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Anti-inflammatory drugs. By Dr Soha AlSayed Lecture of Pharmacology Faculty of Medicine Suez Canal University. Classifications of anti-inflammatory drugs. Steroids: Drugs which contain steroid nucleus They are glucocorticoids or mineralocorticoids
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Anti-inflammatory drugs By Dr Soha AlSayed Lecture of Pharmacology Faculty of Medicine Suez Canal University
Classifications of anti-inflammatory drugs • Steroids: • Drugs which contain steroid nucleus • They are glucocorticoids or mineralocorticoids • Glucocorticoids have significant anti-inflammatory effect 2. Non-steroids anti-inflammatory drugs (NSAIDs) characterized by: • Lower high body temperature (Antipyretic) • Relieve pain (Analgesic) • Some have anti-inflammatory effect
Non steroidal anti-inflammatory drugs Types of COX enzyme: 1. COX-1 (constitutive) especially in stomach decrease HCl (prevent PU) & Kidney vasodilatation 2. COX-2 (inducible) by infection • Infection ►toxins ► IL-1&TNF ► COX-II ►▲ PG ► Inflammation ► A. CNS: a. hypothalamus ► elevates Heat regulatory centre► Fever b. Thalamus► pain 2. Periphery: a. Sensitize Nociceptors to histamine, Bradykinin & 5-HT ► pain b. Potentiates effect of histamine & bradykinin • VD Redness, Hotness, capillary permeability
Non steroidal anti-inflammatory drugs Types of NSAIDS: 1. Non-selective COX inhibitors (COX 1,2,3) 2. Selective COX-2 inhibitors (Celecoxib, Rofecoxib) 3. COX-3 inhibitors : paracetamol (not anti-inflammatory). Why? Mechanism of action of NSAIDS They inhibit cyclo-oxygenase enzyme ►▼Prostaglandins ► ▼Fever, pain, Inflammation. 1. Antipyretic action: decrease set point of heat regulatory centre in hypothalamus, increase sweating
The anti-inflammatory actions of NSAIDS • Due to reduction of PGE2 and PGI2 that participate in the inflammatory process • Stabilize lysosomes • Inhibit granulocyte adherence to damaged vasculature • Inhibit migration of macrophages to the inflammatory sites • Inhibit Kinin-Kallikrein system
Shared Adverse effects of NSAIDS • GIT side effects: Dyspepsia, Gastric ulceration • Disturbances of renal function: (Analgesic abuse nephropathy) due to decreased vasodilatory PGs • Hypersensitivity: e.g. aspirin induced asthma • Bleeding tendency • Displacing other drugs from plasma proteins • Salt and water retention and hyperkalemia • May prolong pregnancy and spontaneous labor
Aspirin=Acetyl salicylic acid Pharmacokinetics: • Administration: Effective orally & pareneterally • Absorption: Absorbed from stomach & Upper intestine. Why? • Distribution: Bound to PP (50-80%). • Metabolism: mainly by conjugation to glycine & glucoronic acid. • Excretion: unchanged and conjugated form by kidney. How can you increase excretion? • In low concentration first order kinetics? • In high concentration zero order kinetics?
Pharmacological actions of Aspirin 1. CNS: A. Analgesic action: central and peripheral B. Antipyretic Action: ▼PGE 2. Anti-inflammatory actions: 3. Respiration and Acid/Base balance: • Ordinary doses; little effect • large dose ►▲RR►R alkalosis. • V. high L doses► Resp. depression ► Resp. acidosis. 4. Renal effects:▲ Na, water retention
Pharmacological actions of aspirin 5. Uric acid: A. Small dose: Retention of UA B. Large dose: Excretion of UA 6. Blood: A. Small dose (75-150 mg/day): ▼platelet aggregation and▲ bleeding time B. In patients with G-6-PD defiiency ►hemolytic anemia (idiosncrasy). 7. GIT: Epigastric distress, nausea, vomiting, ulceration, bleeding.
Indications of Aspirin • Fever: (Not preferred in children. Why?) • Analgesic: Mild to moderate pain. headache, arthritis, myalgia, common cold ( 0.5-2 gm/day) • Acute Rheumatic fever: Symptomatic treatment only, 10 gm /day • Rheumatoid arthritis: 8 gm/day • Antithrombotic: 75-150 mg/day • Gout?: > 5gm /day
Side effects & contraindicationsof Aspirin • GIT: What? • Idiosyncrasy: • Hypoprothrombinemia, bleeding tendency • Chronic use: Salicylism: Headache, mental confusion, drowsiness, vertigo, ringing in ears (Tinnitus), sweating, thirst, nausea, vomiting 5. Hepatic: Severe hepatic injury and encephalopathy in Reye’s syndrome (in children with viral infection especially influenza, Chicken pox) 6. Bronchospasm 7. Allergy
Acute Salicylate poisoning Acute salicylate poisoning: Hallucination, restlessness, tremors, convulsions, vomiting, dehydration, hypotension, hyperglycemia, hyperpyrexia • Treament of acute salicylate poisoning; • Gastric lavage with sod. Bicarbonates. Why? • Correction of hyperpyrexia (cold fomentation, ethyl alcohol evaporation • Correction of dehydration , acid/base balance • Alkalinization of urine with NaHCO3. Why? • Hemodialysis: Symptomatic treatment