🗊Презентация Anti-inflammatory drugs

Anti-inflammatory drugs Anti-allergic drugs Immunomodulators

Plan of lecture: Anti-inflammatory agents Anti-allergic drugs Immunomodulators

Inflammation Inflammation is a complex protective response of the organism to injury caused by damaging agents. It is aimed at inactivation or removal of these agents and promoting healing. The traditional names for signs of inflammation come from Latin: Dolor (pain) Calor (heat) Rubor (redness) Tumor (swelling) Functio laesa (loss of function)

Mediators of inflammation Prostaglandins Bradykinin Serotonin Histamine Interleukins-2 – 6, 10, 12,13 Platelet activating factor

The role of some prostaglandins in the body PGE 2 – vasodilation, bronchodilation, inhibition of gastric acid secretion, stimulation of gastric mucus secretion, sensitization of pain receptors to chemical and mechanical stimuli, promotion of anterior pituitary hormones release; PGF2α - uterus contraction, bronchoconstriction, decrease in intraocular tension; TXA2 (thromboxane), produced by platelets, - induction of platelet aggregation, vasoconstriction; PGI 2 - inhibition of platelet aggregation, potent vasodilation;

Cyclo-oxygenase (COX) Exists in the tissue as constitutive isoform (COX-1). At site of inflammation, cytokines stim the induction of the 2nd isoform (COX-2). Inhibition of COX-2 is thought to be due to the anti-inflammatory actions of NSAIDs. Inhibition of COX-1 is responsible for their GIT toxicity. Most currently used NSAIDs are somewhat selective for COX-1, but selective COX-2 inhibitors are available.

NSAIDs – nonsteroidal anti-inflammatory drugs NSAIDs – nonsteroidal anti-inflammatory drugs

1. Nonsteroidal anti-inflammatory drugs (NSAIDs) Nonselective COX inhibitors 1. Salicylates *Acetylsalicylic acid (Aspirin) * Salicylamide 2. Pyrazolone derivatives *Phenylbutazone *Metamizol (Analginum) 3. Indole derivatives *Indomethacin 4. Propionic acid derivatives *Naproxen

Selective COX inhibitors Preferential COX-2 inhibitors Nimesulide Meloxicam Nabumeton Selective COX-2 inhibitors Celecoxib Parecoxib Rofecoxib NB!!!These drugs cause little gastric mucosa damage, they do not inhibit platelet aggrigation!!!

Mechanism of action of NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) • Act by inhibiting CycloOXygenases (COX) => no PG production – COX-1: Constitutively expressed => house-keeping function – COX-2: Induced by pro-inflammatory factors (TNFα, IL-1) – COX-3: Just recently discovered • PGs do not cause pain, but sensitize nocireceptors to stimulation (e.g. by 5-HT, Bradykinine, capsaicin, …) • IL-1 release from activated macrophages (bacteria, etc.) induces COX-2 in the brain =>PG E produced => affects thermoregulation => fever=> NSAIDs have anti-pyretic effects • Classical NSAIDs: inhibit both COX-1 and COX-2 (inhibition is reversible, with the exception of Aspirin) => housekeeping PGs reduced => side effects (gastrointestinal, bronchospasms,…) • 2nd generation NSAIDs: COX-2 specific => only the inflammatory response is inhibited => fewer side effects.

Mechanism of anti-inflammatory drugs’ action

Pharmacological effects of NSAIDs Anti-inflammatory Analgesic Antipyretic Antiplatelet (Aspirin) Closure of ductus arteriosus in newborn

Clinical uses of NSAIDs 1. Pain: headache, toothache, myalgia, backpain; 2. Fever; 3. Arthritises: rheumatiod arthritis, osteoarthritis, gout, ankylosing spondylitis; 4. Dismenorrhoea (especially ibuprofen); 5. Unclosure of ductus arteriosus (especially aspirin); 6. Prevention of MI, stroke, and reinfarction (aspirin);

Side effects of NSAIDs 1. GIT disturbances: epigastric pain, nausea, gastric peptic ulcer (especially aspirin), gastrointestinal bleeding (especially indomethacin); 2. CNS disturbances: dizziness, mental confusion, hallucination and psychosis, depression (especially indomethacin); 3. Leukopenia, agranulocytosis (indomethacin, phenylbutzone, metamizol); 4. Water and sodium retention, edema (phenylbutzone); 5. Hypersensitivity reactions 6. Reye’s syndrom, bronchospasm (aspirin)

Contraindications A) Pregnancy B) Haemophilic patients C) Hypersensitivity reactions D) Viral infections mainly in children E) Peptic ulcers

Drugs interaction Potentiates the gastric irritant effect of alcohol Potentiates the hypoglycaemic effects of oral hypoglycaemic drugs

The Salicylates - ASPIRIN Duration of action ~ 4 hr. Orally taken. Weak acid (pKa ~ 3.5); so, non-ionized in stomach  easily absorbed. Hydrolyzed by esterases in tissues and blood to salicylate (active) and acetic acid. Most salicylate is converted in liver to H2O-sol conjugates that are rapidly excreted by kids.

ASPIRIN - Therapeutic Uses Antipyretic, analgesic. Anti-inflammatory: rheumatic fever, rheumatoid arthritis (joint dis), other rheumatological diseases. High dose needed (5-8 g/day). But many pts cannot tolerate these doses (GIT); so, proprionic acid derivatives, ibuprofen, naproxen tried first. Prophylaxis of diseases due to platelet aggregation. Pre-eclampsia and hypertension of pregnancy (excess TXA2).

Propionic acid derivatives IBUPROFEN: Pharmacokinetics Rapidly absorbed after oral ingestion. Half-life 1-2 hours Highly bound to plasma proteins Excreted through kidney as metabolites.

IBUPROFEN The same mechanism & pharmacological actions of aspirin Except that it is reversible inhibitor for COX enzymes More potent as antiinflammatory than aspirin!!!

Clinical uses A) Analgesic B) Antipyretic C) Anti-inflammatory D)Acute gouty arthritis E) Patent ductus arteriosus

Preparations of Ibuprofen Oral preparations. Topical cream for osteoarthritis. A liquid gel for rapid relief of postsurgical dental pain. Intravenous route as In patent ductus arteriosus

Adverse effects 1.Gastric upset (less frequent than aspirin). 2.Fluid retention 3.Hypersensetivity reactions 4.Ocular disturbances 5.Rare hematologic effects (agranulocytosis & aplastic anaemia).

Contraindications 1. Peptic ulcer 2. Allergic patients to aspirin 3. Kidney impairment 4.Liver diseases 5.Pregnancy 6.Haemophilic patients The concomitant administration of ibuprofen antagonizes the irrevesible platelet inhibition of ASPIRIN (limit cardioprotective effect of aspirin).

Piroxicam Mechanism of actions: A) Non-selective inhibitors to COX1 & COX2 B) Traps free radicals C) Inhibits polymorphonuclear leukocytes migration D) Inhibits lymphocyte function.

Pharmacokinetics Well absorbed orally Half- Life 45 hours Given once daily

Adverse effects Less frequent gastric upset (20%). Dizziness. Tinnitus. Headache. Allergy.

Acetic acid derivatives DICLOFENAC Mechanism of action Non-selective inhibitor to COX1 & COX2. More potent as anti-inflammatory than analgesic and antipyretics.

Clinical uses DICLOFENAC A) Any inflammatory conditions B) Musculoskeletal pain C) Dysmenorrhoea D)Acute gouty arthritis E) Fever F) Locally to prevent or treat post opthalmic inflammation G) A topical gel for solar keratoses

Adverse effects DICLOFENAC Gastric upset Renal impairment Elevation of serum aminotransferase Salt & water retention

Preparations of DICLOFENAC Diclofenac with misoprostol decreases upper gastrointestinal ulceration, but result in diarrhea. Diclofenac with omeprazole to prevent recurrent bleeding. 1% opthalmic preparation for postoperative opthalmic inflammation. A topical gel 3% for solar keratoses. Rectal suppository as analgesic or for postoperative nausea.

Selective COX 2 inhibitors Advantages: 1. Highly selective inhibitors to COX2 enzyme. 2. Potent anti-inflammatory. 3. Have analgesic & antipyretic properties. 4. Highly bound to plasma proteins.

Selective Cox 2 inhibitors 5. Lower incidence of gastric upset. 6. No effect on platelet aggregation (COX1). 7. Renal toxicities (they are not recommended for patients with severe renal insufficiency). 8. High incidence of cardiovascular thrombotic events with some of them as ROFECOXIB.

Selective Cox 2 inhibitors 9- They are recommended in postoperative patients undergoing bone repair. 10- Also, indicated in primary familial adenomatous polyposis, dysmenorrhea, acute gouty arthritis, acute musculoskeletal pain, ankylosing spondylitis.

SAIDs – steroidal anti-inflammatory drugs SAIDs – steroidal anti-inflammatory drugs

Steroidal anti-inflammatory drugs 1. Short-acting glucocorticoids (natural) Hydrocortisone Cortisone 2. Intermediate-acting glucocorticoids Prednisone Prednisolone Methylprednisolone Triamcinolone

Clinical uses of SAIDs Adrenal insufficiency Arthrities Collagen diseases (systemic lupus erhymatosis, scleroderma) Bronchial asthma Severe allergic reactions Autoimmune diseases Skin diseases Ulcerative colitis, Crohn’s disease Cerebral edema Organ transplantation and skin allograft Septic shock

Main side effects of SAIDs Susceptibility to infections Delayed healing of wounds Osteoporosis Growth retardation in children Peptic ulceration Cushing habitus Hyperglycaemia Muscular weakness Psychiatric disorders Withdrawal syndrom

ANTI-ALLERGIC DRUGS

Allergy An allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid. Allergy is one of four forms of hypersensitivity and is formally called type I (or immediate) hypersensitivity. Allergic reactions are distinctive because of excessive activation of certain white blood cells - lymphocytes called B cells, whose role is production of antibodies, called Immunoglobulin E (IgE). Mast cells are activated and release mediator of allergy (HISTAMINE) that results in an inflammatory response.

Clinical Symptoms Associated With Histamine Release mild/cutaneous mild to moderate severe/ anaphylactic

Histamine exerts its effects on many tissues and organs: It is not a drug but is important due to its physiological and pathophysiological actions. Therefore, drugs that inhibit its release or block its receptors have therapeutic value. Physiological Actions of Histamine Primary stimulant for gastric acid and pepsin secretion (H2) (acid secretion is enhanced by gastrin and vagal stimulation) Has a role as a neurotransmitter (H3) (both in the CNS and peripheral sites)

Pathophysiological Actions of Histamine Cellular mediator of immediate hypersensitivity reaction and acute inflammatory response Anaphylaxis Seasonal allergies Duodenal ulcers Systemic mastocytosis Gastrinoma (Zollinger-Ellison Syndrome)

Pharmacological Effects of Histamine Ranges from mild allergic symptoms to anaphylactic shock Involves both the H1 and H2 receptors dilatation of small blood vessels  flushing (H1) decreased TPR and BP (H1 initial response, H2 sustained reaction) increased capillary permeability, edema (H1)

Antiallergic drugs 1. Antihistaminics 2. Corticosteroids 3. Mast cell stabilisers 4.Antileukotriene drugs

Histamine-related Drugs Mast Cell Stabilizers (Cromolyn Na, Nedocromil –Tilade -, Albuterol) H1 Receptor Antagonists (1st and 2nd generation) H2 Receptor Antagonists (Ranitidine, Cimetidine) H3 Receptor Agonist and Antagonists (potential new drugs being developed)

First Generation ANTIHISTAMINE Agents Ethanolamines: DIPHENHYDRAMINE (Benadryl) CLEMASTINE (Tavist) Ethylenediamine:TRIPELENNAMINE Alkylamine:CHLORPHENIRAMINE (Chlortrimeton) Phenothiazine:PROMETHAZINE (Phenergan) Piperazines: HYDROXYZINE (Vistaril) CYCLIZINE (Antivert)

First Generation Agents Uses: Adjunctive in anaphylaxis and other cases where histamine release can occur (H2 antagonist, and epinephrine must also be used in anaphylaxis) Antiallergy (allergic rhinitis, allergic dermatoses, contact dermatitis) Sedative/sleep aid To prevent motion sickness (MECLIZINE, CYCLIZINE)

First Generation Agents Adverse Effects: Sedation (Paradoxical Excitation in children) Dizziness Fatigue Tachydysrhythmias in overdose - rare Allergic reactions with topical use Peripheral antimuscarinic effects dry Mouth blurred Vision constipation urinary Retention

First Generation Agents Drug interactions: Additive with classical antimuscarinics Potentiate CNS depressants opioids sedatives general and narcotic analgesics alcohol

Second Generation Agents Uses Antiallergy

Histamine H1- Antagonists First Generation: !!!Sedating!!! Second Generation: !!!Non sedating!!!

Advantages of 2nd generation antihistaminics Higher H1 selectivity, absence of anticholinergic side effects Absence of inhibitory action on CNS Additional antiallergic mechanisms: some of them are acting on leukotrienes or by antiplatelet activating factor

Mast cell stabilisers Cromolyn sodium (Sodium cromoglycate) Nedocromil sodium Ketotifen Corticosteroids (vide supra)

Antileukotriene drugs Montelukast Zafirlukast Mechanism: competitive block of LT1 receptors Clinical use: bronchial asthma

Immunomodulators