Drugs for Infections II

Acute infection ( above 10,000/ mm³)

elevated WBC count indicates what?

Penicillins

Drugs that weaken the cell wall, causing bacteria to take up excessive water and rupture

1. inhibits enzymes thar fostre cross-linkage of peptidoglycan chains

2. blocks cell wall synthesis

3. bacterial autolysins disrupt cell wall synthesis

4. promotes actice destruction of bacterial cell wall

5. Weakened wall leads to cell lysis

Pen G MOA

Gram positive affected more than negative.

which bacteria are more affected by pen g?

It cannot penetrate the gram - cell envelope

why isnt pen g as affective for graam negative bacteria?

Pencicillin has a beta-lactam ring that can be cut by enzymes, inactivating the penicillin. Certain bacteria make these enzymes (beta-lactamase/penicillinases)

how does bacterial resistance occur with penicillins?

1. narrow spectrum (pen G)

2. Narrow spectrum (cloxacillin)

3. broad spectrum (ampicillin, amoxicillin)

4. extended spectrum (Ticarcillin, piperacillin)

Classifications of penicillins [4]

pen G

Narrow spectrum penicillin that isp enicillanse sensitive

Cloxacillin

narrow spectrum penicillin that is penicillinase resistant

Bactericidal to gram-positive and some gram-negative bacteria

actions of pen G:

Affects lipid solubility

Why do some penicillins have fats added?

destroyed y stomach acids

Why isn’t pen G given orally?

1. allergy (1-10% of patients)wh

adverse effects of pen G

•due to frequent exposure to penicillins produced by fungi or present in foods or animal-based products

why isn’t a first exposre necessary for penicillin allergies?

•Immediate  (2 to 30 minutes)

•Accelerated (1 to 72 hours)

•Late (days or weeks)

anaphylaxis (0.02%)

types of penicillin allergies [4]

1. benadryl

2. epinephrine

3. respiratory support

4. prevention (skin testing)

treatment for penicillin allergy [4]

Pen V is stable in stomach acids, can be taken with food (reduces chemical irritation to the gut)

Which penicillin can be given orally?

1. apicillin (IV or PO)

2. amoxicillan (PO,)

Broad spectrum penicilins (aminopenicillinss)

pseudomonas aeruginosa (neon green)

Primary taret for Piperacillin

aminoglycoside (Gentamycin)

Piperacillin is often combined with what?

Cephalosporins

Most widely used group of antibiotics

1. Binds to penicillin-binding proteins. can be:

2. Direct: disprupts cell wall synthesis

3. indirect: activate autolysins to cut cell walls

4. cell death from lysis

Cephalosporins MOA [4]

1. cefazolin (Ancef)

2. Cephalexin (Keflex)

First generation cephalosporin prototypes [2]

Cephalexin (Keflex)

First gen cephalosporin with short half life, needs to be taken four times a day

1. for gram-positive infection and mild penicillin allergy

2. most common pre-op drug

When are first gen cephalosporins given? [2]

1. cefaclor (Ceclor)

2. Cefotetan (Cefotan)

second generation cephalosporins [2]

Ceftazidime (fortaz)

Third generation cephalosporin

Ceftazidime (fortaz)

Cephalosporin given for nosocomial infections; gram negative bacteria; resistant to other common antibiotics

increased bleeding risk

Adverse effect of Cefotan

Keflex

Cephalosporin that is given orally

1. increased activity against gram negative germs

2. increased resistance to destruction by beta-lactamase

3. increased ability to reach cerebrospinal fluid

Cephalosporin uses [2]

1. cefazolin (Ancef)

2. Cefotetan (Cefotan)

Which cephalosporins have a disulfaram-like reaction with alcohol?[2]

1. allergy

2. bleeding (Cefotetan)

3. thrombophlebitis at the IV site

rare adverse effects of cephalosporins

1. binds to molecules that serve as precursors for cell wall biosynthesis

2. Does not interact with penicillin-binding proteins

3. inhibits cell wall synthesis

4. weakened cell wall leads to cell lysis

Vancomycin MOA

1. antibiotic related c. difficile

2. MRSA

3. serious infections if pt is allergic to penicillins

Uses for vancomycin [3]

it can be hard on the veins

why is vancomycin slowly infused in 250 mL saline

1. ototoxicity (may be irreversible)

2. nephrotoxicity

3. thrombophlebitis

4. allergy (rare)

Rare side effects of vancomycin [3]

It does not go through much breakdown, is unchanged in the kidneys

Why should pt with kidney impairment be cautious when taking vancomycin?

1. bidns to 30S ribosomal subunit of bacteria

2. blocks initiation of protein synthesis

3. terminates synthesis of protein before it is complete

4. cause misreading of genetic code

5. synthesis of faulty proteins (bactericical)

Aminoglycosides MOA

1. serious infection due to gram- bacterial bacilli

2. narrow spectrum

3. e. coli, klebisella, serratia, proteus, pseudomonas

4. Cannot kill anaerobes, needs oxygen to cross cell wall

Uses for aminoglycosides

most given in eyes or wound irrigation

Neomycin: given pre-op for GI surgery

How are aminoglycosides absorbed?

1. gentamycin

2. amikacin

3. tobramycin

Aminioglycoside prototypes: [3]

That there is a washout period where the drug is below the minimal effective concentration. Do lots of drug monitoring.

Important that there is what following administration of aminoglycosides?

1. loading dose for faster theraopeutic levels and reach plateau quicker

2. maintenance dose to keep in therapeutic range

doses given for aminoglycosides

To make sure the peaks are not too high. if they are too high, cannot get it down enough to prevent nephrotoxcity and ototoxiciy

Why is timing for gentamycin so important?

1. 30 minutes after IM injection

2. right after 30 minute IV infusion

when to monitor serum blood levels of gentamycin? [2]

Trough level

Lowest blood level achieved before giving the next dose

1. divided doses: just prior to next dose

2. Once daily dose: two samples at 2h and 12h post infusion

how often to draw trough levels for gentamycin

Does not get metabolized, so excreted intact. Binds tightly to renal tissues increasing risk for toxicity

How is gentamycin excreted?

lower the dose

What to do with gentamycin dose if pt has kidney disease?

Ototoxicity

Damage to the hair cells within the cohclea of the inner ear; disrupts balance, causes tinnitis, hearing impairment

Excessive trough levels

ototoxicity with gentamycin is due to what?

Nephrotoxicity

injury to cells of proximal renal tubules leading to acute tubular necrosis leading to elevated BUN and creatinine levels

Due to total cumulative dose or excessive trough levels, tight prolonged binding of drug to renal tissue

nephrotoxicity from gentamycin is due to what?

1. inability of kidney to concentrate or filture urine

2. dilute urine

3. proteinuria

S+S of nephrotoxicity [3]

1. acne

2. h. pylori

3. periodontal disease

4. etc

uses for tetracyclines: [3]

1. calcium

2. milk products

3. iron supplements

4. magnesium-containing laxatives

5. antacids

Tetracyclines should not be given with? (give one hour before or after)

patients with renal impairment

Who should not be given tetracyclines?

1. erythromycin

2. azithromycin

3. clarithromycin

macrolides prototypes: [3]

1. GI effects

2. QT prolongation

side effects of macrolides [2]

1. theophylline

2. tegretol

3. warfarin

Macrolides can increase the plasma levels of what? [3]

1. most gram posidive

2. some gram negative bacteria

macrolides are active against what?

1. tetracyclines

2. macrolides

Bacteriostatic inhibitors of protein synthesis: [2}

1. pre-op shaving

2. GI or GU surgery

number of bacteria at the surgical site at the time of surgery increases with [2]

preop bath if antiseptic use

Number of bacteria at the surgical site at the time of surgery decreases with

1. length of hospital stay preop

2. duration of surgery

3. surgeons skill in minimizing tissue trauma

Pre and intro op factors that increase risk for wound infection [3]

1. nutritional status

2. infection at other sites

3. diabetes (Sustained yperglycemia)

4. use of immunosuppressive drugs

Patient risk factors for wound infection [4]

•controlling pain

•reducing stress

•reducing caffeine--

•eliminating nicotine– due to vasoconstriction in the periphery

•ensuring adequate circulatory volume

How can nurses improve tissue oxygenation to decrease wound infection? [5]

1. mechanical cleanser

2. wont damage new cells or good bacteria

Benefits of using normal saline for wound care [2]

none

Risks for using normal saline for wound care

slowly releases iodine (antiseptic)

benefits of sing povidone-iodine for wound care

1. toxic to fibroblasts, WBC (bad) and microbes (good)

2. iodine toxicity

3. intact skin only

risks of sing povidone-iodine for wound care [3]

Thyroid crisis if high dose

iodine toxicity can cause what?

1. weak antiseptic

2. effervescent action - mechanical cleanser

benefits of using hydrogen peroxide for wound care[2]

can break up new clots

risk of using hydrogen peroxide for wound care

1. can strengthen collagen to impede virus entry into cells

2. can decrease length and severity of common cold

3. antioxidant property may contribute

4. may decrease inflammatory effect of free radicals

How can vitamin C help with common cold? [4]

Can lead to more infection

Why shoudn’t patients use a cough suppressant if they have a wet cough?

antipyretic

cold remedy that acts at heat-regulating center to decrease discomfort and complications

Acetaminophen

antipyretic prototype

decongestant

Cold remedy that stimulates alpha receptors, leading to vasoconstriction to decrease nasal edema, congestionm and post-nasal drip

Dristan-pseudophedrine

Decongestant prototype

sympathomimetic, so

1. increased HR

2. Increased BP

3. Increased rebound congestion

Dristan-pseudophedrine problems [3]

Expectorant

cold remedy that causes reflex outflow of respiratory fudis, increasing the amount and fluidity of secretions

(guaifenesin)

expectorant prototype

increased inappropriate use. Drink fluids instead.

(uaifenesin problems