Types of pain.pptx34567890خهعغفقثصشئءؤرلاىة

PHARMA

1. Evalution of analgesic agents

2. Types of pain: 1- According to duration: A- Acute pain : less than 30 days. B- Chronic pain : more than 6 months. C- Sub acute pain : from 1 -6 months. 2-According to type of damage: A-Nociceptive pain: tissue damage; skin, muscles, visceral organs, joints, tendons, or Bones. B- Neuropathic pain: nerve damage; spinal cord injury, multiple sclerosis and diabetic neuropathy.

3. * Breakthrough pain : just occurs, without any obvious trigger such as type of cancer pain Major Classes of Analgesics: 1- NSAIDs and Paracetamol. 2- Opioid Analgesics : Agents that produce morphine-like effect. 3-Specific agents; Anticonvulsants and tricyclic antidepressants.

4. 1-Non-steroidal Anti-inflammatory Drugs (NSAIDs): NSAIDs are a group of chemically dissimilar agents that have: A-analgesic (pain-killing) and. B-antipyretic (fever-reducing). 3-and anti-inflammatory effects.

5. MECHANISM OF ACTIONS: The NSAIDs act by inhibiting the synthesis of prostaglandins : Membrane phospholipid Arachidonic acid Leukotrienes A-Prostaglandins B- Prostacyclin C- Thromboxanes Phospholipase A2 Cyclooxygenase pathway Lipoxygenase pathway

6. Two forms of cyclooxygenase (COX):COX-1 and COX-2. A- CO X-1 is expressed constitutively in gastric mucosa, kidney and platelets. B- COX-2 is expressed in macrophages and monocytes in response to inflammation.

7. Major Roles of Eicosanoids : A-Prostaglandins (PCs): 1-Modulate pain, inflammation and fever. 2- Control acid secretion and mucus production in the GIT. 3- Control renal blood flow. 4- Control uterine contractions . B- Prostacyclin (PGI): 1- Inhibit platelet aggregation. 2- Induce vasodilation .

8. Major Roles of Eicosanoids: C-Thromboxane-A2 (TXA2): 1- Induce platelet aggregation. 2- Induce vasoconstriction. D- Leukotrienes (LTs): 1- Powerful bronchoconstriction. 2- Increase vascular permeability.

9. Therapeutic Actions of NSAIDs: 3 major therapeutic actions: 1 ) Anti-inflammatory actions: decrease prostaglandins synthesis inhibits inflammation. 2 ) Analgesic action: decrease PGE2 synthesis decrease pain sensation. 3) Antipyretic action: decrease PGE2 synthesis thermoregulatory' center Increase heat loss by peripheral vasodilation & sweating in patients with fever.

10. Uses of NSAIDs: Anti-inflammatory and analgesic : such as; rheumatoid arthritis (RA), osteoarthritis (OA) & gout, headache, toothache, backache, menstrual cramps (dysmenorrhea) and cold/flu Antipyretic : Aspirin is contraindicated in children (under 20 years) as antipyretic with viral infections such as chickenpox or influenza), due to increased risk for Reye syndrome .

11. Uses of NSAIDs: C) Antiplatelet: Low-dose Aspirin used in the prophylactic treatment of transient cerebral ischemia and thromboembolic stroke, and reduce the incidence of recurrent MI. D) Pregnancy : Low-dose Aspirin may be beneficial in pregnancies at risk for the development of pregnancy-induced hypertension and pre-eclampsia, and in fetuses with intra uterine growth retardation. E ) Topical: 1) NSAIDs may be used topically as anti-inflammatory and analgesic. 2) Salicylic acid is a keratolytic, used topically to treat corns, calluses and Warts .

12. General side effects for all NSA IDs (commonly dose related); 1- CNS : headaches, tinnitus and dizziness. 2- CVS: hypertension, fluid retention, edema and risk for CV events. 3- GIT: abdominal pain, dysplasia, nausea, vomiting, ulcers or bleeding. 4- Kidney: renal insufficiency, renal failure, hyperkalemia & proteinuria. 5- Lung: asthma. 6- Hematologic (rare); thrombocytopenia and aplastic 7- Hepatic: ( rare) abnormal liver function tests and liver failure. 8- Skin: rashes

13. General side effects for all NSA IDs (commonly dose related); To reduce the risk of gastrointestinal effects: A- NSAIDs may be taken with or after food or milk. B- Taking histamine H2-antagonists, or proton pump inhibitors such as omeprazole. C- Using enteric-coated formulations (1, 2) D- Using some NSAIDs like Celecoxib (called selective COX-2 inhibitors)

14. Pregnancy; Most NSAlDs are category C in the first and second trimesters. All NSAIDs should not (category D) be used in third trimester, may increases the risk of pulmonary hypertension in newborns, due to premature closure of the ducts arteriosus (NSAIDs block the synthesis of PGEi & PGE2 , which are needed to keep open the ductus arteriosus Lactating women: Most NSAIDs displace bilirubin and are contraindicated if a neonate with jaundice. Ibuprofen, Indomethacin and Naproxen safe in breastfeeding women

15. SOME NOTES: 1- Aspirin is now rarely used as anti-inflammatory, and used only as anti-platelet (75-325 mg/d) 2- Antiplatelet effect; Aspirin irreversibly inhibits COX within the platelets <=> blocks the formation of TXA2. 3- Antiplatelet effect of Aspirin lasts 8-10 days ( the life of the platelet ) 4- ASPIRN Is irreversibly inactivating cyclooxygenase (COX-1 and COX-2), other NSAIDs (including other salicylates ), are all reversible inhibitors of cyclooxygenase 5- NSAIDs should be used with caution in patients with asthma , and hypertension (it cause sodium and water retention).