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12.3 Analgesics nlm.nih/medlineplus/druginformation.html

12.3 Analgesics http://www.nlm.nih.gov/medlineplus/druginformation.html. Describe and Explain the different ways in which analgesics prevent pain. Pain Receptor. Nerves that transmit the pain Free nerve endings that transmit the pain based on thermal/ mechanical/ chemical stimuli

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12.3 Analgesics nlm.nih/medlineplus/druginformation.html

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  1. 12.3 Analgesicshttp://www.nlm.nih.gov/medlineplus/druginformation.html Describe and Explain the different ways in which analgesics prevent pain

  2. Pain Receptor • Nerves that transmit the pain • Free nerve endings that transmit the pain based on thermal/ mechanical/ chemical stimuli • Pain receptor generate an impulse • Pain results from interaction between various impulses arriving at the spinal cord and the brain

  3. Prostaglandins • Injures tissues release prostaglandin and leukotriene • Make the pain receptors more sensitive

  4. Prostoglandin • Prostaglandins have an extraordinarily wide range of biological effects • controlling blood pressure and controlling inflammation. • blood clotting, kidney function and the reproductive system • and are the subject of a great deal of research to produce new drugs.

  5. Analgesics • Understanding how neurons work comes from study of membrane potential •   (i.e. the difference in electrical charge between inside and outside of  the neuron); • To record a membrane potential two electrodes are needed:   intracellular and extracellular

  6. Aspirin Analgesics: relives pain Mild : aspirin, acetaminophen( metabolic byproduct of phenacetin) -same as Tylenol, Paracetamol, ibuprofen ( sold as Actiprofen, Advil, MortrinIB, Medipren) NSAIDS ( non-steroidal anti-inflammatory drugs) Mild analgesics : non addictive

  7. Mild Analgesics • Block the enzyme –cyclooxygenase / controlled synthesis of prostaglandins • responsible for constricting of blood vessels • increase the body temperature • Direct effect on hypothalamus / body’s heat regulating center / produces fever • Cause swelling and pain / increase the permeability of capillaries, allowing water to pass out into nearby tissues

  8. Mild Analgesics • Lower the concentration of prostaglandins • Reduce fever • And inflammation

  9. Endorphins and enkephalin

  10. Enkaphalin

  11. Endorphin • Endorphin comes from the words endogenous morphine. • Endogenous means developing from within. • Endorphins are similar to the narcotic morphine in their functions,. • They occur naturally in the brain and bloodstream.

  12. Endorphin • a group of peptide hormones that bind to opiate receptors • and are found mainly in the brain. • Endorphins reduce the sensation of pain and affect emotions.

  13. Endorphin • Russian scientists claim a beating on the buttocks with a strong cane is the perfect way to cure everything from depression to alcoholism by releasing the body's natural "happy chemicals" known as endorphins.

  14. B3.2 Salicylic acid • Describe the uses of derivatives of salicylic acid as mild analgesics and • compare the advantages and disadvantages of using • aspirin and paracetamol • acetaminophen)

  15. Salicylic acid /Acetyl salicylic acid

  16. Salicylic Acid • Antipyretic / fever reducer • Mild analgesic / pain killer • Strong/ damages the membrane lining the mouth, esophagus and stomach • Chemically modified to sodium salt of acid • Less unpleasant, but turn to acid in the stomach • acetyl salicylic acid / reduce acidity/ non irritating /taken orally

  17. Synthesis

  18. Hydrolysis H2O + CH3COOH

  19. ASA • Prodrug :less active form of drug that is converted to the active form of drug after administration • Sometimes sold as sodium salt of ASA / Alka Seltzer. / ionic bonding / dissolves in water

  20. ASA • The presence of OH and COOH group on benzene ring makes salicylic acid as strong acid • Other derivatives are insoluble due the presence of aromatic ring

  21. Uses of the Derivatives of salicylic acid ( Miracle drug) • Antipyretic: reduces fever • Anti-inflammatory • Anti-platelet agent / prevent abnormal blood clotting , anti clotting agent • (inhibits the production of prostaglandins) • Mild analgesic • minor aches/pains, headaches, sunburn, arthritis

  22. Disadvantages of ASA • Stomach upset due to acidity in aq. Solution • Gastrointestinal bleeding following use of alcohol • 0.5% who take ASA (and 3-5% asthmatic) are allergic to ASA leading to skin rashes, respiratory difficulty • Accidental poisoning in infants • Development of Reye’s syndrome/ liver and brain disorder can result in coma, brain damage and death ( children who took ASA for chicken pox symptoms)

  23. Base hydrolysis

  24. Pain reliever

  25. Aspirin Substitute • Paracetomol • Active ingredient in many OTC • USES: • Anti –pyretic / reduces fever • Analgesics reduce pain • Does not upset stomach

  26. Acetaminophen • NOT an anti-inflammatory • Can cause blood disorder and kidney damage • Over dose can cause liver damage, brain damage, coma and even death

  27. Acetaminophen

  28. Phenacetin

  29. Ibuprofen • (2-[4-(2-Methylpropyl)phenyl]propanoic Acid, Isobutylphenylpropionic Acid) • Same as ASA but fewer stomach problems • Anti-inflammatory • Wide margin of safety, • Lower effective dose • Large doses /kidney problems www.wcer.wisc.edu/.../Spr2000/esselman/IBUb.html

  30. 2-(4-Isobutyl-phenyl)-propionic acid • ibuprofen

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