الأدوية غير الستيرويدية المضادة للالتهابات

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• NSAIDs are analgesic, antipyretic, and anti-inflammatory drugs.
• Acetylsalicylic acid (Aspirin) is the prototype of the NSAID group.
• Other NSAIDs include ibuprofen and indomethacin.

Aspirin Pharmacodynamics

• Mechanism of action: Aspirin inhibits prostaglandin E synthesis.
• Pharmacological Actions: This leads to reduced pain (analgesic effect), fever (antipyretic effect), and inflammation (anti-inflammatory effect).
• Therapeutic uses: Analgesic (for headaches, etc.), antipyretic (for fever), anti-inflammatory (for conditions like acute rheumatic fever and rheumatoid arthritis), cardiovascular (to inhibit platelet aggregation, post-myocardial infarction prophylaxis).
• Adverse effects: Gastrointestinal irritation (gastritis, ulcers, bleeding), renal dysfunction (chronic use), hypersensitivity (asthma, rhinitis), salicylism (tinnitus, vertigo, hearing loss), Reye's Syndrome (severe hepatitis and cerebral edema in children).
• Contraindications: Peptic ulcer, renal and hepatic diseases, allergy to aspirin, children during viral infections (such as chickenpox or influenza)

Acetylsalicylic acid (Aspirin) Mechanism of action

• NSAIDs are inhibitors of prostaglandin E synthesis.

Pharmacological Actions (Aspirin - dose-dependent)

• Antiplatelet aggregation: Small doses (75 to 150 mg) used for post-myocardial infarction (MI) prophylaxis.
• Analgesic and antipyretic effects: Moderate doses.
• Anti-inflammatory: High doses.
• Uric acid elimination: Low to moderate doses may lead to hyperuricemia; high doses lead to uricosuria.

Therapeutic uses (indications)

• Systemic uses: Analgesic (for common conditions like headache, arthralgia, myalgia); Antipyretic (for fever); Anti-inflammatory (for acute rheumatic fever and rheumatoid arthritis).
• Cardiovascular applications: Aspirin (in small doses) inhibits platelet aggregation (e.g., post-MI prophylaxis, anti-thrombotic).
• Local uses: Salicylic acid (Topically used to treat acne, corns, calluses, and warts).

Adverse effects & Contraindications

• Adverse effects: Gastrointestinal irritation, renal dysfunction/hepatotoxicity (chronic use), and hypersensitivity reactions (especially asthma, rhinitis; Salicylism (tinnitus, vertigo, hearing loss) and Reye's syndrome (severe hepatitis and cerebral edema in children) are also potential side effects linked to large doses or prolonged use].
• Contraindications: Peptic ulcer, renal and hepatic diseases, allergy to aspirin, children during viral infections.

Comparison: Acetaminophen (Paracetamol) vs Aspirin (ASA)

• USES (Aspirin): Analgesic, antipyretic, anti-inflammatory

• USES (Paracetamol): Analgesic, antipyretic (no anti-inflammatory effects)

• Adverse effects (Aspirin): Gastric irritation, peptic ulceration

• Adverse effects (Paracetamol): No gastric irritation or peptic ulceration

• Contraindications (Aspirin): Contraindicated in children to prevent Reye's syndrome

• Contraindications (Paracetamol): Not Contraindicated in Children

• Anti-ID (Aspirin): No specific antidote for toxicity

• Anti-ID (Paracetamol): N-acetylcysteine (NAC) is the antidote

Overdose and management of Acetaminophen (paracetamol)

• Mechanism: Primarily metabolized in the liver into inactive conjugates, but a minor pathway involving P450 can result in a harmful metabolite (NABQI). In overdose situations, the body's protective stores (GSH) are depleted, causing a reaction with hepatocytes and potentially leading to liver failure.
• Management: N-acetylcysteine (a glutathione precursor), when administered within 12 hours, is effective in preventing liver damage. Beyond 12 hours, the potential for irreversible damage increases, while the effectiveness of the antidote diminishes

Practice Questions

• Q1:* The mechanism of action of aspirin is the inhibition of __________.
• Prostaglandin E synthesis
• Q2:* Aspirin is effective against which disease?
• Anti-inflammatory conditions, and post-myocardial infarction (MI) prophylaxis.
• Q3:* Aspirin is a treatment for which of these conditions?:
• Headache
• Q4:* The most important nurse implication during aspirin treatment is to:
• Assess the patient for a history of gastric ulcers.
• Q5:* Which drug is an analgesic without anti-inflammatory effects?
• Paracetamol
• Q6:* The antidote for paracetamol toxicity is:
• N-acetylcysteine (NAC).