Usnea + Atovaquone
Atovaquone brand name: Mepron.
We found no known interaction between Usnea and Atovaquone 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 states a food rule worth keeping to, and 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.
Usnea and Atovaquone
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 and Usnea 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 Usnea at all — not against Atovaquone, 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.
Usnea safety at a glance
Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Some Atovaquone Products Have a Food Rule — Usnea Should Not Break It
At least one FDA label for a product containing Atovaquone says to take it with food. If you take Usnea on an empty stomach out of habit, keep them separate — and take Atovaquone 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 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.
jirovecii Pneumonia The recommended oral dosage is 1,500 mg (10 mL) once daily administered with food.
From the Dosage and Administration section of the FDA label we read for Atovaquone — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›
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.
See Every Supplement That Interacts With Atovaquone
This page covers Usnea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Atovaquone page lists 17 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).
By severity: 1 major · 7 moderate · 9 minor.
From our pharmacist’s overview on the Atovaquone page
“Atovaquone (Mepron) is usually taken to prevent or treat Pneumocystis pneumonia, often when the immune system is already weakened, so a dose that never absorbs is a treatment failure, not a nuisance. All 17 supplement interactions on file act in the gut, changing how much of the drug reaches the blood, and I read this list as one deser…”
Reviewed by 2 · Jul 18, 2026
Taking Usnea as Part of a Dietary Supplement Product? Check It for Interactions
We hold 138 real supplement products containing Usnea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Usnea. Even though Usnea itself has no known interaction with Atovaquone, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:
Where Usnea and Atovaquone 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.
#625 of 1,452 supplements looked up here in the last 7 days
#927 of 2,830 medications looked up here in the last 7 days
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 Usnea reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Usnea and Atovaquone 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.
About Usnea
What is Usnea?
- Sore throat
- Skin and wound care
- Respiratory infections
- Urinary tract support
- Antimicrobial/antifungal
- Immune support
Usnea is a lichen used in traditional herbal medicine, mainly for sore throats, skin infections, and as a general antimicrobial. Laboratory studies suggest its main compound, usnic acid, can fight bacteria and fungi, but good human studies are lacking. Oral use of concentrated usnic acid has been linked to serious liver injury, so caution is important.
Usnea barbata · Parmeliaceae · Whole lichen (thallus) · Tincture, capsules, tea, throat sprays, topical salves
An interaction check asks whether these two react with each other — it does not ask whether Usnea is a good idea for someone in your situation. Here is what our Usnea record says about it on its own.
Usnea: dosing
There is no well-established standardized dose for Usnea. Products vary widely in strength and in how much usnic acid they contain, which makes safe dosing hard to define.If you choose to use Usnea, follow the directions on the product label and do not exceed them.
From our Usnea monograph — the full record covers uses, side effects and every documented interaction.
About Atovaquone
What Is Atovaquone Used For?
Brand name: Mepron
Atovaquone oral suspension — available as the brand Mepron and as generic products — is used in adults and adolescents aged 13 and older who cannot tolerate trimethoprim-sulfamethoxazole (TMP-SMX), the usual first-choice treatment.
It is approved for two purposes: preventing PCP in people at high risk, and treating mild-to-moderate PCP in those who already have it. It has not been studied for severe PCP or for people whose PCP is not responding to TMP-SMX, so it is not used in those situations.
Other Drugs & Usnea
Browse every other medication we’ve checked against Usnea — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
No interaction 2,829 drugs checked — show the list
We also checked Usnea against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Ivermectin ›
- Aspirin ›
- Abemaciclib ›
- Acetaminophen ›
- Metoprolol ›
- Rosuvastatin ›
- Rivaroxaban ›
- Escitalopram ›
- Clopidogrel ›
- Atorvastatin ›
- Docusate ›
- Tadalafil ›
- Tirzepatide ›
- Methamphetamine ›
- Ibuprofen ›
- Valacyclovir ›
- Warfarin Sodium ›
- Hydroxyurea ›
- Sumatriptan ›
- Semaglutide ›
- Prednisone ›
- Lisdexamfetamine ›
- Propranolol ›
- Metformin ›
- Amitriptyline ›
- Amoxicillin ›
- Isotretinoin ›
- Lisinopril ›
- Amlodipine Besylate ›
- Methotrexate ›
- Bendamustine ›
- Bupropion ›
- Amphetamine ›
- Doxycycline ›
- Fluoxetine ›
- Acyclovir ›
- Azithromycin ›
- Pregabalin ›
- Lamotrigine ›
- Dextroamphetamine ›
- Gabapentin ›
- Acetaminophen, Codeine ›
- Levothyroxine, Liothyronine ›
- Clonazepam ›
- Quetiapine ›
- Naproxen ›
- Omeprazole ›
- Letrozole ›
- Duloxetine ›
- Methylene Blue ›
- Buspirone ›
- Citalopram ›
Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Usnea list.
Usnea References
The 10 references that drive our Usnea 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.
- Favreau JT, Ryu Ml, Braunstein G, et al. Severe hepatotoxicity associated with the dietary supplement LipoKinetix. Ann Intern Med 2002;136:590-5. PubMed
- Ingolfsdottir K. Usnic acid. Phytochemistry 2002;61:729-36.
- Scirpa, P., Scambia, G., Masciullo, V., Battaglia, F., Foti, E., Lopez, R., Villa, P., Malecore, M., and Mancuso, S. [A zinc sulfate and usnic acid preparation used as post-surgical adjuvant therapy in genital lesions by Human Papillomavirus]. Minerva Gin
- Mitchell, J. C. Allergy to lichens. Allergic contact dermatitis from usnic acid produced by lichenized fungi. Arch Dermatol 1965;92(2):142-146.
- Durazo, F. A., Lassman, C., Han, S. H., Saab, S., Lee, N. P., Kawano, M., Saggi, B., Gordon, S., Farmer, D. G., Yersiz, H., Goldstein, R. L., Ghobrial, M., and Busuttil, R. W. Fulminant liver failure due to usnic acid for weight loss. Am.J Gastroenterol. PubMed
- Neff, G. W., Reddy, K. R., Durazo, F. A., Meyer, D., Marrero, R., and Kaplowitz, N. Severe hepatotoxicity associated with the use of weight loss diet supplements containing ma huang or usnic acid. J Hepatol. 2004;41(6):1062-1064. PubMed
- Hsu, L. M., Huang, Y. S., Chang, F. Y., and Lee, S. D. 'Fat burner' herb, usnic Acid, induced acute hepatitis in a family. J Gastroenterol.Hepatol. 2005;20(7):1138-1139. PubMed
- Arneborn, P., Jansson, A., and Bottiger, Y. [Acute hepatitis in a woman after intake of slimming pills bought via Internet]. Lakartidningen 7-11-2005;102(28-29):2071-2072.
- Sanchez, W., Maple, J. T., Burgart, L. J., and Kamath, P. S. Severe hepatotoxicity associated with use of a dietary supplement containing usnic acid. Mayo Clin Proc 2006;81(4):541-544. PubMed
- Rafanelli, S., Bacchilega, R., Stanganelli, I., and Rafanelli, A. Contact dermatitis from usnic acid in vaginal ovules. Contact Dermatitis 1995;33(4):271-272. 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.
Taking Usnea and Atovaquone Together: Common Questions
Is it safe to take Usnea with Atovaquone?
Do Usnea and Atovaquone have any of the same side effects?
Should I take Usnea and Atovaquone at the same time of day?
Does Atovaquone interact with any supplements?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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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.