NSAIDs: Mechanism of Action and Classification

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• NSAIDs are a class of drugs used to reduce inflammation, pain, and fever
• They do not contain steroids and are also known as 'NSAIDs' or 'antipyretic agents'
• NSAIDs work by inhibiting the production of prostaglandins, which are involved in inflammation
• Key NSAIDs include aspirin, ibuprofen, diclofenac, and celecoxib

Mechanism of Action

• NSAIDs target two enzymes: COX-1 and COX-2
• COX-1 is responsible for normal physiological functions like protecting the stomach lining
• COX-2 is induced during inflammation and causes pain, fever, and swelling
• NSAIDs can either be non-selective (inhibit both COX-1 and COX-2) or selective COX-2 inhibitors

Benefits and Risks

• NSAIDs provide analgesic (pain-relieving), antipyretic (fever-reducing), and anti-inflammatory effects
• However, inhibiting COX-1 can also lead to stomach ulcers and bleeding
• Selective COX-2 inhibitors aim to minimize this risk by targeting only the inflammatory pathway

Specific NSAIDs

• Aspirin: Has cardiovascular protective effects but can also cause stomach bleeding and ulcers
• Ibuprofen: Common over-the-counter NSAID used for pain, fever, and inflammation in children
• Diclofenac: Potent NSAID frequently prescribed for musculoskeletal pain and inflammation
• Celecoxib: A selective COX-2 inhibitor with reduced risk of gastrointestinal side effects

Considerations

• NSAIDs should be used cautiously, especially in elderly patients or those with pre-existing conditions
• Monitoring of electrolyte balance and renal function is important with long-term NSAID use
• Potential side effects include hypertension, edema, and increased cardiovascular risk### Acetylsalicylic Acid (Aspirin) Overview
• Aspirin is the only irreversible cyclooxygenase (COX) inhibitor, meaning it permanently blocks the enzyme responsible for prostaglandin production
• This gives aspirin anti-inflammatory, antipyretic (fever-reducing), and anti-platelet (blood thinning) properties
• Aspirin is commonly used to prevent heart attacks and strokes in high-risk patients due to its anti-platelet effects

Aspirin Adverse Effects

• Can cause gastrointestinal ulcers and bleeding due to reduction in protective prostaglandins
• High-dose or long-term use can lead to hyperuricemia (high uric acid levels)
• Should be avoided in children with viral infections due to risk of Reye's syndrome, a rare and serious condition

Aspirin Toxicity

• Aspirin poisoning can lead to respiratory alkalosis initially, as the drug stimulates the respiratory center
• This depletes carbon dioxide in the body, causing a shift towards metabolic acidosis which is a severe, life-threatening condition
• Symptoms include nausea, vomiting, tinnitus, and altered vision

Paracetamol (Acetaminophen) Toxicity

• Paracetamol is a commonly used pain and fever medication, generally considered safe
• However, overdose can cause liver damage, as a toxic metabolite (NAPQI) is produced that depletes glutathione in the liver
• Prompt treatment with the antidote N-acetylcysteine is crucial to prevent irreversible liver injury

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• Reduce inflammation, pain, and fever without containing steroids
• Work by inhibiting prostaglandin production, which is involved in inflammation
• Key examples include aspirin, ibuprofen, diclofenac, and celecoxib

Mechanism of Action

• Target two enzymes: COX-1 and COX-2
• COX-1 is responsible for normal physiological functions like protecting the stomach lining
• COX-2 is induced during inflammation and causes pain, fever, and swelling
• Can be non-selective (inhibit both COX-1 and COX-2) or selective COX-2 inhibitors

Benefits and Risks

• Provide analgesic, antipyretic, and anti-inflammatory effects
• Inhibiting COX-1 can lead to stomach ulcers and bleeding
• Selective COX-2 inhibitors aim to minimize this risk by targeting only the inflammatory pathway

Specific NSAIDs

• Aspirin: Has cardiovascular protective effects, but can cause stomach bleeding and ulcers
• Ibuprofen: Common over-the-counter NSAID used for pain, fever, and inflammation in children
• Diclofenac: Potent NSAID frequently prescribed for musculoskeletal pain and inflammation
• Celecoxib: A selective COX-2 inhibitor with reduced risk of gastrointestinal side effects

Considerations

• Use cautiously, especially in elderly patients or those with pre-existing conditions
• Monitor electrolyte balance and renal function with long-term NSAID use
• Potential side effects include hypertension, edema, and increased cardiovascular risk

Acetylsalicylic Acid (Aspirin)

• Irreversible cyclooxygenase (COX) inhibitor, permanently blocking the enzyme responsible for prostaglandin production
• Has anti-inflammatory, antipyretic, and anti-platelet properties
• Used to prevent heart attacks and strokes in high-risk patients due to its anti-platelet effects

Aspirin Adverse Effects

• Can cause gastrointestinal ulcers and bleeding due to reduction in protective prostaglandins
• High-dose or long-term use can lead to hyperuricemia
• Should be avoided in children with viral infections due to risk of Reye's syndrome

Aspirin Toxicity

• Can lead to respiratory alkalosis initially, followed by metabolic acidosis, a severe and life-threatening condition
• Symptoms include nausea, vomiting, tinnitus, and altered vision

Paracetamol (Acetaminophen) Toxicity

• Overdose can cause liver damage, as a toxic metabolite (NAPQI) depletes glutathione in the liver
• Prompt treatment with the antidote N-acetylcysteine is crucial to prevent irreversible liver injury

Understand the mechanism of action of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), including their effects on inflammation, pain, and fever. Learn about the key enzymes targeted by NSAIDs and their classification.