Drug & supplement interaction

Thunder God Vine + Ethinyl Estradiol, Norethindrone

Ethinyl Estradiol, Norethindrone brand names: Femhrt, Loestrin 21, Ovcon 35 21, Ovcon 50 28, Necon 0.5 35 21, and others.

Moderate Interaction
The bottom line Moderate

Ethinyl Estradiol, Norethindrone falls into 3 drug categories that Thunder God Vine can interact with; the most serious is rated moderate. Theoretically, thunder god vine might increase the levels and clinical effects of CYP1A2 substrates.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions3
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Thunder God Vine and Ethinyl Estradiol, Norethindrone

These two interact in 3 distinct ways. Each one is explained separately below.

Why Are There 3 Interactions?

Thunder God Vine interacts with whole categories of medication. Ethinyl Estradiol, Norethindrone falls into 3 of those categories, so it can interact with Thunder God Vine in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 3

Why this applies to Ethinyl Estradiol, Norethindrone

Ethinyl Estradiol, Norethindrone falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Thunder God Vine interacts with.

Theoretically, thunder god vine might increase the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that triptolide, a constituent of thunder god vine, inhibits CYP1A2 enzymes in human microsomes. This interaction has not been reported in humans.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist for your birth control pill (ethinyl estradiol with norethindrone). One compound in Thunder God Vine, called triptolide, appears to slow down a liver enzyme called CYP1A2 in lab dishes. Your body uses that enzyme to help clear the estrogen part of your pill. If it's slowed, estrogen levels could theoretically creep up a bit, which might mean more estrogen-type side effects like nausea, breast tenderness, headaches, or bloating.

I want to be honest about how soft this evidence is. It comes only from test-tube studies, and it has never actually been reported in real people. Still, since Thunder God Vine can be toxic and needs medical oversight anyway, please loop in your doctor or pharmacist before pairing these two.

References
  1. Song W, Liu M, Wu J, Zhai H, Chen Y, Peng Z. Preclinical Pharmacokinetics of Triptolide: A Potential Antitumor Drug. Curr Drug Metab. 2019;20(2):147-154. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS

2 of 3

Ethinyl Estradiol, Norethindrone also falls under CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS.

Theoretically, CYP3A4 inhibitors might increase the levels and adverse effects of thunder god vine constituents.
Inhibitors of CYP3A4 can increase the concentration of triptolide, a thunder god vine constituent, and its derivative (5R)-5-hydroxytriptolide. In vitro research shows that triptolide and (5R)-5-hydroxytriptolide are about 94% and 64% metabolized by CYP3A4, respectively.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the angle that matters with this pair. Your birth control pill, the ethinyl estradiol and norethindrone combo, mildly blocks the liver enzyme CYP3A4. Thunder God Vine's active compounds (triptolide and a related form) are cleared mainly by that same enzyme. So in theory, the pill could slow how fast your body breaks down the herb, letting it build up and raising the risk of its side effects, which can be serious (liver stress, stomach upset, and more).

Important: this is a theoretical concern based on lab and pharmacology data, not real-world patient reports, so I don't want to alarm you. Still, Thunder God Vine is potent and should only be used with medical supervision. Please loop in your doctor or pharmacist before combining them.

References
  1. Xu Y, Zhang YF, Chen XY, Zhong DF. CYP3A4 inducer and inhibitor strongly affect the pharmacokinetics of triptolide and its derivative in rats. Acta Pharmacol Sin. 2018;39(8):1386-1392. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 3

Ethinyl Estradiol, Norethindrone also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, thunder god vine might increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that triptolide, a constituent of thunder god vine, inhibits CYP3A4 enzymes in human microsomes. This interaction has not been reported in humans.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the basic idea with your birth control pill (the ethinyl estradiol and norethindrone combo). Your liver uses an enzyme called CYP3A4 to clear these hormones from your body. In a lab dish, one compound in Thunder God Vine (triptolide) appears to slow that enzyme down. If that happened in real life, the hormones could build up a bit, which might mean more estrogen-type side effects like nausea, breast tenderness, bloating, or headaches.

I want to be honest though: this is purely theoretical. It has only been seen in test tubes, never reported in actual people, so I wouldn't lose sleep over it. The bigger concern with Thunder God Vine is its own toxicity. Please only use it under a doctor's care, and let your pharmacist know you're taking both.

References
  1. Song W, Liu M, Wu J, Zhai H, Chen Y, Peng Z. Preclinical Pharmacokinetics of Triptolide: A Potential Antitumor Drug. Curr Drug Metab. 2019;20(2):147-154. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Thunder God Vine Also Interacts With Other Medications

Thunder God Vine has 848 moderate known drug interactions in our database — the Ethinyl Estradiol, Norethindrone one above is among them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Thunder God Vine

Covers the 2,830 medications we’ve checked against Thunder God Vine. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Ethinyl Estradiol, Norethindrone

This page covers Thunder God Vine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Ethinyl Estradiol, Norethindrone page lists 240 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 196 moderate · 38 minor.

From our pharmacist’s overview on the Ethinyl Estradiol, Norethindrone page

“If you take a birth control pill or hormone therapy containing ethinyl estradiol and norethindrone (Loestrin, Femhrt, and others), a few supplements can genuinely undermine it, so read this page with care. Six of the 240 ingredients on file are rated major, and those six come first.”

Reviewed by 2 · Jul 18, 2026

Open the Ethinyl Estradiol, Norethindrone interaction page

How much people look this up

Where Thunder God Vine and Ethinyl Estradiol, Norethindrone Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Thunder God Vine
Steady interest

#1,057 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Ethinyl Estradiol, Norethindrone
Top 10%

#231 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Thunder God Vine

What is Thunder God Vine?

Thunder God Vine
  • Rheumatoid arthritis
  • Lupus and autoimmune conditions
  • Inflammation
  • Skin conditions like psoriasis
  • Immune-related disorders

Thunder God Vine is a Chinese herb studied mainly for rheumatoid arthritis and other autoimmune conditions, with some promising but limited evidence. It can be toxic if prepared or dosed improperly, and may cause serious side effects, so it should only be used under medical supervision. Avoid it during pregnancy and breastfeeding.

Read the full Thunder God Vine monograph & all interactions
Keep checking

Other Drugs & Thunder God Vine

Browse every other medication we’ve checked against Thunder God Vine — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
848Moderate
0Minor
1,981No known interaction
Moderate

848 interactions

Showing 60 of 848 moderate interactions — see all 848 on the Thunder God Vine page.

No interaction 1,981 drugs checked — show the list
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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Pharmacist Counseling Corner

Taking Thunder God Vine and Ethinyl Estradiol, Norethindrone Together: Common Questions

Can you take Thunder God Vine with Ethinyl Estradiol, Norethindrone?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 3 interactions listed for Thunder God Vine and Ethinyl Estradiol, Norethindrone?
Ethinyl Estradiol, Norethindrone belongs to more than one drug category, and Thunder God Vine interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Thunder God Vine and Ethinyl Estradiol, Norethindrone interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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