Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

1. General Pharmacological Effects of NSAIDs:

• Antipyretic: Inhibits prostaglandin (PG) synthesis.

• Anti-inflammatory: Inhibits COX (cyclooxygenase), leading to decreased production of PGE2 and PGF1a.

• Analgesic: Inhibits COX, reduces PGF2a production, and decreases the sensitivity of sensory nerves to pain stimuli.

• Antiplatelet: Inhibits COX, reducing TXA2 production.

2. Mechanism of Action:

• Mechanism of Fever: Pyrogens stimulate leukocytes, activate PG synthetase, increase PGE1, PGE2 synthesis, leading to increased heat production and reduced heat dissipation, causing fever.

• Mechanism of Antipyretic: Inhibits COX, reduces PG synthesis, and increases heat dissipation.

• Mechanism of Analgesic: Inhibits COX, reduces PGF2a production, and decreases the sensitivity of sensory nerves to pain stimuli.

• Mechanism of Anti-inflammatory: Inhibits COX, reduces PGE2 and PGF1a production, stabilizes lysosomal membranes, and inhibits the inflammatory cascade.

3. Characteristics of Effects:

• Antipyretic: Reduces fever from all causes, does not lower body temperature in healthy individuals, only treats symptoms.

• Analgesic: Relieves mild to moderate peripheral pain, effective for pain due to inflammation.

• Anti-inflammatory: Anti-inflammatory for all causes.

4. Side Effects:

• Salicylate Syndrome: Tinnitus, dizziness, decreased red blood cells, gastrointestinal irritation, gastrointestinal bleeding.

• Gastrointestinal irritation: Gastritis, peptic ulcer disease, gastrointestinal bleeding.

• Coagulation disorders.

• Allergic reactions.

5. Types of NSAIDs:

• Aspirin:

• Uric acid excretion effect: Reduces excretion (1-2g), increases excretion of urates (2-5g).

• Not for use in children under 12 years old (risk of Reye’s syndrome).

• Paracetamol:

• Analgesic, antipyretic, can be used in patients with gastritis and children.

• Mechanism of toxicity: Paracetamol is metabolized to NAPQI, causing liver cell damage.

• Symptoms of poisoning: Right upper quadrant pain, jaundice, hepatic coma, severe acidosis, increased transaminases.

• Antidote: Glutathione or N-acetyl cysteine.

• Oxicams: Piroxicam, meloxicam, tenoxicam.

• Propionic acid derivatives: Ibuprofen, naproxen, fenoprofen.

• Simple analgesics: Floctafenin.

• Selective COX2 inhibitors: Celecoxib (may cause cardiovascular complications).

6. Other Medications:

• Voltaren: Reduces free arachidonic acid levels in leukocytes.

• Paracetamol: Analgesic, antipyretic, not an NSAID.

7. Notes:

• NSAIDs should not be used to treat gout.

• Piroxicam has stronger analgesic and anti-inflammatory effects than aspirin.

8. Pharmacokinetics:

• Paracetamol: Almost no binding to plasma proteins, T1/2 = 2 hours.

9. Summary:

NSAIDS are a group of drugs that have analgesic, antipyretic, and anti-inflammatory effects, commonly used in the treatment of inflammatory and pain-related conditions. However, it’s crucial to be aware of potential side effects and use them according to a doctor’s prescription.