Herb & supplement monograph

N-acetyl Cysteine (nac) Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how N-acetyl Cysteine (nac) interacts with medications. The heart of this page is the interaction list — every drug N-acetyl Cysteine (nac) is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what N-acetyl Cysteine (nac) is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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N-acetyl Cysteine (nac) Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant N-acetyl Cysteine (nac) drug interaction appears low for most people, with one important exception involving nitroglycerin. Only one interaction is rated major, and nearly all of the rest are moderate concerns supported mainly by theoretical or early-stage research rather than human studies.

Interactions deserving the most attention

The combination that matters most is nitroglycerin given by IV or skin patch, where human research shows NAC can cause severe drops in blood pressure and intense headaches. People taking anticoagulant or antiplatelet drugs should also be careful, since some research shows NAC can slow clotting and reduce platelet activity, which could add to bleeding risk. NAC may also add to the effect of blood pressure medications, and it can work against activated charcoal when both are used, though these concerns rest on weaker evidence.

What the rest of the list means

NAC appears alongside a long list of medications, but that number does not mean every pairing is harmful. Most of these interactions are theoretical, drawn from animal or lab studies of possible effects on clotting, blood pressure, or absorption, and have not been confirmed to cause meaningful problems in people.

Check your medications against N-acetyl Cysteine (nac)

Based on HelloPharmacist’s N-acetyl Cysteine (nac) interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with N-acetyl Cysteine (nac)

294 medications have a known interaction with N-acetyl Cysteine (nac), graded by severity. Select any drug for the full evidence-based detail.

1 major interaction. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with N-acetyl Cysteine (nac).

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against N-acetyl Cysteine (nac) using our pharmacist-reviewed interaction data.

AI summaries are generated from our N-acetyl Cysteine (nac) interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact N-acetyl Cysteine (nac) combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs N-acetyl Cysteine (nac) affects

Every type of medication (drug category) N-acetyl Cysteine (nac) is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 5 drug categories N-acetyl Cysteine (nac) interacts with

NitroglycerinActivated CharcoalAnticoagulant/antiplatelet DrugsAntihypertensive DrugsChloroquine (aralen)

Nitroglycerin

N-acetyl cysteine can increase the risk for hypotension and headaches when taken with intravenous or transdermal nitroglycerin.
Clinical research shows that concomitant administration of N-acetyl cysteine and intravenous or transdermal nitroglycerin can cause severe hypotension and intolerable headaches. Furthermore, in vitro research suggests that N-acetyl cysteine increases the anticoagulant activity of nitroglycerin.

Likelihood Probable Evidence B

Activated Charcoal

N-acetyl cysteine might reduce the effects of activated charcoal, while activated charcoal might reduce the absorption of N-acetyl cysteine.
N-acetyl cysteine appears to reduce the capacity of activated charcoal to adsorb acetaminophen and salicylic acid. Conversely, although clinical research suggests that although activated charcoal can reduce the absorption of N-acetyl cysteine by up to 40%, it does not seem to reduce its clinical effects. Other clinical evidence suggests that activated charcoal does not affect the absorption of N-acetyl cysteine.

Likelihood Possible Evidence D

Anticoagulant/Antiplatelet Drugs

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.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, N-acetyl cysteine might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research suggests that N-acetyl cysteine potentiates the hypotensive effects of the angiotensin-converting enzyme inhibitors (ACEIs) captopril and enalaprilat. Theoretically, combining N-acetyl cysteine with other antihypertensive drugs might increase the risk of hypotension.

Likelihood Possible Evidence D

Chloroquine (Aralen)

Theoretically, N-acetyl cysteine might interfere with the antimalarial effects of chloroquine.
Animal research suggests that N-acetyl cysteine might reduce the antimalarial effects of chloroquine by increasing cellular levels of glutathione.

Likelihood Possible Evidence D

Monograph

N-acetyl Cysteine (nac): Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

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.

Part used: Not applicable (a modified form of the amino acid cysteine)
Common forms: Capsules, tablets, powder, effervescent tablets, and prescription inhalation or injectable solutions

People commonly use it for

Thinning mucus in lung conditions
Acetaminophen (Tylenol) overdose treatment
Antioxidant and glutathione support
Liver support
Respiratory health

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated at typical doses, but talk to a healthcare provider before use.

PregnancyPossibly Safe

When used orally, intratracheally, intravenously, or by inhalation. N-acetyl cysteine crosses the placenta, but has not been associated with adverse e...

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

N-acetyl cysteine (NAC) is a man-made form of the amino acid cysteine, which your body uses to make proteins and the important antioxidant glutathione. Unlike herbs, NAC does not come from a plant — it is made in a laboratory.

NAC has a long history as a prescription medicine. Doctors use it in hospitals to treat acetaminophen (Tylenol) overdose and to help loosen and thin thick mucus in people with certain lung problems. It is also sold as a dietary supplement, often marketed for antioxidant support, liver health, and respiratory wellness.

How it works

NAC supplies cysteine, a building block your body uses to make glutathione. Glutathione is one of the body's main antioxidants, helping protect cells from damage caused by oxidative stress.

In acetaminophen overdose, NAC helps the liver make more glutathione, which neutralizes the harmful byproduct that builds up and damages the liver. As a mucus-thinner, NAC is thought to break the chemical bonds that make mucus thick and sticky, making it easier to clear.

NAC may also have anti-inflammatory effects, but much of this work comes from laboratory and animal research, so the real-world importance for everyday supplement users is not yet clear.

Effectiveness

Does N-acetyl Cysteine (nac) work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 91 uses evaluated

4 Effective 11 Possibly effective 16 Leans ineffective 60 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Effective Acetaminophen poisoning