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Acetylcysteine
Pronunciation
U.S. Brand Names
Generic Available
Synonyms
Pharmacological Index
Use
Pregnancy Risk Factor
Pregnancy/Breast-Feeding Implications
Contraindications
Warnings/Precautions
Adverse Reactions
Overdosage/Toxicology
Drug Interactions
Stability
Mechanism of Action
Pharmacodynamics/Kinetics
Usual Dosage
Reference Range
Mental Health: Effects on Mental Status
Mental Health: Effects on Psychiatric Treatment
Dental Health: Local Anesthetic/Vasoconstrictor Precautions
Dental Health: Effects on Dental Treatment
Patient Information
Nursing Implications
Dosage Forms
References

Pronunciation
(a se teel SIS teen)

U.S. Brand Names
Mucomyst®; Mucosil™

Generic Available

No


Synonyms
Acetylcysteine Sodium; Mercapturic Acid; NAC; N-Acetylcysteine; N-Acetyl-L-cysteine

Pharmacological Index

Antidote; Mucolytic Agent


Use

Adjunctive mucolytic therapy in patients with abnormal or viscid mucous secretions in acute and chronic bronchopulmonary diseases; pulmonary complications of surgery and cystic fibrosis; diagnostic bronchial studies; antidote for acute acetaminophen toxicity


Pregnancy Risk Factor

B


Pregnancy/Breast-Feeding Implications

Clinical effects on the fetus: There are no adequate and well controlled studies in pregnant women; use if only clearly needed


Contraindications

Known hypersensitivity to acetylcysteine


Warnings/Precautions

Since increased bronchial secretions may develop after inhalation, percussion, postural drainage and suctioning should follow; if bronchospasm occurs, administer a bronchodilator; discontinue acetylcysteine if bronchospasm progresses


Adverse Reactions

>10%:

Gastrointestinal: Vomiting

Miscellaneous: Unpleasant odor during administration

1% to 10%:

Central nervous system: Drowsiness, chills

Gastrointestinal: Stomatitis, nausea

Local: Irritation

Respiratory: Bronchospasm, rhinorrhea, hemoptysis

Miscellaneous: Clamminess

<1%: Skin rash


Overdosage/Toxicology

The treatment of acetylcysteine toxicity is usually aimed at reversing anaphylactoid symptoms or controlling nausea and vomiting. The use of epinephrine, antihistamines, and steroids may be beneficial.


Drug Interactions

Adsorbed by activated charcoal; clinical significance is minimal, though, once a pure acetaminophen ingestion requiring N-acetylcysteine is established; further charcoal dosing is unnecessary once the appropriate initial charcoal dose is achieved (5-10 g:g acetaminophen)


Stability

Store opened vials in the refrigerator, use within 96 hours; dilutions should be freshly prepared and used within 1 hour; light purple color of solution does not affect its mucolytic activity


Mechanism of Action

Exerts mucolytic action through its free sulfhydryl group which opens up the disulfide bonds in the mucoproteins thus lowering mucous viscosity. The exact mechanism of action in acetaminophen toxicity is unknown; thought to act by providing substrate for conjugation with the toxic metabolite.


Pharmacodynamics/Kinetics

Oral:

Peak plasma levels: 1-2 hours

Distribution: 0.33-0.47 L/kg

Plasma protein binding: 50%

Onset of action: Inhalation: Mucus liquefaction occurs maximally within 5-10 minutes

Duration: Can persist for >1 hour

Half-life: Reduced acetylcysteine: 2 hours; Total acetylcysteine: 5.5 hours


Usual Dosage

Acetaminophen poisoning: Children and Adults: Oral: 140 mg/kg; followed by 17 doses of 70 mg/kg every 4 hours; repeat dose if emesis occurs within 1 hour of administration; therapy should continue until all doses are administered even though the acetaminophen plasma level has dropped below the toxic range

Inhalation: Acetylcysteine 10% and 20% solution (Mucomyst®) (dilute 20% solution with sodium chloride or sterile water for inhalation); 10% solution may be used undiluted

Infants: 1-2 mL of 20% solution or 2-4 mL 10% solution until nebulized given 3-4 times/day

Children: 3-5 mL of 20% solution or 6-10 mL of 10% solution until nebulized given 3-4 times/day

Adolescents: 5-10 mL of 10% to 20% solution until nebulized given 3-4 times/day

Note: Patients should receive an aerosolized bronchodilator 10-15 minutes prior to acetylcysteine

Meconium ileus equivalent: Children and Adults: 100-300 mL of 4% to 10% solution by irrigation or orally


Reference Range

Determine acetaminophen level as soon as possible, but no sooner than 4 hours after ingestion (to ensure peak levels have been obtained); administer for acetaminophen level >150 mg/mL; toxic concentration with probable hepatotoxicity: >200 mg/mL at 4 hours or 50 mg at 12 hours


Mental Health: Effects on Mental Status

May cause drowsiness


Mental Health: Effects on Psychiatric Treatment

None reported


Dental Health: Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions


Dental Health: Effects on Dental Treatment

Stomatitis has been reported in 1% to 10% of patients


Patient Information

Pulmonary treatment: Prepare solution (may dilute with sterile water to reduce concentrate from impeding nebulizer) and use as directed. Clear airway by coughing deeply before using aerosol. Wash face and face-mask after treatment to remove any residual. You may experience drowsiness (use caution when driving) or nausea or vomiting (small frequent meals may help). Report persistent chills or fever, adverse change in respiratory status, palpitations, or extreme anxiety or nervousness.


Nursing Implications

Assess patient for nausea, vomiting, and skin rash following oral administration for treatment of acetaminophen poisoning; intermittent aerosol treatments are commonly given when patient arises, before meals, and just before retiring at bedtime


Dosage Forms

Solution, as sodium: 10% [100 mg/mL] (4 mL, 10 mL, 30 mL); 20% [200 mg/mL] (4 mL, 10 mL, 30 mL, 100 mL)


References

Douglas D and Smilkstein M, "Deferoxamine-Iron Induced Pulmonary Injury and N-Acetylcysteine," J Toxicol Clin Toxicol, 1995, 33(5):495.

Harrison PM, Wendon JA, Gimson AE, et al, "Improvement by Acetylcysteine of Hemodynamics and Oxygen Transport in Fulminant Hepatic Failure," N Engl J Med, 1991, 324(26):1852-7.

Henderson A and Hayes P, "Acetylcysteine as a Cytoprotective Antioxidant in Patients With Severe Sepsis: Potential New Use for an Old Drug," Ann Pharmacother, 1994, 28(9):1086-8.

Keays R, Harrison PM, Wendon JA, et al, "Intravenous Acetylcysteine in Paracetamol Induced Fulminant Hepatic Failure: A Prospective Controlled Trial," BMJ, 1991, 303(6809):1026-9.

Mohammed S, Jamal AZ, and Robison LR, "Serum Sickness-Like Illness Associated With N-Acetylcysteine Therapy," Ann Pharmacother, 1994, 28(2):285.

Mroz L, Benitez JG, and Krenzelok E, "Angioedema With Oral Acetylcysteine," Clin Toxicol, 1995, 33(5):554-5

Prescott LF, Donovan JW, Jarvie DR, et al, "The Disposition and Kinetics of Intravenous N-acetylcysteine in Patients With Paracetamol Overdosage," Eur J Clin Pharmacol, 1989, 37(5):501-6.

Rodgers G, Matyunas N, Ross M, et al, "Sulfhemoglobinemia Associated With N-Acetylcysteine (NAC) Therapy of Acetaminophen (APAP) Overdose: A Case Report," Clin Toxicol, 1995, 33(5):530.

Smilkstein MJ, Knapp GL, Kulig KW, et al, "Efficacy of N-Acetylcysteine in the Treatment of Acetaminophen Overdose: Analysis of the National Multicenter Study (1976 to 1985)," N Engl J Med, 1988, 319(24):1557-62.

Walson PD and Groth JF Jr, "Acetaminophen Hepatotoxicity After Prolonged Ingestion," Pediatrics, 1993, 91(5):1021-2.

Woo OF, Anderson IB, Kim SY, et al, "Shorter Duration of N-Acetylcysteine (NAC) for Acute Acetaminophen Poisoning," Clin Toxicol, 1995, 33(5):508.


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