Drug & supplement interaction

N-acetyl Cysteine (nac) + Dalteparin

Dalteparin brand name: Fragmin.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

N-acetyl Cysteine (nac) has a moderate interaction with Dalteparin. Theoretically, N-acetyl cysteine might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

N-acetyl Cysteine (nac) and Dalteparin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

Why this applies to Dalteparin

Dalteparin falls under ANTICOAGULANT/ANTIPLATELET DRUGS — the group N-acetyl Cysteine (nac) interacts with.

Theoretically, N-acetyl cysteine might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
Clinical research suggests that intravenous N-acetyl cysteine decreases prothrombin time, prolongs coagulation time, decreases platelet aggregation, and increases blood loss in surgical patients. Furthermore, in vitro research suggests that N-acetyl cysteine increases the anticoagulant activity of nitroglycerin.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Dalteparin (Fragmin) is an injectable blood thinner that lowers your blood's ability to clot. The concern here is that NAC may add to that effect, since lab and surgical studies suggest it can lengthen clotting time, lower platelet stickiness, and increase blood loss. Stacked on top of dalteparin, that could theoretically tip you toward easier bruising, nosebleeds, bleeding gums, or harder-to-stop bleeding.

I want to be honest about the strength of this: it's theoretical, based on pharmacology rather than solid human trials with this combination. Many people take both without trouble. Still, because dalteparin is already a potent anticoagulant, it's worth a quick chat with your pharmacist or doctor before starting NAC, and let them know if you notice any unusual bleeding.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Loscalzo J. N-Acetylcysteine potentiates inhibition of platelet aggregation by nitroglycerin. J Clin Invest. 1985;76(2):703-8. PubMed
  2. Niemi, T. T., Munsterhjelm, E., Poyhia, R., Hynninen, M. S., and Salmenpera, M. T. The effect of N-acetylcysteine on blood coagulation and platelet function in patients undergoing open repair of abdominal aortic aneurysm. Blood Coagul.Fibrinolysis 2006;1 PubMed
  3. Wijeysundera, D. N., Karkouti, K., Rao, V., Granton, J. T., Chan, C. T., Raban, R., Carroll, J., Poonawala, H., and Beattie, W. S. N-acetylcysteine is associated with increased blood loss and blood product utilization during cardiac surgery. Crit Care Me PubMed
  4. Chirkov, Y. Y. and Horowitz, J. D. N-Acetylcysteine potentiates nitroglycerin-induced reversal of platelet aggregation. J Cardiovasc.Pharmacol 1996;28(3):375-380. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • 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.
Evidence the quality of the studies behind the rating (graded A–D)
  • 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.

Keep it in perspective

N-acetyl Cysteine (nac) Also Interacts With Other Medications

N-acetyl Cysteine (nac) has 1 major, 292 moderate known drug interactions in our database — the Dalteparin one above is one of them. If you take anything else, check it against the full list below.

Major 1 Moderate 292 No known interaction 2,537 (incl. Dalteparin)
Taking anything else?

Check Another of Your Medications Against N-acetyl Cysteine (nac)

Covers the 2,830 medications we’ve checked against N-acetyl Cysteine (nac). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Dalteparin

This page covers N-acetyl Cysteine (nac) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dalteparin page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Piracetam (major), Aconite (moderate) and Allspice (moderate).

By severity: 3 major · 190 moderate · 25 minor.

From our pharmacist’s overview on the Dalteparin page

“Dalteparin (Fragmin) is an injectable blood thinner used to prevent and treat dangerous clots, which is exactly why this list warrants real vigilance, and nearly all 218 ingredients on it thin the blood too. They are herbs and extracts with clot-inhibiting or antiplatelet effects of their own, so stacking them on dalteparin can push bl…”

Reviewed by 2 · Jul 18, 2026

Open the Dalteparin interaction page

One more smart check

Taking N-acetyl Cysteine (nac) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 3,554 real supplement products containing N-acetyl Cysteine (nac), each one broken down to its full ingredient list — and combination products often carry several ingredients besides N-acetyl Cysteine (nac). Your product may carry other ingredients that interact with Dalteparin too, on top of N-acetyl Cysteine (nac) — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where N-acetyl Cysteine (nac) and Dalteparin 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 N-acetyl Cysteine (nac)
Top 5%

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

29 days ago today
Medication Dalteparin
Steady interest

#1,513 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.

Supplement

About N-acetyl Cysteine (nac)

What is N-acetyl Cysteine (nac)?

N-acetyl Cysteine (nac)
  • Thinning mucus in lung conditions
  • Acetaminophen (Tylenol) overdose treatment
  • Antioxidant and glutathione support
  • Liver support
  • Respiratory health

N-acetyl cysteine (NAC) is a supplement form of the amino acid cysteine and a building block for the antioxidant glutathione. It has well-established prescription uses for acetaminophen overdose and thinning mucus, but evidence for many over-the-counter uses is still limited. It is generally well tolerated, but you should check with a pharmacist or doctor before starting it.

Read the full N-acetyl Cysteine (nac) monograph & all interactions
Medication

About Dalteparin Injection

What Is Dalteparin Injection Used For?

Brand name: Fragmin

Fragmin (dalteparin) injection is used to prevent blood clots (deep vein thrombosis and pulmonary embolism) in patients having abdominal surgery, hip replacement surgery, or in medical patients who are severely immobile during a serious illness. It is also used to reduce the risk of dangerous complications from unstable angina and a type of heart attack called non-Q-wave myocardial infarction, given alongside aspirin.

Fragmin is also used for the extended treatment of symptomatic venous thromboembolism (VTE — blood clots in the veins or lungs) to prevent recurrence in adult cancer patients, and for the treatment of symptomatic VTE in children from birth (gestational age at least 35 weeks). Fragmin is not intended for the immediate (acute) treatment of VTE.

See full Dalteparin Injection drug information
Keep checking

Other Drugs & N-acetyl Cysteine (nac)

Browse every other medication we’ve checked against N-acetyl Cysteine (nac) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

1Major
292Moderate
0Minor
2,536No known interaction
1 Major 292 Moderate 2,536 No interaction
Major

1 interaction

Moderate

292 interactions

Showing 60 of 292 moderate interactions — see all 292 on the N-acetyl Cysteine (nac) page.

No interaction 2,536 drugs checked — show the list

We also checked N-acetyl Cysteine (nac) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,536 medications checked with no known interaction — see the full N-acetyl Cysteine (nac) list.

See the full N-acetyl Cysteine (nac) interactions page
See every supplement checked against Dalteparin, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

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

Keep exploring
N-acetyl Cysteine (nac) monograph › Uses, safety, and every drug interaction in one place Dalteparin supplement interactions › Every supplement checked against Dalteparin, ranked by severity Dalteparin Injection drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking N-acetyl Cysteine (nac) and Dalteparin Together: Common Questions

Can you take N-acetyl Cysteine (nac) with Dalteparin?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the N-acetyl Cysteine (nac) and Dalteparin interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Dalteparin and N-acetyl Cysteine (nac)?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.