, particularly after starting or increasing a serotonergic product.
Evidence and practical considerations
Side effects & toxicity
The exact medication label supports a serotonin-syndrome precaution and clinician-managed co-use, not a protective spacing interval.
- Exact scope
- Oral Hypericum perforatum supplements with prescribed oral methamphetamine hydrochloride; product-specific risk size is unknown. with Prescribed oral S-methamphetamine hydrochloride; RxNorm 6816 IN and label section 11 establish active-moiety relationship, not dose or stereoisomer interchangeability.
- Medication form and route
- oral
- Timing or duration
- Dose, pattern of use and preparation matter; no universal protective spacing interval established.
What remains uncertain
- Regulatory warning names the herb but provides no exact-pair event rate or preparation-specific safe dose.
Factors that may matter: exact product; other medicines; prescribed dose; baseline cardiovascular or serotonergic risk.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed oral methamphetamine hydrochloride tablets.
Sections 2.4 and 7.1 identify acidifying agents such as ascorbic acid as lowering levels and alkalinizing agents such as sodium bicarbonate as increasing levels; avoid gastrointestinal and urinary alkalinizing co-use. Sections 5.8 and 7.1 warn about serotonin syndrome with serotonergic agents, specifically including tryptophan and St Johns wort. Section 5.3 calls for blood-pressure and pulse monitoring.
How this applies: RxNorm 6816 IN maps to this SPL, and description confirms active ingredient salt relationship. Applies to prescribed oral S-methamphetamine hydrochloride, not other stimulants or unapproved routes.
Regulatory guidance is not a quantified trial for every named pair. No one-hour supplement spacing instruction. General amphetamine language is explicitly incorporated in this exact methamphetamine product label.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Current available claims adjudicated from inspected sources; no clinical review asserted. | |
| Research summary published |
Article revision: 81267b0aa562a567
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.