N-acetylcysteine

What is N-acetylcysteine?

N-acetylcysteine is a derivative of the amino acid cysteine, which plays an important role in the formation of glutathione. Glutathione is an antioxidant that protects cells from harmful free radicals. NAC can increase glutathione levels in the body and thus improve antioxidant capacity.

How does N-acetylcysteine work in respiratory diseases?

N-acetylcysteine has a mucolytic effect, which means that it can liquefy mucus in the airways and make it easier to cough it up. It does this by reducing the disulphide bonds between the mucus proteins, which make the mucus viscous and sticky. NAC can also stimulate cilia movement in the bronchial tubes and thus promote self-cleaning of the lungs.

N-acetylcysteine can be used for various respiratory diseases, such as

• Chronic bronchitis
• asthma
• pneumonia
• Cystic fibrosis
• Smoke inhalation

How does N-acetylcysteine work in paracetamol poisoning?

Paracetamol is a painkiller that is well tolerated by humans but can be very toxic to dogs. An overdose of paracetamol can lead to severe liver damage and anemia. This is because paracetamol is converted to a toxic metabolite in the liver, which damages the liver cells and destroys the haemoglobin in the blood.

N-acetylcysteine can act as an antidote to paracetamol poisoning by binding the toxic metabolite and rendering it harmless. It can also increase glutathione levels in the liver and thus support the regeneration of liver cells.

How is N-acetylcysteine administered?

N-acetylcysteine can be administered in various ways, depending on the area of application and severity of the disease. The most common methods are

• Inhalation: this involves spraying a solution of NAC in a nebulizer or bronchoscope directly into the airways. This is the most effective method for the mucolytic effect, as NAC reaches the mucus directly. However, it can cause irritation or spasms of the bronchial tubes, which is why a bronchodilator (e.g. clenbuterol) is often administered at the same time.
• Oral: A solution or tablet of NAC is swallowed or administered via a gastric tube. This is the usual method for the antioxidant effect or the treatment of paracetamol poisoning. However, NAC has a very bad taste and can lead to nausea or vomiting.
• Intravenous: This involves administering a solution of NAC directly into the bloodstream via an infusion. This is a quick and effective method of treating paracetamol poisoning, especially if given early.

The dosage of N-acetylcysteine depends on the dog's body weight and must be adjusted individually. The recommended doses for different areas of application are

• Respiratory diseases: 10-20 mg/kg orally or 5-10 ml per 50 kg body weight as a 10% solution by inhalation, 2-3 times daily, over a period of 13-20 days.
• Paracetamol poisoning: 150 mg/kg intravenously, undiluted and slowly, followed by 50 mg/kg over a period of 4 hours and then 100 mg/kg within the following 16 hours. Alternatively, 140 mg/kg orally, followed by 70 mg/kg orally, 5-7 times at 6-hour intervals.

What are the advantages and disadvantages of N-acetylcysteine for dogs?

N-acetylcysteine has several benefits for dogs, such as:

• It can facilitate breathing and improve lung function.
• It can protect and regenerate the liver
• It can increase antioxidant capacity and reduce cell damage.
• It has a wide therapeutic range and is relatively safe.

However, N-acetylcysteine also has some disadvantages for dogs, such as:

• It has a very bad taste and can cause nausea or vomiting.
• It can cause bronchial irritation or spasms, which is why a bronchodilator is often necessary.
• It can prevent mucociliary clearance if used for too long.
• It can interact with other medications, such as antibiotics or anticoagulants.