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Related to Mucomyst: Acetylcysteine

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.


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Therapeutic: antidotes
Pregnancy Category: B


Oral: Antidote for the management of potentially hepatotoxic overdose of acetaminophen (administer within 8–10 hours [IV] or 24 hours [PO] of ingestion). Inhalation: Mucolytic in the management of conditions associated with thick viscid mucous secretions.Prevention of radiocontrast-induced renal dysfunction (oral).


Oral: Decreases the buildup of a hepatotoxic metabolite in acetaminophen overdosage.
Intravenous: Decreases the buildup of a hepatotoxic metabolite in acetaminophen overdosage.
Inhalation: Degrades mucus, allowing easier mobilization and expectoration.

Therapeutic effects

Oral: Prevention or lessening of liver damage following acetaminophen overdose.
Inhalation: Lowers the viscosity of mucus.


Absorption: Absorbed from the GI tract following oral administration. Action is local following inhalation; remainder may be absorbed from pulmonary epithelium.
Distribution: Crosses the placenta; 0.47 L/kg.
Protein Binding: 83% bound to plasma proteins.
Metabolism and Excretion: Partially metabolized by the liver, 22% excreted renally.
Half-life: Adults—5.6 hr (↑ in hepatic impairment) newborns—11 hr.

Time/action profile

PO (antidote)unknown30–60 min4 hr
Inhaln (mucolytic)1 min5–10 minshort


Contraindicated in: Hypersensitivity.
Use Cautiously in: Severe respiratory insufficiency, asthma, or history of bronchospasm;History of GI bleeding (oral only); Obstetric / Lactation: Safety not established.

Adverse Reactions/Side Effects

Central nervous system

  • drowsiness


  • vasodilation
  • tachycardia
  • hypotension

Ear, Eye, Nose, Throat

  • rhinorrhea


  • bronchospasm (most frequent)
  • bronchial/tracheal irritation
  • chest tightness
  • ↑ secretions


  • nausea (most frequent)
  • vomiting (most frequent)
  • stomatitis


  • rash (most frequent)
  • clamminess
  • pruritus
  • urticaria


  • allergic reactions (primarily with IV), including anaphylaxis (life-threatening)
  • angioedema (life-threatening)
  • chills
  • fever


Drug-Drug interaction

Activated charcoal may adsorb orally administered acetylcysteine and ↓ its effectiveness as an antidote.


Acetaminophen Overdose
Oral (Adults and Children) 140 mg/kg initially, followed by 70 mg/kg q 4 hr for 17 additional doses.
Intravenous (Adults and Children) Loading dose—150 mg/kg (maximum: 15 g) over 60 min initially followed by First maintenance dose—50 mg/kg (maximum: 5 g) over 4 hr, then second maintenance dose—100 mg/kg (maximum: 10 g) over 16 hr.
Inhalation (Adults and Children 1–12 yrs) Nebulization via face mask—3–5 mL of 20% solution or 6–10 mL of the 10% solution 3–4 times daily ; nebulization via tent or croupette—volume of 10–20% solution required to maintain heavy mist; direct instillation—1–2 mL of 10–20% solution q 1–4 hr; intratracheal instillation via tracheostomy—1–2 mL of 10–20% solution q 1–4 hr (up to 2–5 mL of 20% solution via tracheal catheter into particular segments of the bronchopulmonary tree).
Inhalation (Infants) Nebulization—1–2 ml of 20% solution or 2–4 mL of 10% solution 3–4 times daily.
Prevention of Radiocontrast-Induced Renal Dysfunction
Oral (Adults) 600 mg twice daily for 2 days, beginning the day before the procedure.

Availability (generic available)

Solution for inhalation: 10% (100 mg/mL), 20% (200 mg/mL)
Solution for injection: 20% (200 mg/mL)

Nursing implications

Nursing assessment

  • Antidote in Acetaminophen Overdose: Assess type, amount, and time of acetaminophen ingestion. Assess plasma acetaminophen levels. Initial levels are drawn at least 4 hr after ingestion of acetaminophen. Plasma level determinations may be difficult to interpret following ingestion of extended-release preparations. Do not wait for results to administer dose.
    • IV:Assess for anaphylaxis. Erythema and flushing are common, usually occurring 30–60 min after initiating infusion, and may resolve with continued administration. If rash, hypotension, wheezing, or dyspnea occur, initiate treatment for anaphylaxis (antihistamine and epinephrine). Interrupt acetylcysteine infusion until symptoms resolve and restart carefully. If anaphylaxsis recurs, discontinue acetylcysteine and use alternative form of treatment.
    • Assess patient for nausea, vomiting, and urticaria. Notify health care professional if these occur.
  • Mucolytic: Assess respiratory function (lung sounds, dyspnea) and color, amount, and consistency of secretions before and immediately following treatment to determine effectiveness of therapy.
  • Lab Test Considerations: Monitor AST, ALT, and bilirubin levels along with prothrombin time every 24 hr for 96 hr in patients with plasma acetaminophen levels indicating potential hepatotoxicity.
    • Monitor cardiac and renal function (creatinine, BUN), serum glucose, and electrolytes. Maintain fluid and electrolyte balance, correct hypoglycemia, and administer vitamin K or fresh frozen plasma or clotting factor concentrate if prothrombin time ratio exceeds 1.5 or 3, respectively.

Potential Nursing Diagnoses

Risk for self-directed violence (Indications)
Ineffective airway clearance (Indications)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)


  • Do not confuse Mucomyst with Mucinex.
  • After opening, solution for inhalation may turn light purple; does not alter potency. Refrigerate open vials and discard after 96 hr.
    • Drug reacts with rubber and metals (iron, nickel, copper); avoid contact.
  • Oral: Dilute 20% solution with cola, water, or juice to a final concentration of 1:3 for patients weighing up to 20 kg or with enough diluent to make a 5% solution for patients weighing more than 20 kg, to increase palatability. May be administered by duodenal tube if patient is unable to swallow. If patient vomits loading dose or maintenance doses within 1 hr of administration, readminister dose.
    • Acetaminophen Overdose—Empty stomach contents by inducing emesis or lavage prior to administration.
  • Intravenous Administration
  • pH: 6–75.
  • Intermittent Infusion: Most effective if administered within 8 hr of acetaminophen ingestion. Diluent: Dilute in D5W.Concentration: For loading dose:For patients 5-20 kg: Dilute 150 mg in 3 mL/kg of diluent. For patients 21–40 kg: Dilute 150 mg/kg in 100 mL. For patients 41–100 kg: Dilute 150 mg/kg in 200 mL. For Second Dose:For patients 5-20 kg: Dilute 50 mg/kg in 7 mL/kg of diluent. For patients 21–40 kg: Dilute 50 mg/kg in 250 mL of diluent. For patients 41–100 kg: Dilute 50 mg/kg in 500 mL. For Third Dose:For patients 5-20 kg: Dilute 100 mg/kg in 14 mL/kg of diluent. For patients 21–40 kg: 100 mg/kg diluted in 500 mL of diluent. For patients 41–100 kg: Dilute 100 mg/kg in 1000 mL. Adjust fluid volume for patients requiring fluid restriction. Vials are single-use. Discard after using. Reconstituted solution is stable for 24 hr at room temperature.
  • Rate: Administer Loading Dose over 1 hr.
    • Administer For Second Dose: over 4 hr.
    • Administer For Third Dose: over 16 hr.
  • Inhalation: Mucolytic—Encourage adequate fluid intake (2000–3000 mL/day) to decrease viscosity of secretions.
    • For nebulization, the 20% solution may be diluted with 0.9% NaCl for injection or inhalation or sterile water for injection or inhalation. May use 10% solution undiluted. May be administered by nebulization, or 1–2 mL may be instilled directly into airway. During administration, when 25% of medication remains in nebulizer, dilute with equal amount of 0.9% NaCl or sterile water.
    • An increased volume of liquefied bronchial secretions may occur following administration. Have suction equipment available for patients unable to effectively clear airways.
    • If bronchospasm occurs during treatment, discontinue and consult health care professional regarding possible addition of bronchodilator to therapy. Patients with asthma or hyperactive airway disease should be given a bronchodilator prior to acetylcysteine to prevent bronchospasm.
    • Rinse patient’s mouth and wash face following treatment, as drug leaves a sticky residue.

Patient/Family Teaching

  • Acetaminophen Overdose: Explain purpose of medication to patient.
  • Inhalation: Instruct patient to clear airway by coughing deeply before taking aerosol treatment.
    • Inform patient that unpleasant odor of this drug becomes less noticeable as treatment progresses and medicine dissipates.

Evaluation/Desired Outcomes

  • Decreased acetaminophen levels.
    • No further increase in hepatic damage during acetaminophen overdose therapy.
  • Decreased dyspnea and clearing of lung sounds when used as a mucolytic.
  • Prevention of radiocontrast-induced renal dysfunction.


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.
References in periodicals archive ?
Inclusion criteria used during the search were any medical procedure that utilized intravenous contrast dye, oral, or intravenous mucomyst, as well as hydration therapy that included saline or bicarbonate and saline, which was employed specifically for renal protection.
Table 1 Search Results--Key Words Mucomyst and Databases Mucomyst N-Actylcystein IV Contrast CINAHL 6 197 4 The Cochrane 687,344 19,708 0 Library PubMed 12,836 136 1 ClinicalTrial.Gov 233 20 18 Dynamed 3 0 0 Agency for 0 0 0 Healthcare Research and Quality N-Actylcystein IV Hydration Renal and and Protection and Databases IV Contrast IV Contrast IV Contrast CINAHL 1,241 1,028 1,105 The Cochrane 0 13 2 Library PubMed 0 1 5 ClinicalTrial.Gov 0 1 0 Dynamed 0 0 0 Agency for 0 0 9 Healthcare Research and Quality Note: Filtering subjects within those databases that offered the option included human trials, the English language, limited 2007 to 2013, evidence-based, and treatment specificity.
As a clinician, with an integrated multilevel reference, I can learn how to use Mucomyst right away, if I need it quickly; I can scan an expert review of different options and controversies in managing contrast-dye toxicity with one more click, and then I can study the original references later on, for my own education.
Orders are received for serial assessment of acetaminophen levels, routine ICU observation and nursing care, oxygen at 3 L per nasal cannula, an IV infusion of D5-1/2NS at 60 mL/hr, Mucomyst 385 mg q4h x 17 doses, and a formal gastroenterology consultation.
Food and Drug Administration in both oral (Mucomyst) and intravenous (Acetadote) forms for the treatment of acute overdoses.
Medical management for an acetaminophen overdose included administering N-acethylcysteine (Mucomyst) at 140 mg/kg by NG followed by 70 mg/kg every 4 hours for 17 doses.
Apart from bronchodilators, actively heated ("old fashioned") humidification of the air stream (to 376), vibro-percussion, appropriate body positioning and encouragement to cough, reasonable interventions include therapeutic bronchoscopy, aerosolized acetylcysteine (Mucomyst), guaifenesin (Mucinex) and an old tried and true remedy-aerosolized bicarbonate.
Preventive therapy with Nacetylcysteine (Mucomyst) or fenoldopam (Corlopam) has been advocated for such.