Pharmacology of NSAIDs and Coxibs

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Questions and Answers

Which of the following is a consequence of long-term use of COX-2 selective NSAIDs?

Increased production of mucus in the stomach

Increased risk of gastrointestinal toxicity (correct)

Improved efficacy of diuretics

Decreased risk of thromboembolic events

What is the primary mechanism by which aspirin produces antiplatelet effects?

Inhibition of PGI2 in platelets

Inhibition of COX-1 in platelets (correct)

Stimulation of prostacyclin in endothelium

Inhibition of COX-2 in endothelium

What is the primary mechanism by which NSAIDs cause gastrointestinal effects?

Increased production of thromboxane A2

Inhibition of COX-1 leading to decreased prostaglandin production (correct)

Inhibition of COX-2 leading to increased prostaglandin production

Direct gastric irritation

Which of the following is a contraindication for the use of NSAIDs?

Peptic ulcer disease Signup and view all the answers

What is the primary mechanism by which NSAIDs cause renal effects?

Inhibition of local prostaglandins leading to decreased renal blood flow Signup and view all the answers

Which of the following is a drug interaction associated with NSAIDs?

Decreased effect of diuretics Signup and view all the answers

Which of the following is a unique property of aspirin compared to other NSAIDs?

Irreversible inhibition of COX-1 Signup and view all the answers

What is the primary indication for the use of low-dose aspirin?

Secondary prophylaxis of MI and unstable angina Signup and view all the answers

What is the major concern of using aspirin in children and teens for treating viral acute febrile illness?

Increased risk of Reye's syndrome Signup and view all the answers

What is the impact of chronic and high-dose intake of aspirin on the kidneys?

Increased salt and water retention Signup and view all the answers

Which of the following drugs is known to increase the activity of warfarin?

Aspirin Signup and view all the answers

What is the major difference between the effects of aspirin and ibuprofen on the gastrointestinal system?

Ibuprofen is better tolerated and has a lower risk of gastrointestinal ADRs Signup and view all the answers

What is the contraindication of aspirin during pregnancy?

Closure of patent ductus arteriosus (PDA) in babies Signup and view all the answers

What is the effect of non-selective COX inhibitors on platelet function?

Increased bleeding time Signup and view all the answers

Which of the following drugs does not interact with oral anticoagulants and oral antidiabetic agents?

Ibuprofen Signup and view all the answers

What is the main mechanism by which NSAIDs mediate their effects?

Inhibiting the enzyme cyclooxygenase (COX) Signup and view all the answers

What is the major risk of paracetamol poisoning?

Hepatotoxicity Signup and view all the answers

What is the role of COX-1 in the body?

It is constitutively expressed in the body and plays a role in maintaining gastrointestinal mucosa lining, kidney function, and platelet aggregation Signup and view all the answers

Which of the following NSAIDs is classified as a nonselective COX inhibitor with high efficacy and analgesic activity?

Indomethacin Signup and view all the answers

What is the effect of NSAIDs on gastrointestinal mucosa?

They decrease the production of prostaglandins, which can lead to gastrointestinal ulceration Signup and view all the answers

What is the main difference between COX-1 and COX-2?

COX-1 is constitutively expressed in the body, while COX-2 is inducibly expressed during an inflammatory response Signup and view all the answers

Which of the following NSAIDs is contraindicated in patients with kidney disease?

All of the above Signup and view all the answers

What is the effect of NSAIDs on platelet aggregation?

They inhibit platelet aggregation, mainly through the inhibition of COX-1 Signup and view all the answers

What is the anti-inflammatory mechanism of NSAIDs?

Inhibition of prostaglandin synthesis at the site of inflammation Signup and view all the answers

Study Notes

NSAIDs Overview

NSAIDs have four major actions: anti-inflammatory, analgesic, antipyretic, and antiplatelet
Main mechanism of action is inhibiting enzyme COX, which is required to convert arachidonic acid into thromboxanes, prostaglandins, and prostacyclins
COX-1 is constitutively expressed in the body and plays a role in maintaining gastrointestinal mucosa lining, kidney function, and platelet aggregation
COX-2 is not constitutively expressed in the body and is instead inducibly expressed during an inflammatory response

Non-Selective COX Inhibitors

Examples: Ibuprofen, Aspirin, Indomethacin, Piroxicam, Diclofenac, Naproxen, Ketoprofen, Mefenamic acid
Irreversible inhibition of platelets with Aspirin
Efficacy varies among non-selective COX inhibitors
Ibuprofen is equipotent to Aspirin and has a moderate efficacy
Aspirin is an irreversible inhibitor of COX with a moderate efficacy

Selective COX2 Inhibitors

Examples: Celecoxib, Etoricoxib
Moderate efficacy

Actions of NSAIDs

Anti-Inflammatory Action

Main mechanism of action: ↓ prostaglandins synthesis at site of inflammation
Other mechanisms of action: free radical scavenging, inhibition of lipooxygenase pathway

Analgesic Action

↓ pain
Used for analgesia and anti-inflammatory action in conditions such as toothache, headache, backache, joint sprains, dysmenorrhea, and mild postoperative pain

Antipyretic Action

↓ body temperature in fever
Paracetamol is preferred as an antipyretic

Antiplatelet Action

Inhibits COX-1, mainly with Aspirin
Used for antiplatelet action in low doses for secondary prophylaxis of MI and unstable angina or transient ischaemic attacks

Adverse Drug Reactions (ADRs)

GIT: nausea, vomiting, dyspepsia, gastric erosion, hematemesis
Renal: salt and water retention, edema, analgesic nephropathy
CVS: closure of patent ductus arteriosus, CCF, MI, stroke
Psychiatric reactions: excitement with indomethacin
Hepatotoxicity: with large doses of paracetamol
Hypersensitivity: skin rash, precipitation of asthma

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Description

This quiz covers the mechanisms of action of NSAIDs and Coxibs, including their effects on platelet aggregation, thromboembolic events, and gastrointestinal effects. It also touches on their adverse drug reactions.