What is acetylcysteine?

Acetylcysteine (alternate and brand names: N-acetylcysteine, NAC, ACC, Mucomyst®, Acetadote®, Cetylev®, Parvolex®) is a supplement that is a modified form of an amino acid and acts as an antioxidant.  Acetylcysteine is useful in treating conditions that involve tissue damage or toxicity due to oxidative stress, such as acetaminophen, xylitol, or phenol toxicity, degenerative myelopathy in dogs, chronic kidney disease, respiratory inflammation in cats, and FIV in cats. It may also be useful when treating sulfonamide reactions, sago palm, mushroom, or doxorubicin toxicity of the liver, or other toxicities.

"It may also be useful when treating sulfonamide reactions, sago palm, mushroom, or doxorubicin toxicity of the liver, or other toxicities."

It also acts as a mucolytic, meaning it will make secretions thinner. This is useful for respiratory conditions where mucus accumulates in the airways; acetylcysteine works to improve the clearing of this mucus. In some cases, it has also been used topically or as an infusion to thin secretions in the lungs and other areas of the body.


What is a supplement?

Supplements are substances that can be used to supplement the diet, such as vitamins, minerals, amino acids, herbs, botanicals, enzymes, and probiotics. While many supplements are sold over the counter, they still contain ingredients that have biological effects that should be managed by your veterinarian. Follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

There are differences in how countries regulate supplements. In the United States, these substances are not as vigorously regulated by the FDA as other medications, which means they can be sold without the manufacturer proving their effectiveness, safety, and without a guarantee of consistent or accurately reported ingredients. In Canada, products that have been evaluated for quality, safety, and effectiveness by Health Canada and authorized for sale will have a license number on the label.


How effective is acetylcysteine?

Limited studies in animals have been performed, but there is anecdotal evidence that acetylcysteine works to treat toxicities and to break up mucus.


How is acetylcysteine given?

Acetylcysteine is given by mouth in the form of a liquid, capsule, tablet, or powder. It may also be given into the vein, or directly into the airways in the hospital setting. Give oral forms with food to prevent stomach upset.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.


What if I miss giving my pet the supplement?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.


Are there any potential side effects?

When administered by mouth, nausea and vomiting may occur. Rare side effects include allergic skin reactions. This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.


Are there any risk factors for this supplement?

Acetylcysteine should not be used in pets that are allergic to it. It should be used cautiously in pets with stomach or intestinal ulcers. It should also be used cautiously pregnant or nursing pets as studies are limited.


Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with acetylcysteine: activated charcoal or nitroglycerin.

Vitamins, herbal therapies, and supplements have the potential to interact with each other, as well as with prescription and over the counter medications. It is important to tell your veterinarian about any medications (including all vitamins, supplements, or herbal therapies) that your pet is taking.


Is there any monitoring that needs to be done with this supplement?

When used for toxicosis, liver enzymes, electrolytes, and a complete blood count may be monitored. Your veterinarian may monitor your pet to be sure that the medication is working.


How do I store acetylcysteine?

Store the tablets, capsules, or powder at room temperature between 68°F to 77°F (20°C and 25°C) and protect from moisture. Store tablets in their original blister packs until use. Store freshly prepared liquid formulations for up to 4 days in the refrigerator.


What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

© Copyright 2020 LifeLearn Inc. Used and/or modified with permission under license.