Costus + Darunavir, Cobicistat
Darunavir, Cobicistat brand name: Prezcobix.
We found no known interaction between Costus and Darunavir, Cobicistat 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 Darunavir, Cobicistat 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.
Costus and Darunavir, Cobicistat
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 Darunavir, Cobicistat and Costus 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 Costus at all — not against Darunavir, Cobicistat, 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.
Costus safety at a glance
Safety guidance is general; always confirm with your pharmacist or doctor for your situation.
Some Darunavir, Cobicistat Products Have a Food Rule — Costus Should Not Break It
At least one FDA label for a product containing Darunavir, Cobicistat says to take it with food. If you take Costus on an empty stomach out of habit, keep them separate — and take Darunavir, Cobicistat 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 Darunavir, Cobicistat 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 Recommended dosage: Adults and pediatric patients weighing at least 40 kg: One 800 mg/150 mg tablet taken once daily with food.
From the Dosage and Administration section of the FDA label we read for Darunavir, Cobicistat — 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 Darunavir, Cobicistat
This page covers Costus only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Darunavir, Cobicistat page lists 145 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).
By severity: 3 major · 102 moderate · 40 minor.
From our pharmacist’s overview on the Darunavir, Cobicistat page
“Prezcobix (darunavir with cobicistat) treats HIV, and it only works if it holds a steady blood level, so this list of 145 supplements deserves real care. Three carry a major rating and matter most: St.”
Reviewed by 2 · Jul 18, 2026
Taking Costus as Part of a Dietary Supplement Product? Check It for Interactions
We hold 113 real supplement products containing Costus, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Costus. Even though Costus itself has no known interaction with Darunavir, Cobicistat, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:
Where Costus and Darunavir, Cobicistat 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.
#693 of 1,452 supplements looked up here in the last 7 days
#855 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 Costus reference on this page ↓
- Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Costus and Darunavir, Cobicistat records this page draws on were last updated July 10, 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 Costus
What is Costus?
- Digestive upset and gas
- Cough and breathing complaints
- Skin conditions (topical)
- Worm and parasite remedies (traditional)
- General tonic in traditional medicine
Costus (Saussurea costus) is a root used in Ayurvedic, Unani, and traditional Chinese medicine, mostly for digestive and respiratory complaints. High-quality human evidence is very limited, so its benefits are not well proven. Talk with a pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.
Saussurea costus · Asteraceae · Dried roots and root essential oil · Dried root powder, capsules, decoctions (teas), essential oil, and topical pastes
An interaction check asks whether these two react with each other — it does not ask whether Costus is a good idea for someone in your situation. Here is what our Costus record says about it on its own.
Costus: dosing
There is no well-established or standardized dose of costus for any health condition. Traditional preparations vary widely, and the strength of commercial products is not consistent.If you choose to use a costus product, follow the directions on the label and do not exceed them. The essential oil is very concentrated and should not be taken by mouth without professional guidance.
From our Costus monograph — the full record covers uses, side effects and every documented interaction.
About Darunavir and Cobicistat
What Is Darunavir and Cobicistat Used For?
Brand name: Prezcobix
Prezcobix and Prezcobix Ped are used to treat HIV-1 (human immunodeficiency virus type 1) infection. They are always used together with other antiretroviral (anti-HIV) medicines — never alone. Both products are approved for people who are new to HIV treatment (treatment-naïve) and for those who have taken HIV medicines before (treatment-experienced), as long as certain darunavir resistance mutations are not present.
Prezcobix tablets are approved for adults and pediatric patients weighing at least 40 kg. Prezcobix Ped tablets for oral suspension extend coverage to pediatric patients 3 years of age and older weighing at least 15 kg.
Other Drugs & Costus
Browse every other medication we’ve checked against Costus — 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 Costus against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Abemaciclib ›
- Ivermectin ›
- Testosterone ›
- Sertraline ›
- Losartan Potassium ›
- Acetaminophen ›
- Aspirin ›
- Rosuvastatin ›
- Escitalopram ›
- Metoprolol ›
- Clopidogrel ›
- Atorvastatin ›
- Rivaroxaban ›
- Isotretinoin ›
- Warfarin Sodium ›
- Tirzepatide ›
- Ibuprofen ›
- Amlodipine Besylate ›
- Methamphetamine ›
- Docusate ›
- Tadalafil ›
- Hydroxyurea ›
- Valacyclovir ›
- Metformin ›
- Prednisone ›
- Sumatriptan ›
- Semaglutide ›
- Amitriptyline ›
- Lisdexamfetamine ›
- Amphetamine ›
- Levothyroxine, Liothyronine ›
- Propranolol ›
- Methotrexate ›
- Amoxicillin ›
- Lisinopril ›
- Bupropion ›
- Fluoxetine ›
- Azithromycin ›
- Bendamustine ›
- Pregabalin ›
- Doxycycline ›
- Gabapentin ›
- Dextroamphetamine ›
- Lamotrigine ›
- Acyclovir ›
- Naproxen ›
- Acetaminophen, Aspirin, Caffeine ›
- Quetiapine ›
- Clonazepam ›
- Buspirone ›
- Omeprazole ›
- Duloxetine ›
- Letrozole ›
- Citalopram ›
- Methylene Blue ›
Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Costus list.
Costus References
The 6 references that drive our Costus 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.
- Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
- Marzulli, F. N. and Maibach, H. I. Effects of vehicles and elicitation concentration in contact dermatitis testing. I. Experimental contact sensitization in humans. Contact Dermatitis 1976;2(6):325-329. PubMed
- Mitchell, J. C. Contact hypersensitivity to some perfume materials. Contact Dermatitis 1975;1(4):196-199. PubMed
- Benezra, C. and Epstein, W. L. Molecular recognition patterns of sesquiterpene lactones in costus-sensitive patients. Contact Dermatitis 1986;15(4):223-230. PubMed
- Mitchell, J. C. and Epstein, W. L. Contact hypersensitivity to a perfume material, Costus Absolute. The role of sesquiterpene lactones. Arch.Dermatol 1974;110(6):871-873. DOI
- Cheminat, A., Stampf, J. L., Benezra, C., Farrall, M. J., and Frechet, J. M. Allergic contact dermatitis to costus: removal of haptens with polymers. Acta Derm.Venereol. 1981;61(6):525-529. DOI
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 Costus and Darunavir, Cobicistat Together: Common Questions
Is it safe to take Costus with Darunavir, Cobicistat?
Do Costus and Darunavir, Cobicistat have any of the same side effects?
Should I take Costus and Darunavir, Cobicistat at the same time of day?
Does Darunavir, Cobicistat 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.