Drug & supplement interaction

Blackthorn + Atovaquone, Proguanil

Atovaquone, Proguanil brand name: Malarone.

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 Blackthorn and Atovaquone, Proguanil 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 label for Atovaquone, Proguanil states a food rule worth keeping to.

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Interaction report

Blackthorn and Atovaquone, Proguanil

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 Atovaquone, Proguanil and Blackthorn 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Blackthorn at all — not against Atovaquone, Proguanil, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Blackthorn safety at a glance

Blackthorn overall Use caution Culinary amounts of the fruit are generally well tolerated, but medicinal use is not well studied.
Pregnancy Possibly Unsafe When the seeds or fresh flowers are used orally; avoid using. The seeds and fresh flowers contain small amounts of the cyanogenic glycoside amygdalin, which can... Read the full pregnancy detail
Breastfeeding Avoid Safety has not been established, so avoid medicinal use 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.

Still wondering about combining Atovaquone, Proguanil and Blackthorn? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Blackthorn Itself Has Been Linked To

This is not an interaction — nothing below involves Atovaquone, Proguanil. It is the side-effect record for Blackthorn on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Blackthorn, this list is the first place to look.

  • Joint pain / A skin rash Additional detail

    “Avoid contact with the thorns on blackthorn branches. They can break off and become embedded in the deep layers of the skin, the tendons, or in the small joints of the fingers, requiring surgical removal. When left embedded they can cause cysts, abscesses, dermatitis, cellulitis, foreign body granuloma, chronic inflammation, tendinitis, synovitis, and septic arthritis.”

    Blackthorn · Natural Medicines adverse-effect record, reported in dermatitis.

    2 sources cited
    1. 100919. Sharma H, Meredith AD. Blackthorn injury: a report of three interesting cases. Emerg Med J 2004;21(3):392. PubMed
    2. 100920. Sharma H, Meredith AD. A report of 18 blackthorn injuries of the upper limb. Injury 2004;35(9):930-5. PubMed

Everything above comes from the Natural Medicines adverse-effect record for Blackthorn — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Atovaquone, Proguanil’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Atovaquone, Proguanil column appears here.

Special populations

Blackthorn in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When the seeds or fresh flowers are used orally; avoid using. The seeds and fresh flowers contain small amounts of the cyanogenic glycoside amygdalin, which can be teratogenic.

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

How to take them

Some Atovaquone, Proguanil Products Have a Food Rule — Blackthorn Should Not Break It

At least one FDA label for a product containing Atovaquone, Proguanil says to take it with food. If you take Blackthorn on an empty stomach out of habit, keep them separate — and take Atovaquone, Proguanil with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Atovaquone, Proguanil products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

2 DOSAGE AND ADMINISTRATION The daily dose should be taken at the same time each day with food or a milky drink.

From the Dosage and Administration section of the FDA label we read for Atovaquone, Proguanil — where that label names a specific product, the instruction is that product's. See the Atovaquone, Proguanil drug page ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Atovaquone, Proguanil

This page covers Blackthorn only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Atovaquone, Proguanil page lists 54 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Adrafinil (moderate), Artichoke (moderate), Bacopa (moderate) and Baikal Skullcap (moderate).

By severity: 1 major · 40 moderate · 13 minor.

From our pharmacist’s overview on the Atovaquone, Proguanil page

“Most people taking atovaquone-proguanil (Malarone) are travelers trying to prevent malaria, so this list of 54 interacting supplements deserves real attention, since anything that weakens the drug can leave you exposed to the disease itself. The single major-rated entry is activated charcoal, a common travel remedy for stomach upset, w…”

Reviewed by 2 · Jul 18, 2026

Open the Atovaquone, Proguanil interaction page

One more smart check

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

We hold 2 real supplement products containing Blackthorn, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Blackthorn. Even though Blackthorn itself has no known interaction with Atovaquone, Proguanil, 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 Blackthorn and Atovaquone, Proguanil 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 Blackthorn
Top half

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

29 days ago today
Medication Atovaquone, Proguanil
Steady interest

#2,082 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 Blackthorn reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Blackthorn and Atovaquone, Proguanil 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 Blackthorn

What is Blackthorn?

  • Digestive upset
  • Mild constipation
  • Cold and cough symptoms
  • Mouth and throat irritation
  • Mild diuretic ('blood cleansing') tonic

Blackthorn is a thorny shrub whose flowers and dark blue-black fruit (sloes) are used in traditional European herbal medicine, mostly for digestive complaints and as a mild tonic. Solid human research is lacking, so its benefits are not proven, though small culinary amounts of the fruit are generally considered safe. Talk to your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or taking other medicines.

Prunus spinosa · Rosaceae · Flowers, fruit (sloes), leaves, and bark · Tea, syrup, juice, tincture, jam/preserves, and liqueur (sloe gin)

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

Blackthorn: dosing

There is no established or standardized medicinal dose for blackthorn. Traditional use varies widely depending on whether the flowers, fruit, or other parts are used and how they are prepared.If you choose to use a commercial blackthorn product, follow the directions on the label and do not exceed the recommended amount. Avoid making your own preparations from the seeds, leaves, or bark.

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

Read the full Blackthorn monograph & all interactions
Medication

About Atovaquone and Proguanil

What Is Atovaquone and Proguanil Used For?

Brand name: Malarone

Atovaquone and proguanil is used for two purposes: preventing P. falciparum malaria before and during travel to areas where malaria is common, and treating an active, uncomplicated P. falciparum malaria infection. This includes regions where other antimalarials — such as chloroquine, mefloquine, halofantrine, and amodiaquine — may no longer be effective due to drug resistance.

Both the adult-strength and pediatric-strength tablet formulations share these same two approved uses. The brand Malarone is approved for both prevention and treatment of P. falciparum malaria in adults and in pediatric patients, with dosing based on body weight for children.

See full Atovaquone and Proguanil drug information
Keep checking

Other Drugs & Blackthorn

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Blackthorn list.

See the full Blackthorn interactions page
See every supplement checked against Atovaquone, Proguanil, ranked by severity
Evidence & sources

Blackthorn References

The 3 references that drive our Blackthorn 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Sharma H, Meredith AD. Blackthorn injury: a report of three interesting cases. Emerg Med J 2004;21(3):392. PubMed
  3. Sharma H, Meredith AD. A report of 18 blackthorn injuries of the upper limb. Injury 2004;35(9):930-5. 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 Blackthorn and Atovaquone, Proguanil Together: Common Questions

Is it safe to take Blackthorn with Atovaquone, Proguanil?
We do not list a known interaction between Blackthorn and Atovaquone, Proguanil. 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.
Should I take Blackthorn and Atovaquone, Proguanil at the same time of day?
At least one FDA label for a product containing Atovaquone, Proguanil says to take it with food. If you take Blackthorn on an empty stomach out of habit, keep them separate and take Atovaquone, Proguanil with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Atovaquone, Proguanil products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Atovaquone, Proguanil interact with any supplements?
Yes. Atovaquone, Proguanil has documented interactions with 54 supplements in our database — Blackthorn is not one of them. The Atovaquone, Proguanil 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

Blackthorn monograph Uses, safety profile, and every drug interaction in one place Atovaquone and Proguanil drug information The full plain-English guide to this medication Atovaquone, Proguanil supplement interactions Every supplement checked against Atovaquone, Proguanil, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Atovaquone, Proguanil and Blackthorn?

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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.