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pharmacology - antibacterial

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    ANTIBACTERIALS

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    ANTIBACTERIAL

    Administered in the treatment of bacterialinfections

    Act to destroy or suppress the growth of microorganisms

    Drugs that are designed to act selectively onforeign organisms that have invaded and

    infected the body of a human host

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    ANTIBACTERIAL

    ACTION: Interfere with biosynthesis of bacterial cell wall (penicillin) Prevent cells from invading organisms from using

    substances essential to their growth and development(sulfonamides, trimethoprin) Interfere with protein synthesis (aminoglycosides,

    macrolides)

    Interfere with DNA synthesis (fluroquinolones) Alter the permeability of the cell membrane (antifungals,

    antiprotozoal)

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    ANTIBACTERIAL SPECTRUM effectiveness of the anti-

    infective against invading organisms BACTERICIDAL anti-infective agents that

    causes the death of the cells BACTERIOSTATIC anti-infective agents that

    interfere with the ability of the cells to

    reproduce or divide PROPHYLAXIS use of anti-infective agents to

    prevent infection before they occur

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    ANTIBACTERIAL

    Classifications: Penicillins Cephalosphorins Aminoglycosides Macrolides Tetracyclines Quinolones Lactams Sulfonamides

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    PENICILLINS

    Derived form the cultures of molds ormanufactured semi-synthetically

    1st generation natural extracts from severalstrains of Penicillium mold

    Natural penicillins potent gram positivekillers ; have little to no coverage against gramnegative organisms

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    PENICILLINS PHARMACODYNAMICS

    Bactericidal interfere with cell wall synthesis Most effective on immature cell walls of rapidly

    multiplying bacteria PHARMACOHERAPEUTICS

    Gram (+) cocci S. pneumoniae Gram (-) cocci N. gonorrheae, N. meningitidis

    Gram (+) bacilli B. anthracis, C. tetani, C. diphtheriae, T.pallidum Prophylaxis against subacute bacterial endocarditis, RHD

    or CHD undergoing surgery

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    PENICILLINS

    CONTRAINDICATIONS Hypersensitivity and allergy

    Allergy to penicillin Sx: simple rash to anaphylaxis

    Used with caution to: Nursing mothers Neonates Clients with rena, GI, hepatic dysfunctions, bleeding

    disorders, MG, and epilepsy

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    PENICILLINS

    INTERACTIONS: Probenecid increases serum levels of penicillin by

    decreasing renal elimination of the antibiotic May decrease effectiveness of oral contraceptives Increased risk of bleeding when given concurrently

    with anticoagulants and thrombolytic agents Tetracyclines, erythromycin and other bacteriostatic

    antibiotics may interfere with effectiveness of penicilli Antacids may impair absorption of PO penicillins

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    PENICILLINS

    INTERACTIONS Cloxacillin, dicloxacillin, nafcillin, and oxacilin may

    be poentiated by PO anticoagulants and anti-inflammatory agents

    Increased risk of bleeding when high IV doses of carbeicillin and ticarcillin is given concurrently

    with anti-inflammatory agents, NSAIDs, andplatelet aggregation inhibitors Aminoglycosides may be chemically inactivated if

    mixed in a solution with penicilin

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    PENICILLINS

    INTERACTIONS Chloramphenicol may decrease effetiveness of

    penicillin and reduce elimination of chloramphenicol

    May have ampicillin-induced rash when given withallopurinol

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    PENICILLINS SIDE/ADVERSE EFFECTS

    GI: diarrhea, N/V, flatulence, abnormal taste,epigastric distress, sore mouth and tongue, dark

    discoloration of tongue, oral thrush RENAL: glomerulonephritis HEMA: bone marrow depression, decreased blood

    cell counts CNS: neuromascular irritability, lethargy, anxiety

    depression, agitation, confusion, hallucinations RESPI: wheezes, laryngospasm, laryngeal edema

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    PENICILLINS

    NURSING RESPONSIBILITY History taking

    Prior hypersensitivity to penicillins Other conditions: bleeding disorders, GI disease, renal

    impairment Given on an empty stomach ( 1 hr before or 2

    hours after meals) except for amoxicillin, penicillinV, augmentin

    Obesrve for electrolyte imbalance

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    PENICILLINS

    PENICILLIN G Nursing responsibility

    IM or IV Dosage vary according to severity of infections Dosages >10 M u/day must be given via IV infusion Deep IM injections to large muscles Monitor for signs of hyperkalemia and hypernatremia Used with caution to clients with renal insufficiency

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    PENICILLINS

    Penicillin V Peak: 30 60 minutes Half life: 1 hour Protein binding: 80 90% Excretion: tubular secretion in the kidney

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    PENICILLINS

    Ampicillin Pregnancy category B Effective against spectrum of both gram (+) and

    gram (-) organisms Stable in gastric acid Used in RTI, soft tissue infections, otitis media,

    septicemia, bacterial meningitis, gonococcalinfections, PID, prevention of bacterialendocarditis

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    PENICILLINS

    Ampicillin Peak (PO): 1.5 2 hrs; (IM): 1 hour Half life: 1 1.5 hours Protein binding: 20 -25% Nursing responsibility:

    Given on an empty stomach Stable in saline for 24hrs and in D5W for 2hrs, IV

    preparation should be given over 15-30mins

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    PENICILLINS

    Amoxicillin Pregnancy category B Acid-stable penicillin with a spectrum similar to

    ampicillin but is better absorbed from the GIT Less effective to Shigella than ampicillin Used againts infections of ENT, lower RT due to

    streptococci, pneumococci; GU infections causedby E. coli; skin and soft tissue infections

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    PENICILLINS

    Amoxicillin Peak: 2 hours Protein binding: 20 25% Half life: 1 1.3 hours Nursing reponsibility

    Available only in PO form Usually given Q8hrs (TID) Available in combination with potassium clavulanate

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    PENICILLINS

    Methicillin Pregnancy category B Semisynthetic salt of penicillin that is active against

    penicillinase-producing strains of staphylococci Peak: 0.5 to 1hr Half life: 0.4 to 0.8 hour

    Protein binding: 40 -50% Given IV or IM Excretion: hepatic, bile, real routes

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    CEPHALOSPORIN

    1st Generation Indications:

    Respiratory tract infections Otitis media Skin infections Bone infections Genitourinary tract infcetions

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    CEPHALOSPORIN

    1st Generation Cefazolin Cefadroxil Cephalexin

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    CEPHALOSPORIN

    2nd Generation Cefamandole Cefuroxime Cefoxitin Cefotetan Cefonicid Cefmetazol

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    CEPHALOSPORIN

    3 rd Generation Treatment of previously mentioned infections,

    also enhance the spectrum of coverage for

    additional gram negative infections Prophylaxis for perioperative infection

    4 th Generation

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    CEPHALOSPORIN

    3 rd Generation Ceftizoxine Cefoperazone Cefprozil Cefotaxime Ceftazidime Cetriaxone Cefixime

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    CEPHALOSPORIN

    Pharmacokinetics Absorbed rapidly in the GIT May be given w/o regard to meals but presence of

    food will delay the absorption Peak levels:

    1hr PO

    45mins IM; 15mins IV Maximum concentrations occur in liver and

    kidneys; excretion kidneys

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    CEPHALOSPORIN

    Contraindications/Cautions Use cautiously in patients with penicillin allergy Use cautiously in patients with GI or renal disease

    especially those receiving diuretics Drug-drug interactions

    Alcohol: antabuse-like effect Aminoglycosides: increased risk of nephrotoxicity Aspirin: increased potential risk of bleeding Anticoagulants: increased anticoagulant effect

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    AMINOGLYCOSIDES

    Particularly useful against gram (-) pathogens Used for treatment of sepsis, endocarditis,

    bacteremia Ineffective against anaerobes Work poorly under conditions of low oxygen

    tension and in acid environments BACTERICIDAL inhibit protein synthesis

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    AMINOGLYCOSIDES

    Indications: Gram (-) enteric bacilli Tuberculosis Sepsis or bacteremia Strongly indicated in combination with other

    antibiotics for aerobic infections Given in combination with penicillin to encourage

    facilitation of the aminoglycosides into the cell

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    AMINOGLYCOSIDES

    Pharmacokinetics: Poor GI absorption Half life is 1-4hrs Excretion: kidneys

    Contraindications/Cautions: Preexisting renal disease Neuromuscular disease Patients taking skeletal muscle relaxants

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    AMINOGLYCOSIDES

    Drug interactions Amphotericin B, cisplatin, cyclosporine,

    vancomycin, enflurane, cephalosporin,

    methoxyflurane increased nephrotoxicity Loop diuretics increased ototoxicity Increase effect of neuromuscular blocking agents

    Synergistic effect when given with penicillinagainst pseudomonas

    Decreases absorption of dogoxin

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    AMINOGLYCOSIDES

    Streptomycin Amikacin Gentamycin (Garamycin) Tobramycin Neomycin

    Kanamycin

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    MACROLIDES

    BACTERIOSTATIC inhibit the growth of microorganism

    Inhibit protein synthesis Indications:

    Infections caused by gram (+) bacteria Indicated for acute diphthria Penicillin-sensitive/allergic clients Prophylactic treatment of ophthalmia

    neonatorum

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    MACROLIDES

    Indications Erythromycin drug of choice for legionnaires

    disease, whooping cough Intestinal amoebiasis, upper and lower RTI

    Treatment of H. influenza when used withsulfonamide

    Uncomplicated urethral, endocervical, rectalinfections Syphilis caused by T. pallidum

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    MACROLIDES

    Pharmacokinetics PO: good absorption, should be given on empty

    stomach, peak: 1-4hrs, duration: 6hrs Excreted mostly in bile

    Contraindications/cautions Liver disease Pregnant or breatfeeding

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    MACROLIDES

    Drug interactions Carbamazepine, cyclosporine, digoxin, ergotamine,

    terfenadine, triazolam, warfarin may increase serumlevels

    Chloramphenicol, clindamycin, lincomycin decreasedeffects of these drugs

    Common Macrolides

    Erythromycin Clarithromycin azithromycin

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    TETRACYCLINES

    BACTERIOSTATIC Inhibit protein synthesis Indications

    Ricketssiae, C. trachomatis V. cholerae, H. ducreyi DOXYCLINE

    T. pallidum hypersensitive to penicillin Adjunct therapy fro intestinal ameobiasis

    Uncomplicated gonococcal infections

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    TETRACYCLINES

    Pharmacokinetics Action

    Short acting: tetracycline Intermediate: methacycline Long acting: doxycycline

    Concentrated in bile, excreted in kidneys Drug interactions

    Do not use during tooth development Lactation Renal disease

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    TETRACYCLINES

    Contraindications: Do not use during tooth development Avoid use in lactation

    Pts with renal failure: minocycline and doxycycline Drug interaction:

    Oral contraceptives: decrease effectiveness of contraceptives

    Oral anticoagulants: increase effect of these agents Cimetidine: decrease GI absorption of tetracycline Digoxin: increase effect of digoxin

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    TETRACYCLINES

    Adverse/Side Effects Photosensitivity, manifested by an exaggerated

    sunburn Common Tetracyclines

    Doxycycline Minocycline

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    QUINOLONES Broad spectrum synthetic antibiotic class with

    both gram (+) and gram (-) At by interference with DNA replication BACTERICIDAL Indications:

    Uncomplicated gonorrhea Respiratory, soft tissue, and skin infections, STD

    caused by gonorrhea and chlamydia Prophylaxis: Transurethral surgery

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    QUINOLONES Drug interactions

    Theophylline: elevated levels Antacids: decreased intestinal absorption Food: intake of 1-2 hours of administration will interfere

    absorption Common Quinolones

    Ciprofloxacin Ofloxacin Norfloxacin Nalidixic acid Lomefloxacin


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