Cat - N-Acetylcysteine

What is N-acetylcysteine?

N-acetylcysteine (NAC) is a chemically modified form of the dietary amino acid cysteine. Cysteine and NAC contain sulphur, which is key to protecting the body from damage by oxidation. Other sulphur containing antioxidants include alpha-lipoic acid and glutathione. Glutathione levels are considered the most reliable indicator of the body's resistance to oxidation, and NAC plays a role in glutathione metabolism. While touted by many supplement manufacturers as a precursor to glutathione, NAC probably has more of a sparing effect. That is, it neutralises oxidants in place of glutathione, allowing glutathione levels to be maintained.

Because of its role in preventing oxidation, NAC is potentially useful wherever oxidative stress is a concern. Tissue damage by oxidation is common in bacterial and especially in viral infections, such as those seen in chronic disease in cats such as Cat Flu, FIV, FeLV or FIP.

One drug commonly overdosed in small animals that NAC is believed to specifically antidote is paracetamol. Paracetamol, a commonly used anti-inflammatory and pain killer in humans, is toxic to small animals, especially cats.

NAC has long been used to counteract the anaemia that occurs following oxidative damage by paracetamol. While theoretically useful, it has not been proven effective in several clinical trials.

Most NAC is not used as an antidote to paracetamol, but rather to neutralise oxidants produced in a variety of diseases. Chronic inflammation produces significant numbers of reactive oxygen species. NAC is used to counter the damaging effects of inflammation, particularly where delicate and vital organs are being damaged.

One example is the use of NAC to help prevent oxidative damage to the spinal cord in degenerative myelopathy (CDRM) in dogs.Hepatitis may also be helped with the use of NAC.

NAC also helps prevent kidney damage from lack of blood flow in humans and therefore may help with chronic kidney failure of geriatric cats. It can even be speculated that cats are more vulnerable to chronic renal failure because of their lower antioxidant levels.

A surprising potential benefit of NAC is in the treatment of retrovirus infection such as FIV (Feline Immunodeficiency Virus) in cats. NAC may be useful in the treatment of other chronic viral diseases of cats such as FIP and Feline Leukaemia.

A final potential application of NAC in small animals is the breakdown of mucous accumulation in the airways.

Why would I be recommended administration of N-acetylcysteine to my pet?

N-acetylcysteine is used in veterinary medicine for the treatment of paracetamol toxicity in cats and dogs. Other potential applications for NAC include the treatment of degenerative myelopathy, respiratory disease, chronic renal failure, feline immune deficiency virus (FIV), chronic viral infections in cats and as a support following chemotherapy.

How much experience is there with the use of N-acetylcysteine in pets?

N-acetylcysteine has been used in emergency medicine as a paracetamol antidote for several years.

Use of NAC in degenerative myelopathy in dogs is also common. Treatment of chronic renal failure, chronic respiratory disorders, and FIV are new potential uses for NAC drawn from the research literature. NAC should also be considered as a supportive treatment following chemotherapy.

How much research has been conducted on this supplement?

While there is a large amount of laboratory research on the effects of NAC, very few clinical trials have been performed. Most trials have explored the use of NAC to antidote with paracetamol, with efficacy not necessarily being demonstrated. Clinical trials are entirely lacking for the benefits of NAC in degenerative myelopathy, renal failure, airway disease, and FIV. Despite the lack of clinical trials, practitioners using NAC for degenerative myelopathy and paracetamol toxicity report positive results.

How safe is N-acetylcysteine?

Because damage due to oxidation is extremely common in a variety of diseases, there may be a tendency to simply use NAC preventatively as a routine dietary supplement. Surprisingly, however, there is some research that routine use of NAC in high doses in the absence of disease can actually promote the production of oxidants and free radicals, therefore having a detrimental effect on your pet. Consequently NAC is probably best reserved for clinical cases.

Where do I obtain N-acetylcysteine and do I need a prescription?

Please speak to one of the vets if you would like to discuss the use of N-Acetylcysteine in your animal. We would be happy to advise. A prescription is not required.