Hepatoprotective Agents and Mechanisms
24 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the main mechanism by which hepatotoxic chemicals damage liver cells?

  • By inducing lipid peroxidation and other oxidative damages (correct)
  • By enhancing sulphate conjugation
  • By reducing apoptosis
  • By increasing glutathione stores
  • What is the brand name of N-acetylcysteine (NAC)?

  • Paracetamol and Acetaminophen
  • HepatoGuard and LiverShield
  • Silymarin and Milk Thistle
  • Acetadote and Parvolex (correct)
  • What is the primary use of NAC in the treatment of acetaminophen overdose?

  • To reduce apoptosis
  • As a precursor to glutathione (correct)
  • As a mucolytic agent
  • To enhance sulphate conjugation
  • What is the estimated market value of Silymarin in Germany?

    <p>240 million US dollars</p> Signup and view all the answers

    What is the common name of the plant Silybum marianum, which is used to treat liver diseases?

    <p>Milk Thistle</p> Signup and view all the answers

    What is the empirical formula of Silymarin?

    <p>C25H22O10</p> Signup and view all the answers

    What is the result of Silymarin's action on RNA polymerase enzymes?

    <p>Increased ribosomal formation</p> Signup and view all the answers

    What is the primary mechanism of NAC as an antidote in acetaminophen overdose?

    <p>Increasing glutathione levels</p> Signup and view all the answers

    What is a common off-label use of NAC?

    <p>Prevention of contrast-induced nephrotoxicity</p> Signup and view all the answers

    What is the therapeutic implication of Silymarin's protein synthesis facilitatory action?

    <p>Restoration of normal liver functions</p> Signup and view all the answers

    What is the pivotal pharmacological property of Silymarin?

    <p>Inhibition of 5-lipoxygenase pathway</p> Signup and view all the answers

    What is a common adverse effect of NAC administration?

    <p>Drowsiness</p> Signup and view all the answers

    What is the type of liver injury that can be caused by hepatotoxic chemicals?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of Silymarin on hepatic stellate cells (HSC)?

    <p>Inhibition of HSC activation</p> Signup and view all the answers

    How does Silymarin regulate cellular and mitochondrial membrane permeability?

    <p>By increasing membrane stability against xenobiotic injury</p> Signup and view all the answers

    What is the mechanism by which Silymarin prevents liver damage?

    <p>Regulation of cellular and mitochondrial membrane permeability</p> Signup and view all the answers

    What is the main reason for using pancreatic enzyme supplements in patients with exocrine pancreatic insufficiency?

    <p>To prevent steatorrhea and azotorrhea</p> Signup and view all the answers

    What is the difference between pancreatin and pancrelipase?

    <p>Pancreatin is less effective than pancrelipase</p> Signup and view all the answers

    Why are enteric-coated preparations of pancrelipase commonly used?

    <p>Because they do not require acid suppression therapy</p> Signup and view all the answers

    What is the primary concern when dosing pancreatic enzyme supplements?

    <p>All of the above</p> Signup and view all the answers

    What is the main advantage of using pancrelipase over pancreatin?

    <p>It has higher lipolytic and proteolytic activity than pancreatin</p> Signup and view all the answers

    Why are non-enteric-coated preparations of pancrelipase often given with acid suppression therapy?

    <p>To prevent the inactivation of the enzyme by gastric acid</p> Signup and view all the answers

    What is the main indication for using pancreatic enzyme supplements?

    <p>Treatment of exocrine pancreatic insufficiency</p> Signup and view all the answers

    What is the composition of pancreatic enzyme supplements?

    <p>Amylase, lipase, and proteases</p> Signup and view all the answers

    Study Notes

    Hepatoprotective Agents

    • Mechanisms of hepatotoxicity:
      • Induction of lipid peroxidation and oxidative damages in liver cells
      • Formation of reactive free oxygen radicals, leading to direct hepatotoxicity
      • Increase in apoptosis
      • Reduction in glutathione stores, an antioxidant in the human body
    • Types of liver injury:
      • Fatty liver
      • Cholestasis
      • Fibrosis
      • Cirrhosis
      • Necrosis
      • Apoptosis
      • Hepatitis
      • Carcinogenesis

    N-Acetylcysteine (NAC)

    • Derivative of L-cysteine
    • Brand names: Acetadote, Parvolex
    • Pharmacologic category: Antidote, Mucolytic
    • FDA-labelled indications:
      • Acetaminophen/paracetamol overdose
      • Adjunctive mucolytic therapy
      • Diagnostic bronchial therapy
    • Off-label use:
      • Prevention of contrast-induced nephrotoxicity
      • H. pylori infection

    NAC as an Antidote

    • Mechanism of action:
      • Precursor of glutathione, increasing glutathione available for conjugation of NAPQI
      • Enhancement of sulphate conjugation of unmetabolized acetaminophen
      • Supply of thiol groups, which can directly bind with NAPQI in hepatocytes
      • Involvement in scavenging of free radicals or changes in hepatic blood flow

    Adverse Effects of NAC

    • Oral:
      • Drowsiness
      • Chills/fever
      • Nausea/vomiting
    • IV:
      • Anaphylactoid reactions
      • Vomiting
      • Bronchospasm
      • Rhinorrhea
      • Unpleasant odor

    Silymarin

    • Derived from Silybum marianum (milk thistle)
    • Used in the treatment of liver diseases for centuries
    • Complex mixture of four flavonolignan isomers: silybin, isosilybin, silydianin, and silychristin
    • Structural similarity to steroid hormones believed to facilitate protein synthesis

    Mechanism of Action of Silymarin

    • Stimulation of protein synthesis:
      • Entering the nucleus and acting on RNA polymerase enzymes
      • Increasing ribosomal formation and hastening protein and DNA synthesis
    • Anti-inflammation actions:
      • Inhibition of 5-lipoxygenase pathway, leading to inhibition of leukotriene synthesis
      • Strong inhibitory effect on LTB4, but not on TNF alpha or prostaglandin formation
    • Antifibrotic action:
      • Inhibition of hepatic stellate cell activation, preventing liver fibrosis
      • Inhibition of protein kinase and other kinases involved in signal transduction
    • Regulation of cellular and mitochondrial membrane permeability, increasing membrane stability against xenobiotic injury

    Pancreatic Enzyme Supplements

    • Indications:
      • Exocrine pancreatic insufficiency
      • Cystic fibrosis
      • Chronic pancreatitis
      • Pancreatic resection (pancreatectomy)
    • Constituents:
      • Amylase
      • Lipase
      • Proteases
    • Types:
      • Pancreatin (no longer used due to low efficiency)
      • Pancrelipase (enriched preparation, 12 times more lipolytic activity and 4 times more proteolytic activity than pancreatin)

    Pancrelipase

    • Enteric-coated preparation:
      • Rapidly and permanently inactivated by gastric acid
      • Can be taken with meals and snacks without acid suppression therapy
    • Formulations:
      • Varying amounts of lipase, amylase, and protease
    • Dosing:
      • Individualized according to age, weight, degree of pancreatic insufficiency, and dietary fat intake

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Description

    Learn about the mechanisms of hepatotoxicity, types of liver injury, and hepatoprotective agents like N-Acetylcysteine (NAC). Understand the role of antioxidants and oxidative damage in liver cells.

    Use Quizgecko on...
    Browser
    Browser