General

Pronunciation
a-se-teel-SIS-teen

Trade Name(s)

• Acetadote

• Mucomyst

• Mucosil

Pregnancy Category
Category B

Ther. class.
antidotes
(for acetaminophen toxicity)
mucolytic

Indications

• PO: Antidote for the management of potentially hepatotoxic overdosage of acetaminophen (should be administered within 24 hours of ingestion)

• IV: Antidote for the management of potentially hepatotoxic overdosage of acetaminophen (should be administered within 8–10 hours of ingestion)

• Inhaln: Mucolytic in the management of conditions associated with thick viscid mucous secretions

Unlabelled Use(s):
Prevention of radiocontrast-induced renal dysfunction (oral)

Action

• PO: Decreases the buildup of a hepatotoxic metabolite in acetaminophen overdosage

• IV: Decreases the buildup of a hepatotoxic metabolite in acetaminophen overdosage

• Inhaln: Degrades mucus, allowing easier mobilization and expectoration

Therapeutic Effect(s):

• PO: Prevention or lessening of liver damage following acetaminophen overdose

• Inhaln: Lowers the viscosity of mucus

Pharmacokinetics

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

ROUTE	ONSET	PEAK	DURATION
PO (antidote)	unknown	30–60 min	4 hr
Inhalation (mucolytic)	1 min	5–10 min	short

Contraindication/Precautions

Contraindicated in:
Hypersensitivity

Use Cautiously in:

• Severe respiratory insufficiency, asthma or history of bronchospasm

• History of GI bleeding (oral only)

• OB: Lactation: Safety not established

Adverse Reactions/Side Effects

CNS: drowsiness.

CV: vasodilation.

EENT: rhinorrhea.

Resp: bronchospasm, bronchial/tracheal irritation, chest tightness, increased secretions.

GI: nausea, vomiting, stomatitis.

Derm: pruritus, rash, urticaria, clamminess.

Misc: allergic reactions (primarily with IV), including anaphylaxis, ANGIOEDEMA, chills, fever.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug
Activated charcoal may adsorb orally administered acetylcysteine and decrease its effectiveness as an antidote

Route/Dosage

Acetaminophen Overdose

• PO (Adults and Children): 140 mg/kg initially, followed by 70 mg/kg q 4 hr for 17 additional doses.

• IV (Adults and Children):
Loading dose —150 mg/kg over 15 min initially followed by
First maintenance dose —50 mg/kg over 4 hr, then
second maintenance dose —100 mg/kg over 16 hr.

Mucolytic

• Inhaln (Adults and Children):
Nebulization via face mask—3–5 ml of 20% solution or 6–10 ml of the 10% solution 3–4 times daily (range —1–10 ml of 20% solution or 2–20 ml of 10% solution q 2–6 hr);
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).

Unlabeled Use (prevention of radiocontrast-induced renal dysfunction)

• PO (Adults): 600 mg twice daily for 2 days, beginning the day before the procedure.

Availability

• Solution for inhalation: 10% in 4-, 10-, and 30-ml vials, 20% in 4-, 10-, 30-, and 100–mL vials

• Solution for injection: 20% in 30–mL vials

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 anaphylactoid reaction. Erythema and flushing are common, usually occurring 30–60 min after initiating infusion, and may resolve with continued administration. If rash, hypotension, wheezing, dyspnea occur, initiate treatment for anaphylaxis (antihistamine and epinephrine). Acetylcysteine infusion should be interrupted until symptoms resolve and carefully restarted. If anaphylactoid reaction recurs, discontinue acetylcysteine and use alternative form of treatment

» 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 K₁ or fresh frozen plasma or clotting factor concentrate if prothrombin time ratio exceeds 1.5 or 3, respectively

» Assess patient for nausea, vomiting, and urticaria. Notify physician 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

Potential Nursing Diagnoses

• Risk for self-directed violence (Indications)

• Ineffective airway clearance (Indications)

• Deficient knowledge, related to medication regimen (Patient/Family Teaching)

Implementation

• 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 with these substances

• PO: Acetaminophen Overdose— First empty stomach contents by inducing emesis or lavage. 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

IV Adminstration:

• Intermittent Infusion:
Most effective if administered within 8 hrs of acetaminophen ingestion. Dilute in D5W. For loading dose: Dilute 150 mg/kg in 200 mL. For 1st Maintenance Dose: Dilute 50 mg/kg in 500 mL. For 2nd Maintenance Dose: Dilute 100 mg/kg in 1000 ML. Adjust fluid volume for patients <40 kg or 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 15 min
Administer 1st Maintenance Dose over 4 hr
Administer 2nd Maintenance Dose over 16 hr

• Inhaln:
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

• Inhaln: 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

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