Acetylcysteine (By mouth)


Acetylcysteine (a-seet-il-SIS-teen)

Helps prevent liver damage caused by an overdose of acetaminophen.

Brand Name(s)


When This Medicine Should Not Be Used

How to Use This Medicine


  • This medicine will be given to you while you are in the hospital. It works best when it is given within 16 hours after the overdose. The more time that goes by after the overdose, the less effective the medicine will be in protecting your liver.
  • A nurse or other trained health professional will give you this medicine.
  • This medicine will be mixed with a diet soft drink right before you take it. Drink the medicine immediately after it is mixed.
  • You should receive a total of 17 doses of this medicine, about 4 hours apart. If you vomit within 1 hour after you take your medicine, you will need to take another dose to make up for it.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

Warnings While Using This Medicine

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney or liver disease, an ulcer or other stomach problems, or you had an allergic reaction to any medicine.
  • Your doctor will need to check your blood on a regular basis while you are in the hospital.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Rash with a fever
  • Severe or ongoing vomiting

If you notice these less serious side effects, talk with your doctor:

  • Mild nausea, vomiting, or upset stomach

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 12/4/2015

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