Acetylcysteine

Not to be confused with N-Acetylcarnosine, for the proposed treatment of cataracts.

N-acetylcysteine, also known as Acetylcysteine and NAC, is a medication that is used to treat paracetamol (acetaminophen) overdose and to loosen thick mucus in individuals with chronic bronchopulmonary disorders, such as pneumonia and bronchitis.^[9] It has been used to treat lactobezoar in infants. It can be taken intravenously, orally (swallowed by mouth), or inhaled as a mist.^{[9][clarification needed]} It is also sometimes used as a dietary supplement.^[12][13]

Acetylcysteine

Clinical data
Pronunciation	/əˌsiːtəlˈsɪstiːn/ and similar (/əˌsɛtəl-, ˌæsɪtəl-, -tiːn/)
Trade names	ACC 200, Acetadote, Fluimucil, Mucomyst, others
Other names	N-acetylcysteine; N-acetyl-L-cysteine; NALC; NAC
AHFS/Drugs.com	Monograph
License data	US DailyMed: Acetylcysteine
Pregnancy category	AU: B2
Routes of administration	oral, intravenous, inhalation
ATC code	R05CB01 (WHO) S01XA08 (WHO) V03AB23 (WHO)
Legal status
Legal status	AU: S4 (Prescription only)[1][2][3] NZ: Prescription only UK: POM (Prescription only)[4] US: ℞-only[5]
Pharmacokinetic data
Bioavailability	6–10% (Oral)[6][7] nearly 100% (intravenous)[8]
Protein binding	50 to 83%[9]
Metabolism	Liver[9]
Elimination half-life	5.6 hours[5]
Excretion	Kidney (30%),[9] faecal (3%)
Identifiers
IUPAC name (2R)-2-acetamido-3-sulfanylpropanoic acid[10]
CAS Number	616-91-1 Y
PubChem CID	12035
DrugBank	DB06151 Y
ChemSpider	11540 Y
UNII	WYQ7N0BPYC
KEGG	D00221 Y
ChEBI	CHEBI:28939 Y
ChEMBL	ChEMBL600 Y
CompTox Dashboard (EPA)	DTXSID5020021
ECHA InfoCard	100.009.545
Chemical and physical data
Formula	C5H9NO3S
Molar mass	163.19 g·mol−1
3D model (JSmol)	Interactive image
Specific rotation	+5° (c = 3% in water)[11]
Melting point	109 to 110 °C (228 to 230 °F) [11]
SMILES C/C(=N/[C@@H](CS)C(=O)O)/O
InChI InChI=1S/C5H9NO3S/c1-3(7)6-4(2-10)5(8)9/h4,10H,2H2,1H3,(H,6,7)(H,8,9)/t4-/m0/s1 Y Key:PWKSKIMOESPYIA-BYPYZUCNSA-N Y
(verify)

Common side effects include nausea and vomiting when taken orally.^[9] The skin may occasionally become red and itchy with any route of administration.^[9] A non-immune type of anaphylaxis may also occur.^[9] It appears to be safe in pregnancy.^[9] For paracetamol overdose, it works by increasing the level of glutathione, an antioxidant that can neutralize the toxic breakdown products of paracetamol.^[9] When inhaled, it acts as a mucolytic by decreasing the thickness of mucus.^[14]

Acetylcysteine was initially patented in 1960 and came into medical use in 1968.^[15][16][17] It is on the World Health Organization's List of Essential Medicines.^[18] It is available as a generic medication.^[19]

The sulfur-containing amino acids cysteine and methionine are more easily oxidized than the other amino acids.^[20][21]

Uses

Medical uses

Paracetamol overdose antidote

Main article: Paracetamol poisoning

Intravenous and oral formulations of acetylcysteine are available for the treatment of paracetamol (acetaminophen) overdose.^[22] When paracetamol is taken in large quantities, a minor metabolite called N-acetyl-p-benzoquinone imine (NAPQI) accumulates within the body. It is normally conjugated by glutathione, but when taken in excess, the body's glutathione reserves are not sufficient to deactivate the toxic NAPQI. This metabolite is then free to react with key hepatic enzymes, thereby damaging liver cells. This may lead to severe liver damage and even death by acute liver failure.

In the treatment of paracetamol (acetaminophen) overdose, acetylcysteine acts to maintain or replenish depleted glutathione reserves in the liver and enhance non-toxic metabolism of acetaminophen.^[23] These actions serve to protect liver cells from NAPQI toxicity. It is most effective in preventing or lessening hepatic injury when administered within 8–10 hours after overdose.^[23] Research suggests that the rate of liver toxicity is approximately 3% when acetylcysteine is administered within 10 hours of overdose.^[22]

Although IV and oral acetylcysteine are equally effective for this indication, oral administration is generally poorly tolerated due to the higher dosing required to overcome its low oral bioavailability,^[24] its foul taste and odor, and a higher incidence of adverse effects when taken orally, particularly nausea and vomiting. Prior pharmacokinetic studies of acetylcysteine did not consider acetylation as a reason for the low bioavailability of acetylcysteine.^[25] Oral acetylcysteine is identical in bioavailability to cysteine precursors.^[25] However, 3% to 6% of people given intravenous acetylcysteine show a severe, anaphylaxis-like allergic reaction, which may include extreme breathing difficulty (due to bronchospasm), a decrease in blood pressure, rash, angioedema, and sometimes also nausea and vomiting.^[26] Repeated doses of intravenous acetylcysteine will cause these allergic reactions to progressively worsen in these people.

Several studies have found this anaphylaxis-like reaction to occur more often in people given intravenous acetylcysteine despite serum levels of paracetamol not high enough to be considered toxic.^{[27][28][29][30]}

Mucolytic agent

Acetylcysteine exhibits mucolytic properties, meaning it reduces the viscosity and adhesiveness of mucus. This therapeutic effect is achieved through the cleavage of disulfide bonds^[31] within mucoproteins (strongly cross-linked mucins),^[32] thereby decreasing the mucus viscosity and facilitating its clearance from the respiratory tract. This mechanism is particularly beneficial in conditions characterized by excessive or thickened mucus,^[33] such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, rhinitis or sinusitis.^[34] Acetylcysteine can be administered as a part of a complex molecule, Thiamphenicol glycinate acetylcysteine, which also contains thiamphenicol, an antibiotic.^[35]

Lungs

Inhaled acetylcysteine has been used for mucolytic therapy in addition to other therapies in respiratory conditions with excessive and/or thick mucus production. It is also used post-operatively, as a diagnostic aid, and in tracheotomy care. It may be considered ineffective in cystic fibrosis.^[36] A 2013 Cochrane review in cystic fibrosis found no evidence of benefit.^[37]

Acetylcysteine is used in the treatment of obstructive lung disease as an adjuvant treatment.^[38][39][40]

Other uses

Acetylcysteine has been used to complex palladium, to help it dissolve in water. This helps to remove palladium from drugs or precursors synthesized by palladium-catalyzed coupling reactions.^[41] N-acetylcysteine can be used to protect the liver.^[42]

Microbiological use

Acetylcysteine can be used in Petroff's method of liquefaction and decontamination of sputum, in preparation for recovery of mycobacterium.^[43] It also displays significant antiviral activity against influenza A viruses.^[44]

Acetylcysteine has bactericidal properties and breaks down bacterial biofilms of clinically relevant pathogens including Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Enterobacter cloacae, Staphylococcus epidermidis, and Klebsiella pneumoniae.^[45]

Side effects

"SNOAC" redirects here. For the gene, see snoaC.

The most commonly reported adverse effects for IV formulations of acetylcysteine are rash, urticaria, and itchiness.^[23]

Adverse effects for inhalational formulations of acetylcysteine include nausea, vomiting, stomatitis, fever, rhinorrhea, drowsiness, clamminess, chest tightness, and bronchoconstriction. Although infrequent, bronchospasm has been reported to occur unpredictably in some patients.^[46]

Adverse effects for oral formulations of acetylcysteine have been reported to include nausea, vomiting, rash, and fever.^[46]

Large doses in a mouse model showed that acetylcysteine could potentially cause damage to the heart and lungs.^[47] They found that acetylcysteine was metabolized to S-nitroso-N-acetylcysteine (SNOAC), which increased blood pressure in the lungs and right ventricle of the heart (pulmonary artery hypertension) in mice treated with acetylcysteine. The effect was similar to that observed following a 3-week exposure to an oxygen-deprived environment (chronic hypoxia). The authors also found that SNOAC induced a hypoxia-like response in the expression of several important genes both in vitro and in vivo. The implications of these findings for long-term treatment with acetylcysteine have not yet been investigated. The dose used by Palmer and colleagues was dramatically higher than that used in humans, the equivalent of about 20 grams per day.^[47] In humans, a much lower dosages (600 mg per day) have been observed to counteract some age-related decline in the hypoxic ventilatory response as tested by inducing prolonged hypoxia.^[48]

Although N-acetylcysteine prevented liver damage in mice when taken before alcohol, when taken four hours after alcohol it made liver damage worse in a dose-dependent fashion.^[49]

Pharmacology

Pharmacodynamics

Acetylcysteine serves as a prodrug to L-cysteine, a precursor to the biologic antioxidant glutathione. Hence administration of acetylcysteine replenishes glutathione stores.^[50]

• Glutathione, along with oxidized glutathione (GSSG) and S-nitrosoglutathione (GSNO), have been found to bind to the glutamate recognition site of the NMDA and AMPA receptors (via their γ-glutamyl moieties), and may be endogenous neuromodulators.^[51][52] At millimolar concentrations, they may also modulate the redox state of the NMDA receptor complex.^[52] In addition, glutathione has been found to bind to and activate ionotropic receptors that are different from any other excitatory amino acid receptor, and which may constitute glutathione receptors, potentially making it a neurotransmitter.^[53] As such, since N-acetylcysteine is a prodrug of glutathione, it may modulate all of the aforementioned receptors as well.
• Glutathione also modulates the NMDA receptor by acting at the redox site.^[54][55]

L-cysteine also serves as a precursor to cystine, which in turn serves as a substrate for the cystine-glutamate antiporter on astrocytes; hence there is increasing glutamate release into the extracellular space. This glutamate in turn acts on mGluR_2/3 receptors, and at higher doses of acetylcysteine, mGluR₅.^[56][57] Acetylcysteine may have other biological functions in the brain, such as the modulation of dopamine release and the reduction in inflammatory cytokine formation possibly via inhibiting NF-κB and modulating cytokine synthesis.^[54] These properties, along with the reduction of oxidative stress and the re-establishment of glutamatergic balance, would lead to an increase in growth factors, such as brain-derived neurotrophic factor (BDNF), and the regulation of neuronal cell death through B-cell lymphoma 2 expression (BLC-2).^[58]

Pharmacokinetics

The oral bioavailability of acetylcysteine is relatively low due to extensive first-pass metabolism in the gut wall and liver. It ranges between 6% and 10%.

Intravenous administration of acetylcysteine bypasses the first-pass metabolism, resulting in higher bioavailability compared to oral administration. Intravenous administration of acetylcysteine ensures nearly 100% bioavailability as it directly enters the bloodstream.

Acetylcysteine is extensively liver metabolized, CYP450 minimal, urine excretion is 22–30% with a half-life of 5.6 hours in adults and 11 hours in newborns.^{[medical citation needed]}

Acetylcysteine is the N-acetyl derivative of the amino acid L-cysteine, and is a precursor in the formation of the antioxidant glutathione in the body. The thiol (sulfhydryl) group confers antioxidant effects and is able to reduce free radicals.

Chemistry

Pure acetylcysteine is in a solid state at room temperature, appearing as a white crystalline powder or granules.^[59] The solid form of acetylcysteine is stable under normal conditions, but it can undergo oxidation if exposed to air or moisture over time, leading to the formation of its dimeric form, diacetylcysteine, which can have different properties.^[60] Acetylcysteine is highly hygroscopic, i.e., it absorbs moisture if exposed to open air.^[59]

Acetylcysteine can sometimes appear as a light yellow cast powder instead of pure white due to oxidation. The sulfur-containing amino acids, like cysteine, are more easily oxidized than other amino acids. When exposed to air or moisture, acetylcysteine can oxidize, leading to a slight yellowish tint.^[59]

Acetylcysteine in a form of a white or white with light yellow cast powder has a pK_a of 9.5 at 30 °C.^[11]

N-acetyl-L-cysteine is soluble in water and alcohol, and practically insoluble in chloroform and ether.^[61]

Acetylcysteine is highly soluble in water: it dissolves readily in water, forming a clear solution. The pH of a maximum-saturated acetylcysteine solution typically ranges between 6.0 and 7.5,^[62] depending on temperature, purity of the compount, presense of other ions (thet can affect the pH by interacting with acetylcysteine or altering the overall ionic strength of the solution), thus on the concentraton of acetylcysteine itself: higher concentrations of acetylcysteine can lead to a lower pH due to the increased presence of the acetylcysteine molecule itself. This range of pH between 6.0 and 7.5 ensures that the solution is neither too acidic nor too alkaline, making it suitable for various medical applications. Aqueous solutions of acetylcysteine are compatible with 0.9% sodium chloride solution; compatibility with 5% and 10% glucose solutions is also good.^[59]

As for the sunlight stability, acetylcysteine in dry powder form is relatively stable and does not degrade quickly when exposed to sunlight, but when dissolved in aqueous solution, acetylcysteine can degrade when exposed to sunlight, especially if the solution is not stored in a dark, cool place. Besides that, acetylcysteine in aqueous solution can undergo hydrolysis, leading to the breakdown of the amide bond in the molecule. Still, aqueous solutions of acetylcysteine are generally stable when stored properly: the solutions should be kept in tightly sealed containers and stored at controlled room temperature to prolong the stability.^[63][59]

Society and culture

Acetylcysteine was first studied as a drug in 1963. Amazon removed acetylcysteine for sale in the US in 2021, due to claims by the FDA of it being classified as a drug rather than a supplement.^{[64][65][66][67]} In April 2022, the FDA released draft guidance on FDA's policy regarding products labeled as dietary supplements that contain N-acetyl-L-cysteine.^[68] Amazon subsequently re-listed NAC products as of August 2022.^[69]

Research

While many antioxidants have been researched to treat a large number of diseases by reducing the negative effect of oxidative stress, acetylcysteine is one of the few that has yielded promising results, and is currently already approved for the treatment of paracetamol overdose.^[70]

• In mouse mdx models of Duchenne's muscular dystrophy, treatment with 1–2% acetylcysteine in drinking water significantly reduces muscle damage and improves strength.^[70]
• It is being studied in conditions such as autism, where cysteine and related sulfur amino acids may be depleted due to multifactorial dysfunction of methylation pathways involved in methionine catabolism.^[71]
• Animal studies have also demonstrated its efficacy in reducing the damage associated with moderate traumatic brain or spinal injury, and also ischaemia-induced brain injury. In particular, it has been demonstrated to reduce neuronal losses and to improve cognitive and neurological outcomes associated with these traumatic events.^[72]
• Research on acetylcysteine usage seems to show a positive efficiency in treating androgenetic alopecia (male baldness), with or without adjacent treatments such as the use of topical minoxidil solution.^[73]
• Research on mouse models also shows that acetylcysteine could be "used as an efficient and safe therapeutic option for hair loss induced by chemotherapy".^[74]
• It has been suggested that acetylcysteine may help people with aspirin-exacerbated respiratory disease by increasing levels of glutathione allowing faster breakdown of salicylates, although there is no evidence that it is of benefit.^[75]
• Small studies have shown acetylcysteine to be of benefit to people with blepharitis.^[76] It has been shown to reduce ocular soreness caused by Sjögren's syndrome.^[77]
• Research has found that acetylcysteine may have otoprotective properties and could potentially be useful for preventing hearing loss and tinnitus in some cases.^[78][79] A 2011 study showed that N-acetylcysteine may protect the human cochlea from subclinical hearing loss caused by loud noises such as impulse noise.^[80] In animal models, it reduced age-related hearing loss.^{[citation needed]}
• It has been shown effective in the treatment of Unverricht-Lundborg disease in an open trial in four patients. A marked decrease in myoclonus and some normalization of somatosensory evoked potentials with acetylcysteine treatment has been documented.^[81][82]
• Addiction to certain addictive drugs (including cocaine, heroin, alcohol, and nicotine) is correlated with a persistent reduction in the expression of excitatory amino acid transporter 2 (EAAT2) in the nucleus accumbens (NAcc);^[83] the reduced expression of EAAT2 in this region is implicated in addictive drug-seeking behavior.^[83] In particular, the long-term dysregulation of glutamate neurotransmission in the NAcc of long-term, drug-dependent users is associated with an increase in vulnerability to relapse after re-exposure to the addictive drug or its associated drug cues.^[83] Drugs that help to normalize the expression of EAAT2 in this region, such as N-acetylcysteine, have been proposed as an adjunct therapy for the treatment of addiction to cocaine, nicotine, alcohol, and other drugs.^[83]
• It has been tested for the reduction of hangover symptoms, though the overall results indicate very limited efficacy.^[84][85]
• A double-blind placebo controlled trial of 262 patients has shown NAC treatment was well-tolerated and resulted in a significant decrease in the frequency of influenza-like episodes, severity, and length of time confined to bed.^[86]

Kidney and bladder

N-acetylcysteine has been widely believed to prevent adverse effects of long term Ketamine use on the bladder and kidneys, and there is growing body of evidence to support this.^[87]

Evidence for the benefit of acetylcysteine to prevent radiocontrast induced kidney disease is mixed.^[88]

Acetylcysteine has been used for cyclophosphamide-induced haemorrhagic cystitis, although mesna is generally preferred due to the ability of acetylcysteine to diminish the effectiveness of cyclophosphamide.^[89]

Psychiatry

Acetylcysteine has been studied for major psychiatric disorders,^{[90][58][54][72]} including bipolar disorder,^[90] major depressive disorder, and schizophrenia.^[58][54]

Tentative evidence exists for N-acetylcysteine also in the treatment of Alzheimer's disease, autism, obsessive-compulsive disorder,^[91] specific drug addictions (cocaine), drug-induced neuropathy, trichotillomania, excoriation disorder, and a certain form of epilepsy (progressive myoclonic).^[58][54][92] Preliminary evidence showed efficacy in anxiety disorder, attention deficit hyperactivity disorder and mild traumatic brain injury although confirmatory studies are required.^{[92][93][94][95]} Tentative evidence also supports use in cannabis use disorder.^[96]

It is also being studied for use as a treatment of body-focused repetitive behavior.^[97][98]

Addiction

Evidence to date does not support the efficacy for N-acetylcysteine in treating addictions to gambling, methamphetamine, or nicotine.^[92] Based upon limited evidence, NAC appears to normalize glutamate neurotransmission in the nucleus accumbens and other brain structures, in part by upregulating the expression of excitatory amino acid transporter 2 (EAAT2), a.k.a. glutamate transporter 1 (GLT1), in individuals with addiction.^[83] While NAC has been demonstrated to modulate glutamate neurotransmission in adult humans who are addicted to cocaine, NAC does not appear to modulate glutamate neurotransmission in healthy adult humans.^[83] NAC has been hypothesized to exert beneficial effects through its modulation of glutamate and dopamine neurotransmission as well as its antioxidant properties.^[54]

Bipolar disorder

In bipolar disorder, N-acetylcysteine has been repurposed as an augmentation strategy for depressive episodes in light of the possible role of inflammation in the pathogenesis of mood disorders. Nonetheless, meta-analytic evidence shows that add-on N-acetylcysteine was more effective than placebo only in reducing depression scales scores (low quality evidence), without positive effects on response and remission outcomes, limiting its possible role in clinical practice to date.^[90][99]

COVID-19

Acetylcysteine has been studied as a possible treatment for COVID-19.^{[100][101][102]}

A combination of guanfacine and N-acetylcysteine has been found to lift the "brain fog" of eight patients with long COVID, according to researchers, but the results are inconclusive and have not been confirmed by other studies.^[103]

A combination of glycine and N-acetylcysteine is suspected to have potential to safely replenish depleted glutathione levels in COVID-19 patients.^[104]

External links

• Media related to Acetylcysteine at Wikimedia Commons

References

1. DBL ACETYLCYSTEINE injection concentrate acetylcysteine 2 g/ 10 mL injection ampoule
2. "TGA eBS - Product and Consumer Medicine Information Licence". Archived from the original on 30 December 2022. Retrieved 30 December 2022.
3. "Acetylcysteine (Omegapharm)". Healthdirect Australia. 30 November 2022. Archived from the original on 30 December 2022. Retrieved 29 December 2022.
4. "Acepiro 600 mg effervescent tablets - Summary of Product Characteristics (SmPC)". (emc). 30 August 2022. Archived from the original on 30 December 2022. Retrieved 29 December 2022.
5. "Acetadote- acetylcysteine injection, solution". DailyMed. 1 October 2021. Archived from the original on 30 December 2022. Retrieved 29 December 2022.
6. Tsikas D, Mikuteit M (September 2022). "N-acetyl-L-cysteine in human rheumatoid arthritis and its effects on nitric oxide (NO) and malondialdehyde (MDA): analytical and clinical considerations". Amino Acids. 54 (9): 1251–1260. doi:10.1007/s00726-022-03185-x. PMC 9372125. PMID 35829920.
7. Stockley RA (2008). Chronic Obstructive Pulmonary Disease a Practical Guide to Management. Chichester: John Wiley & Sons. p. 750. ISBN 9780470755280. Archived from the original on 8 September 2017.
8. Luo A, Liu X, Hu Q, Yang M, Jiang H, Liu W (March 2022). "Efficacy of N-acetylcysteine on idiopathic or postinfective non-cystic fibrosis bronchiectasis: a systematic review and meta-analysis protocol". BMJ Open. 12 (3): e053625. doi:10.1136/bmjopen-2021-053625. PMC 8971804. PMID 35361640. Archived from the original on 6 August 2024. Retrieved 5 August 2024.
9. "Acetylcysteine". The American Society of Health-System Pharmacists. Archived from the original on 23 September 2015. Retrieved 22 August 2015.
10. "L-Cysteine, N-acetyl- — Compound Summary". PubChem. National Center for Biotechnology Information, U.S. National Library of Medicine. 25 March 2005. Identification. Archived from the original on 12 January 2014. Retrieved 9 January 2012.
11. "N-Acetyl-L-cysteine Product Information" (PDF). Sigma. Sigma-Aldrich. Archived from the original (PDF) on 11 June 2014. Retrieved 9 November 2014.
12. Talbott SM (2012). A Guide to Understanding Dietary Supplements. Routledge. p. 469. ISBN 9781136805707. Archived from the original on 8 September 2017.
13. "Cysteine". University of Maryland Medical Center. Archived from the original on 1 July 2017. Retrieved 23 June 2017.
14. Sadowska AM, Verbraecken J, Darquennes K, De Backer WA (December 2006). "Role of N-acetylcysteine in the management of COPD". International Journal of Chronic Obstructive Pulmonary Disease. 1 (4): 425–434. doi:10.2147/copd.2006.1.4.425. PMC 2707813. PMID 18044098.
15. Fischer J, Ganellin CR (2006). Analogue-Based Drug Discovery. Weinheim: Wiley-VCH. p. 544. ISBN 9783527607495. Archived from the original on 8 September 2017.
16. US3091569A, Sheffner AL, "Mucolytic-nu-acylated sulfhydryl compositions and process for treating animal mucus", issued 28 May 1963 Archived 6 August 2024 at the Wayback Machine
17. US patent 3091569, Sheffner AL, "Mucolytic-N-acylated sulfhydryl compositions and process for treating animal mucus", published 28 May 1963, issued 28 May 1963, assigned to Mead Johnson & Co Archived 30 June 2024 at the Wayback Machine
18. World Health Organization (2023). The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023). Geneva: World Health Organization. hdl:10665/371090. WHO/MHP/HPS/EML/2023.02.
19. Baker E (2014). "Acetylcysteine". Top 100 Drugs: Clinical pharmacology and practical prescribing. Elsevier Health Sciences. ISBN 9780702055157. Archived from the original on 8 September 2017.
20. Bin P, Huang R, Zhou X (2017). "Oxidation Resistance of the Sulfur Amino Acids: Methionine and Cysteine". BioMed Research International. 2017: 9584932. doi:10.1155/2017/9584932. PMC 5763110. PMID 29445748.
21. Lee BC, Dikiy A, Kim HY, Gladyshev VN (November 2009). "Functions and evolution of selenoprotein methionine sulfoxide reductases". Biochimica et Biophysica Acta (BBA) - General Subjects. 1790 (11): 1471–1477. doi:10.1016/j.bbagen.2009.04.014. PMC 3062201. PMID 19406207.
22. Green JL, Heard KJ, Reynolds KM, Albert D (May 2013). "Oral and Intravenous Acetylcysteine for Treatment of Acetaminophen Toxicity: A Systematic Review and Meta-analysis". The Western Journal of Emergency Medicine. 14 (3): 218–226. doi:10.5811/westjem.2012.4.6885. PMC 3656701. PMID 23687539.
23. "Acetadote Package Insert" (PDF). FDA. Archived (PDF) from the original on 25 August 2013. Retrieved 19 April 2014.
24. Borgström L, Kågedal B, Paulsen O (1986). "Pharmacokinetics of N-acetylcysteine in man". European Journal of Clinical Pharmacology. 31 (2): 217–222. doi:10.1007/bf00606662. PMID 3803419. S2CID 41004554.
25. Dilger RN, Baker DH (July 2007). "Oral N-acetyl-L-cysteine is a safe and effective precursor of cysteine". Journal of Animal Science. 85 (7): 1712–1718. doi:10.2527/jas.2006-835. PMID 17371789.
26. Kanter MZ (October 2006). "Comparison of oral and i.v. acetylcysteine in the treatment of acetaminophen poisoning". American Journal of Health-System Pharmacy. 63 (19): 1821–1827. doi:10.2146/ajhp060050. PMID 16990628. S2CID 9209528.
27. Dawson AH, Henry DA, McEwen J (March 1989). "Adverse reactions to N-acetylcysteine during treatment for paracetamol poisoning". The Medical Journal of Australia. 150 (6): 329–331. doi:10.5694/j.1326-5377.1989.tb136496.x. PMID 2716644. S2CID 40296724.
28. Bailey B, McGuigan MA (June 1998). "Management of anaphylactoid reactions to intravenous N-acetylcysteine". Annals of Emergency Medicine. 31 (6): 710–715. doi:10.1016/S0196-0644(98)70229-X. PMID 9624310.
29. Schmidt LE, Dalhoff K (January 2001). "Risk factors in the development of adverse reactions to N-acetylcysteine in patients with paracetamol poisoning". British Journal of Clinical Pharmacology. 51 (1): 87–91. doi:10.1046/j.1365-2125.2001.01305.x. PMC 2014432. PMID 11167669.
30. Lynch RM, Robertson R (January 2004). "Anaphylactoid reactions to intravenous N-acetylcysteine: a prospective case controlled study". Accident and Emergency Nursing. 12 (1): 10–15. doi:10.1016/j.aaen.2003.07.001. PMID 14700565.
31. Pedre B, Barayeu U, Ezeriņa D, Dick TP (December 2021). "The mechanism of action of N-acetylcysteine (NAC): The emerging role of H₂S and sulfane sulfur species". Pharmacology & Therapeutics. 228: 107916. doi:10.1016/j.pharmthera.2021.107916. PMID 34171332.
32. Raghu G, Berk M, Campochiaro PA, Jaeschke H, Marenzi G, Richeldi L, et al. (2021). "The Multifaceted Therapeutic Role of N-acetylcysteine (NAC) in Disorders Characterized by Oxidative Stress". Current Neuropharmacology. 19 (8): 1202–1224. doi:10.2174/1570159X19666201230144109. PMC 8719286. PMID 33380301.
33. Schwalfenberg GK (2021). "N-acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks)". Journal of Nutrition and Metabolism. 2021: 9949453. doi:10.1155/2021/9949453. PMC 8211525. PMID 34221501.
34. Saltagi MZ, Comer BT, Hughes S, Ting JY, Higgins TS (November 2021). "Management of Recurrent Acute Rhinosinusitis: A Systematic Review". American Journal of Rhinology & Allergy. 35 (6): 902–909. doi:10.1177/1945892421994999. PMID 33622038.
35. Serra A, Schito GC, Nicoletti G, Fadda G (2007). "A therapeutic approach in the treatment of infections of the upper airways: thiamphenicol glycinate acetylcysteinate in sequential treatment (systemic-inhalatory route)". International Journal of Immunopathology and Pharmacology. 20 (3): 607–617. doi:10.1177/039463200702000319. PMID 17880774.
36. Rossi S, ed. (2006). Australian Medicines Handbook. Adelaide: Australian Medicines Handbook.
37. Tam J, Nash EF, Ratjen F, Tullis E, Stephenson A (July 2013). "Nebulized and oral thiol derivatives for pulmonary disease in cystic fibrosis" (PDF). The Cochrane Database of Systematic Reviews. 2013 (7): CD007168. doi:10.1002/14651858.CD007168.pub3. PMC 8078644. PMID 23852992. Archived from the original (PDF) on 27 March 2022. Retrieved 16 May 2018.
38. Grandjean EM, Berthet P, Ruffmann R, Leuenberger P (February 2000). "Efficacy of oral long-term N-acetylcysteine in chronic bronchopulmonary disease: a meta-analysis of published double-blind, placebo-controlled clinical trials". Clinical Therapeutics. 22 (2): 209–221. doi:10.1016/S0149-2918(00)88479-9. PMID 10743980.
39. Stey C, Steurer J, Bachmann S, Medici TC, Tramèr MR (August 2000). "The effect of oral N-acetylcysteine in chronic bronchitis: a quantitative systematic review". The European Respiratory Journal. 16 (2): 253–262. CiteSeerX 10.1.1.516.9510. doi:10.1034/j.1399-3003.2000.16b12.x. PMID 10968500.
40. Poole PJ, Black PN (May 2001). "Oral mucolytic drugs for exacerbations of chronic obstructive pulmonary disease: systematic review". BMJ. 322 (7297): 1271–1274. doi:10.1136/bmj.322.7297.1271. PMC 31920. PMID 11375228.
41. Garrett CE, Prasad K (2004). "The Art of Meeting Palladium Specifications in Active Pharmaceutical Ingredients Produced by Pd-Catalyzed Reactions". Advanced Synthesis & Catalysis. 346 (8): 889–900. doi:10.1002/adsc.200404071. S2CID 94929244.
42. "Acetylcysteine", livertox.nih.gov, 2012, PMID 31643176, archived from the original on 25 April 2019, retrieved 26 April 2019
43. Buijtels PC, Petit PL (July 2005). "Comparison of NaOH-N-acetyl cysteine and sulfuric acid decontamination methods for recovery of mycobacteria from clinical specimens". Journal of Microbiological Methods. 62 (1): 83–88. doi:10.1016/j.mimet.2005.01.010. PMID 15823396.
44. Geiler J, Michaelis M, Naczk P, Leutz A, Langer K, Doerr HW, et al. (February 2010). "N-acetyl-L-cysteine (NAC) inhibits virus replication and expression of pro-inflammatory molecules in A549 cells infected with highly pathogenic H5N1 influenza A virus" (PDF). Biochemical Pharmacology. 79 (3): 413–420. doi:10.1016/j.bcp.2009.08.025. PMID 19732754. Archived (PDF) from the original on 6 August 2024. Retrieved 14 October 2021.
45. Aslam S, Darouiche RO (September 2011). "Role of antibiofilm-antimicrobial agents in controlling device-related infections". The International Journal of Artificial Organs. 34 (9): 752–758. doi:10.5301/ijao.5000024. PMC 3251652. PMID 22094553.
46. "Mucomyst Package Insert". Archived from the original on 21 April 2014. Retrieved 20 April 2014.
47. Palmer LA, Doctor A, Chhabra P, Sheram ML, Laubach VE, Karlinsey MZ, et al. (September 2007). "S-nitrosothiols signal hypoxia-mimetic vascular pathology". The Journal of Clinical Investigation. 117 (9): 2592–2601. doi:10.1172/JCI29444. PMC 1952618. PMID 17786245.
48. Hildebrandt W, Alexander S, Bärtsch P, Dröge W (March 2002). "Effect of N-acetyl-cysteine on the hypoxic ventilatory response and erythropoietin production: linkage between plasma thiol redox state and O(2) chemosensitivity". Blood. 99 (5): 1552–1555. doi:10.1182/blood.V99.5.1552. PMID 11861267. S2CID 24375953.
49. Wang AL, Wang JP, Wang H, Chen YH, Zhao L, Wang LS, et al. (March 2006). "A dual effect of N-acetylcysteine on acute ethanol-induced liver damage in mice". Hepatology Research. 34 (3): 199–206. doi:10.1016/j.hepres.2005.12.005. PMID 16439183.
50. "Product Information: Aceradote Concentrated Injection" (PDF). TGA eBusiness Services. Phebra Pty Ltd. 16 January 2013. Archived from the original on 8 September 2017. Retrieved 8 November 2013.
51. Steullet P, Neijt HC, Cuénod M, Do KQ (February 2006). "Synaptic plasticity impairment and hypofunction of NMDA receptors induced by glutathione deficit: relevance to schizophrenia". Neuroscience. 137 (3): 807–819. doi:10.1016/j.neuroscience.2005.10.014. PMID 16330153. S2CID 1417873.
52. Varga V, Jenei Z, Janáky R, Saransaari P, Oja SS (September 1997). "Glutathione is an endogenous ligand of rat brain N-methyl-D-aspartate (NMDA) and 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors". Neurochemical Research. 22 (9): 1165–1171. doi:10.1023/A:1027377605054. PMID 9251108. S2CID 24024090.
53. Oja SS, Janáky R, Varga V, Saransaari P (2000). "Modulation of glutamate receptor functions by glutathione". Neurochemistry International. 37 (2–3): 299–306. doi:10.1016/S0197-0186(00)00031-0. PMID 10812215. S2CID 44380765.
54. Berk M, Malhi GS, Gray LJ, Dean OM (March 2013). "The promise of N-acetylcysteine in neuropsychiatry". Trends in Pharmacological Sciences. 34 (3): 167–177. doi:10.1016/j.tips.2013.01.001. PMID 23369637.
55. Lavoie S, Murray MM, Deppen P, Knyazeva MG, Berk M, Boulat O, et al. (August 2008). "Glutathione precursor, N-acetyl-cysteine, improves mismatch negativity in schizophrenia patients". Neuropsychopharmacology. 33 (9): 2187–2199. doi:10.1038/sj.npp.1301624. hdl:10536/DRO/DU:30071388. PMID 18004285.
56. Dodd S, Dean O, Copolov DL, Malhi GS, Berk M (December 2008). "N-acetylcysteine for antioxidant therapy: pharmacology and clinical utility". Expert Opinion on Biological Therapy. 8 (12): 1955–1962. doi:10.1517/14728220802517901. PMID 18990082. S2CID 74736842.
57. Kupchik YM, Moussawi K, Tang XC, Wang X, Kalivas BC, Kolokithas R, et al. (June 2012). "The effect of N-acetylcysteine in the nucleus accumbens on neurotransmission and relapse to cocaine". Biological Psychiatry. 71 (11): 978–986. doi:10.1016/j.biopsych.2011.10.024. PMC 3340445. PMID 22137594.
58. Dean O, Giorlando F, Berk M (March 2011). "N-acetylcysteine in psychiatry: current therapeutic evidence and potential mechanisms of action". Journal of Psychiatry & Neuroscience. 36 (2): 78–86. doi:10.1503/jpn.100057. PMC 3044191. PMID 21118657.
59. Rind L, Ahmad M, Khan MI, Badruddeen, Akhtar J, Ahmad U, et al. (2022). "An insight on safety, efficacy, and molecular docking study reports of N-acetylcysteine and its compound formulations". Journal of Basic and Clinical Physiology and Pharmacology. 33 (3): 223–233. doi:10.1515/jbcpp-2020-0099. PMID 33638319.
60. Amini A, Masoumi-Moghaddam S, Morris DL (2016). "N-Acetylcysteine". Utility of Bromelain and N-Acetylcysteine in Treatment of Peritoneal Dissemination of Gastrointestinal Mucin-Producing Malignancies. pp. 81–98. doi:10.1007/978-3-319-28570-2_4. ISBN 978-3-319-28570-2.
61. N-acetyl-L-cysteine#section=Chemical-and-Physical-Properties "N-Acetyl-L-cysteine | C₅H₉NO₃S". PubChem. National Center for Biotechnology Information, U.S. National Library of Medicine. N-acetyl-L-cysteine#section=Chemical-and-Physical-Properties Archived from the original on 16 August 2016. Retrieved 22 July 2016.
62. "USP Monographs: Acetylcysteine Solution".
63. Fohl AL, Johnson CE, Cober MP (2011). "Stability of extemporaneously prepared acetylcysteine 1% and 10% solutions for treatment of meconium ileus". American Journal of Health-System Pharmacy. 68 (1): 69–72. doi:10.2146/ajhp100214. PMID 21164069.
64. Long J (6 May 2021). "Amazon confirms plans on removing NAC supplements". Archived from the original on 16 May 2021. Retrieved 21 September 2023.
65. Long J (22 April 2021). "Amazon reportedly removes NAC-containing dietary supplements". Natural Products Inside. Archived from the original on 16 May 2021. Retrieved 16 May 2021.
66. "Warning Letter". benjaminmcevoy.com. U.S. Food and Drug Administration. Archived from the original on 3 May 2022. Retrieved 3 May 2022.
67. "FDA Sends Warning Letters to Seven Companies Illegally Selling Hangover Products". Archived from the original on 3 May 2022. Retrieved 3 May 2022.
68. "FDA Releases Draft Guidance on Enforcement Discretion for Certain NAC Products". Archived from the original on 3 May 2022. Retrieved 3 May 2022.
69. Long J (25 August 2022). "Amazon resumes sales of NAC supplements". Natural Products Insider. Retrieved 11 January 2023.
70. Head SI (December 2017). "Antioxidant therapy in a mouse model of Duchenne muscular dystrophy: some promising results but with a weighty caveat". The Journal of Physiology. 595 (23): 7015. doi:10.1113/jp275232. PMC 5709324. PMID 29034480.
71. Gu F, Chauhan V, Chauhan A (January 2015). "Glutathione redox imbalance in brain disorders". Current Opinion in Clinical Nutrition and Metabolic Care. 18 (1): 89–95. doi:10.1097/MCO.0000000000000134. PMID 25405315. S2CID 25333289.
72. Bavarsad Shahripour R, Harrigan MR, Alexandrov AV (March 2014). "N-acetylcysteine (NAC) in neurological disorders: mechanisms of action and therapeutic opportunities". Brain and Behavior. 4 (2): 108–122. doi:10.1002/brb3.208. PMC 3967529. PMID 24683506.
73. Mahira Hamdy El Sayed, Marwa Yassin Soltan, Ahmed Sadek, Mohamed Abo Shabana Hussein Mohamed (October 2021). Oxford University Press (ed.). "Efficacy and Tolerability of N-Acetyl-Cysteine for Treatment of The Early-onset Androgenetic Alopecia in Men". QJM: An International Journal of Medicine. 114 (Suppl.1). doi:10.1093/qjmed/hcab093.024.
74. Yomna F Hassan, Dalia A Shabaan (20 April 2024). "Effect of N-acetylcysteine on hair follicle changes in mouse model of cyclophosphamide-induced alopecia: histological and biochemical study". Histochemistry and Cell Biology. 161 (6): 477–491. doi:10.1007/s00418-024-02282-0. PMC 11162382. PMID 38641701.
75. Bachert C, Hörmann K, Mösges R, Rasp G, Riechelmann H, Müller R, et al. (March 2003). "An update on the diagnosis and treatment of sinusitis and nasal polyposis". Allergy. 58 (3): 176–191. doi:10.1034/j.1398-9995.2003.02172.x. PMID 12653791. S2CID 35319457.
76. Aitio ML (January 2006). "N-acetylcysteine -- passe-partout or much ado about nothing?". British Journal of Clinical Pharmacology. 61 (1): 5–15. doi:10.1111/j.1365-2125.2005.02523.x. PMC 1884975. PMID 16390346.
77. Williamson J, Doig WM, Forrester JV, Tham MH, Wilson T, Whaley K, et al. (September 1974). "Management of the dry eye in Sjogren's syndrome". The British Journal of Ophthalmology. 58 (9): 798–805. doi:10.1136/bjo.58.9.798. PMC 1215027. PMID 4433493.
78. Schlee W, Langguth B, Ridder DD, Vanneste S, Kleinjung T, Møller AR (2024). Textbook of Tinnitus (2nd ed.). Springer. p. 394, 620. ISBN 978-3-031-35646-9.
79. Chang PH, Liu CW, Hung SH, Kang YN (2022). "Effect of N-acetyl-cysteine in prevention of noise-induced hearing loss: a systematic review and meta-analysis of randomized controlled trials". Archives of Medical Science. 18 (6): 1535–1541. doi:10.5114/aoms/109126. PMC 9710288. PMID 36457967.
80. Lindblad AC, Rosenhall U, Olofsson A, Hagerman B (November–December 2011). "The efficacy of N-acetylcysteine to protect the human cochlea from subclinical hearing loss caused by impulse noise: a controlled trial". Noise & Health. 13 (55): 392–401. doi:10.4103/1463-1741.90293. PMID 22122955.
81. Edwards MJ, Hargreaves IP, Heales SJ, Jones SJ, Ramachandran V, Bhatia KP, et al. (November 2002). "N-acetylcysteine and Unverricht-Lundborg disease: variable response and possible side effects". Neurology. 59 (9): 1447–1449. doi:10.1212/wnl.59.9.1447. PMID 12427904.
82. Ataxia with Identified Genetic and Biochemical Defects at eMedicine
83. McClure EA, Gipson CD, Malcolm RJ, Kalivas PW, Gray KM (February 2014). "Potential role of N-acetylcysteine in the management of substance use disorders". CNS Drugs. 28 (2): 95–106. doi:10.1007/s40263-014-0142-x. PMC 4009342. PMID 24442756.
84. Clinical trial number NCT02541422 for "Use of NAC in Alleviation of Hangover Symptoms – Study Results" at ClinicalTrials.gov
85. Coppersmith V, Hudgins S, Stoltzfus J, Stankewicz H (June 2021). "The use of N-acetylcysteine in the prevention of hangover: a randomized trial". Scientific Reports. 11 (1): 13397. Bibcode:2021NatSR..1113397C. doi:10.1038/s41598-021-92676-0. PMC 8238992. PMID 34183702. S2CID 235673455.
86. De Flora S, Grassi C, Carati L (July 1997). "Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment". The European Respiratory Journal. 10 (7): 1535–1541. doi:10.1183/09031936.97.10071535. PMID 9230243.
87. Ryu CM, Shin JH, Yu HY, Ju H, Kim S, Lim J, et al. (May 2019). "N-acetylcysteine prevents bladder tissue fibrosis in a lipopolysaccharide-induced cystitis rat model". Scientific Reports. 9 (1): 8134. Bibcode:2019NatSR...9.8134R. doi:10.1038/s41598-019-44631-3. PMC 6544636. PMID 31148586.
88. Pistolesi V, Regolisti G, Morabito S, Gandolfini I, Corrado S, Piotti G, et al. (December 2018). "Contrast medium induced acute kidney injury: a narrative review". Journal of Nephrology. 31 (6): 797–812. doi:10.1007/s40620-018-0498-y. PMID 29802583. S2CID 44128861.
89. "Hemorrhagic Cystitis Treatment & Management: Approach Considerations, Clot Evacuation, Bladder Irrigation Agents". 5 December 2019. Archived from the original on 29 October 2020. Retrieved 18 December 2019.
90. Bartoli F, Cavaleri D, Bachi B, Moretti F, Riboldi I, Crocamo C, et al. (November 2021). "Repurposed drugs as adjunctive treatments for mania and bipolar depression: A meta-review and critical appraisal of meta-analyses of randomized placebo-controlled trials". Journal of Psychiatric Research. 143: 230–238. doi:10.1016/j.jpsychires.2021.09.018. PMID 34509090. S2CID 237485915.
91. Carollo M, Carollo N, Montan G (February 2024). "The promise of N-acetylcysteine in the treatment of obsessive-compulsive disorder". CNS Neuroscience & Therapeutics. 30 (2): e14653. doi:10.1111/cns.14653. PMC 10883097. PMID 38385640.
92. Slattery J, Kumar N, Delhey L, Berk M, Dean O, Spielholz C, et al. (August 2015). "Clinical trials of N-acetylcysteine in psychiatry and neurology: A systematic review". Neuroscience and Biobehavioral Reviews. 55: 294–321. doi:10.1016/j.neubiorev.2015.04.015. PMID 25957927.
93. Berk M, Dean OM, Cotton SM, Jeavons S, Tanious M, Kohlmann K, et al. (June 2014). "The efficacy of adjunctive N-acetylcysteine in major depressive disorder: a double-blind, randomized, placebo-controlled trial". The Journal of Clinical Psychiatry. 75 (6): 628–636. doi:10.4088/JCP.13m08454. PMID 25004186.
94. Oliver G, Dean O, Camfield D, Blair-West S, Ng C, Berk M, et al. (April 2015). "N-acetyl cysteine in the treatment of obsessive compulsive and related disorders: a systematic review". Clinical Psychopharmacology and Neuroscience. 13 (1): 12–24. doi:10.9758/cpn.2015.13.1.12. PMC 4423164. PMID 25912534.
95. Samuni Y, Goldstein S, Dean OM, Berk M (August 2013). "The chemistry and biological activities of N-acetylcysteine". Biochimica et Biophysica Acta (BBA) - General Subjects. 1830 (8): 4117–4129. doi:10.1016/j.bbagen.2013.04.016. hdl:11343/43874. PMID 23618697. S2CID 2567773.
96. Minarini A, Ferrari S, Galletti M, Giambalvo N, Perrone D, Rioli G, et al. (March 2017). "N-acetylcysteine in the treatment of psychiatric disorders: current status and future prospects". Expert Opinion on Drug Metabolism & Toxicology. 13 (3): 279–292. doi:10.1080/17425255.2017.1251580. hdl:11380/1116466. PMID 27766914. S2CID 20873065.
97. Hwang AS, Campbell EH, Sartori-Valinotti JC (July 2022). "Evidence of N-acetylcysteine efficacy for skin picking disorder: A retrospective cohort study". Journal of the American Academy of Dermatology. 87 (1): 148–150. doi:10.1016/j.jaad.2021.06.874. PMID 34224772. S2CID 235746237.
98. Popova L, Mancuso J (2022). "Dramatic Improvement of Trichotillomania with 6 Months of Treatment With N-acetylcysteine". Global Pediatric Health. 9: 2333794X221086576. doi:10.1177/2333794X221086576. PMC 9133858. PMID 35647220.
99. Nery FG, Li W, DelBello MP, Welge JA (November 2021). "N-acetylcysteine as an adjunctive treatment for bipolar depression: A systematic review and meta-analysis of randomized controlled trials". Bipolar Disorders. 23 (7): 707–714. doi:10.1111/bdi.13039. PMID 33354859. S2CID 229692736.
100. Wong KK, Lee SW, Kua KP (2021). "N-acetylcysteine as Adjuvant Therapy for COVID-19 - A Perspective on the Current State of the Evidence". Journal of Inflammation Research. 14: 2993–3013. doi:10.2147/JIR.S306849. PMC 8274825. PMID 34262324.
101. Assimakopoulos SF, Aretha D, Komninos D, Dimitropoulou D, Lagadinou M, Leonidou L, et al. (November 2021). "N-acetyl-cysteine reduces the risk for mechanical ventilation and mortality in patients with COVID-19 pneumonia: a two-center retrospective cohort study". Infectious Diseases. 53 (11): 847–854. doi:10.1080/23744235.2021.1945675. PMID 34182881. S2CID 235673520.
102. Kapur A, Sharma M, Sageena G (March 2022). "Therapeutic potential of N-acetyl cysteine during COVID-19 epoch". World Journal of Virology. 11 (2): 104–106. doi:10.5501/wjv.v11.i2.104. PMC 8966593. PMID 35433335.
103. Fesharaki-Zadeh A, Lowe N, Arnstien A (2022). "Clinical experience with the α2A-adrenoceptor agonist, guanfacine, and N-acetylcysteine for the treatment of cognitive deficits in "Long-COVID19"". Neuroimmunology Reports. 3 (3): 100154. doi:10.1016/j.nerep.2022.100154.
104. Kumar P, Osahon O, Vides DB, Hanania N, Minard CG, Sekhar RV (December 2021). "Severe Glutathione Deficiency, Oxidative Stress and Oxidant Damage in Adults Hospitalized with COVID-19: Implications for GlyNAC (Glycine and N-Acetylcysteine) Supplementation". Antioxidants. 11 (1): 50. doi:10.3390/antiox11010050. PMC 8773164. PMID 35052554.