Herb & supplement monograph

Passion Flower Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Passion Flower interacts with medications. The heart of this page is the interaction list — every drug Passion Flower is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Passion Flower is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Passion Flower Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Passion Flower drug interaction appears low for most people. None of the listed interactions are rated major, and the great majority are minor, with the rest moderate and supported by limited evidence.

Interactions deserving the most attention

The combination that deserves the most attention is passion flower with sedative medications, sometimes called CNS depressants, such as lorazepam. Passion flower has shown calming, sedative effects in both animal and human research, so taking it alongside these medicines could add to drowsiness or slowed thinking. This is the only moderate concern in the profile, and even here the documentation is limited rather than well established.

What the rest of the list means

Passion flower shows up alongside a very long list of medications, but most of those entries are theoretical. They rest on lab studies suggesting passion flower might affect enzymes or transport proteins the body uses to process certain drugs, and these effects have not been shown to cause meaningful changes in people. A long list here reflects caution, not proven harm.

Check your medications against Passion Flower

Based on HelloPharmacist’s Passion Flower interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Passion Flower

838 medications have a known interaction with Passion Flower, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Passion Flower using our pharmacist-reviewed interaction data.

AI summaries are generated from our Passion Flower interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Passion Flower combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Passion Flower affects

Every type of medication (drug category) Passion Flower is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Passion Flower interacts with

Cns DepressantsCytochrome P450 3a4 (cyp3a4) SubstratesOrganic Anion-transporting Polypeptide Substrates (oatp)

Cns Depressants

Concomitant use of passion flower with sedative drugs might cause additive effects and side effects.
Research in animals and humans shows that passion flower has sedative effects which can be additive when used with sedative medications like lorazepam.

Likelihood Possible Evidence D

Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, passion flower might decrease the effects of CYP3A4 substrates.
In vitro research suggests that passion flower can induce CYP3A4 enzymes, albeit to a much lower degree than rifampin, a known CYP3A4 inducer.

Likelihood Possible Evidence D

Organic Anion-Transporting Polypeptide Substrates (Oatp)

Theoretically, passion flower might reduce the bioavailability of OATP2B1 and OATP1A2 substrates.
In vitro research shows that the passion flower constituents apigenin and vitexin inhibit OATP2B1 and OATP1A2. This inhibition may be dose-dependent. One specific high-flavonoid passion flower extract (Valverde) seems to inhibit OATP2B1 and OATP1A2, while another extract with a lower flavonoid concentration (Arkocaps) shows less potent inhibition. OATPs are responsible for the uptake of drugs and other compounds into the body; however, the specific activities of OATP2B1 and OATP1A2 are not well characterized.

Likelihood Possible Evidence D

Monograph

Passion Flower: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Passion flower is a traditional calming herb that many people use for anxiety and sleep. Early studies hint it may help with mild anxiety and restlessness, but the evidence is limited and more research is needed. It is generally well tolerated short-term, but should be avoided in pregnancy and discussed with your pharmacist or doctor first.

Scientific name: Passiflora incarnata
Family: Passifloraceae
Part used: Above-ground parts (flowers, leaves, stems)
Common forms: Tea, capsules, tablets, liquid extracts, tinctures

People commonly use it for

Anxiety and stress
Trouble sleeping
Restlessness
Mild nervous tension
Muscle tension

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated short-term, but it can cause drowsiness.

PregnancyPossibly Unsafe

When used orally. Some case reports suggest that passion flower use during the first and second trimesters of pregnancy may be associated with an incr...

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Passion flower (Passiflora incarnata) is a climbing vine with striking white and purple flowers. It is native to the Americas, especially the southeastern United States, and is also grown in other warm parts of the world. It is sometimes called maypop, apricot vine, or maracuja.

People have used passion flower in traditional medicine for a long time, mainly as a calming herb. Today it is taken as a tea, capsule, tablet, tincture, or liquid extract. It is often combined with other calming herbs such as valerian or lemon balm in sleep and stress products.

How it works

Passion flower is thought to work mainly by affecting GABA, a brain chemical that helps calm nerve activity and regulate mood and sleep. By gently boosting GABA activity, it may produce a mild relaxing or sedative effect.

The plant contains compounds such as flavonoids (including vitexin) that are believed to be involved in its effects. Much of what we know about how it works comes from laboratory and animal studies, so the exact mechanism in people is still not fully understood.

Effectiveness

Does Passion Flower work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 14 uses evaluated

2 Possibly effective 12 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Possibly Effective Insomnia