Download Hemotherapeutics - My Illinois State

MENNONITE COLLEGE OF NURSING
AT
ILLINOIS STATE UNIVERSITY
Pharmacotherapeutics for Advanced Practice Nursing 433
Hemotherapeutics
Factors influencing antimicrobial efficacy
 Possible goals of therapy
 Eradication
 Suppression
 Prophylaxis
 The involved pathogen
 Identity
 Examples of gram-positive cocci
 Streptococcus, such as S. pneumonia
 Staphylococcus, such as S. aureus
 Other gram-positive bacteria
 Listeria
 Bacillus
 Clostridium
 Gram-negative bacteria
 Gram-negative cocci: Neisseria
 Gram-negative coccobacilli
 Acinetobacter
 Moraxella
 Legionella
 Gram-negative rods
 Campylobacter
 Haemophilus
 Escherichia coli (E. coli)
 Klebsiella-Enterobacter
 Proteus
 Salmonella
 Shigella
 Pseudomonas
 Virulence
 Patterns of resistance
 The infected host
 Site of infection
 Severity of the infection
 Other complicating diseases or problems
 Age of the patient
 “Compliance” issues
 Choice of antibiotic
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Spectrum of activity
Toxicity profile
Pharmacokinetic profile
Route of administration
Dose and duration of therapy
 Consider vascularity of target organ (e.g.: sinuses, prostate)
Relative cost
Effect on other medications the patient takes (drug interactions, contraindications)
Combination therapy
 Reasons to prescribe combination antimicrobial therapy
 To prevent resistance
 To broaden coverage
 To achieve synergistic killing
 Disadvantages of combination therapy
 Possible antagonism
 Risk of “superinfection”
 C. difficile risks
 Increased toxicity
 Increased cost
Antibiotic Resistance
 Cause of the problem
 What to do about the problem
 Prevent infection (avoid invasive medical devices such as indwelling urinary
catheters, central venous catheters, intubation when possible)
 Vaccination of children and adults: S. penumoniae, Haemophilus influenza,
Neisseria meningitides
 Tailor treatment to fit the infection, based on the likely pathogens or culture
results; avoid broad-spectrum antibiotics when possible
 Prevent transmission of resistant bacteria between patients: handwashing
The Sanford Guide to Antimicrobial Therapy
Antibiotic characteristics
 Bacteriostatic means that the antibiotic inhibits the growth of the bacteria but does not
directly kill it.
 Bactericidal means that the antibiotic directly kills the bacteria.
Bacteria characteristics
 If a bacteria’s surroundings include an antibiotic, over time it can mutate in such a
way that it can survive an attack by an antibiotic
 The production of beta-lactamases is one way in which bacteria can fend off the
effects of antibiotics.
Main classes of antibiotic agents
Penicillins
 Penicillin discovered by alexander Fleming in 1928; became available for general use
in the 1940’s
 Mechanism of action: bactericidal
 Spectrum/usage
 Natural penicillins (penicillin G, penicillin V)
 Aminopenicillins (ampicillin, amoxicillin)
 Bacteria “smarten up”: production of enzymes (beta-lactamases)
 Humans fight back: PCN-beta lactamase inibitor combinations
 Amoxicillin+clavulanic acid = Augmentin
 Penicillinase-resistant penicillins (dicloxacillin)
 Antipseudomonal penicillins= “extended-spectrum penicillins [(carbenicillin
(oral), ticarcillin and piperacillin (parenteral)]
Side effects
Cephalosporins
 First discovered in 1948
 Mechanism of action: bactericidal
 Spectrum/usage
 As a general rule, as one goes from the first to third generations of agents, gramnegative coverage is gained and gram-positive coverage is lost. Beta-lactamase
stability (resistance to) gets better.
 First generation (cephalexin [Keflex], cefaclor [Ceclor], cefadroxil [Duracef])
 Second generation
 Increased beta-lactamase stability
 Not as good at staph coverage
 Covers H. flu and gram negative better
 Examples: cefuroxime axetil (Ceftin), loracarbef (Lorabid), cefprozil (Cefzil)
 Third generation (cefdinir [Omnicef], ceftriaxone [Rocephin], cefixime [Suprax],
cefpodoxime proxetil [Vantin])
 Fourth generation: cefepime (Maxipime) has good activity against both grampositive and gram-negative bacteria
 Side effects
Carbapenems
 Mechanism of action: bactericidal
 Wide antimicrobial spectrum with excellent activity against anaerobic bacteria; also
cover many gram-negative bacteria; all parenteral (IV, IM)
 meropenem (Merrem)
 imipenem/cilastatin (Primaxin)
 doripenem (Doribax)
 ertapenem (Invanz)
Macrolides and Ketolides
 First available in 1950’s
 Mechanism of action: bacteriostatic
 Spectrum/usage: Macrolides
 Erythromycin
 Azithromycin (Zithromax, Z-pak)
 Clarithromycin (Biaxin, Biaxin XL pak)
 Ketolide: telithromycin (Ketek)
 Side effects
Tetracyclines
 Mechanism of action: bacteriostatic
 Spectrum/usage
 Tetracycline
 Doxycycline (hyclate vs. monohydrate)
 Minocycline
 Tigecycline (Tygacil) - IV
 Side effects
 Don’t use in pregnancy
Aminoglycosides
 Developed during the 1940’s
 Mechanism of action: bactericidal
 Not p.o. (poor oral absorption)
 Very potent
 Potentially serious toxicities (ototoxicity, nephrotoxicity)
 Examples: gentamycin, tobramycin, streptomycin
Sulfonamides
 Mechanism of action: bacteriostatic
 Spectrum/usage
 Sulfisoxazole (Gantrisin)
 Trimethoprim/sulfamethoxazole (Septra, Bactrim)
 Side effects
 Allergies
Fluoroquinolones (= fluorinated quinolones)
 Fluorination broadens spectrum, decreases CNS side effects
 Mechanism of action: bactericidal
 Spectrum/usage
 Norfloxacin (Noroxin)
 Ciprofloxacin (Cipro)
 Ofloxacin (Floxin)
 Levofloxacin (Levaquin)
 Moxifloxacin (Avelox)
 Gatifloxacin (Tequin)
Other:
Metronidazole (Flagyl)
 Mechanism of action: antibacterial (bactericidal), antiprotozoal, antihelmintic
 Spectrum/usage
 Side effects
Monobactams – bactericidal
 Aztreonam (Azactam)
Oxazolidinones – bactericidal and bacteriostatic
 Linezolid (Zyvox) – Used for vancomycin-resistant enterococcus faecium, MRSA
Use with OCPs
Pediatric dosing
Anti-Virals
 Used for CMV, hepatitis, HIV, HSV, influenza, herpes zoster
 Examples: acyclovir, famciclovir, valacyclovir, amantadine, interferon, ribavirin
Anti-Fungals
 Forms: systemic, topical, vaginal
 Examples: amphotericin, griseofulvin, clotrimazole, econazole, fluconazole
(Diflucan), ketoconazole, nystatin, terbinafine (Lamisil)