Pharmacology of Acetaminophen
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What is the mechanism of action of acetaminophen in the body?

  • Inhibits COX I and COX II enzymes systemically
  • Inhibits PGs synthesis in the peripheral tissues
  • Increases the synthesis of endocannabinoids
  • Inhibits PGs synthesis in the brain only (correct)

    • Which of the following correctly describes the metabolism of acetaminophen?

  • Converted into a toxic metabolite at high doses (correct)
  • Metabolized exclusively by the kidneys
  • Converted into a toxic metabolite at low doses
  • Metabolized by the liver primarily through oxidation

    • What effect does acetaminophen have on peripheral prostaglandin synthesis?

  • Inhibition of synthesis with significant side effects
  • Stimulates the synthesis of peripheral prostaglandins
  • No significant effect on synthesis (correct)
  • Potent anti-inflammatory action

    • In what situations is acetaminophen commonly used?

    <p>As an analgesic when NSAIDs are contraindicated</p> Signup and view all the answers

    What is the primary route of excretion for acetaminophen?

    <p>Renal excretion via urine</p> Signup and view all the answers

    Which statement accurately reflects the cardiovascular effects of acetaminophen?

    <p>Has little to no effects on the cardiovascular system</p> Signup and view all the answers

    What peak level is typically achieved after the administration of acetaminophen?

    <p>30 minutes</p> Signup and view all the answers

    In patients with which of the following conditions should acetaminophen be used with caution?

    <p>Peptic ulcers</p> Signup and view all the answers

    What is the primary risk associated with long-term use of acetaminophen?

    <p>Kidney damage</p> Signup and view all the answers

    What can happen at toxic doses of acetaminophen?

    <p>Liver failure</p> Signup and view all the answers

    Which metabolite's buildup contributes to acetaminophen's hepatotoxicity?

    <p>N-acetyl-p-benzoquinone imine</p> Signup and view all the answers

    What typical clinical symptom may occur within 24 hours of acetaminophen toxicity?

    <p>Nausea and vomiting</p> Signup and view all the answers

    Which treatment option is used for acetaminophen overdose?

    <p>Activated charcoal</p> Signup and view all the answers

    What is the safe upper therapeutic dose of acetaminophen for adults?

    <p>4 gm</p> Signup and view all the answers

    Which adverse reaction can occur from acetaminophen as an allergic reaction?

    <p>Skin rash</p> Signup and view all the answers

    What type of necrosis is associated with acetaminophen toxicity?

    <p>Centrilobular necrosis</p> Signup and view all the answers

    What is the initial loading dose of acetylcysteine administered IV for treating toxicity?

    <p>150 mg/kg</p> Signup and view all the answers

    What is a significant contraindication for the use of Nefopam?

    <p>History of epilepsy</p> Signup and view all the answers

    Which statement regarding Dipyrone's safety profile is correct?

    <p>Agranulocytosis is reversible in 10 days after discontinuation.</p> Signup and view all the answers

    What mechanisms may contribute to the analgesic effects of Nefopam?

    <p>Inhibition of many transmitters reuptake</p> Signup and view all the answers

    What is a potential adverse effect of Nefopam linked to its atropine-like actions?

    <p>Dry mouth</p> Signup and view all the answers

    Within how many hours should acetylcysteine be started after toxicity to be effective?

    <p>8 hours</p> Signup and view all the answers

    Which of the following adverse reactions can Dipyrone trigger in patients with asthma?

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

    Which of the following best describes Nefopam's classification?

    <p>Central analgesic</p> Signup and view all the answers

    Acetaminophen is considered safer than aspirin for use during pregnancy.

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

    Administering acetaminophen in toxic doses leads to dose-independent hepatotoxicity.

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

    Skin rash and drug fever can occur as allergic reactions to acetaminophen.

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

    Signs of hepatic damage can occur within 24 hours after acetaminophen toxicity.

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

    The toxic metabolite of acetaminophen requires detoxification by oxidized glutathione.

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

    Acetaminophen may cause renal failure with long-term use.

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

    Activated charcoal is used in treating acetaminophen toxicity to absorb the drug.

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

    Acetaminophen acts as a selective Cox III inhibitor, impacting only the synthesis of peripheral prostaglandins.

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

    The threshold for toxic acetaminophen dosage in adults is about 15 grams.

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

    N-acetyl-benzene is a toxic metabolite of acetaminophen that leads to hepatotoxicity.

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

    Acetaminophen is primarily absorbed through the respiratory system.

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

    The therapeutic uses of acetaminophen include applications when aspirin is contraindicated.

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

    At high doses, acetaminophen has significant anti-inflammatory effects.

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

    Following acetaminophen administration, peak plasma levels are typically reached within 30 minutes.

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

    Acetaminophen has significant effects on cardiovascular functions.

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

    Renal excretion is the primary method through which acetaminophen is metabolized.

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

    Acetylcysteine must be started within 6 hours of toxicity for effective treatment.

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

    Nefopam is an analgesic that has anti-inflammatory properties.

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

    Dipyrone is considered less potent than aspirin in its analgesic effects.

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

    Agranulocytosis associated with Dipyrone is not dose-dependent.

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

    Nefopam is effective in treating hiccups and does not have significant adverse effects.

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

    The initial loading dose of acetylcysteine is 150 mg/kg administered over 30 minutes.

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

    Nefopam may inhibit the reuptake of multiple transmitters in its analgesic mechanism.

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

    Patients with a history of epilepsy can safely use Nefopam without any risk.

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

    What can deplete glutathione stores and lead to acetaminophen toxicity?

    <p>Large doses of acetaminophen can deplete glutathione stores.</p> Signup and view all the answers

    What adverse reactions can occur with acetaminophen at therapeutic doses?

    <p>Skin rash and drug fever may occur as allergic reactions.</p> Signup and view all the answers

    What is the typical time frame for the onset of symptoms and signs of hepatic damage in acetaminophen toxicity?

    <p>Symptoms may occur within 24 hours, while signs of hepatic damage appear after 2-6 days.</p> Signup and view all the answers

    What is the threshold for toxic acetaminophen dosage in children?

    <p>The toxic dose is about 4 grams in children.</p> Signup and view all the answers

    What is the mechanism behind acetaminophen's hepatotoxicity?

    <p>Acetaminophen is metabolized to a toxic metabolite that damages liver cells when glutathione is depleted.</p> Signup and view all the answers

    What is a common treatment approach for acetaminophen toxicity?

    <p>Gastric lavage with activated charcoal is commonly used.</p> Signup and view all the answers

    Why is acetaminophen considered safer than aspirin during pregnancy?

    <p>Acetaminophen poses fewer risks and is better tolerated during pregnancy compared to aspirin.</p> Signup and view all the answers

    What can long-term use of acetaminophen result in regarding kidney health?

    <p>Long-term use may lead to renal failure.</p> Signup and view all the answers

    What should be the next dose of acetylcysteine after the initial loading dose administered over 60 minutes?

    <p>12.5 mg/kg per hour IV for 4 hours.</p> Signup and view all the answers

    What serious adverse effect is associated with Dipyrone that is not dose-dependent?

    <p>Agranulocytosis.</p> Signup and view all the answers

    What is a contraindication for the use of Nefopam?

    <p>History of epilepsy.</p> Signup and view all the answers

    What mechanism may contribute to Nefopam's analgesic effects?

    <p>Inhibition of many neurotransmitter reuptake or blocking central voltage-gated Na+ channels.</p> Signup and view all the answers

    How long after ingestion should acetylcysteine be started to be effective?

    <p>Within 8 hours.</p> Signup and view all the answers

    What potent effect does Nefopam have that differentiates it from typical NSAIDs?

    <p>It has central analgesic properties without anti-inflammatory or antipyretic activity.</p> Signup and view all the answers

    What are the primary adverse effects of Nefopam related to its atropine-like actions?

    <p>Dry mouth and urine retention.</p> Signup and view all the answers

    What type of drug classification does Dipyrone fall under?

    <p>Analgesic antipyretic.</p> Signup and view all the answers

    What is the significance of acetaminophen being a selective Cox III inhibitor?

    <p>It primarily inhibits prostaglandin synthesis in the brain, leading to analgesic and antipyretic effects without affecting peripheral synthesis.</p> Signup and view all the answers

    How does the metabolism of acetaminophen relate to its hepatotoxic effects?

    <p>At high doses, acetaminophen is converted into a toxic metabolite, N-acetyl-benzene, which can lead to liver damage.</p> Signup and view all the answers

    In which specific patient populations is acetaminophen considered a safer alternative to aspirin?

    <p>Acetaminophen is safer for patients with peptic ulcers or hemorrhagic disorders.</p> Signup and view all the answers

    How does renal excretion play a role in the safety profile of acetaminophen?

    <p>Renal excretion helps eliminate acetaminophen and its metabolites, reducing the risk of accumulation and toxicity.</p> Signup and view all the answers

    What clinical implications arise from the rapid absorption of acetaminophen from the gastrointestinal tract?

    <p>Rapid absorption leads to quicker onset of pain relief, making it effective in acute pain management.</p> Signup and view all the answers

    What is the role of N-acetylcysteine in the context of acetaminophen toxicity?

    <p>N-acetylcysteine is an antidote that replenishes glutathione levels, aiding in the detoxification of harmful metabolites.</p> Signup and view all the answers

    Which organ's function is primarily affected by excessive acetaminophen intake and how?

    <p>The liver is primarily affected, as it metabolizes acetaminophen, leading to potential hepatotoxicity when overwhelmed.</p> Signup and view all the answers

    What distinguishes the pharmacological effects of acetaminophen from those of non-steroidal anti-inflammatory drugs (NSAIDs)?

    <p>Acetaminophen primarily provides analgesic and antipyretic effects without significant anti-inflammatory properties.</p> Signup and view all the answers

    Absorption is complete and rapid from GIT with peak levels after ______ min.

    <p>30</p> Signup and view all the answers

    At high doses, acetaminophen is converted into a toxic metabolite known as ______ that is responsible for hepatotoxicity.

    <p>N-acetyl-benzene</p> Signup and view all the answers

    Acetaminophen acts as a selective ______ inhibitor, inhibiting PG synthesis in the brain only.

    <p>Cox III</p> Signup and view all the answers

    Acetaminophen has analgesic and antipyretic actions without effects on peripheral ______.

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

    The main route of excretion for acetaminophen is ______.

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

    Therapeutic uses of acetaminophen include applications when ______ is contraindicated.

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

    Acetaminophen has little or no effects on the ______, GIT, respiratory or platelet functions.

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

    When overdosing on acetaminophen, the initial loading dose of ______ is administered for treatment.

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

    The initial loading dose of acetylcysteine is ______ mg/kg administered over 60 minutes.

    <p>150</p> Signup and view all the answers

    Nefopam is a central analgesic without ______ or anti-inflammatory activity.

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

    Dipyrone is more potent than ______ as an analgesic antipyretic.

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

    Acetaminophen can be administered in pregnancy with greater safety than ______.

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

    At therapeutic doses, acetaminophen is well-tolerated but may cause skin rash and ______.

    <p>drug fever</p> Signup and view all the answers

    Agranulocytosis associated with Dipyrone can be lethal in ______% of cases.

    <p>10</p> Signup and view all the answers

    The analgesic mechanism of Nefopam may be related to inhibition of transmitter ______.

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

    Long term use of acetaminophen may lead to ______ failure.

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

    Nefopam can precipitate ______ in patients with a history of epilepsy.

    <p>epileptic convulsions</p> Signup and view all the answers

    Toxic doses of acetaminophen can cause dose-dependent ______ toxicity.

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

    Acetylcysteine must be started within ______ hours of toxicity to be effective.

    <p>8</p> Signup and view all the answers

    The toxic metabolite of acetaminophen requires detoxification by reduced ______.

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

    Clinical symptoms of acetaminophen toxicity occur within ______ hours.

    <p>24</p> Signup and view all the answers

    Dipyrone has no ______ inflammatory action.

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

    Activated charcoal is used in treating acetaminophen toxicity to absorb the ______.

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

    The threshold for toxic acetaminophen dosage in adults is about ______ grams.

    <p>15</p> Signup and view all the answers

    Match the following effects of acetaminophen with their descriptions:

    <p>Skin rash = Possible allergic reaction Renal failure = Long-term use effect Hepatotoxicity = Dose-dependent toxicity Jaundice = Sign of hepatic damage after 2-6 days</p> Signup and view all the answers

    Match the following treatment methods with their indications in acetaminophen toxicity:

    <p>Gastric lavage = Used to remove drug from the stomach Activated charcoal = Absorbs drug to prevent further absorption IV protocol = 20 hours protocol for treatment Monitor liver function = Assess for signs of hepatic damage</p> Signup and view all the answers

    Match the following toxic doses of acetaminophen to the corresponding age groups:

    <p>15 gm = Approximate toxic dose in adults 4 gm = Approximate toxic dose in children Long-term low doses = Possible renal failure risk Therapeutic doses = Generally well tolerated</p> Signup and view all the answers

    Match the following toxic metabolites of acetaminophen with their effects:

    <p>N-acetyl-p-benzoquinone imine = Covalently binds to cellular proteins Glutathione depletion = Increases risk of hepatotoxicity Centrilobular necrosis = Associated with liver damage Toxic metabolites = Lead to hepatocellular damage</p> Signup and view all the answers

    Match the following symptoms of acetaminophen overdose with their onset times:

    <p>Vomiting = Occurs within 24 hours Hepatic damage signs = Develop after 2-6 days Skin rash = Possible allergic reaction time varies Drug fever = Can appear with allergic symptoms</p> Signup and view all the answers

    Match the following phases of acetaminophen overdose with their details:

    <p>First phase = Initial symptoms like vomiting Second phase = Signs of liver injury begin Third phase = Potential for jaundice appearance Fourth phase = Recovery or progression to severe damage</p> Signup and view all the answers

    Match the following attributes of acetaminophen with their categories:

    <p>N-acetylcysteine = Antidote for acetaminophen toxicity Pregnancy safety = Safer than aspirin High doses = Lead to dose-dependent hepatotoxicity Therapeutic doses = Relatively well tolerated</p> Signup and view all the answers

    Match the following risks associated with acetaminophen with their context:

    <p>Allergic reactions = Skin rash &amp; drug fever Long-term use = Potentially leads to renal failure Toxic doses in adults = Around 15 gm Initial treatment protocol = IV protocol lasting 20 hours</p> Signup and view all the answers

    Match the following drugs with their respective primary adverse effects:

    <p>Acetylcysteine = Restores hepatic glutathione Nefopam = Dry mouth and urine retention Dipyrone = Agranulocytosis risk</p> Signup and view all the answers

    Match the following drugs with their corresponding mechanism of action:

    <p>Acetylcysteine = Sulfhydryl donor for glutathione restoration Nefopam = Blocking central voltage-gated Na+ channels Dipyrone = Analgesic and antipyretic without anti-inflammatory action</p> Signup and view all the answers

    Match the following drugs with their corresponding administration guidelines:

    <p>Acetylcysteine = Must be started within 8 hours of toxicity Nefopam = Used to combat severe hiccups Dipyrone = Restricted use in many countries due to severe effects</p> Signup and view all the answers

    Match the following drugs with their contraindications:

    <p>Nefopam = None specified regarding atropy Dipyrone = Patients with asthma at risk for bronchoconstriction Acetylcysteine = None specified regarding toxicity</p> Signup and view all the answers

    Match the following drugs with their global safety status:

    <p>Dipyrone = Lethal agranulocytosis risk in 10% of cases Acetylcysteine = Widely used for acetaminophen toxicity Nefopam = Not commonly restricted</p> Signup and view all the answers

    Match the following drugs with their common side effects:

    <p>Nefopam = May trigger bronchoconstriction in asthmatics Acetylcysteine = Generally well tolerated Dipyrone = Allergic reactions and anaphylaxis</p> Signup and view all the answers

    Match the following dosages to the respective drugs:

    <p>Acetylcysteine = Stepped dosage of 12.5 mg/kg per hour for 4 hours then 6.25 mg/kg per hour for 16 hours Nefopam = Usual dosage not specified Dipyrone = Dosage based on severity and contraindications</p> Signup and view all the answers

    Match the following drugs with their classification:

    <p>Acetylcysteine = Hepatoprotectant Nefopam = Non-opioid analgesic Dipyrone = Analgesic antipyretic</p> Signup and view all the answers

    Match the following pharmacokinetic properties of acetaminophen with their descriptions:

    <p>Absorption = Complete and rapid from the gastrointestinal tract, peak levels after 30 minutes Metabolism = Liver by conjugation, can lead to hepatotoxicity at high doses Excretion = Mainly renal excretion Toxic metabolite = N-acetyl-benzene, responsible for hepatotoxicity</p> Signup and view all the answers

    Match the following therapeutic uses of acetaminophen with their indications:

    <p>Analgesic = Used when aspirin is contraindicated Antipyretic = Effective in reducing fever Hepatoprotection = Not applicable at high doses Peripheral anti-inflammatory = No effect on peripheral prostaglandin synthesis</p> Signup and view all the answers

    Match the following statements regarding acetaminophen with their truth values:

    <p>Has significant cardiovascular effects = False Does not affect central nervous system prostaglandins = True Is a selective Cox III inhibitor = True Provides anti-inflammatory effects = False</p> Signup and view all the answers

    Match the following statements about acetaminophen metabolism with their effects:

    <p>Conjugation in the liver = Produces non-toxic forms Formation of N-acetyl-benzene = Leads to hepatotoxicity Renal excretion = Clears metabolites from the body Excessive doses = Depletes glutathione stores</p> Signup and view all the answers

    Match the following patient conditions with recommendations for acetaminophen use:

    <p>Peptic ulcer = Recommended as analgesic Hemophilia = Preferred over aspirin Liver disease = Caution advised Pregnancy = Considered safer than aspirin</p> Signup and view all the answers

    Match the following pharmacological effects of acetaminophen with their classifications:

    <p>Analgesic action = Pain relief without anti-inflammatory effects Antipyretic action = Reduces fever Toxicity risk = Occurs at high doses Lack of data on cardiovascular impact = Minimal effects observed</p> Signup and view all the answers

    Match the following scientific findings related to acetaminophen with their implications:

    <p>Complete absorption = Rapid onset of action Renal excretion = Main route of elimination Selectivity for Cox III = Limited anti-inflammatory role High dose toxicity = Risk of acute liver damage</p> Signup and view all the answers

    Match the following biochemical processes related to acetaminophen with their outcomes:

    <p>Conjugated metabolites = Non-toxic outcome Decreased glutathione levels = Increases risk of hepatotoxicity Rapid peak absorption = Effective for quick symptom relief Kilocalories from metabolism = Not relevant for pharmacodynamics</p> Signup and view all the answers

    Study Notes

    Acetaminophen (Paracetamol)

    • Rapid absorption from the gastrointestinal tract, peak levels occur 30 minutes post-administration.
    • Metabolized in the liver by conjugation; high doses lead to conversion into hepatotoxic metabolite (N-acetyl-benzoquinone).
    • Mainly excreted through the kidneys.
    • Acts as a selective COX III inhibitor, reducing prostaglandin (PG) synthesis in the brain; provides analgesic and antipyretic effects.
    • Lacks anti-inflammatory properties, minimal effects on cardiovascular, gastrointestinal, respiratory systems, or platelet functions.
    • Safe for use in pregnancy compared to aspirin; suitable for patients with peptic ulcers or hemophilia.
    • Potential adverse effects: skin rash, drug fever, with long-term use possibly leading to renal failure.
    • Toxic doses (≥15g in adults, 4g in children) cause dose-dependent hepatotoxicity (centrilobular necrosis).
    • Symptoms of toxicity (e.g., vomiting) can manifest within 24 hours; hepatic damage signs (e.g., jaundice) appear after 2-6 days.

    Mechanism of Hepatotoxicity

    • Acetaminophen converts to toxic metabolite in the liver, requiring detoxification by glutathione.
    • Depletion of glutathione stores leads to the toxic metabolite binding to proteins, resulting in liver cell damage.
    • Treatment includes gastric lavage with activated charcoal and administration of acetylcysteine to restore glutathione, with a specific dosing regimen.

    Nefopam (Acupan)

    • Central analgesic that lacks antipyretic and anti-inflammatory properties; more potent than NSAIDs.
    • Analgesic mechanism is unclear but may inhibit neurotransmitter reuptake or block central voltage-gated Na+ channels.
    • Also effective in relieving severe hiccups.
    • Adverse effects include potential precipitation of seizures in epileptics and weak atropine-like symptoms such as dry mouth and urinary retention.
    • Contraindicated in patients with a history of epilepsy.

    Dipyrone (Novalgin)

    • Potent analgesic and antipyretic, more effective than aspirin but lacks anti-inflammatory effects.
    • Use restricted in various countries due to the risk of agranulocytosis, not dose-dependent.
    • Adverse effects include reversible agranulocytosis (10% lethal cases), allergic reactions, anaphylaxis, and bronchoconstriction in asthmatic patients.

    Acetaminophen (Paracetamol)

    • Rapid absorption from the gastrointestinal tract, peak levels occur 30 minutes post-administration.
    • Metabolized in the liver by conjugation; high doses lead to conversion into hepatotoxic metabolite (N-acetyl-benzoquinone).
    • Mainly excreted through the kidneys.
    • Acts as a selective COX III inhibitor, reducing prostaglandin (PG) synthesis in the brain; provides analgesic and antipyretic effects.
    • Lacks anti-inflammatory properties, minimal effects on cardiovascular, gastrointestinal, respiratory systems, or platelet functions.
    • Safe for use in pregnancy compared to aspirin; suitable for patients with peptic ulcers or hemophilia.
    • Potential adverse effects: skin rash, drug fever, with long-term use possibly leading to renal failure.
    • Toxic doses (≥15g in adults, 4g in children) cause dose-dependent hepatotoxicity (centrilobular necrosis).
    • Symptoms of toxicity (e.g., vomiting) can manifest within 24 hours; hepatic damage signs (e.g., jaundice) appear after 2-6 days.

    Mechanism of Hepatotoxicity

    • Acetaminophen converts to toxic metabolite in the liver, requiring detoxification by glutathione.
    • Depletion of glutathione stores leads to the toxic metabolite binding to proteins, resulting in liver cell damage.
    • Treatment includes gastric lavage with activated charcoal and administration of acetylcysteine to restore glutathione, with a specific dosing regimen.

    Nefopam (Acupan)

    • Central analgesic that lacks antipyretic and anti-inflammatory properties; more potent than NSAIDs.
    • Analgesic mechanism is unclear but may inhibit neurotransmitter reuptake or block central voltage-gated Na+ channels.
    • Also effective in relieving severe hiccups.
    • Adverse effects include potential precipitation of seizures in epileptics and weak atropine-like symptoms such as dry mouth and urinary retention.
    • Contraindicated in patients with a history of epilepsy.

    Dipyrone (Novalgin)

    • Potent analgesic and antipyretic, more effective than aspirin but lacks anti-inflammatory effects.
    • Use restricted in various countries due to the risk of agranulocytosis, not dose-dependent.
    • Adverse effects include reversible agranulocytosis (10% lethal cases), allergic reactions, anaphylaxis, and bronchoconstriction in asthmatic patients.

    Acetaminophen (Paracetamol)

    • Rapid absorption from the gastrointestinal tract, peak levels occur 30 minutes post-administration.
    • Metabolized in the liver by conjugation; high doses lead to conversion into hepatotoxic metabolite (N-acetyl-benzoquinone).
    • Mainly excreted through the kidneys.
    • Acts as a selective COX III inhibitor, reducing prostaglandin (PG) synthesis in the brain; provides analgesic and antipyretic effects.
    • Lacks anti-inflammatory properties, minimal effects on cardiovascular, gastrointestinal, respiratory systems, or platelet functions.
    • Safe for use in pregnancy compared to aspirin; suitable for patients with peptic ulcers or hemophilia.
    • Potential adverse effects: skin rash, drug fever, with long-term use possibly leading to renal failure.
    • Toxic doses (≥15g in adults, 4g in children) cause dose-dependent hepatotoxicity (centrilobular necrosis).
    • Symptoms of toxicity (e.g., vomiting) can manifest within 24 hours; hepatic damage signs (e.g., jaundice) appear after 2-6 days.

    Mechanism of Hepatotoxicity

    • Acetaminophen converts to toxic metabolite in the liver, requiring detoxification by glutathione.
    • Depletion of glutathione stores leads to the toxic metabolite binding to proteins, resulting in liver cell damage.
    • Treatment includes gastric lavage with activated charcoal and administration of acetylcysteine to restore glutathione, with a specific dosing regimen.

    Nefopam (Acupan)

    • Central analgesic that lacks antipyretic and anti-inflammatory properties; more potent than NSAIDs.
    • Analgesic mechanism is unclear but may inhibit neurotransmitter reuptake or block central voltage-gated Na+ channels.
    • Also effective in relieving severe hiccups.
    • Adverse effects include potential precipitation of seizures in epileptics and weak atropine-like symptoms such as dry mouth and urinary retention.
    • Contraindicated in patients with a history of epilepsy.

    Dipyrone (Novalgin)

    • Potent analgesic and antipyretic, more effective than aspirin but lacks anti-inflammatory effects.
    • Use restricted in various countries due to the risk of agranulocytosis, not dose-dependent.
    • Adverse effects include reversible agranulocytosis (10% lethal cases), allergic reactions, anaphylaxis, and bronchoconstriction in asthmatic patients.

    Acetaminophen (Paracetamol)

    • Rapid absorption from the gastrointestinal tract, peak levels occur 30 minutes post-administration.
    • Metabolized in the liver by conjugation; high doses lead to conversion into hepatotoxic metabolite (N-acetyl-benzoquinone).
    • Mainly excreted through the kidneys.
    • Acts as a selective COX III inhibitor, reducing prostaglandin (PG) synthesis in the brain; provides analgesic and antipyretic effects.
    • Lacks anti-inflammatory properties, minimal effects on cardiovascular, gastrointestinal, respiratory systems, or platelet functions.
    • Safe for use in pregnancy compared to aspirin; suitable for patients with peptic ulcers or hemophilia.
    • Potential adverse effects: skin rash, drug fever, with long-term use possibly leading to renal failure.
    • Toxic doses (≥15g in adults, 4g in children) cause dose-dependent hepatotoxicity (centrilobular necrosis).
    • Symptoms of toxicity (e.g., vomiting) can manifest within 24 hours; hepatic damage signs (e.g., jaundice) appear after 2-6 days.

    Mechanism of Hepatotoxicity

    • Acetaminophen converts to toxic metabolite in the liver, requiring detoxification by glutathione.
    • Depletion of glutathione stores leads to the toxic metabolite binding to proteins, resulting in liver cell damage.
    • Treatment includes gastric lavage with activated charcoal and administration of acetylcysteine to restore glutathione, with a specific dosing regimen.

    Nefopam (Acupan)

    • Central analgesic that lacks antipyretic and anti-inflammatory properties; more potent than NSAIDs.
    • Analgesic mechanism is unclear but may inhibit neurotransmitter reuptake or block central voltage-gated Na+ channels.
    • Also effective in relieving severe hiccups.
    • Adverse effects include potential precipitation of seizures in epileptics and weak atropine-like symptoms such as dry mouth and urinary retention.
    • Contraindicated in patients with a history of epilepsy.

    Dipyrone (Novalgin)

    • Potent analgesic and antipyretic, more effective than aspirin but lacks anti-inflammatory effects.
    • Use restricted in various countries due to the risk of agranulocytosis, not dose-dependent.
    • Adverse effects include reversible agranulocytosis (10% lethal cases), allergic reactions, anaphylaxis, and bronchoconstriction in asthmatic patients.

    Acetaminophen (Paracetamol)

    • Rapid absorption from the gastrointestinal tract, peak levels occur 30 minutes post-administration.
    • Metabolized in the liver by conjugation; high doses lead to conversion into hepatotoxic metabolite (N-acetyl-benzoquinone).
    • Mainly excreted through the kidneys.
    • Acts as a selective COX III inhibitor, reducing prostaglandin (PG) synthesis in the brain; provides analgesic and antipyretic effects.
    • Lacks anti-inflammatory properties, minimal effects on cardiovascular, gastrointestinal, respiratory systems, or platelet functions.
    • Safe for use in pregnancy compared to aspirin; suitable for patients with peptic ulcers or hemophilia.
    • Potential adverse effects: skin rash, drug fever, with long-term use possibly leading to renal failure.
    • Toxic doses (≥15g in adults, 4g in children) cause dose-dependent hepatotoxicity (centrilobular necrosis).
    • Symptoms of toxicity (e.g., vomiting) can manifest within 24 hours; hepatic damage signs (e.g., jaundice) appear after 2-6 days.

    Mechanism of Hepatotoxicity

    • Acetaminophen converts to toxic metabolite in the liver, requiring detoxification by glutathione.
    • Depletion of glutathione stores leads to the toxic metabolite binding to proteins, resulting in liver cell damage.
    • Treatment includes gastric lavage with activated charcoal and administration of acetylcysteine to restore glutathione, with a specific dosing regimen.

    Nefopam (Acupan)

    • Central analgesic that lacks antipyretic and anti-inflammatory properties; more potent than NSAIDs.
    • Analgesic mechanism is unclear but may inhibit neurotransmitter reuptake or block central voltage-gated Na+ channels.
    • Also effective in relieving severe hiccups.
    • Adverse effects include potential precipitation of seizures in epileptics and weak atropine-like symptoms such as dry mouth and urinary retention.
    • Contraindicated in patients with a history of epilepsy.

    Dipyrone (Novalgin)

    • Potent analgesic and antipyretic, more effective than aspirin but lacks anti-inflammatory effects.
    • Use restricted in various countries due to the risk of agranulocytosis, not dose-dependent.
    • Adverse effects include reversible agranulocytosis (10% lethal cases), allergic reactions, anaphylaxis, and bronchoconstriction in asthmatic patients.

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    Description

    Explore the pharmacokinetics, metabolism, and effects of Acetaminophen (Paracetamol) in this quiz. Understand its safe usage, potential adverse effects, and toxic doses. Test your knowledge about its analgesic properties and unique mechanism of action.

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