PDR Health


What is N-acetylcysteine?

N-acetylcysteine (NAC) is a derivative of the amino acid cysteine. It is used as a medication to treat acetaminophen overdose, and to help prevent damage from exposure to smoke inhalation. NAC has mucolytic, antioxidant, and anti-inflammatory properties.


What are the benefits of taking N-acetylcysteine?

There is some evidence that NAC can help to protect against liver damage from acetaminophen overdose, and may also help to reduce symptoms of bronchitis and other respiratory conditions. Additionally, NAC has been shown to have helpful effects in treating certain mental health conditions such as schizophrenia and bipolar disorder.

What are the potential side effects of taking N-acetylcysteine?

NAC is generally well tolerated, but some people may experience gastrointestinal side effects such as nausea, vomiting, or diarrhea. Rarely, more serious side effects such as low blood pressure or liver damage may occur.

It is important to speak with a healthcare provider before taking NAC to make sure it is the right treatment for you.

Dosage and Preparation

NAC is available in oral tablets, capsules, and powders. It can also be given intravenously (by IV). The typical dose for adults is 600-1200 mg per day.


NAC may interact with certain medications such as warfarin, methotrexate, or penicillamine. It is important to speak with a healthcare provider before taking NAC to ensure that there are no potential interactions with any medications you are currently taking.

Mechanism of Action

NAC works by increasing levels of glutathione, an important antioxidant that helps to protect cells from damage. NAC also has mucolytic effects, which means it can help to break down mucus in the respiratory tract. Additionally, NAC has anti-inflammatory effects and can help to modulate the immune system.


NAC is rapidly absorbed from the gastrointestinal tract. It is metabolized in the liver and excreted in the urine. The half-life of NAC is 2-3 hours.

Alternatives to N-acetylcysteine

There are no direct alternatives to NAC. However, there are other medications that may be used to treat the same conditions. Some examples include acetaminophen for liver damage and bronchodilators for respiratory conditions. Speak with a healthcare provider to determine if there are any alternative treatments that may be appropriate for you.

Research and General Availability

NAC is a relatively new medication, and additional research is needed to determine its full efficacy. However, it is generally well tolerated and available without a prescription in most countries. It can be purchased online or at many pharmacies.

Pregnancy and Breastfeeding

There is limited data on the use of NAC during pregnancy, but it is generally considered safe. N-acetylcysteine should not be used during breastfeeding unless recommended by a healthcare provider.

How long does it take to work?

NAC begins to work within 1-2 hours after taking it. However, it may take several days or weeks to see the full effects.

Is N-acetylcysteine Effective?

Yes, NAC is an effective medication for treating acetaminophen overdose, bronchitis, and other respiratory conditions. It can also be helpful in treating certain mental health conditions such as schizophrenia and bipolar disorder. More research is needed to determine the full efficacy of NAC.