MENNONITE COLLEGE OF NURSING

AT

ILLINOIS STATE UNIVERSITY

Pharmacotherapeutics for Advanced Practice Nursing 433

Hemotherapeutics

 

Factors influencing antimicrobial efficacy

·         Possible goals of therapy

·         The involved pathogen

·         The infected host

·         Choice of antibiotic

 

Combination therapy

·         Reasons to prescribe combination antimicrobial therapy

·         Disadvantages of combination 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.

 

7 main classes of antibiotic agents

·         Penicillins

·         Cephalosporins

·         Macrolides

·         Tetracycline

·         Aminoglycosides

·         Sulfonamides

·         Fluoroquinolones

 

Other:  Flagyl (metronidazole)

 

Penicillins

·         First introduced in early 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

o      ampicillin/sulbactam (Unasyn)

o      piperacillin/tazobactam (Zosyn)

o      ticarcillin/clavulanate (Timentin)

·         Penicillinase-resistant penicillins (dicloxacillin, methicillin, nafcillin, oxacillin)

·         Antipseudomonal penicillins and Extended-spectrum penicillins (piperacillin, piperacillin/tazobactam, ticarcillin, ticarcillin/clavulanate)

·         Side effects

 

Cephalosporins

·         Mechanism of action:  bactericidal

·         Spectrum/usage

·         As a general rule, as one goes from the first to third generations of agents, gram-negative coverage is gained and gram-positive coverage is lost.  Beta-lactamase stability (resistance to) gets better.

·         First generation (cefadroxil [Duracef], cefazolin [Ancef], cephalexin [Keflex] )

·         Second generation

·         Increased beta-lactamase stability

·         Not as good at staph coverage

·         Covers H. flu and gram negative better

·         Examples:  cefaclor (Ceclor), cefuroxime axetil (Ceftin), loracarbef (Lorabid), cefprozil (Cefzil)

·         Third generation (cefdinir, cefixime [Suprax], ceftriaxone [Rocephin], cefpodoxime proxetil [Vantin])

o      Fourth generation (cefepime [Maxipime])

·         Side effects

 

Macrolides

·         First available in 1950’s

·         Mechanism of action:  bacteriostatic

·         Spectrum/usage

·         Erythromycin

·         Azithromycin (Zithromax, Z-pak)

·         Clarithromycin (Biaxin, Biaxin XL pak)

·         Side effects

 

Tetracyclines

·         Mechanism of action:  bacteriostatic

·         Spectrum/usage

·         Tetracycline

·         Doxycycline

o      Minocycline

·         Side effects

·         Don’t use in pregnancy

 

Aminoglycosides

·         Mechanism of action:  bactericidal

·         Not p.o. (poor oral absorption)

·         Very potent

·         Potentially serious toxicities (ototoxicity, nephrotoxicity)

·         Examples:  gentamycin, tobramycin, streptomycin, amikacin (Amikin)

 

Sulfonamides

·         Mechanism of action:  bacteriostatic

·         Spectrum/usage

·         Sulfisoxazole (Gantrisin)

·         Trimethoprim/sulfamethoxazole (Septra, Bactrim)

o      sulfadiazine (used for toxoplasmosis)

·         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

 

Carbapenems -- bactericidal

ertapenem (Invanz)

imipenem/cilastatin (Primaxin)

meropenem (Merrem)

 

 

Monobactams - bactericidal

aztreonam (Azactam)

 

Oxazolidinones -bactericidal and bacteriostatic

linezolid (Zyvox)--Used for vancomycin-resistant Enterococcus faecium, MRSA

 

 

Antibiotic Resistance

 

 

Anti-Virals

 

 

Anti-Fungals