N-Acetyl-L-Cysteine

N-Acetyl-L-Cysteine

What is it?

• Cysteine is an amino acid. The supplemental form taken is N-acetyl-L-cysteine (NAC) which the body breaks down into cysteine.

How does it work in the body?

• After the body breaks down N-acetyl-1 cysteine to make cysteine, it further breaks down into glutathione which functions as an antioxidant.

What is it used for?

• The main use is to help prevent kidney and liver damage in acetaminophen overdose patients. NAC is typically given intravenously after an acetaminophen overdose.

• When NAC is combined with nitroglycerin, it can reduce chest pain, heart attacks, or death. NAC has also shown effectiveness in increasing glutathione levels for those with HIV/AIDS.

• While further research is needed, NAC may reduce flare-ups in those with COPD.

Dosage:

• The dosage varies depending on health conditions but seems to have conclusive recommendations for acetaminophen overdose.

• Acetaminophen poisoning: 20 h protocol via IV: First administer 150 mg/kg for 15-60 min and then decrease the dose to 50 mg/kg for the 4 h. For the last 16 h, increase the dosage to 100 mg/kg. Overall this provides a total of 300 mg/kg for-20 h.

• 72 h protocol orally: First provide a loading dose of 140 mg/kg and then provide 70 mg/kg every 4 h.

Evidence for or against its different uses:

• Acetaminophen overdose: A review from 2008, studied the pathophysiology. clinical manifestation, and management of acute acetaminophen toxicity. In a case involving a middle aged woman suffering from acetaminophen overdose, NAC was found to possibly improve liver failure [72].

• Angina: A randomized control study evaluated the effects of nitroglycerin and NAC on individuals suffering from angina. Although there was a large per-centage of side effects, primarily headaches, it was found that when taking nitroglycerin and NAC together, reductions in angina can occur [73].

• HIV/AIDS: A commonality between HIV patients is glutathione deficiency, and it has been theorized that NAC supplementation can be used to repleted glutathione. A randomized, double blind placebo controlled trial by Rosa et al. studied the supplementation of N-acetylcysteine in HIV patients and concluded that glutathione was successfully replete in those given N-acetylcysteine [74].

• COPD: A meta-analysis completed in 2009 concluded that NAC supplementation can significantly reduce the risk of COPD exacerbation. It is important to proceed with caution when choosing NAC supplementation over traditional inhaled corticosteroids as further research is needed [75].

Safety concerns/side effects/precautions:

• Toxic forms of cysteine are D-cysteine, D-cystine and 5-methyl cysteine which should all be avoided [70].

• Homocysteine levels could become elevated with NAC supplementation. It is important to check homocysteine levels when supplementing NAC as high levels of homocysteine have been linked to heart disease [70]. NAC can cause nausea, vomiting, and diarrhea [70].

Interactions with medication:

• N-Acetyl cysteine has been shown to increase the effects of some medications, such as immunosuppressants, nitroglycerin, oxiconazole, and isosorbide.

• N-Acetyl cysteine may lessen the effects of activated charcoal.

• When taking NAC with nitroglycerin, it can lead to severe headaches.