Antimicrobial agents

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Antimicrobial agents

  1. 1. ANTIMICROBIAL AGENTS Nelia B. Perez RN, MSN PCU MJCN
  2. 2. Susceptibility to Infection
  3. 3. Sources of Infection• Endogenous• Exogenous
  4. 4. IDENTIFICATION OF THE INFECTING ORGANISM* Selection of Antimicrobial Agents
  5. 5. Antibiotics– Medications used to treat bacterial infections– Ideally, before beginning antibiotic therapy, the suspected areas of infection should be cultured to identify the causative organism and potential antibiotic susceptibilities.
  6. 6. Antibiotics– Empiric therapy: treatment of an infection before specific culture information has been reported or obtained– Prophylactic therapy: treatment with antibiotics to prevent an infection, as in intra-abdominal surgery
  7. 7. Antibiotics– Bactericidal: kill bacteria– Bacteriostatic: inhibit growth of susceptible bacteria, rather than killing them immediately; will eventually lead to bacterial death
  8. 8. Antibiotics: Sulfonamides– One of the first groups of antibiotics– sulfadiazine– sulfamethizole– sulfamethoxazole– sulfisoxazole
  9. 9. Sulfonamides: Mechanism of Action– Bacteriostatic action– Prevent synthesis of folic acid required for synthesis of purines and nucleic acid– Does not affect human cells or certain bacteria— they can use preformed folic acid
  10. 10. Sulfonamides: sulfamethoxazole Therapeutic Uses– Azo-Gantanol– Combined with phenazopyridine (an analgesic- anesthetic that affects the mucosa of the urinary tract).– Used to treat urinary tract infections (UTIs) and to reduce the pain associated with UTIs .– Bactrim– Combined with trimethoprim.– Used to treat UTIs, Pneumocystis carinii pneumonia, ear infections, bronchitis, gonorrhea, etc.
  11. 11. Sulfonamides: sulfisoxazole Therapeutic Uses– Azo-Gantrisin– Combined with phenazopyridine– Used for UTIs– Pediazole– Combined with erythromycin– Used to treat otitis media
  12. 12. Sulfonamides: Side Effects– Body System Effect– Blood Hemolytic and aplastic anemia, thrombocytopenia– Integumentary Photosensitivity, exfoliative dermatitis, Stevens-Johnson syndrome, epidermal necrolysis
  13. 13. • Sulfonamides: Side Effects – Body System Effect – GI Nausea, vomiting, diarrhea, pancreatitis – Other Convulsions, crystalluria, toxic nephrosis, headache, peripheral neuritis, urticaria
  14. 14. • Antibiotics: Penicillins – Natural penicillins – Penicillinase-resistant penicillins – Aminopenicillins – Extended-spectrum penicillins
  15. 15. • Antibiotics: Penicillins – Natural penicillins – penicillin G, penicillin V potassium – Penicillinase-resistant penicillins – cloxacillin, dicloxacillin, methicillin, nafcillin, oxacillin
  16. 16. • Antibiotics: Penicillins – Aminopenicillins – amoxicillin, ampicillin, bacampicillin – Extended-spectrum penicillins – piperacillin, ticarcillin, carbenicillin, mezlocillin
  17. 17. • Antibiotics: Penicillins – First introduced in the 1940s – Bactericidal: inhibit cell wall synthesis – Kill a wide variety of bacteria – Also called “beta-lactams”
  18. 18. • Antibiotics: Penicillins – Bacteria produce enzymes capable of destroying penicillins. – These enzymes are known as beta-lactamases. – As a result, the medication is not effective.
  19. 19. • Antibiotics: Penicillins – Chemicals have been developed to inhibit these enzymes: • clavulanic acid • tazobactam • sulbactam – These chemicals bind with beta-lactamase and prevent the enzyme from breaking down the penicillin
  20. 20. • Antibiotics: Penicillins – Penicillin-beta-lactamase inhibitor combination drugs: • ampicillin + sulbactam = Unasyn • amoxicillin + clavulanic acid = Augmentin • ticarcillin + clavulanic acid = Timentin • piperacillin + tazobactam = Zosyn
  21. 21. • Penicillins: Mechanism of Action – Penicillins enter the bacteria via the cell wall. – Inside the cell, they bind to penicillin-binding protein. – Once bound, normal cell wall synthesis is disrupted. – Result: bacteria cells die from cell lysis. – Penicillins do not kill other cells in the body.
  22. 22. • Penicillins: Therapeutic Uses – Prevention and treatment of infections caused by susceptible bacteria, such as: • gram-positive bacteria • Streptococcus, Enterococcus, Staphylococcus species
  23. 23. • Penicillins: Adverse Effects – Allergic reactions occur in 0.7% – 8% of treatments • urticaria, pruritus, angioedema – 10% of allergic reactions are life-threatening – and – 10% of these are fatal
  24. 24. • Penicillins: Side Effects – Common side effects: • nausea, vomiting, diarrhea, abdominal pain – Other side effects are less common
  25. 25. • Antibiotics: Cephalosporins – First Generation – Second Generation – Third Generation – Fourth Generation
  26. 26. • Antibiotics: Cephalosporins – Semisynthetic derivatives from a fungus – Structurally and pharmacologically related to penicillins – Bactericidal action – Broad spectrum – Divided into groups according to their antimicrobial activity
  27. 27. • Cephalosporins: First Generation – cefadroxil – cephalexin – cephradine – cefazolin – cephalothin – cephapirin • Good gram-positive coverage • Poor gram-negative coverage
  28. 28. • Cephalosporins: First Generation – cefazolin cephalexin – (Ancef and Kefzol) (Keflex and Keftab) – IV and PO PO • used for surgical prophylaxis, URIs, otitis media
  29. 29. • Cephalosporins: Second Generation – cefaclor • cefonicid – cefprozil • ceforanide – cefamandole • cefmetazole – cefoxitin • cefotetan – cefuroxime • Good gram-positive coverage • Better gram-negative coverage than first generation
  30. 30. • Cephalosporins: Second Generation – Cefoxitin cefuroxime – (Mefoxin) (Kefurox and Ceftin) – IV and IM PO – Used prophylactically for Surgical prophylaxis abdominal or colorectal surgeries Does not kill Also kills anaerobes anaerobes
  31. 31. • Cephalosporins: Third Generation – cefixime • ceftizoxime – cefpodoxime proxetil • ceftriaxone – cefoperazone • ceftazidime – cefotaxime • moxalactam • Most potent group against gram-negative • Less active against gram-positive
  32. 32. • Cephalosporins: Third Generation – cefixime (Suprax) – Only oral third-generation agent – Best of available oral cephalosporins against gram- negative – Tablet and suspension – ceftriaxone (Rocephin) – IV and IM, long half-life, once-a-day dosing – Easily passes meninges and diffused into CSF to treat CNS infections
  33. 33. • Cephalosporins: Third Generation – ceftazidime (Ceptaz, Fortaz, Tazidime, Tazicef) – IV and IM – Excellent gram-negative coverage – Used for difficult-to-treat organisms such as Pseudomonas spp. – Eliminated renally instead of biliary route – Excellent spectrum of coverage
  34. 34. • Cephalosporins: Fourth Generation – cefepime (Maxipime) – Newest cephalosporin agents. – Broader spectrum of antibacterial activity than third generation, especially against gram-positive bacteria.
  35. 35. • Cephalosporins: Side Effects – similar to penicillins
  36. 36. • Antibiotics: Tetracyclines – demeclocycline (Declomycin) – oxytetracycline – tetracycline – doxycycline (Doryx, Doxy-Caps, Vibramycin) – minocycline
  37. 37. • Antibiotics: Tetracyclines – Natural and semi-synthetic – Obtained from cultures of Streptomyces – Bacteriostatic—inhibit bacterial growth – Inhibit protein synthesis – Stop many essential functions of the bacteria
  38. 38. • Antibiotics: Tetracyclines – Bind to Ca 2+ and Mg 2+ and Al 3+ ions to form insoluble complexes – Thus, dairy products, antacids, and iron salts reduce absorption of tetracyclines
  39. 39. • Tetracyclines: Therapeutic Uses – Wide spectrum: • gram-negative, gram-positive, protozoa, Mycoplasma, Rickettsia, Chlamydia, syphilis, Lyme disease – Demeclocycline is also used to treat SIADH, and pleural and pericardial effusions
  40. 40. • Tetracyclines: Side Effects – Strong affinity for calcium – Discoloration of permanent teeth and tooth enamel in fetuses and children – May retard fetal skeletal development if taken during pregnancy
  41. 41. • Tetracyclines: Side Effects – Alteration in intestinal flora may result in: – Superinfection (overgrowth of nonsusceptible organisms such as Candida) – Diarrhea – Pseudomembranous colitis
  42. 42. • Tetracyclines: Side Effects – May also cause: – Vaginal moniliasis – Gastric upset – Enterocolitis – Maculopapular rash
  43. 43. • Antibiotics: Aminoglycosides – gentamicin (Garamycin) – kanamycin – neomycin – streptomycin – tobramycin – amikacin (Amikin) – netilmicin
  44. 44. • Antibiotics: Aminoglycosides – gentamicin (Garamycin) – kanamycin – neomycin – streptomycin – tobramycin – amikacin (Amikin) – netilmicin
  45. 45. • Aminoglycosides – Natural and semi-synthetic – Produced from Streptomyces – Poor oral absorption; no PO forms – Very potent antibiotics with serious toxicities – Bactericidal – Kill mostly gram-negative; some gram-positive also
  46. 46. • Aminoglycosides – Used to kill gram-negative bacteria such as Pseudomonas spp., E. coli, Proteus spp., Klebsiella spp., Serratia spp. – Often used in combination with other antibiotics for synergistic effect.
  47. 47. • Aminoglycosides – Three most common (systemic): gentamicin, tobramycin, amikacin – Cause serious toxicities: • Nephrotoxicity (renal failure) • Ototoxicity (auditory impairment and vestibular [eighth cranial nerve]) – Must monitor drug levels to prevent toxicities
  48. 48. • Aminoglycosides: Side Effects – Ototoxicity and nephrotoxicity are the most significant – Headache – Paresthesia – Neuromuscular blockade – Dizziness – Vertigo – Skin rash – Fever – Superinfections
  49. 49. • Antibiotics: Quinolones – ciprofloxacin (Cipro) – enoxacin (Penetrex) – lomefloxacin (Maxaquin) – norfloxacin (Noroxin) – ofloxacin (Floxin)
  50. 50. • Quinolones – Excellent oral absorption – Absorption reduced by antacids – First oral antibiotics effective against gram- negative bacteria
  51. 51. • Quinolones: Mechanism of Action – Bactericidal – Effective against gram-negative organisms and some gram-positive organisms – Alter DNA of bacteria, causing death – Do not affect human DNA
  52. 52. • Quinolones: Therapeutic Uses – Lower respiratory tract infections – Bone and joint infections – Infectious diarrhea – Urinary tract infections – Skin infections – Sexually transmitted diseases
  53. 53. • Quinolones: Side Effects – Body System Effects – CNS headache, dizziness, fatigue, depression, restlessness – GI nausea, vomiting, diarrhea, constipation, thrush, increased liver function studies
  54. 54. • Quinolones: Side Effects – Body System Effects – Integumentary rash, pruritus, urticaria, flushing, photosensitivity (with lomefloxacin) – Other fever, chills, blurred vision, tinnitus
  55. 55. • Antibiotics: Macrolides – erythromycin – azithromycin (Zithromax) – clarithromycin (Biaxin) – dirithromycin – troleandomycin • bactericidal action
  56. 56. • Macrolides: Therapeutic Uses – Strep infections – Streptococcus pyogenes (group A beta-hemolytic streptococci) – Mild to moderate URI – Haemophilus influenzae – Spirochetal infections – Syphilis and Lyme disease – Gonorrhea, Chlamydia, Mycoplasma
  57. 57. • Macrolides: Side Effects – GI effects, primarily with erythromycin: – nausea, vomiting, diarrhea, hepatotoxicity, flatulence, jaundice, anorexia – Newer agents, azithromycin and clarithromycin: fewer side effects, longer duration of action, better efficacy, better tissue penetration
  58. 58. • Antibiotics: Nursing Implications – Before beginning therapy, assess drug allergies; hepatic, liver, and cardiac function; and other lab studies. – Be sure to obtain thorough patient health history, including immune status. – Assess for conditions that may be contraindications to antibiotic use, or that may indicate cautious use. – Assess for potential drug interactions.
  59. 59. • Antibiotics: Nursing Implications – It is ESSENTIAL to obtain cultures from appropriate sites BEFORE beginning antibiotic therapy.
  60. 60. • Antibiotics: Nursing Implications – Patients should be instructed to take antibiotics exactly as prescribed and for the length of time prescribed; they should not stop taking the medication early when they feel better. – Assess for signs and symptoms of superinfection: fever, perineal itching, cough, lethargy, or any unusual discharge.
  61. 61. • Antibiotics: Nursing Implications – For safety reasons, check the name of the medication carefully since there are many agents that sound alike or have similar spellings.
  62. 62. • Antibiotics: Nursing Implications – Each class of antibiotics has specific side effects and drug interactions that must be carefully assessed and monitored. – The most common side effects of antibiotics are nausea, vomiting, and diarrhea. – All oral antibiotics are absorbed better if taken with at least 6 to 8 ounces of water.
  63. 63. • Antibiotics: Nursing Implications – Sulfonamides – Should be taken with at least 2400 mL of fluid per day, unless contraindicated. – Due to photosensitivity, avoid sunlight and tanning beds. – These agents reduce the effectiveness of oral contraceptives.
  64. 64. • Antibiotics: Nursing Implications – Penicillins – Any patient taking a penicillin should be carefully monitored for an allergic reaction for at least 30 minutes after its administration. – The effectiveness of oral penicillins is decreased when taken with caffeine, citrus fruit, cola beverages, fruit juices, or tomato juice.
  65. 65. • Antibiotics: Nursing Implications – Cephalosporins – Orally administered forms should be given with food to decrease GI upset, even though this will delay absorption. – Some of these agents may cause an Antabuse-like reaction when taken with alcohol.
  66. 66. • Antibiotics: Nursing Implications – Tetracyclines – Milk products, iron preparations, antacids, and other dairy products should be avoided because of the chelation and drug-binding that occurs. – All medications should be taken with 6 to 8 ounces of fluid, preferably water. – Due to photosensitivity, avoid sunlight and tanning beds.
  67. 67. • Antibiotics: Nursing Implications – Aminoglycosides – Monitor peak and trough blood levels of these agents to prevent nephrotoxicity and ototoxicity. – Symptoms of ototoxicity include dizziness, tinnitus, and hearing loss. – Symptoms of nephrotoxicity include urinary casts, proteinuria, and increased BUN and serum creatinine levels.
  68. 68. • Antibiotics: Nursing Implications – Macrolides – These agents are highly protein-bound and will cause severe interactions with other protein- bound drugs. – The absorption of oral erythromycin is enhanced when taken on an empty stomach, but because of the high incidence of GI upset, many agents are taken after a meal or snack.
  69. 69. • Antibiotics: Nursing Implications – Monitor for therapeutic effects: – Disappearance of fever, lethargy, drainage, and redness
  70. 70. Thank you and God bless!
  71. 71. ANTIVIRALS
  72. 72. Viruses• Obligate intracellular parasites• Consist of a core genome in a protein shell and some are surrounded by a lipoprotein• lack a cell wall and cell membrane• do not carry out metabolic processes• Replication depends on the host cell machinery
  73. 73. Anti Viral Agents• Block viral entry into the cell or must work inside the cell• Most agents are pyrimidine or purine nucleoside analogs
  74. 74. Understanding VirusesViral Replication• A virus cannot replicate on its own.• It must attach to and enter a host cell.• It then uses the host cell’s energy to synthesize protein, DNA, and RNA.
  75. 75. Understanding VirusesViruses are difficult to kill because they live inside our cells.• Any drug that kills a virus may also kill our cells.
  76. 76. Viral InfectionsCompetent immune system:• Best response to viral infections• A well-functioning immune system will eliminate or effectively destroy virus replicationImmunocompromised patients have frequent viral infections• Cancer patients, especially leukemia or lymphoma• Transplant patients, due to pharmacological therapy• AIDS patients, disease attacks immune system
  77. 77. AntiviralsKey characteristics of antiviral drugs:• Able to enter the cells infected with virus.• Interfere with viral nucleic acid synthesis and/or regulation.• Some agents interfere with ability of virus to bind to cells.• Some agents stimulate the body’s immune system.
  78. 78. AntiviralsViruses killed by current antiviral therapy:• cytomegalovirus (CMV)• herpes simplex virus (HSV)• human immunodeficiency virus (HIV)• influenza A (the “flu”)• respiratory syncytial virus (RSV)
  79. 79. Anti Herpes Agents• Acyclovir- prototype• Valacyclovir• Famciclovir• Penciclovir• Trifluridine• Vidarabine
  80. 80. Acyclovir• Oral, IV, and Topical formulations• Cleared by glomerular filtration and tubular secretion• Uses: – Herpes Simplex Virus 1 and 2 (HSV) – Varicella-zoster virus (VZV)• Side Effects: nausea, diarrhea, headache, tremors, and delirium
  81. 81. Anti Retroviral Agents• Oral, IV, and Topical formulations• Cleared by glomerular filtration and tubular secretion• Uses: – Herpes Simplex Virus 1 and 2 (HSV) – Varicella-zoster virus (VZV)• Side Effects: nausea, diarrhea, headache, tremors, and delirium
  82. 82. Anti Retroviral Agents - HIV1) Nucleoside Reverse Transcriptase Inhibitors (NRTIs)2) Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs)3)Protease inhibitors
  83. 83. Reverse Transcriptase Inhibitors• Zidovudine (AZT)• Didanosine- causes pancreatitis*• Lamivudine- causes pancreatitis• Zalcitabine- causes peripheral neuropathy*• Stavudine- causes peripheral neuropathy*• Abacavir
  84. 84. Clinical Uses Zidovudine• Available in IV and oral formulations• activity against HIV-1, HIV-2, and human T cell lymphotropic viruses• mainly used for treatment of HIV, decreases rate of progression and prolongs survival• prevents mother to newborn transmission of HIV
  85. 85. Nucleotide Inhibitors• Tenofovir• Adefovir
  86. 86. Tenofavir• An acyclic nucleoside phosphonate analog of adenosine• M.O.A.- competively inhibits HIV reverse transcriptase and causes chain termination after incorporation into DNA• Uses – in combination with other antiretrovirals for HIV-1 suppression
  87. 87. Adefovir• An analog of adenosine monophosphate• Phosphorylated by cellular kinases• M.O.A. - Competitively inhibits HBV DNA polymerase and results in chain termination after incorporation into viral DNA• Uses - Hepatitis B• Side effects - nephrotoxicity
  88. 88. Anti-Hepatitis Agents• Lamivudine -Nucleoside Reverse Transcriptase Inhibitor (NRTI)• Adefovir -Nucleotide Inhibitor• Interferon Alfa• Pegylated Interferon Alfa• Ribavirin
  89. 89. Interferons• Interferon Alfa• Endogenous proteins• induce host cell enzymes that inhibit viral RNA translation and cause degradation of viral mRNA and tRNA• Bind to membrane receptors on cell surface• May also inhibit viral penetration, uncoating, mRNA synthesis, and translation, and virion assembly and release www.freelivedoctor.com
  90. 90. Interferons• Pegylated interferon Alfa• A linear or branced polyethylene gylcol (PEG) moiety is attached to covalently to interferon• Increased half-life and steady drug concentrations• Less frequent dosing• Tx chronic hepatitis C in combination with ribavirin www.freelivedoctor.com
  91. 91. Ribavirin• A guanosine analog• phosphorylated intracellularly by host enzymes• inhibits capping of viral messenger RNA• inhibits the viral RNA-dependent RNA polymerase• inhibits replication of DNA and RNA viruses www.freelivedoctor.com
  92. 92. www.freelivedoctor.com
  93. 93. Anti-Influenza Agents• Amantadine• Rimantadine• Zanamivir www.freelivedoctor.com
  94. 94. Amantadine and Rimantadine– cyclic amines– inhibit the uncoating of viral RNA therefore inhibiting replication– resistance due to mutations in the RNA sequence coding for the structural M2 protein– used in the prevention and treatment of Influenza A www.freelivedoctor.com
  95. 95. Zanamivir and Oseltamivir• Inhibits the enzyme neuraminidase• inhibit the replication of influenza A and Influenza B• treats uncomplicated influenza infections• administered intranasally www.freelivedoctor.com
  96. 96. Antivirals: Nursing Implications• Before beginning therapy, thoroughly assess underlying disease and medical history, including allergies.• Assess baseline VS and nutritional status.• Assess for contraindications, conditions that may indicate cautious use, and potential drug interactions.
  97. 97. Antivirals: Nursing Implications• Be sure to teach proper application technique for ointments, aerosol powders, etc.• Emphasize hand washing before and after administration of medications to prevent site contamination and spread of infection.• Patients should wear a glove or finger cot when applying ointments or solutions to affected areas.
  98. 98. Antivirals: Nursing Implications• Instruct patients to consult their physician before taking any other medication, including OTC medications.• Emphasize the importance of good hygiene.• Inform patients that antiviral agents are not cures, but do help to manage symptoms.
  99. 99. Antivirals: Nursing Implications• Instruct patients on the importance of taking these medications exactly as prescribed and for the full course of treatment.• With zidovudine:• Inform patients that hair loss MAY occur so that they are prepared for this rare adverse reaction.• This medication should be taken on an empty stomach.
  100. 100. Antivirals: Nursing ImplicationsMonitor for side effects:• effects are varied and specific to each agent
  101. 101. Antivirals: Nursing ImplicationsMonitor for therapeutic effects:• effects will vary depending on the type of viral infection• Effects range from delayed progression of AIDS and ARC to decrease in flu-like symptoms, decreased frequency of herpes-like flare-ups, or crusting over of herpetic lesions.
  102. 102. ANTIFUNGALS• Antifungal Agents – Drugs used to treat infections caused by fungi – Systemic and topical
  103. 103. • Fungi – Also known as mycoses – Very large and diverse group of microorganisms – Broken down into yeasts and molds
  104. 104. • Yeasts – Single-cell fungi – Reproduce by budding – Very useful organisms • Baking • Alcoholic beverages
  105. 105. • Molds – Multicellular – Characterized by long, branching filaments called hyphae
  106. 106. • Mycotic Infections – Four General Types – Cutaneous – Subcutaneous – Superficial – Systemic* • *Can be life-threatening • *Usually occur in immunocompromised host
  107. 107. • Mycotic Infections – Candida albicans – Due to antibiotic therapy, antineoplastics, or immunosuppressants – May result in overgrowth and systemic infections
  108. 108. • Mycotic Infections – In the mouth: – Oral candidiasis or thrush – Newborn infants and immunocompromised patients
  109. 109. • Mycotic Infections – Vaginal candidiasis: – “ Yeast infection” – Pregnancy, diabetes mellitus, oral contraceptives
  110. 110. • Antifungal Agents – Systemic – Examples: amphotericin B, fluconazole, ketoconazole, itraconazole – Topical – Examples: clotrimazole, miconazole, nystatin
  111. 111. • Antifungal Agents – Broken down into four major groups based on their chemical structure – Polyenes: amphotericin B and nystatin – Flucytosine – Imidazoles: ketoconazole, miconazole, clotrimazole, fluconazole – Griseofulvin
  112. 112. • Antifungal Agents: Mechanism of Action – Polyenes: amphotericin B and nystatin – Bind to sterols in cell membrane lining – Allow K+ & Mg++ to leak out, altering fungal cell metabolism – Result: fungal cell death
  113. 113. • Antifungal Agents: Mechanism of Action – flucytosine – Also known as 5-fluorocytosine (antimetabolite) – Taken up by fungal cells and interferes with DNA synthesis – Result: fungal cell death• Antifungal Agents: Mechanism of Action – Imidazoles ketoconazole, miconazole, clotrimazole, fluconazole – Inhibit an enzyme, resulting in cell membrane leaking – Lead to altered cell membrane – Result: fungal cell death
  114. 114. • Antifungal Agents: Mechanism of Action – griseofulvin – Disrupts cell division – Result: inhibited fungal mitosis (reproduction)
  115. 115. • Antifungal Agents: Side Effects – amphotericin B “Shake and Bake” – fever chills headache anorexia – malaise nausea hypotension tachycardia – muscle and joint pain – lowered potassium and magnesium levels – *renal toxicity – *neurotoxicity: seizures and paresthesias
  116. 116. • Antifungal Agents: Side Effects – fluconazole – nausea, vomiting, diarrhea, abdominal pain, – increased liver function studies – flucytosine – nausea, vomiting, anorexia – griseofulvin – rash, urticaria, headache, nausea, vomiting, anorexia
  117. 117. • Antifungal Agents: Nursing Implications – Before beginning therapy, assess for hypersensitivity, possible contraindications, and conditions that require cautious use. – Obtain baseline VS, CBC, liver function studies, and ECG. – Assess for other medications used (prescribed and OTC) in order to avoid drug interactions.
  118. 118. • Antifungal Agents: Nursing Implications – Follow manufacturer’s directions carefully for reconstitution and administration. – Monitor VS of patients receiving IV infusions every 15 to 30 minutes. – During IV infusions, monitor I & O and urinalysis findings to identify adverse renal effects.
  119. 119. • Antifungal Agents: Nursing Implications – amphotericin B – To reduce the severity of the infusion-related reactions, pretreatment with an antipyretic (acetaminophen), antihistamines, and antiemetics may be given. – A test dose of 1 mg per 20 mL 5% dextrose in water infused over 30 minutes should be given. – Use IV infusion pumps and the most distal veins possible.
  120. 120. • Antifungal Agents: Nursing Implications – Tissue extravasation of fluconazole at the IV site may lead to tissue necrosis—monitor IV site carefully. – Oral forms of griseofulvin should be given with meals to decrease GI upset. – Monitor carefully for side/adverse effects.
  121. 121. • Antifungal Agents: Nursing Implications – Monitor for therapeutic effects: – Easing of the symptoms of infection – Improved energy levels – Normal vital signs, including temperature
  122. 122. ANTIHELMINTHIC• Antihelmintics• Drugs used to treat parasitic worm infections: helmintic infections• Unlike protozoa, helminths are large and have complex cellular structures• Drug treatment is very specific
  123. 123. • Antihelmintics• It is VERY IMPORTANT to identify the causative worm• Done by finding the parasite ova or larvae in feces, urine, blood, sputum, or tissue – cestodes (tapeworms) – nematodes (roundworms) – trematodes (flukes)
  124. 124. • Antihelmintics: Mechanism of Action and Uses• diethylcarbamazine (Hetrazan)• Inhibits rate of embryogenesis• thiabendazole (Mintezol)• Inhibits the helminth-specific enzyme, fumarate reductase – Both used for nematodes (tissue and some roundworms)
  125. 125. • Antihelmintics: Mechanism of Action• piperazine (Vermizine) and pyrantel (Antiminth)• Blocks acetylcholine at the neuromuscular junction, resulting in paralysis of the worms, which are then expelled through the GI tract – Used to treat nematodes (giant worm and pinworm)
  126. 126. • Antihelmintics: Mechanism of Action• mebendazole (Vermox)• Inhibits uptake of glucose and other nutrients, leading to autolysis and death of the parasitic worm – Used to treat cestodes and nematodes
  127. 127. • Antihelmintics: Mechanism of Action• niclosamide (Niclocide)• Causes the worm to become dislodged from the GI wall• They are then digested in the intestines and expelled – Used to treat cestodes
  128. 128. • Antihelmintics: Mechanism of Action• oxamniquine (Vansil) and praziquantel (Biltricide)• Cause paralysis of worms’ musculature and immobilization of their suckers• Cause worms to dislodge from mesenteric veins to the liver, then killed by host tissue reactions – Used to treat trematodes, cestodes (praziquantel only)
  129. 129. • Antihelmintics: Side Effects• niclosamide, oxamniquine, praziquantel, thiabendazole, piperazine, pyrantel• nausea, vomiting, diarrhea, dizziness, headache• mebendazole• diarrhea, abdominal pain, tissue necrosis
  130. 130. ANTIPROTOZOALs• Protozoal Infections• Parasitic protozoa: live in or on humans• malaria• leishmaniasis• amebiasis• giardiasis• trichomoniasis
  131. 131. Malaria• Caused by the plasmodium protozoa.• Four different plasmodium species.• Cause: the bite of an infected adult mosquito.• Can also be transmitted by infected individuals via blood transfusion, congenitally, or via infected needles by drug abusers.
  132. 132. Malarial Parasite (plasmodium)• Two Interdependent Life Cycles• Sexual cycle: in the mosquito• Asexual cycle: in the human – Knowledge of the life cycles is essential in understanding antimalarial drug treatment. – Drugs are only effective during the asexual cycle.
  133. 133. Plasmodium Life Cycle• Asexual cycle: two phases• Exoerythrocytic phase: occurs “outside” the erythrocyte• Erythrocytic phase: occurs “inside” the erythrocyte – Erythrocytes = RBCs
  134. 134. Antimalarial Agents• Attack the parasite during the asexual phase, when it is vulnerable• Erythrocytic phase drugs: chloroquine, hydroxychloroquine, quinine, mefloquine• Exoerythrocytic phase drug: primaquine• May be used together for synergistic or additive killing power.
  135. 135. Antimalarials: Mechanism of Action• 4-aminoquinoline derivatives chloroquine and hydroxychloroquine• Bind to parasite nucleoproteins and interfere with protein synthesis.• Prevent vital parasite-sustaining substances from being formed.• Alter pH within the parasite.• Interfere with parasite’s ability to metabolize and use erythrocyte hemoglobin.• Effective only during the erythrocytic phase
  136. 136. Antimalarials: Mechanism of Action• 4-aminoquinoline derivatives quinine and mefloquine• Alter pH within the parasite.• Interfere with parasite’s ability to metabolize and use erythrocyte hemoglobin.• Effective only during the erythrocytic phase.
  137. 137. Antimalarials: Mechanism of Action• diaminophyrimidines pyrimethamine and trimethoprim• Inhibit dihydrofolate reductase in the parasite.• This enzyme is needed by the parasite to make essential substances.• Also blocks the synthesis of tetrahydrofolate.• These agents may be used with sulfadoxine or dapsone for synergistic effects.
  138. 138. Antimalarials: Mechanism of Action• primaquine• Only exoerythrocytic drug.• Binds and alters DNA.• sulfonamides, tetracyclines, clindamycin• Used in combination with antimalarials to increase protozoacidal effects
  139. 139. Antimalarials: Drug Effects• Kill parasitic organisms.• Chloroquine and hydroxychloroquine also have antiinflammatory effects.
  140. 140. Antimalarials: Therapeutic Uses• Used to kill plasmodium organisms, the parasites that cause malaria.• The drugs have varying effectiveness on the different malaria organisms.• Some agents are used for prophylaxis against malaria.• Chloroquine is also used for rheumatoid arthritis and lupus.
  141. 141. Antimalarials: Side Effects• Many side effects for the various agents• Primarily gastrointestinal: nausea, vomiting, diarrhea, anorexia, and abdominal pain
  142. 142. Antiprotozoals• atovaquone (Mepron)• metronidazole (Flagyl)• pentamidine (Pentam)• iodoquinol (Yodoxin, Di-Quinol)• paromomycin (Humatin)
  143. 143. Protozoal Infections• amebiasis• giardiasis• pneumocystosis• toxoplasmosis• trichomoniasis
  144. 144. Protozoal Infections• Transmission• Person-to-person• Ingestion of contaminated water or food• Direct contact with the parasite• Insect bite (mosquito or tick)
  145. 145. Antiprotozoals: Mechanism of Action and Uses• atovaquone (Mepron)• Protozoal energy comes from the mitochondria• Atovaquone: selective inhibition of mitochondrial electron transport• Result: no energy, leading to cellular death – Used to treat mild to moderate P. carinii
  146. 146. Antiprotozoals: Mechanism of Action and Usesmetronidazole• Disruption of DNA synthesis as well as nucleic acid synthesis• Bactericidal, amebicidal, trichomonacidal – Used for treatment of trichomoniasis, amebiasis, giardiasis, anaerobic infections, and antibiotic- associated pseudomembranous colitis
  147. 147. Antiprotozoals: Mechanism of Action and Usespentamidine• Inhibits DNA and RNA• Binds to and aggregates ribosomes• Directly lethal to Pneumocystis carinii• Inhibits glucose metabolism, protein and RNA synthesis, and intracellular amino acid transport – Mainly used to treat P. carinii pneumonia and other protozoal infections
  148. 148. Antiprotozoals: Mechanism of Action and Usesiodoquinol (Yodoxin, Di-Quinol)• “ Luminal” or “contact” amebicide• Acts primarily in the intestinal lumen of the infected host• Directly kills the protozoa – Used to treat intestinal amebiasis
  149. 149. Antiprotozoals: Mechanism of Action and Usesparomomycin• “Luminal” or “contact” amebicide• Kills by inhibiting protein synthesis – Used to treat amebiasis and intestinal protozoal infections, and also adjunct therapy in management of hepatic coma
  150. 150. Antiprotozoals: Side Effects• atovaquone• nausea, vomiting, diarrhea, anorexia• metronidazole• metallic taste, nausea, vomiting, diarrhea, abdominal cramps• iodoquinol• nausea, vomiting, diarrhea, anorexia, agranulocytosis
  151. 151. Antiprotozoals: Side Effects• pentamidine• bronchospasms, leukopenia, thrombocytopenia, acute pancreatitis, acute renal failure, increased liver function studies• paromomycin• nausea, vomiting, diarrhea, stomach cramps
  152. 152. • Antimalarial, Antiprotozoal, Antihelmintic Agents: Nursing Implications• Before beginning therapy, perform a thorough health history and medication history, and assess for allergies.• Check baseline VS.• Check for conditions that may contraindicate use, and for potential drug interactions.
  153. 153. • Antimalarial, Antiprotozoal, Antihelmintic Agents: Nursing Implications• Some agents may cause the urine to have an asparagus-like odor, or cause an unusual skin odor, or a metallic taste; be sure to warn the patient ahead of time.• Administer ALL agents as ordered and for the prescribed length of time.• Most agents should be taken with food to reduce GI upset.
  154. 154. • Antimalarial Agents: Nursing Implications• Assess for presence of malarial symptoms.• When used for prophylaxis, these agents should be started 2 weeks before potential exposure to malaria, and for 8 weeks after leaving the area.• Medications are taken weekly, with 8 ounces of water.
  155. 155. • Antimalarial Agents: Nursing Implications• Instruct patient to notify physician immediately if ringing in the ears, hearing decrease, visual difficulties, nausea, vomiting, profuse diarrhea, or abdominal pain occur.• Alert patients to the possible recurrence of the symptoms of malaria so that they will know to seek immediate treatment.
  156. 156. • Antimalarial, Antiprotozoal, Antihelmintic Agents: Nursing Implications• Monitor for side effects:• Ensure that patients know the side effects that should be reported.• Monitor for therapeutic effects and adverse effects with long-term therapy.
  157. 157. END OF LECTUREFOR PHARMA2011

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