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a mucolytic agent used by instillation or nebulization to reduce the viscosity of respiratory tract secretions and orally or intravenously as an antidote to acetaminophen poisoning.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

acetylcysteine (N-acetylcysteine)

Acetadote, Mucomyst (CA), Mucosil-10, Mucosil-20, Parovelex (CA) (UK)

Pharmacologic class: N-acetyl derivative of naturally occurring amino acid (L-cysteine)

Therapeutic class: Mucolytic, acetaminophen antidote

Pregnancy risk category B


Decreases viscosity of secretions, promoting secretion removal through coughing, postural drainage, and mechanical means. In acetaminophen overdose, maintains and restores hepatic glutathione, needed to inactivate toxic metabolites.


Injection: 200 mg/ml

Solution: 10%, 20%

Indications and dosages

Mucolytic agent in adjunctive treatment of acute and chronic bronchopulmonary disease (bronchitis, bronchiectasis, chronic asthmatic bronchitis, emphysema, pneumonia, primary amyloidism of lungs, tuberculosis, tracheobronchitis), pulmonary complications of cystic fibrosis, atelectasis, or pulmonary complications related to surgery, posttraumatic chest conditions, tracheostomy care, or use during anesthesia

Adults and children: Nebulization (face mask, mouthpiece, tracheostomy)-6 to 10 ml of 10% solution or 3 to 5 ml of 20% solution three or four times daily. Dosage range is 2 to 20 ml of 10% solution or 1 to 10 ml of 20% solution q 2 to 6 hours.

Nebulization (tent or croupette)-Volume of 10% or 20% solution that will maintain heavy mist for desired period Instillation (direct)-1 to 2 ml of 10% to 20% solution q 1 hour p.r.n.

Instillation via syringe attached to percutaneous intratracheal catheter-2 to 4 ml of 10% solution or 1 to 2 ml of 20% solution q 1 to 4 hours

Diagnostic bronchial studies

Adults and children: Two to three doses of 2 to 4 ml of 10% solution or 1 to 2 ml of 20% solution by nebulization or intratracheal instillation before procedure

Acetaminophen overdose

Adults, elderly patients, children: Give immediately if 24 hours or less have elapsed since acetaminophen ingestion. Use the following protocol: empty stomach by lavage or emesis induction, and then have patient drink copious amounts of water. If activated charcoal has been given, perform lavage before giving acetylcysteine. Draw blood for acetaminophen plasma assay and baseline aspartate aminotransferase (AST), alanine aminotransferase (ALT), prothrombin time, bilirubin, blood glucose, blood urea nitrogen, electrolyte, and creatinine clearance levels. If ingested acetaminophen dose is in toxic range, give acetylcysteine 140 mg/kg P.O. as loading dose from 20% solution. Administer 17 maintenance doses of 70 mg/kg P.O. q 4 hours, starting 4 hours after loading dose. Repeat procedure until acetaminophen blood level is safe. If patient vomits loading dose or any maintenance dose within 1 hour of administration, repeat that dose.

Off-label uses

• Unstable angina


• Hypersensitivity to drug (except with antidotal use)

• Status asthmaticus (except with antidotal use)


Use cautiously in:

• renal or hepatic disease, Addison's disease, alcoholism, brain tumor, bronchial asthma, seizure disorder, hypothyroidism, respiratory insufficiency, psychosis

• elderly patients

• pregnant or breastfeeding patients.


• Separate administration times of this drug and antibiotics.

• Use plastic, glass, or stainless steel container when giving by nebulizer, because solution discolors on contact with rubber and some metals.

• Once solution is exposed to air, use within 96 hours.

• Dilute solution before administering for acetaminophen overdose, to reduce risk of vomiting, drug's unpleasant odor, and irritating or sclerosing properties.

• Chill solution and have patient sip through straw, or, if necessary, give by nasogastric tube when administering for acetaminophen overdose.

Adverse reactions

CNS: dizziness, drowsiness, headache

CV: hypotension, hypertension, tachycardia

EENT: severe rhinorrhea

GI: nausea, vomiting, stomatitis, constipation, anorexia

Hepatic: hepatotoxicity

Respiratory: hemoptysis, tracheal and bronchial irritation, increased secretions, wheezing, chest tightness, bronchospasm

Skin: urticaria, rash, clamminess, angioedema

Other: tooth damage, chills, fever, hypersensitivity including anaphylaxis


Drug-drug. Activated charcoal: increased absorption and decreased efficacy of acetylcysteine

Nitroglycerin: increased nitroglycerin effects, causing hypotension and headache

Drug-diagnostic tests. Liver function tests: abnormal results

Patient monitoring

• Monitor respirations, cough, and character of secretions.

Patient teaching

• Instruct patient to report worsening cough and other respiratory symptoms.

• Advise patient to mix oral form with juice or cola to mask bad taste and odor.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


, N-acetylcysteine (a-sĕ'til-sis'tē-in),
A mucolytic agent that reduces the viscosity of mucous secretions; used to prevent liver injury produced by acetaminophen toxicity.
Farlex Partner Medical Dictionary © Farlex 2012


A mucolytic used to reduce the viscosity of lung secretions, and thought to improve O2 delivery and consumption by replenishing glutathione stores; acetylcysteine is also used orally or IV as an antidote, and minimises hepatocellular necrosis in patients with fulminant liver failure due to acetaminophen overdose. Acetylcysteine has also been used for treating dry eye (keratoconjunctivitis sicca) and as an enema for managing bowel obstruction caused by meconium ileus.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


Mucomyst Therapeutics A mucolytic used to ↓ the viscosity of lung secretions, and is thought to improve O2 delivery and consumption by replenishing glutathione stores; acetylcysteine is also used per os or IV as an antidote, and minimizes hepatocellular necrosis in Pts with fulminant liver failure; it has also been used for treating dry eye–keratoconjunctivitis sicca, and as an enema for managing bowel obstruction caused by meconium ileus. See Cystic fibrosis.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


, N-acetylcysteine (as'ĕ-til-sis'tē-in)
A mucolytic agent used to prevent liver injury due to acetaminophen toxicity.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


A mucolytic drug used to reduce the stickiness and viscosity of MUCUS. It is useful for freeing sputum in bronchitis and in liquefying mucus in CYSTIC FIBROSIS. It improves eye comfort in KERATOCONJUNCTIVITIS SICCA. Acetylcysteine increases the production of the antioxidant glutathione and other antioxidant thiols. It can reduce the risk of kidney damage from X-ray contrast media (contrast nephropathy) and reduce the risk of liver damage from acetaminophen (Paracetamol). It can prolong life in people with idiopathic pulmonary fibrosis. A brand name is Parvolex. Formulated with hypromellose it is marketed as Ilube.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


, N-acetylcysteine (as'ĕ-til-sis'tē-in)
A mucolytic agent that reduces the viscosity of mucous secretions.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Zidek, "Prevention of radiographic-contrastagent-induced reductions in renal function by acetylcysteine," The New England Journal of Medicine, vol.
Wendon et al., "Intravenous acetylcysteine in paracetamol induced fulminant hepatic failure: A prospective controlled trial," British Medical Journal, vol.
Back and colleagues (2016) reported on the first randomized controlled trial of 35 veterans who, in the treatment arm of the study, received 2,400 mg/day orally of acetylcysteine. Preliminary results suggest significant improvement in PTSD symptoms and provide impetus for continued and larger studies.
PLA, placebo; NAC, N- acetylcysteine; WBC, white blood cell count; (1) significantly different from baseline at P < 0.05; (2) significantly different from the previous time point at P < 0.05; (3) significant difference between trials at P < 0.05.
(31.) Hamamsy IE, Stevens LM, Carrier M et al; Effect of intravenous N- acetylcysteine on outcomes after coronary artery bypass surgery: A randomized, double-blind, placebo- controlled clinical trial.
Matetzky et al., "Oral acetylcysteine as an adjunct to saline hydration for the prevention of contrast-induced nephropathy following coronary angiography: a randomized controlled trial and review of the current literature," European Heart Journal, vol.
Rationale, design, and baseline characteristics of the acetylcysteine for contrast- induced nephropathy (ACT) trail: a pragmatic randomized controlled trial to evaluate the efficacy of acetylcysteine for the prevention of contrast induced nephropathy: The ACT Trial Investigators; Published: 4 June 2009.
(12-14) Although it is clear that acetylcysteine is an effective antidote for acetaminophen poisoning, (15-18) specific criteria defining those at risk for hepatotoxicity or even attributing enzyme abnormalities to acetaminophen are not clear.
High dose acetylcysteine in idiopathic pulmonary fibrosis.
Acetylcysteine for prevention of contrast-induced nephropathy after intravascular angiography: A systematic review and meta-analysis.
At that time, she was treated with the macrolide roxithromycin, without bacteriologic documentation, in addition to acetylcysteine (3 x 200 mg/d) and aerosolized terbutaline.