Article
St Johns Wort Interactions: The Long List of Medicines, in Plain Words
St johns wort interactions are numerous because the herb speeds up liver enzymes that break down many medicines. It can weaken birth control pills, warfarin, cyclosporine and some HIV drugs, and cause serious serotonin effects with certain antidepressants. St. John's wort is one of six names listed for MemoPryl.
Prepared by the MemoPryl label deskUpdated · 4 min read
The list01
What are the main st johns wort interactions?
The main st johns wort interactions are weaker medicines and, with some antidepressants, a dangerous rise in serotonin. NIH calls the overall interaction risk high (NCCIH, herb-drug interactions).
Keep taking prescribed medicine and ask your doctor or pharmacist before starting it.
| Medicine | What can happen |
|---|---|
| Birth control pills | Weaker effect (NCCIH, St. John's wort in depth) |
| Warfarin | Weaker effect (NCCIH, herb-drug interactions) |
| Cyclosporine | Weaker effect (NCCIH, herb-drug interactions) |
| Some HIV drugs | Weaker effect (NCCIH, St. John's wort in depth) |
| Digoxin, oxycodone | Weaker effect (NCCIH, St. John's wort in depth) |
| Some antidepressants | Serotonin rise (NCCIH, St. John's wort in depth) |
Why02
Why does it interact with so many medicines?
It is a strong inducer of liver enzymes and a gut transporter, so many medicines are cleared faster. Faster clearing means less medicine in the blood (NCCIH, herb-drug interactions).
Before you start03
How can you check for an interaction?
Check by listing every medicine and showing the list with the bottle to a pharmacist. Serotonin signs include agitation, fast heartbeat and fever; they need urgent care (NCCIH, St. John's wort in depth).
- 01
Read the bottle first
This site has no Supplement Facts panel. When the bottle arrives, read its serving size, every ingredient name and the warnings before the first capsule.
- 02
Match it to the six names
The brief names phosphatidylserine, ginkgo, N-Acetyl L-Carnitine, St. John's wort, bacopa and L-glutamine. If your panel lists other ingredients, it is a different formula.
- 03
Show it to your pharmacist
Put the bottle next to your medicine list. St. John's wort and ginkgo are the two names that most often matter.
- 04
Note a start date and check in
Write down the date and how you feel about memory and focus. If the signs of memory trouble grow, see a doctor instead of waiting out a bottle.
Next step04
Is it on the MemoPryl name list?
Yes, six names are listed and St. John's wort is one. Its amount is not published.
The price shows at checkout if you look; ask first.
FAQ05
Interaction questions
Does St. John's wort make birth control fail?
It can weaken birth control pills (NCCIH, St. John's wort in depth). If you use them, ask your prescriber about backup options before taking the herb, and keep taking your pill as directed.
Can you take St. John's wort with an antidepressant?
Not without the prescriber's approval. Mixing it with certain antidepressants can cause a life-threatening rise in serotonin (NCCIH, St. John's wort in depth). Keep taking your prescription and never stop it on your own.
How long do interactions last after stopping the herb?
Our sources do not give a time. Ask a pharmacist before you stop or restart anything, especially if you take warfarin or a transplant drug.
Who wrote this06
Written and reviewed by
Pages built from the label, the official site, the sales page and linked NIH, FDA, FTC and peer-reviewed sources.
Last updated . Find our editorial standards and how we check reviews. This website is run by a U.S. order-link partner, not by the maker of MemoPryl. This site earns a commission when you buy through our order links.
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