NSAID Classification – A Complete Guide for Pharmacy Students

Introduction

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used medications globally. They are primarily prescribed for their analgesic, anti-inflammatory, and antipyretic properties. Whether it’s managing acute pain, chronic arthritis, or postoperative inflammation, NSAIDs are essential tools in clinical practice. Understanding their classification is critical for pharmacy students and healthcare professionals to ensure rational and safe use.

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What are NSAIDs?

NSAIDs inhibit cyclooxygenase enzymes (COX-1 and COX-2), which are essential for prostaglandin synthesis. Prostaglandins play a role in pain, fever, and inflammation, as well as in protecting the gastric mucosa and regulating renal blood flow. By blocking COX enzymes, NSAIDs reduce inflammation and pain but can also lead to adverse effects like gastric ulcers and renal dysfunction.

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Classification of NSAIDs

NSAIDs can be classified based on various parameters such as selectivity, chemical structure, and duration of action.

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1. Based on COX Selectivity

Category	Example Drugs	Notes
Non-selective COX inhibitors	Ibuprofen, Diclofenac, Naproxen, Indomethacin	Inhibit both COX-1 and COX-2
Preferential COX-2 inhibitors	Nimesulide, Meloxicam, Etodolac	Higher affinity for COX-2, safer for GI
Selective COX-2 inhibitors (Coxibs)	Celecoxib, Etoricoxib, Parecoxib	Least GI toxicity, but cardiovascular risks

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2. Based on Chemical Structure

Class	Examples
Salicylates	Aspirin, Diflunisal
Propionic acid derivatives	Ibuprofen, Naproxen, Ketoprofen
Acetic acid derivatives	Diclofenac, Indomethacin, Etodolac
Oxicams	Piroxicam, Meloxicam, Tenoxicam
Fenamates (Anthranilic acid derivatives)	Mefenamic acid, Flufenamic acid
Pyrazolones	Metamizole (Dipyrone), Phenylbutazone
Coxibs	Celecoxib, Etoricoxib, Parecoxib

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3. Based on Duration of Action

Category	Examples
Short-acting NSAIDs	Ibuprofen, Diclofenac
Long-acting NSAIDs	Piroxicam, Naproxen, Meloxicam

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Pharmacological Actions of NSAIDs

• Anti-inflammatory – reduces inflammation by decreasing prostaglandin synthesis.
• Analgesic – relieves mild-to-moderate pain.
• Antipyretic – lowers fever via hypothalamic thermoregulatory center.
• Antiplatelet (e.g., Aspirin) – used in cardiovascular prophylaxis.

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Common Clinical Uses

• Rheumatoid arthritis, osteoarthritis
• Dysmenorrhea
• Fever
• Postoperative pain
• Gout (acute attack)
• Cardiovascular prophylaxis (low-dose aspirin)

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Adverse Effects of NSAIDs

• Gastrointestinal: Gastritis, ulcers, bleeding
• Renal: Acute kidney injury, fluid retention
• Cardiovascular: Hypertension, myocardial infarction (especially with selective COX-2 inhibitors)
• Hematologic: Bleeding risk (due to platelet inhibition)
• Hypersensitivity reactions

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Conclusion

NSAIDs are indispensable but must be used cautiously. Knowing their classification helps in choosing the most appropriate drug based on therapeutic need and patient safety. As future pharmacists, mastering NSAID classification is key to optimizing therapy and preventing adverse effects.

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References

1. KD Tripathi – Essentials of Medical Pharmacology, 8th Edition
   • Chapter: Anti-inflammatory Drugs
   • Details on NSAID classification, COX enzymes, pharmacological actions, and adverse effects.
2. Sparsh Gupta – Review of Pharmacology, 10th Edition
   • Quick reference for classification and therapeutic uses of NSAIDs.
3. Goodman & Gilman – The Pharmacological Basis of Therapeutics, 13th Edition
   • In-depth details on the mechanism of COX inhibition, pharmacokinetics, and safety profiles.