General principles in liver treatment

Liver Oxidative Damage

• The liver is susceptible to oxidative damage due to its role in metabolism and detoxification.
• Glutathione is a crucial antioxidant mainly stored in hepatocytes.
• Reduced glutathione levels are found in cats with various liver diseases, suggesting oxidative injury's significant role.

S-adenosyl Methionine (SAMe)

• SAMe is vital for synthesizing glutathione, a crucial antioxidant.
• SAMe might prevent oxidative damage by maintaining hepatic glutathione levels.
• SAMe may possess anti-inflammatory, anti-apoptotic, and anticarcinogenic properties.
• SAMe is generally well-tolerated, with occasional vomiting and decreased appetite reported.
• Limited evidence suggests SAMe's effectiveness in dogs and cats, including mitigating oxidative stress and inflammation.
• Further clinical trials are needed to confirm SAMe's efficacy in treating hepatic diseases.

N-acetylcysteine (NAC)

• NAC replenishes hepatic intracellular cysteine and glutathione, protecting against oxidative injury.
• Oral NAC is associated with vomiting, leading to intravenous administration for hepatic disease treatment.
• NAC showed improvement in hepatic circulation and redox status in dogs undergoing bile duct ligation.
• NAC did not demonstrate a beneficial effect in experimental canine models of ischemic liver injury and reperfusion.
• NAC is a recognized therapy for acetaminophen intoxication in humans and is used for dogs and cats.
• Long-term NAC administration may impair ammonia metabolism via the urea cycle.

Silymarin

• Silymarin is a mixture of flavanolignans and flavonoids extracted from milk thistle, with silibinin being the most active component.
• Silymarin exhibits antioxidant and anti-inflammatory effects, including scavenging free radicals, reducing lipid peroxidation, and suppressing inflammatory cytokines.
• Silymarin is generally well-tolerated at common dosages.
• Silymarin's bioavailability is enhanced when combined with phosphatidylcholine.
• Limited evidence supports silymarin's efficacy in veterinary medicine.
• Silymarin is recommended for dogs and cats with Amanita mushroom intoxication.

Vitamin E

• Vitamin E is a group of lipid-soluble vitamins with alpha-tocopherol being the most active form.
• Vitamin E's primary role is as an antioxidant, protecting phospholipids by scavenging free radicals.
• Vitamin E is generally well-tolerated with rare side effects in dogs and cats.
• Alpha-tocopherol is typically administered at 10-15 IU/kg PO q 24 h to dogs and cats.