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Drugs Targeting the CNS

Drugs Targeting the CNS. Parkinson Epilepsy Hypnotics General Anesthetics Anxiolytics Antidepressants. Diabetes mellitus. Pancreas : Islets of Langerhans: site of hormone production A (alpha) cells – produce Glucagon B (beta) cells – produce Insulin

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Drugs Targeting the CNS

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  1. Drugs Targeting the CNS • Parkinson • Epilepsy • Hypnotics • General Anesthetics • Anxiolytics • Antidepressants

  2. Diabetes mellitus Pancreas: • Islets of Langerhans: site of hormone production • A (alpha) cells – produce Glucagon • B (beta) cells – produce Insulin • D (delta) cells – produce Somatostatin Insulin and Glucagon are the major regulators of blood glucose

  3. Antimicrobials Unit X

  4. Selective toxicity • Injure target organism without affecting the host • Can accomplish this by attacking processes that critical to microbial well-being, but that don’t affect mammals • Bacterial cell wall • Inhibition of an enzyme unique to bacteria • Disruption of bacterial protein synthesis

  5. classification • Susceptible organism • Narrow spectrum, broad spectrum • Antibacterial • Antiviral • antifungal

  6. Mechanism of action • Cell wall • Cell membrane permeability • Lethal inhibition of bacterial protein synthesis • Nonlethal inhibition of bacterial protein synthesis • Drugs that inhibit bacterial synthesis of nucleic acids

  7. Mechanism of action • Antimetabolites • Inhibitors of viral enzymes

  8. Microbial drug resistance • Organisms – staphylococcus aureus, enterococcus faecalis, enterococcus faecium, pseudomonas aeruginosa and mycobacterium tuberculosisi

  9. Microbes may increase manufacture of drug-metabolizing enzymes (penicillins) • Microbes may cease active uptake of certain drugs (tetracyclines) • Changes in receptors which decrease antibiotic binding and action • May synthesize compounds that antagonize drug actions

  10. Antibiotic use promotes the emergence of drug-resistant microbes – especially the use of broad-spectrum antibiotics • The more the use – the greater the chance

  11. Delaying the emergence of resistance • Prescribed only when needed • Narrow-spectrum • Limit use of newer drugs • Minimize giving antibiotics to livestock

  12. selection • Identify the infecting organism • Drug sensitivity of the infecting organism • Host factors – site of infection, host defenses, allergies, inability of drug of choice to penetrate the site of infection, unusual susceptibility of the patient to toxicity

  13. Cultures must be obtained prior to initiation of therapy • Drug sensitivity may or may not be done

  14. Antibiotic combinations Severe infection Mixed infections Prevention of resistance – tuberculosis Decreased toxicity Enhanced antibacterial action

  15. Appropriate prophylactic use • Surgery • Bacterial endocarditis • Neutropenia • others

  16. Inappropriate uses • Viruses • Treat FUO • Improper dosage • Inadequate information • Omission of surgical drainage

  17. Weaken bacterial cell wall • Penicillins – cause the bacterial wall to weaken and take up water and burst • Mechanisms of resistance – inability to reach targets and inactivation of penicillins by bacterial enzymes

  18. classification • Narrow spectrum – penicillinase sensitive • Narrow spectrum – penicillinase resistant • Broad spectrum penicillins • Extended-spectrum penicillins

  19. Penicillin G • Against most gram positive, gram negative cocci and nonpenicillinase-producing strains of Neisseria gonorrhoeae, anaerobic bacterial and spirochetes

  20. Sodium penicillin • Potassium penicillin • Procaine penicillin • Benzathine penicillin – highly sensitive • Not given orally • IM usually • Only sodium and potassium given IV

  21. allergy • Most common cause of drug allergy • Prior exposure required but may not be known • May have cross-sensitivity to cephalosporins

  22. Penicillinase-resistant penicillins • Resistant to inactivation by beta-lactamases • Naficillin • Oxacillini • Cloxavillin • Dicloxacillin • Methycillin – resistant strains – respond to vancomycin and/or rifampin

  23. Broad spectrum penicillins • Ampicillin – strep, pertussis, proteus, e.coli, salmonella, shigella and h influenzae • Diarrhea and rash – most common side effects

  24. Amoxicillin – more acid resistant • Less diarrhea • Amoxicillin with clavulanate – augmentin (inhibits bacterial beta-lactamases)

  25. Extended spectrum penicillins • Ticarcillin • Carbenicillin indanyl • Mezlocillin • Pipercillin • Pseudomonas, enterbacter, proteus, klebsiella • Given with aminoglycoside for pseudomonas

  26. Drugs that weaken bacterial cell wall II • Cephalosporins, imipenem, astreonam, vancomycin, teicoplanin, fosfomycin

  27. cephalosporins • Most commonly used antibiotic • Similar to penicillins • Bactericidal • First generation highly susceptible – to beta-lactamases

  28. generations • 1-4 • Increasing in activity against gram-negative bacterial and anaerobes • Increasing resistance to destruction by beta-lactamases • Increasing ability to reach cerebrospinal fluid

  29. Most given parenterally • Some can cause bleeding tendencies • allergy

  30. First generation • Prophylaxis against infection in surgical patients • Gram positive infection

  31. Second generation • Some pneumonias • Otitis, sinusitis, respiratory tract infections

  32. Third generation • Menigitis • Gram negative bacilli • Gonorrhea, proteus, salmonella, klebsiella

  33. imipenem • Broadest antimicrobial spectrum of any drug – good for mixed infections – always given in conjunction with cilastatin to inhibit destruction of imipenem by renal cells • Carbapenems – new class of beta-lactam antibiotics • Only given – IV, IM • Nausea, vomiting, diarrhea, rash

  34. Aztreonam – monobactams • Gram-negative aerobic bacteria • IM, IV

  35. Vancomycin • Pseudomembranous colitis • MRSA • Other serious infections • Oral for GI infection • Mostly given slow IV • Ototoxicity, hypotension (with rapid IV infusion), thrombophlebitis

  36. Bacteriostatic inhibitors of protein synthesis • Tetracyclines, macrolides, clindamycin, chloramphenicol, spectinomycin and dalflopristin/quinupristin • Suppress bacterial growth and replication but do not kill • Second-line agents

  37. tetracyclines • Broad-spectrum • Inhibit protein synthesis – suppress bacterial growth • Gram-positive and gram-negative bacterial – rickettsia, spirochetes, brucella, chlamydia, myocoplasma, helicobacter pylori and vibrio cholerae

  38. Due to use – has increasing bacterial resistance • Infectious diseases, acne, PUD, periodontal disease, rheumatoid arthritis

  39. Adverse effects • GI • Bones and teeth • Suprainfection • Hepatotoxicity • Renal toxicity • Photosensitivity • Orally, IV, and IM

  40. macrolides • Inhibit bacterial protein synthesis • Azithromycin, erythromicin, clarithromycin, dirithromycin • Effective against most gram-positive bacterial as well as some gram-negative bacterial • May be good alternative to those allergic to PCN

  41. Therapeutic uses • May be used as an alternative patients allergic to penicillins – respiratory tract infections • Legionella • Pertussis • Diphtheriae • Mycoplasmic pneumoniae • strep

  42. Oral, IV • Adverse effects - GI, Liver, suprainfection of the bowel, thrombophlebitis • Clarithromycin – not as much nausea (h. pylori), respiratory tract

  43. Adverse effects – GI, dizziness, h/a restlessness • Candida infections • Tendon rupture – not for children under 18 yrs. • Should not be taken with milk or food • Watch for bleeding – elevates warfarin levels

  44. Zithromax – respiratory tract infections, others • Not as much nausea

  45. clindamycin • Cleocin – given for specific conditions • Causes pseudomembranous colitis • Inhibits protein synthesis • Anaerobic bacteria – streptococci, some pelvic and abdominal infections • Given orally, IV, IM

  46. Adverse effects – pseudomembranous colitis, diarrhea, rashes, hepatotoxicity

  47. aminoglycosides • Bactericidal inhibitors of protein synthesis • Narrow-spectrum – aerobic gram-negative bacilli • Gentamycin, tobramycin, amikacin

  48. Amikacin – least susceptible to resistance • E.coli, Klebsiella pneum., serratia, proteurs mirabilis, pseudomonas • Reserved for serious infections due to aerobic gram-negative bacilli • Most given IM or IV

  49. Binds tightly to renal tissue – easily causes nephrotoxicity • Ototoxicity • Reduce dosage in patients with renal disease • Narrow therapeutic range – peak and trough levels (avoid high trough levels) – not greater than 2mcg/ml

  50. Neomycin – often given topically, eye, ear, skin • Also given – orally prior to surgeries of the bowel, suppress bowel flora

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