Drug & supplement interaction

Passion Flower + Acyclovir

Acyclovir brand names: Zovirax, Zovirax Injection, Sitavig, Avaclyr.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Passion Flower and Acyclovir in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Passion Flower and Acyclovir

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Acyclovir and Passion Flower in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Passion Flower safety at a glance

Passion Flower overall Use caution Generally well tolerated short-term, but it can cause drowsiness.
Pregnancy Possibly 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 increased risk... Read the full pregnancy detail
Breastfeeding Avoid Not enough safety information, so it is best avoided while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Pharmacist analysis

Passionflower is not known to have many clinically significant drug interactions.

Nevertheless, it has been shown to have sedative effects, which can be additive when used in conjunction with sedative medications (e.g., Benadryl, benzodiazepines, opioids, etc...).

Therefore, we do list interactions between Passionflower and CNS (central nervous system) depressants or other drugs with strong sedative effects.

Additionally, certain constituents of Passionflower (such as apigenin and vitexin) may inhibit certain drug transports, specifically OATP2B1 and OATP1A2.

These are responsible for the uptake of certain drugs and other compounds into the body.

As Passionflower can inhibit these transports, it is possible that it might reduce the bioavailability of drugs that are substrates for these transporters but studies are far from conclusive on the matter.

There is no known drug interaction between Passionflower and the drug in question here, however.

As always, be sure to speak with your doctor before making any changes to your medication regimen.

—

Still wondering about combining Acyclovir and Passion Flower? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Acyclovir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Acyclovir is filed under 6 classifications — including organic anion transporter 1 (oat1) substrates, topical drugs, nephrotoxic drugs. Passion Flower has documented interactions with 3 drug classes — the most serious being cns depressants (moderate), cytochrome p450 3a4 (cyp3a4) substrates (minor) and organic anion-transporting polypeptide substrates (oatp) (minor) — and none of Acyclovir’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Passion Flower Does Interact With Other Medications

Passion Flower has 248 moderate, 588 minor known drug interactions in our database — Acyclovir isn’t one of them. If you take anything else, check it against the full list below.

Moderate 248 Minor 588 No known interaction 1,994 (incl. Acyclovir)
Taking anything else?

Check Another of Your Medications Against Passion Flower

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

What to actually watch for

No Interaction Found — But Data Suggests Passion Flower and Acyclovir May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Joint pain Additional detail

    Passion Flower

    “An idiosyncratic hypersensitivity reaction characterized by urticaria and cutaneous vasculitis has been reported in a 77-year-old male with rheumatoid arthritis after taking a specific combination product that included passion flower extract (Naturest).”

    Passion Flower · Natural Medicines adverse-effect record, reported in allergic rhinitis (hay fever).

    2 sources cited
    1. 68308. Smith, G. W., Chalmers, T. M., and Nuki, G. Vasculitis associated with herbal preparation containing Passiflora extract. Br J Rheumatol. 1993;32(1):87-88.
    2. 95038. Dantas LP, de Oliveira-Ribeiro A, de Almeida-Souza LM, Groppo FC. Effects of passiflora incarnata and midazolam for control of anxiety in patients undergoing dental extraction. Med Oral Patol Oral Cir Bucal. 2017;22(1):e95-e101. PubMed

    Acyclovir

    Listed in the ADVERSE REACTIONS section of the FDA label for Acyclovir. Read the label on DailyMed ›

  • Dizziness Additional detail

    Passion Flower

    “Orally, sedation, dizziness, ataxia, and confusion have been reported in clinical trials. However, these events generally do not necessitate discontinuation. Altered consciousness has been reported with use of a specific herbal product (Relaxir) produced mainly from the fruits of passion flower (6).”

    Passion Flower · Natural Medicines adverse-effect record, reported in vertigo.

    6 sources cited
    1. 8007. Akhondzadeh S, Naghavi HR, Shayeganpour A, et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther 2001;26:363-7. PubMed
    2. 15391. Mori A, Hasegawa K, Murasaki M, et al. Clinical evaluation of Passiflamin (passiflora extract) on neurosis - multicenter double blind study in comparison with mexazolam. Rinsho Hyoka (Clinical Evaluation) 1993;21:383-440.
    3. 15392. Miyasaka LS, Atallah AN, Soares BG. Passiflora for anxiety disorder. Cochrane Database Syst Rev 2007;(1):CD004518. DOI
    4. 95036. Nojoumi M, Ghaeli P, Salimi S, Sharifi A, Raisi F. Effects of Passion Flower Extract, as an Add-On Treatment to Sertraline, on Reaction Time in Patients ?with Generalized Anxiety Disorder: A Double-Blind Placebo-Controlled Study. Iran J Psychiatry. 2016;1
    5. 95038. Dantas LP, de Oliveira-Ribeiro A, de Almeida-Souza LM, Groppo FC. Effects of passiflora incarnata and midazolam for control of anxiety in patients undergoing dental extraction. Med Oral Patol Oral Cir Bucal. 2017;22(1):e95-e101. PubMed
    6. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

    Acyclovir

    Listed in the ADVERSE REACTIONS section of the FDA label for Acyclovir. Read the label on DailyMed ›

  • Nausea / Vomiting reported in 4.9% of FDA reports for Acyclovir Additional detail

    Passion Flower

    “There is a case report involving a 34-year-old female who was hospitalized with severe nausea, vomiting, drowsiness, prolonged QT interval, and episodes of nonsustained ventricular tachycardia following use of passion flower extract tablets (Sedacalm, Bioplus Healthcare), 1500 mg on day 1 and 2000 mg on day 2 to relieve stress. All symptoms resolved within one week after passion flower was discontinued.”

    Passion Flower · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    1 source cited
    1. 6251. Fisher AA, Purcell P, Le Couteur DG. Toxicity of Passiflora incarnata L. J Toxicol Clin Toxicol 2000;38:63-6.

    Acyclovir

    Listed in the ADVERSE REACTIONS section of the FDA label for Acyclovir, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Passion Flower but not commonly for Acyclovir: an irregular heartbeat, an allergic reaction, a fast or pounding heartbeat and drowsiness.

Effects for Acyclovir come from the ADVERSE REACTIONS section of its FDA label; effects for Passion Flower come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 114,761 voluntary FDA FAERS reports for Acyclovir that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Passion Flower in Pregnancy & Breastfeeding

Pregnancy Possibly 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 increased risk for premature rupture of membranes and meconium aspiration syndrome; however, causality has not been confirmed. The alkaloids harman and harmaline, which are sometimes found in passion flower, have been reported to have uterine stimulant activity. It is not known whether these constituents are present in sufficient quantities to have an effect.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Passion Flower or Acyclovir

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Passion Flower or Acyclovir, 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 Acyclovir

This page covers Passion Flower only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acyclovir page lists 37 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), African Wild Potato (moderate) and Aristolochia (moderate).

By severity: 3 major · 23 moderate · 11 minor.

From our pharmacist’s overview on the Acyclovir page

“Kidney strain is the risk to understand first. Acyclovir (Zovirax) can stress the kidneys on its own, and a few ingredients here, Siberian cocklebur especially, are toxic to kidney tissue, so pairing them could compound the harm.”

Reviewed by 2 · Jul 18, 2026

Open the Acyclovir interaction page

One more smart check

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

We hold 2,129 real supplement products containing Passion Flower, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Passion Flower. Even though Passion Flower itself has no known interaction with Acyclovir, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Passion Flower and Acyclovir 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 Passion Flower
Top 10%

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

29 days ago today
Medication Acyclovir
Top 5%

#59 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Passion Flower reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Passion Flower and Acyclovir records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Passion Flower

What is Passion Flower?

Passion Flower
  • Anxiety and stress
  • Trouble sleeping
  • Restlessness
  • Mild nervous tension
  • Muscle tension

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.

Passiflora incarnata · Passifloraceae · Above-ground parts (flowers, leaves, stems) · Tea, capsules, tablets, liquid extracts, tinctures

An interaction check asks whether these two react with each other — it does not ask whether Passion Flower is a good idea for someone in your situation. Here is what our Passion Flower record says about it on its own.

Passion Flower: dosing

There is no single official or proven dose for passion flower. The amount in products varies widely depending on the form (tea, capsule, tincture, or extract) and how it is prepared. Many supplements are standardized to contain a certain percentage of the flavonoid vitexin.The safest approach is to follow the directions on the product label and not exceed them.

From our Passion Flower monograph — the full record covers uses, side effects and every documented interaction.

Read the full Passion Flower monograph & all interactions
Medication

About Acyclovir

What Is Acyclovir Used For?

Brand names: Zovirax, Zovirax Injection, Sitavig, Avaclyr

Acyclovir treats infections caused by herpes viruses. Depending on the form, it is used for cold sores (herpes labialis), genital herpes (initial episodes and recurrent flare-ups), shingles (herpes zoster), and chickenpox (varicella). It can also be used long-term to suppress recurrent genital herpes outbreaks.

Some forms are approved for more serious situations: acyclovir injection is used in hospital settings for herpes simplex encephalitis (herpes infection of the brain), neonatal herpes (in newborns), and herpes or shingles infections in immunocompromised patients. Avaclyr ophthalmic ointment is specifically indicated for acute herpetic keratitis (a herpes ulcer on the cornea of the eye). Sitavig buccal tablet and Zovirax cream are specifically indicated for recurrent cold sores in immunocompetent adults.

Most-Reported Side Effects for Acyclovir

From FAERS, the FDA’s public side-effect reporting system (114,761 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 8,029 reports
Diarrhea 7,348 reports
Pneumonia 5,700 reports
Nausea 5,643 reports
Fever 4,989 reports
See full Acyclovir drug information
Keep checking

Other Drugs & Passion Flower

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

0Major
248Moderate
588Minor
1,993No known interaction
248 Moderate 588 Minor 1,993 No interaction
Moderate

248 interactions

Showing 60 of 248 moderate interactions — see all 248 on the Passion Flower page.

Minor

588 interactions

Showing 60 of 588 minor interactions — see all 588 on the Passion Flower page.

No interaction 1,993 drugs checked — show the list

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

Showing the 60 most looked-up of 1,993 medications checked with no known interaction — see the full Passion Flower list.

See the full Passion Flower interactions page
See every supplement checked against Acyclovir, ranked by severity
Evidence & sources

Passion Flower References

The 19 references that drive our Passion Flower monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  3. Fisher AA, Purcell P, Le Couteur DG. Toxicity of Passiflora incarnata L. J Toxicol Clin Toxicol 2000;38:63-6.
  4. Akhondzadeh S, Naghavi HR, Shayeganpour A, et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther 2001;26:363-7. PubMed
  5. Farnsworth N, Bingel A, Cordell G, et al. Potential value of plants as sources of new antifertility agents I. J Pharm Sci 1975;64:535-98. DOI
  6. Mori A, Hasegawa K, Murasaki M, et al. Clinical evaluation of Passiflamin (passiflora extract) on neurosis - multicenter double blind study in comparison with mexazolam. Rinsho Hyoka (Clinical Evaluation) 1993;21:383-440.
  7. Miyasaka LS, Atallah AN, Soares BG. Passiflora for anxiety disorder. Cochrane Database Syst Rev 2007;(1):CD004518. DOI
  8. Speroni E., Minghetti A. Neuropharmacological activity of extracts from Passiflora incarnata. Planta Med. 1988;54:488-91.
  9. Capasso A., Sorrentino L. Pharmacological studies on the sedative and hypnotic effect of Kava kava and Passiflora extracts combination. Phytomedicine. 2005;12:39-45. PubMed
  10. Carrasco MC, Vallejo JR, Pardo-de-Santayana M, et al. Interactions of Valeriana officinalis L. and Passiflora incarnata L. in a patient treated with lorazepam. Phytother Res. 2009 Dec;23:1795-6.
  11. Smith, G. W., Chalmers, T. M., and Nuki, G. Vasculitis associated with herbal preparation containing Passiflora extract. Br J Rheumatol. 1993;32(1):87-88.
  12. Soulimani, R., Younos, C., Jarmouni, S., Bousta, D., Misslin, R., and Mortier, F. Behavioural effects of Passiflora incarnata L. and its indole alkaloid and flavonoid derivatives and maltol in the mouse. J Ethnopharmacol. 1997;57(1):11-20. PubMed
  13. Nojoumi M, Ghaeli P, Salimi S, Sharifi A, Raisi F. Effects of Passion Flower Extract, as an Add-On Treatment to Sertraline, on Reaction Time in Patients ?with Generalized Anxiety Disorder: A Double-Blind Placebo-Controlled Study. Iran J Psychiatry. 2016;1
  14. Rokhtabnak F, Ghodraty MR, Kholdebarin A, et al. Comparing the Effect of Preoperative Administration of Melatonin and Passiflora incarnata on Postoperative Cognitive Disorders in Adult Patients Undergoing Elective Surgery. Anesth Pain Med. 2016;7(1):e4123 PubMed
  15. Dantas LP, de Oliveira-Ribeiro A, de Almeida-Souza LM, Groppo FC. Effects of passiflora incarnata and midazolam for control of anxiety in patients undergoing dental extraction. Med Oral Patol Oral Cir Bucal. 2017;22(1):e95-e101. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Passion Flower and Acyclovir Together: Common Questions

Is it safe to take Passion Flower with Acyclovir?
We do not list a known interaction between Passion Flower and Acyclovir. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Passion Flower and Acyclovir have any of the same side effects?
Yes — our sources link each of them separately to 4 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Passion Flower and Acyclovir combination checked?
Interactions in our licensed database are recorded against drug classes. Acyclovir is filed under 6 classifications, and Passion Flower has documented interactions with 3 drug classes — none of Acyclovir's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Passion Flower interact with any other medications?
Yes. Passion Flower has 836 documented drug interactions in our database — Acyclovir is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Acyclovir interact with any supplements?
Yes. Acyclovir has documented interactions with 37 supplements in our database — Passion Flower is not one of them. The Acyclovir interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Passion Flower monograph Uses, safety profile, and every drug interaction in one place Acyclovir drug information The full plain-English guide to this medication Acyclovir supplement interactions Every supplement checked against Acyclovir, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 19 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Acyclovir and Passion Flower?

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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.