Please check your internet connection and try again.
# Acetylcysteine
## Overview
Acetylcysteine is a mucolytic agent that breaks disulfide bonds in mucoproteins, decreasing mucus viscosity. It also serves as an antidote for acetaminophen overdose by replenishing hepatic glutathione stores.
## Primary Indications
* Acetaminophen overdose (antidote)
* Thick bronchial secretions (mucolytic)
## Adult Dosing
**Acetaminophen Overdose:**
* **Loading dose:** 150 mg/kg IV infused over 1 hour.
* **Second infusion:** 50 mg/kg IV infused over 4 hours.
* **Third infusion:** 100 mg/kg IV infused over 16 hours.
* Maximum total dose: 300 mg/kg (over the first 21 hours).
* **Note:** IV formulation can cause anaphylactoid reactions. Oral administration is an alternative if IV access is problematic or anaphylaxis is a concern. Oral dosing protocol varies; consult local protocol.
**Thick Bronchial Secretions:**
* **Nebulization:** 3 mL to 5 mL of a 10% or 20% solution every 4 to 6 hours as needed.
* **Oral:** 200 mg twice daily to 600 mg three times daily. Dosing varies by indication and formulation.
## Pediatric Dosing
**Acetaminophen Overdose:**
* Dosing is the same as adults based on weight (150 mg/kg, then 50 mg/kg, then 100 mg/kg).
* **Note:** Pediatric patients are at higher risk of anaphylactoid reactions with IV acetylcysteine.
**Thick Bronchial Secretions:**
* **Nebulization:** 1 mL to 3 mL of a 20% solution or 2 mL to 5 mL of a 10% solution every 4 to 6 hours as needed.
* **Oral:** Dosing varies by indication; consult specific pediatric guidelines.
## Dose Adjustments
No dose adjustments are typically required for renal or hepatic impairment for the antidote indication, as the drug is primarily metabolized and cleared. For mucolytic use, monitoring may be necessary in patients with severe respiratory compromise.
## Contraindications
* Hypersensitivity to acetylcysteine or any component of the formulation.
* Acute bronchospasm (for inhaled preparations).
## Adverse Effects
* **Common (Nebulized):** Bronchospasm, nausea, vomiting, stomatitis, rhinorrhea.
* **Common (IV for Overdose):** Anaphylactoid reactions (ranging from rash, pruritus, urticaria to bronchospasm, angioedema, and rarely anaphylaxis), rash, nausea, vomiting.
* **Common (Oral):** Nausea, vomiting, diarrhea, stomatitis.
## Key Drug Interactions
* **Activated Charcoal:** May bind to oral acetylcysteine, potentially reducing its absorption. Administer oral acetylcysteine at least 1 hour after activated charcoal.
* **Nitroglycerin:** May potentiate the vasodilatory effects of nitroglycerin, leading to hypotension.
## Monitoring
* **Acetaminophen Overdose:**
* Serum acetaminophen levels (to assess adequacy of antidote treatment).
* Liver function tests.
* Prothrombin time.
* Renal function.
* Signs and symptoms of anaphylactoid reaction.
* **Thick Bronchial Secretions:**
* Respiratory status, breath sounds.
* Signs and symptoms of bronchospasm.
## Clinical Pearls
* For IV administration in acetaminophen overdose, the rate of infusion of the loading dose should not exceed 15 mg/kg/hr to minimize the risk of anaphylactoid reactions.
* A palpable pulse is essential for administering epinephrine during anaphylaxis.
* Oral acetylcysteine has a characteristic sulfur odor and taste, which may lead to poor adherence.
* N-acetylcysteine's efficacy in acetaminophen overdose is time-dependent; prompt administration is crucial.
***
*Please verify the current prescribing information for complete details before initiating treatment.*
