Niacin + Sitaxsentan sodium
Sitaxsentan sodium brand name: Thelin.
Sitaxsentan sodium falls into 2 drug categories that Niacin can interact with; the most serious is rated moderate. Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.
Read the full interaction reportNiacin and Sitaxsentan sodium
These two interact in 2 distinct ways. Each one is explained separately below.
Why Are There 2 Interactions?
Niacin interacts with whole categories of medication. Sitaxsentan sodium falls into 2 of those categories, so it can interact with Niacin in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).
ANTIHYPERTENSIVE DRUGS
1 of 2Why this applies to Sitaxsentan sodium
Sitaxsentan sodium falls under ANTIHYPERTENSIVE DRUGS — the group Niacin interacts with.
The vasodilating effects of niacin can cause hypotension. Furthermore, some clinical evidence suggests that a one-hour infusion of niacin can reduce systolic, diastolic, and mean blood pressure in hypertensive patients. This effect is not observed in normotensive patients.
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.
Here's the thing to know about pairing high-dose niacin with sitaxsentan (Thelin). Sitaxsentan is used to relax blood vessels and lower the high pressures in the lungs seen with pulmonary hypertension. Niacin, especially at the bigger cholesterol-type doses, can also widen blood vessels and nudge your blood pressure down. Stack the two and your pressure could dip a little lower than expected.
In plain terms, you might feel more lightheaded, dizzy, flushed, or tired, particularly when standing up quickly. This is a theoretical concern backed by limited data, and ordinary food amounts of niacin are very unlikely to matter. Concentrated supplements are the real question. Please check with your pharmacist or doctor before starting high-dose niacin so they can guide you safely.
- American Society of Health-System Pharmacists. ASHP Therapeutic Position Statement on the safe use of niacin in the management of dyslipidemias. Am J Health Syst Pharm 1997;54:2815-9. DOI
- McKenney J. New perspectives on the use of niacin in the treatment of lipid disorders. Arch Intern Med 2004;164:697-705. PubMed
- Gadegbeku CA, Dhandayuthapani A, Shrayyef MZ, Egan BM. Hemodynamic effects of nicotinic acid infusion in normotensive and hypertensive subjects. Am J Hypertens. 2003;16(1):67-71. PubMed
- Aramwit P, Srisawadwong R, Supasyndh O. Effectiveness and safety of extended-release nicotinic acid for reducing serum phosphorus in hemodialysis patients. J Nephrol. 2012 May-Jun;25(3):354-62. PubMed
HEPATOTOXIC DRUGS
2 of 2Sitaxsentan sodium also falls under HEPATOTOXIC DRUGS.
Niacin has been associated with cases of liver toxicity, especially when used in pharmacologic doses. Sustained-release niacin preparations appear to be associated with a higher risk of hepatotoxicity than immediate-release niacin.
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.
Here's the short version: both of these can be tough on the liver, so stacking them may add up. Sitaxsentan (Thelin) is an endothelin receptor blocker that was used for pulmonary arterial hypertension, and liver injury was a real concern with it. High, drug-like doses of niacin can also irritate the liver, especially the sustained-release kind.
Put them together and the worry is a higher chance of liver trouble, things like nausea, belly pain, unusual tiredness, dark urine, or yellowing of the skin or eyes. To be fair, this is a theoretical caution based on how each one behaves, not proven cases of the pair. Everyday food amounts of niacin aren't the issue. Before using any high-dose niacin, please check with your pharmacist or doctor first.
- American Society of Health-System Pharmacists. ASHP Therapeutic Position Statement on the safe use of niacin in the management of dyslipidemias. Am J Health Syst Pharm 1997;54:2815-9. DOI
- Bays HE, Dujovne CA. Drug interactions of lipid-altering drugs. Drug Saf 1998;19:355-71. PubMed
- Rader JI, Calvert RJ, Hathcock JN. Hepatic toxicity of unmodified and time-release preparations of niacin. Am J Med 1992;92:77-81. PubMed
- Etchason JA, Miller TD, Squires RW, et al. Niacin-induced hepatitis: a potential side effect with low-dose time-release niacin. Mayo Clin Proc. 1991;66(1):23-8. PubMed
- Henkin Y, Johnson KC, Segrest JP. Rechallenge with crystalline niacin after drug-induced hepatitis from sustained-release niacin. JAMA. 1990;264(2):241-3. DOI
- Henkin Y, Oberman A, Hurst DC, Segrest JP. Niacin revisited: clinical observations on an important but underutilized drug. Am J Med. 1991;91(3):239-46. PubMed
- Bassan M. A case for immediate-release niacin. Heart Lung. 2012 Jan-Feb;41(1):95-8. PubMed
- Nawaz N, Mistretta T, Karime C, Lewis J, Wolf E. Cholestatic Drug-Induced Liver Injury in a Patient Taking High-Dose Niacin for Hyperlipidemia. J Investig Med High Impact Case Rep 2024;12:23247096231224349. PubMed
What These Ratings Mean
Every interaction above is graded three ways — here’s the key to each label.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
- ProbableInteraction 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.
- PossibleInteraction 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.
- UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
- AHigh-quality meta-analysis (quantitative systematic review).
- BCase-control study.
- CConsensus.
- DAnecdotal evidence.
These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.
Niacin Also Interacts With Other Medications
Niacin has 726 moderate known drug interactions in our database — the Sitaxsentan sodium one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Niacin
We haven’t checked that one against Niacin yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Niacin. Pick one to open its full report.
See Every Supplement That Interacts With Sitaxsentan sodium
This page covers Niacin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Sitaxsentan sodium page lists 173 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Beer (major) and Siberian Cocklebur (major).
By severity: 7 major · 145 moderate · 21 minor.
From our pharmacist’s overview on the Sitaxsentan sodium page
“Sitaxsentan (Thelin) treats pulmonary arterial hypertension and carries a well known liver warning of its own, which is exactly why I read this list of 173 interacting supplements with genuine concern rather than a shrug. Most entries, 119 of them, either add to its blood pressure lowering effect or work against it, but the group I wou…”
Reviewed by 2 · Jul 18, 2026
Taking Niacin as Part of a Dietary Supplement Product? Check It for Interactions
We hold 933 real supplement products containing Niacin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Niacin. Your product may carry other ingredients that interact with Sitaxsentan sodium too, on top of Niacin — and those would not show on this page. Find your product and we’ll check every ingredient on its label:
Where Niacin and Sitaxsentan sodium 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.
#229 of 1,452 supplements looked up here in the last 7 days
#1,447 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.
About Niacin
What is Niacin?
- High cholesterol
- Vitamin B3 deficiency (pellagra)
- Heart health support
- General energy and metabolism
Niacin (vitamin B3) is an essential nutrient your body needs for energy and metabolism, and deficiency is uncommon in most developed countries. Prescription-strength niacin has been used to adjust cholesterol levels, but high doses can cause flushing and other side effects and should only be taken under medical supervision. Always talk with a pharmacist or doctor before using high-dose niacin supplements.
Other Drugs & Niacin
Browse every other medication we’ve checked against Niacin — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
726 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Nifedipine ›
- Ibuprofen ›
- Aspirin ›
- Insulin (rdna) ›
- Naproxen ›
- Doxycycline ›
- Minocycline ›
- Propranolol ›
- Tetracycline ›
- Levothyroxine ›
- Amoxicillin ›
- Hydrochlorothiazide ›
- Testosterone ›
- Verapamil ›
- Fenofibrate ›
- Levonorgestrel ›
- Quinidine ›
- Cyclosporine ›
- Glyburide ›
- Insulin (pork) ›
- Methyltestosterone ›
- Ciprofloxacin ›
- Nicotine ›
- Phenytoin ›
- Allopurinol ›
- Carbamazepine ›
- Diclofenac Potassium ›
- Dipyridamole ›
- Hydralazine ›
- Insulin (human) ›
- Acetaminophen ›
- Conjugated Estrogens ›
- Ketoprofen ›
- Methotrexate ›
- Nitrofurantoin ›
- Ofloxacin ›
- Propoxyphene ›
- Rifampin ›
- Testosterone Undecanoate ›
- Trichlormethiazide ›
- Acarbose ›
- Bendroflumethiazide ›
- Bivalirudin ›
- Dapsone ›
- Doxycycline Hyclate ›
- Duloxetine ›
- Eltrombopag ›
- Insulin Glargine ›
- Interferon Alfa-2b ›
- Interferon Beta-1b ›
- Isoniazid ›
- Itraconazole ›
- Levofloxacin ›
- Levothyroxine Sodium ›
- Liotrix ›
- Lisinopril ›
- Metolazone ›
- Minoxidil ›
Showing 60 of 726 moderate interactions — see all 726 on the Niacin page.
No interaction 2,103 drugs checked — show the list
We also checked Niacin against these medications and found no known interaction in our sources. Open any page to confirm.
- Methylphenidate ›
- Sertraline ›
- Ivermectin ›
- Escitalopram ›
- Tadalafil ›
- Docusate ›
- Valacyclovir ›
- Hydroxyurea ›
- Abemaciclib ›
- Methamphetamine ›
- Sumatriptan ›
- Prednisone ›
- Lisdexamfetamine ›
- Bupropion ›
- Acyclovir ›
- Bendamustine ›
- Amitriptyline ›
- Fluoxetine ›
- Lamotrigine ›
- Amphetamine ›
- Gabapentin ›
- Pregabalin ›
- Dextroamphetamine ›
- Azithromycin ›
- Isotretinoin ›
- Clonazepam ›
- Omeprazole ›
- Methylene Blue ›
- Quetiapine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Diazepam ›
- Cyclopentolate ›
- Cephalexin ›
- Roxithromycin ›
- Acetaminophen, Dextromethorphan, Doxylamine ›
- Pegunigalsidase Alfa-iwxj ›
- Daptomycin ›
- Finasteride ›
- Estrogen ›
- Mirtazapine ›
- Hexobarbitone ›
- Dexmethylphenidate ›
- Levetiracetam ›
- Alprazolam ›
- Factor 7a ›
- Phentermine, Topiramate ›
- Bromocriptine ›
- Dutasteride ›
- Aripiprazole ›
- Carbidopa, Levodopa ›
- Mitomycin ›
- Levodopa ›
- Ezetimibe ›
- Dexamethasone ›
- Cefaclor ›
- Venlafaxine ›
- Phenylephrine ›
- Vancomycin ›
Showing the 60 most looked-up of 2,103 medications checked with no known interaction — see the full Niacin list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Sitaxsentan sodium Is Linked to Lower Levels of One Nutrient
Natural Medicines records Sitaxsentan sodium as a medicine that can lower these. This is not an interaction with Niacin — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Read the full Sitaxsentan sodium nutrient depletion report ›
Niacin is itself a nutrient we track — see which medications may deplete NIACIN.
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Niacin and Sitaxsentan sodium Together: Common Questions
Can you take Niacin with Sitaxsentan sodium?
Why are there 2 interactions listed for Niacin and Sitaxsentan sodium?
How serious is the Niacin and Sitaxsentan sodium interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Still Have a Question About Sitaxsentan sodium and Niacin?
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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.