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Nursing Pharmacology

Nursing Pharmacology. Antimicrobials NUR 127. Medications and Administration. Prototype approach to teaching pharmacology:

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Nursing Pharmacology

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  1. Nursing Pharmacology Antimicrobials NUR 127

  2. Medications and Administration Prototype approach to teaching pharmacology: Uses a prototype (a drug that is representative of it’s class) to help students learn by grouping the medications. It is a method of learning and organizing large amounts of information.

  3. Drugs for Bacterial Infections OBJECTIVES: Identify various types of pathogenic organisms Identify and describe pathogenicity and virulence of common bacterial pathogens Discuss the development of anti-infective drug resistance and identify the nurse/patient role in preventing development of resistant pathogens Discuss the development and common symptoms of superinfections caused by anti-infective therapy Identify prototype drugs within the anti-infective drug classes. Discuss mechanism of action, indication for use, contraindications, adverse effects and administration. Identify drugs within each class with specific features differing from the prototype.

  4. Terminology • Pathogenicity—ability of an organism to cause disease in a human • Virulence—severity of disease that an organism is able to cause; a highly virulent pathogens causes disease when present in very small numbers • Acquired Resistance—when a microbe is no longer affected by an anti-infective • Nephrotoxicity—an adverse effect on the kidneys • Hepatotoxicity—an adverse effect on the liver • Ototoxicity—an adverse effect on hearing • Superinfection—condition caused when a microorganism grows rapidly as a result of having less competition in its environment

  5. Terminology • Anti-infective aka antimicrobial—General term referring to drugs active against pathogens • Antibiotic aka antibacterial—Drugs active against bacteria • Bacteriocidal—kill bacteria • Bacteriostatic—slow the growth of bacteria • Chemoprophylaxis—prophylactic use of a medication

  6. Characteristics of Anti-Infectives • Includes antibacterials, antivirals and antifungals • Antibacterials (antibiotics) refer to drugs which treat bacterial infections • Narrow spectrum • Broad spectrum • Bactericidal (kills) vs. Bacteriostatic (inhibits)

  7. Common Human Pathogens • Viruses • Gram+: • enterococci, streptococci and staphylococci • Gram- organisms: • E.coli, Bacteroides, Klebsiella, Proteus, Pseudomonas • Opportunistic • Community-acquired vs. nosocomial

  8. Common Bacterial Pathogens • Staphylococci—Common in wounds , URI’s and pneumonia (MRSA—resistant strain) • Streptococci—Common infection in URI’s, ear infections & pneumonia • Enterococci—Common infection in UTI’s & wounds (VRE—resistant strain) • Escherichia coli—UTI’s; GI infection most commonly related to contaminated ground beef • Klebsiella—Causes respiratory tract infections, UTI’s, bloodstream, burn wound infections • Pneumococci—Most common cause of pneumonia in children; otitis media • Proteus—Cause UTI’s and wound infections • Pseudomonas—Cause respiratory tract infections, UTI’s, wound & burn wound infections (high resistance to many antibiotics)

  9. Disease Process • Pathogens generally cause disease by one of two basic mechanisms • Rapid growth • Production of toxins

  10. Normal Bacterial Flora • Colonized areas include the skin, upper respiratory tract, colon and vagina • Skin Flora (eg, staphylococci, streptococci) • Upper Respiratory Tract (eg, staphylococci, streptococci, pneumococci, Haemophilus influenzae) • Colon (eg, escherichia coli, Klebsiella, Enterobacter, Proteus, Pseudomonas, Bacteroids, clostridia, lactobacilli, strep, staph) • Vaginal (eg, Candida, lactobacilli, Bacteroids)

  11. Infectious Diseases • Presence of a pathogen plus clinical s/sx of infection • Patient with a compromised immune system may be prone to opportunistic infections caused by endogenous or environmental flora

  12. Drug Classification Classified by their chemical structure or by their mechanism of action • Mechanism of action • Cell-wall synthesis inhibitors, protein synthesis inhibitors, RNA or DNA synthesis inhibitors, antimetabolites ( • Bacteriocidal vs. Bacteriostatic • Bactericidal drugs kill organisms • Bacteriostatic drugs inhibit growth of organisms • Classification by chemical class • Share similar mechanisms of action and side effects (aminoglycoside, fluoroquinolone, sulfonamide)

  13. Antimicrobials • Used to prevent or treat infections caused by pathogenic microorganisms • Broad-spectrum drugs are effective against a wide variety of microorganisms • Narrow-spectrum drugs are effective against one or a restricted group of microorganisms

  14. Guidelines for use • Collect specimens before beginning therapy • Avoid use of broad-spectrum drugs • Use with other interventions—universal precautions, hand hygeine, isolation techniques, preoperative skin and bowel cleansing • Multidrug therapy should be avoided except in specific circumstances

  15. Anti-microbial Drug Administration • Dosage should be individualized • Dosages often determined by grams or milligrams per kilogram of body weight • Routes of administration • Most PO or IV • IM doses : deep and into a large muscle (Ventrogluteal preferred for adults) • Topical • Duration of therapy varies from single dose to years; most acute infections treated for 7 to 10 days

  16. Anti-microbial Drug Reactions • Hypersensitivity reactions • Occur most often with the ____________ administration • S/Sx: Low grade fever, rash, hives and swelling • Anaphylactic reactions • More likely to occur with IV route • Most often occur within 5-30min of injection • S/Sx: ________________________________________ ______________________________________________

  17. Common Adverse Effects • Phlebitis at IV sites; pain at IM sites • Nausea & Vomiting—Most Common Side Effect • Diarrhea (severe colitis possible with some antimicrobial therapy—s/sx blood stool, pus mucous) • Bone marrow suppression with thrombocytopenia (decreased plt)—most common with penicillins and cephalosporins • Nephrotoxicity—espaminoglycosides and sulfonamides • -

  18. Common Adverse Effects • Neurotoxicity—IV penicillins or cephalosporins • Ototoxicity: S/Sx: Tinnitus , vertigo, hearing loss • Hepatoxicity • Monitor Liver Function Tests: ALT, AST, Bilirubin • S/Sx: Jaundice, dark urine, pale stools, abd pain, fever • Photosensitivity

  19. Age-Related Considerations-Children • Penicillins and Cephalosporins generally safe • Fewer clinical trials on children • Erythromycin, Zithromax (azithromycin) and Biaxin (clarithromycin) considered safe

  20. Antimicrobials and Children • Aminoglycosides can cause ototoxicity and nephrotoxicity. • Tetracyclines are contraindicated in children younger than 8 years old, effects on teeth • Cleocin (clindamycin) admin. requires liver and kidney monitoring in neonates and infants

  21. Antimicrobials and Children • Fluoroquinolones contraindicated in children under 18 yo. May have effects on weight bearing joints. • Bactrim (trimethoprim-sulfamethoxazole) no longer 1st line due to resistance

  22. Antimicrobials and Older Adults • Penicillins are generally safe, IV admin. can cause hyperkalemia • Cephalosporins are considered sage but can affect or worsen renal failure • Macrolides are generally safe • Aminoglycosides are contraindicated in severe renal impairment

  23. Antimicrobials and Older Adults • Aminoglycosides can also cause ototoxicity • Cleocin (clindamycin)-diarrhea, colitis • Bactrim (trimethoprim-sulfamethoxazole) may be associated with impaired liver or kidney function • Tetracyclines (except doxycycline) and Macrodantin (nitrofurantoin) are contraindicated in impaired renal function

  24. In General • With most oral antibiotics, liberal fluid intake is recommended • Always be aware of pregnancy category before administering medication

  25. Lab ID of Pathogens • Culture and sensitivity • Serology-measures antibody levels • Polymerase Chain Reaction (PCR) detects the specific DNA for a specific organism

  26. Antibiotic-Resistant Microorganisms Occurs when: • Clinical condition of host is impaired • Normal flora have been suppressed • interrupted or inadequate tx • Type of bacteria • Widespread use of broad spectrum abx • Environmental setting of host

  27. Host Defense Weakened by • Breaks in skin and mucous membranes • Impaired blood supply • Neutropenia • Malnutrition • Poor personal hygiene • Suppression of normal flora • Diabetes, advanced age or immunosuppression

  28. Mechanisms of Action • Inhibit cell wall synthesis • Alter membrane permeability (PCNs, Cephalosporins, Vancomycin_ • Inhibition of protein synthesis (EES, tetracyclines, clindamycin, aminoglycosides)

  29. Mechanisms of Action cont. • Disruption of microbial cell membranes (anti-fungals) • Inhibition of organism reproduction by interfering w/nucleic acid synthesis (fluoroquinolones, HIV anti-retrovirals) • Inhibition of cell metabolism and growth (sulfonamides)

  30. Administration • Labs to Monitor • Blood levels of the antibiotic • CBC (complete blood count) • WBC (white blood cell) count • WBC should return to normal if med is effective

  31. Prophylactic Therapy • STD exposure • Recurrent UTIs • TB • Perioperative infections in high risk patients or high risk surgeries

  32. Antibiotic Combination Therapy • Used when infection is caused by multiple microorganisms • Nosocomial infections • Serious infections in which a combination is synergistic (aminoglycoside and antipseudomonal PCN)

  33. Antibiotic Combination Therapy cont. • Likely emergence of drug resistant organisms • In those who are immunosuppressed

  34. Antibiotics Affecting the Bacterial Cell Wall • Monobactam Antibiotics • Penicillins • Penicillin (P) • Cephalosporins • Cefotaxime (P) • Vancomycins • vancomycin • Carbapenems • meropenem

  35. Beta Lactams • Contain a beta-lactam ring that is part of their chemical structure • An intact beta-lactam ring is essential for antibacterial activity • Include: Penicillins, Cephalosporins, Carbapenems • Cross-sensitivity

  36. Penicillins • Prototype is Penicillin G • Most serious complication is hypersensitivity. Can cause seizures and nephropathy. • Contraindicated in patients with known allergy to PCN, cephalosporins, or imipenem.

  37. Indications for Penicillins

  38. Examples of Penicillins • Penicillins G and V (parenteral); dicloxacillin (antistaph); • Ampicillins—Principen, Amoxil • Antipseudomonals—Geocillin (carbenicillin), Ticar (ticaracillin), Pipracil (piperacillin) • Combinations for beta lactamase—Unasyn (ampicillin/sulbactam), Zosyn (piperacillin/taxobactam)

  39. Cephalosporins • Also derived from a mold • Broad spectrum with activity against both gram positive and gram negative bacteria • Cefotamine (P)- 3rd generation

  40. Cephalosporins • Indications-surgical prophy, tx infections of the respiratory tract, skin, bone and joints, urinary tract, brain and spinal cord and in septicemia

  41. Cephalosporins • Contraindicated in anaphylaxis to a penicillin • May develop a delayed reaction or cross-sensitivity • A/E: • Hypersensitivity • Anaphylaxis • GI: n/v/d • Pain at injection site

  42. Examples • Oral—Keflex (cephalexin); Ceclor (cefaclor), Lorabid (lorcarbef); Omnicef (cefdinir) • Parenteral—Ancef (kefzol); Mefoxin (cefoxitin); Claforan (cefotaxime), Fortaz (ceftazidime), Rocephin (ceftriaxone); Maxipime (cefepime)

  43. Carbapenems • Broad spectrum, bactericidal, beta-lactam anti-microbials. Inhibit synthesis of cell walls. • All are parenteral • Indicated for organisms resistant to other drugs • Examples: Merrem (meropenem) and Primaxin (imipenem-cilastatin)

  44. Monobactam Antibiotics • Azactam (aztreonam) is active against gram-negative bacteria and to many resistant strains • Stable in presence of beta lactamase • Preserves normal gram positive and anaerobic flora

  45. FYI • Penicillins may be given with Probenecid or aminoglycosides for serious infections • PCN can cause nephropathies • Ticaracillin has been linked to hypernatremia • PCN G can cause hyperkalemia • Caution w/Augmentin in hepatic impairment • Need to adjust dosages of all beta lactams in the presence of renal impairment whether PCN, cephalosporins, carbapenems and monobactams

  46. Antibiotics affecting Protein Synthesis • Aminoglycosides • Gentamicin (P) • Tetracyclines • Tetracycline (P) • Macrolide Antibiotics • Erythromycin (P)

  47. Aminoglycosides • Bactericidal agents to treat gram negative organisms such as: Proteus, Klebsiella, Enterobacter, Serratia, Escherichia coli, and Pseudomonas • Narrow specturm • Accumulate in kidneys and ears • Gentamycin (P)

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