Drug & supplement interaction

Danshen + Sildenafil Citrate

Sildenafil Citrate brand name: Viagra.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Sildenafil Citrate falls into 2 drug categories that Danshen can interact with; the most serious is rated moderate. Theoretically, danshen may increase the levels and clinical effects of drugs metabolized by CYP2C9.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Danshen and Sildenafil Citrate

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Danshen interacts with whole categories of medication. Sildenafil Citrate falls into 2 of those categories, so it can interact with Danshen in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

1 of 2

Why this applies to Sildenafil Citrate

Sildenafil Citrate falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Danshen interacts with.

Theoretically, danshen may increase the levels and clinical effects of drugs metabolized by CYP2C9.
In vitro research shows that various constituents of danshen inhibit the activity of CYP2C9. So far, 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 with Danshen and sildenafil (Viagra). Your liver uses an enzyme called CYP2C9 to help break sildenafil down. In lab dish studies, compounds in Danshen seem to slow that enzyme. If that happens in the body, sildenafil could clear out a bit more slowly and build up, which may make its effects (and side effects) stronger.

For sildenafil, that could mean more headache, facial flushing, a stuffy nose, dizziness, or a bigger drop in blood pressure. The important thing to know: this is only a theoretical concern based on lab data, and it hasn't actually been reported in people. Still, since both can affect blood vessels, it's worth a quick chat with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Wang X, Cheung CM, Lee WY, Or PM, Yeung JH. Major tanshinones of Danshen (Salvia miltiorrhiza) exhibit different modes of inhibition on human CYP1A2, CYP2C9, CYP2E1 and CYP3A4 activities in vitro. Phytomedicine. 2010 Sep;17(11):868-75. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Sildenafil Citrate also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Danshen might alter the levels and clinical effects of drugs metabolized by CYP3A4.
Preliminary clinical research in healthy males shows that the administration of danshen for 10-14 days induces intestinal CYP3A4 and increases the clearance of midazolam, a CYP3A4 substrate. The maximum concentration of midazolam was decreased by 31% to 67%, and drug levels were decreased by 27% to 80%. However, a single dose of danshen has the opposite effect, increasing maximum concentrations of midazolam by 87%.
Severity Moderate Likelihood Possible Evidence B

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 deal with sildenafil (Viagra) and danshen. Your liver and gut use an enzyme called CYP3A4 to break down sildenafil. In a small study, taking danshen for 10 to 14 days actually sped up that enzyme, which would clear sildenafil out faster. That could mean a weaker effect, so the medicine may not work as well for you.

Interestingly, a single dose of danshen seemed to do the opposite and could raise levels, which might bring more flushing, headache, or a bigger drop in blood pressure. The evidence here is fairly limited, so I wouldn't panic. Just talk with your pharmacist or doctor before pairing these, especially since danshen can also thin the blood.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Qiu F, Wang G, Zhang R, Sun J, et al. Effect of danshen extract on the activity of CYP3A4 in healthy volunteers. Br J Clin Pharmacol 2010;69:656-62. PubMed
  2. Qiu F, Jiang J, Ma Y, Wang G, Gao C, Zhang X, Zhang L, Liu S, He M, Zhu L, Ye Y, Li Q, Miao P. Opposite Effects of Single-Dose and Multidose Administration of the Ethanol Extract of Danshen on CYP3A in Healthy Volunteers. Evid Based Complement Alternat Me 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

Danshen Also Interacts With Other Medications

Danshen has 123 major, 935 moderate known drug interactions in our database — the Sildenafil Citrate one above is among them. If you take anything else, check it against the full list below.

Major 123 Moderate 935 No known interaction 1,772 (incl. Sildenafil Citrate)
Taking anything else?

Check Another of Your Medications Against Danshen

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

From our Q&A

Questions About Danshen or Sildenafil Citrate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Danshen or Sildenafil Citrate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Sildenafil Citrate

This page covers Danshen only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Sildenafil Citrate page lists 160 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Mistletoe (major), Grapefruit (major), Hawthorn (major) and St. John's Wort (major).

Open the Sildenafil Citrate interaction page

One more smart check

Taking Danshen as Part of a Dietary Supplement Product? Check It for Interactions

We hold 18 real supplement products containing Danshen, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Danshen. Your product may carry other ingredients that interact with Sildenafil Citrate too, on top of Danshen — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Danshen and Sildenafil Citrate 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 Danshen
Top half

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

29 days ago today
Medication Sildenafil Citrate
Top half

#937 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 Danshen

What is Danshen?

Danshen
  • Heart and circulation support
  • Angina (chest pain)
  • High blood pressure
  • Anxiety and stress
  • Liver health

Danshen is a root used in traditional Chinese medicine, mainly for heart and circulation problems. Some early research is promising, but the evidence is not strong enough to confirm it works for any condition, and it may affect blood clotting. Talk to a pharmacist or doctor before using it, especially if you take other medicines or have a health condition.

Read the full Danshen monograph & all interactions
Medication

About Sildenafil

What Is Sildenafil Used For?

Brand name: Viagra

Sildenafil treats two distinct conditions depending on the product. Viagra (tablet) and Vybrique (dissolving oral film) are approved for erectile dysfunction (ED) — difficulty getting or keeping an erection. Generic sildenafil tablets and oral film are also approved for ED.

Revatio and several generic sildenafil products (tablets, oral suspension, and injection) are used for pulmonary arterial hypertension (PAH) — high blood pressure in the arteries of the lungs — in adults to improve exercise ability and slow the disease from getting worse. Revatio oral suspension and injection are also approved for PAH in children ages 1 to 17.

See full Sildenafil drug information
Keep checking

Other Drugs & Danshen

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

123Major
935Moderate
0Minor
1,771No known interaction
123 Major 935 Moderate 1,771 No interaction
Major

123 interactions

Showing 60 of 123 major interactions — see all 123 on the Danshen page.

Moderate

935 interactions

Showing 60 of 935 moderate interactions — see all 935 on the Danshen page.

No interaction 1,771 drugs checked — show the list

We also checked Danshen against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,771 medications checked with no known interaction — see the full Danshen list.

See the full Danshen interactions page
See every supplement checked against Sildenafil Citrate, ranked by severity
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

Keep exploring
Danshen monograph › Uses, safety, and every drug interaction in one place Sildenafil Citrate supplement interactions › Every supplement checked against Sildenafil Citrate, ranked by severity Sildenafil drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Danshen and Sildenafil Citrate Together: Common Questions

Can you take Danshen with Sildenafil Citrate?
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 2 interactions listed for Danshen and Sildenafil Citrate?
Sildenafil Citrate belongs to more than one drug category, and Danshen 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 Danshen and Sildenafil Citrate 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

Still Have a Question About Sildenafil Citrate and Danshen?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.