Acetylcysteine

Reviewed on 1/31/2022

What Is Acetylcysteine (Antidote) and How Does It Work?

Acetylcysteine (Antidote) is a prescription medication used to treat Acetaminophen Overdose. 

  • Acetylcysteine (Antidote) is available under the following different brand names: Acetadote, Cetylev, N-acetylcysteine (Antidote).

What Are Dosages of Acetylcysteine (Antidote)?

Adult and pediatric dosage

Injectable solution

  • 20% (200mg/mL)

Effervescent tablets for oral solution (Cetylev)

  • 500mg (DSC)
  • 2.5g (DSC)

Acetaminophen Overdose

Adult and pediatric dosage

May administer injectable orally

  • Continuous IV infusion recommended for acute ingestion (ideally within 8-10 hour following ingestion, but may administer if more than 10 hours)
  • Intermittent IV infusion may be considered for late presenting or chronic ingestion (more than 10 hours after ingestion)

Oral administration 

Adult and pediatric (Cetylev) dosage

  • May administer injectable orally
  • Loading dose: 140 mg/kg orally
  • Maintenance dose: 4 hours after loading dose, start 70 mg/kg orally every 4 hours for a total 17 doses; repeat dose if emesis occurs within 1 hour of administration

IV continuous infusion

Adult dosage

  • Acute ingestion (within 8-10 hour after ingestion)
  • Administer as 3 doses
  • Loading dose: 150 mg/kg IV; mix in 200 mL of D5W and infuse over 1 hour
  • Dose 2: 50 mg/kg IV in 500 mL D5W over 4 hours, then 
  • Dose 3: 100 mg/kg IV in 1000 mL D5W over 16 hours
  • Weight over 100 kg: No specific studies have conducted; limited data suggest a loading dose of 15,000 mg infused IV over 1 hour, then a first maintenance dose of 5,000 mg IV dose over 4 hours and a second maintenance dose of 10,000 mg over 16 hours

Pediatric dosage

  • IV continuous infusion (Acetadote) weight less than 20 kg:
  • Loading dose: 150 mg/kg IV in 3 mL diluent/kg body-weight over 1 hour
  • Dose 2: 50 mg/kg IV in 7 mL diluent/kg body-weight over 4 hours
  • Dose 3: 100 mg/kg in 14 mL diluent/kg body-weight over 16 hours
  • IV continuous infusion (Acetadote) weight over 20 kg to 39 kg:
  • Loading dose: 150 mg/kg IV in 100 mL of diluent administered over 1 hour
  • Dose 2: 50 mg/kg IV in 250 mL of diluent administered over 4 hours
  • Dose 3: 100 mg/kg IV in 500 mL of diluent administered over 16 hours
  • IV continuous infusion (Acetadote) weight over 40 kg: 

As adults

  • Loading dose: 150 mg/kg IV; mix in 200 mL of D5W and infuse over 1 hour
  • Dose 2: 50 mg/kg IV in 500 mL D5W over 4 hours, then 
  • Dose 3: 100 mg/kg IV in 1000 mL D5W over 16 hours

Dosage Considerations – Should be Given as Follows: 

  • See "Dosages."

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What Are Side Effects Associated with Using Acetylcysteine (Antidote)?

Common side effects of Acetylcysteine (Antidote) include:

  • mild nausea, 
  • stomach upset, and
  • vomiting

Serious side effects of Acetylcysteine (Antidote) include:

  • hives, 
  • difficulty breathing, 
  • swelling of the face, lips, tongue, or throat, 
  • fever, 
  • itching, 
  • nausea, 
  • rash with or without a fever, 
  • reddening of the skin (especially around the ears), 
  • severe or ongoing vomiting, 
  • unusual tiredness, and 
  • weakness

Rare side effects of Acetylcysteine (Antidote) include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Acetylcysteine (Antidote)?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Acetylcysteine (Antidote)?

Contraindications

  • Hypersensitivity

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Acetylcysteine (Antidote)?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Acetylcysteine (Antidote)?”

Cautions

  • Obtain serum acetaminophen concentration at least 4 hours post ingestion to determine if toxic levels present before treatment or whether full course necessary
  • IV used if persistent vomiting precludes oral administration in 1st 8 hr
  • Consult local regional PCC or medical toxicologist for assistance
  • Asthma patient reported to develop bronchospasm and die after intravenous administration of drug; should be used with caution in patients with asthma, or where there is a history of bronchospasm; patients with asthma should be closely monitored during initiation of therapy and throughout therapy
  • Total volume administered should be adjusted for patients weighing less than 40 kg and for those requiring fluid restriction; to avoid fluid overload, volume of diluent should be reduced as needed; if volume not adjusted fluid overload can occur, potentially resulting in hyponatremia, seizure and death
  • Hypersensitivity reactions
    • Serious acute hypersensitivity reactions during acetylcysteine administration including rash, hypotension, wheezing, and/or shortness of breath reported in patients receiving intravenous acetylcysteine for acetaminophen overdose; occurred soon after initiation
    • Acute flushing and erythema of skin may occur in patients receiving drug intravenously; these reactions usually occur 30 to 60 minutes after initiating the infusion and often resolve spontaneously despite continued infusion of the drug; If a reaction to acetylcysteine involves more than simply flushing and erythema of the skin, it should be treated as a hypersensitivity reaction
    • IV may cause severe anaphylactic reactions, however, new 2011 IV formulation (replaces original 2004 IV formulation) does not contain ethylene diamine tetraacetic acid or any other stabilization and chelating agents and is free of preservatives
    • Management of less severe hypersensitivity reactions should be based upon the severity of the reaction and include temporary interruption of the infusion and/or administration of antihistaminic drugs; infusion may be carefully restarted after treatment of hypersensitivity symptoms initiated; however, if hypersensitivity reaction returns upon re-initiation of treatment or increases in severity, the drug should be discontinued and alternative patient management considered

Pregnancy and Lactation

  • May be acceptable during pregnancy
  • Delaying treatment in pregnant women with acetaminophen overdose and potentially toxic acetaminophen plasma levels may increase risk of maternal and fetal morbidity and mortality
  • Lactation: Developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for therapy and potential adverse effects on the breastfed child from therapy or from underlying maternal condition
References
Medscape. Acetylcysteine.

https://reference.medscape.com/drug/acetadote-cetylev-antidote-acetylcysteine-antidote-343740

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