Antimicrobials

Question 1

Penicillin MOA and uses

Answer 1

bactericidal - messes with cell walls - peptidoglycan

broad spectrum - good for a lot of things - gram positive

Question 2

how is PCN excreted

Answer 2

renal
plasma concentration decreases by half in first hour
anuria increases elimination half time by 10x
if you’re giving a probenecid, excretion is reduced

Question 3

PCN big problem

Answer 3

beta-lactam ring = hypersensitivy in up to 10% of people

cross-sensitivity 3% of the time with cephalosporins because they share the ring

Question 4

second generation penicillins?

Answer 4

amoxicillin and ampicillin - wider range of activity including gram neg

Question 5

what is a good abx substitue for patients with documented IgE mediated anaphylactic reaction to B-lactum abx?

Answer 5

clindamycin or vanc

Question 6

Cephalosporins MOA and use

Answer 6

cefazolin (ancef)
bactericidal, broad spectrum, but more widely used because low toxicity
higher generations = more reactive to gram neg

*also renal excretion

Question 7

what are the macrolides, MOA, and use

Answer 7

Erythromycin, azithromycin
bacteriostatic or bactericidal - dose-dependent
block protein synthesis
broad spectrum - respiratory probs, STIs - chlamydia, gram positives

Question 8

macrolides metabolism and excretion

Answer 8

CYP450 metabolism (can act like an inducer and increase serum concentraion of theophylline, warfarin, cyclosporine, methylprednisone, digoxin)

excreted in bile

good for renal patients**

Question 9

macrolides side effects

Answer 9

INCREASED PERISTALSIS - gi upset
qt prolongation = torsades

thrombophlebitis so give in a good IV

Question 10

Clindamycin (linomycins) - MOA, use

Answer 10

bacteriostatic
ACTIVE WITH ANAEROBES
commonly used for GU females

Question 11

clindamycin probs

Answer 11

CAN CAUSE C DIFF
bad for liver disease

POTENTIATE BLOCKADE

Question 12

Vancomycin MOA and use

Answer 12

bactericidal - impairs cell wall synthesis
gram positives!!!
Drug of choice for MRSA
used in combo with aminoglycosides for endocarditis
used for cardiac/ortho procedures with implants
CROSSES BBB (slowly unless meningeal inflammation)
used for bacteria resistant to other abx

Question 13

vanc PK

Answer 13

renal excretion - half time is up to 6 hours and can be prolonged up to 9 days with renal failure patients (give them half the dose once a week)

poor PO absorption - give IV

Question 14

Vanc dosing and adminstration

Answer 14

10-15mg/kg
give IV SLOW over 60 minutes
1 gram mixed in 250 ml

Question 15

vanc side effects

Answer 15

rapid administration = profound hypotension
red man syndrome from histamine release
ototoxicity (with concentration >30mcg/ml) and nephrotoxicity (rare except when in combo with aminoglycosides)
give in big IV - phlebosclerotic

RETURN OF neuromuscular blockade

Question 16

what can you administer with vanc to decrease histamine effects

Answer 16

give within 1 hr of induction:

1mgkg benadryl
4mg/kg cimetidine

Question 17

Aminoglycosides what are they/uses. MOA

Answer 17

Bactericidal, inhibits protein synthesis good for TB and aerobic gram neg and pos

streptomycin - we don’t use
kanamycin - we don’t use
gentamicin - broad spectrum
amikacin - pseudomonas, infections caused by a gentamicin or tobramycin resistant gram neg bacilli
neomycin - skin, eye, mucous membrane (think neosporin), decrease bacteria in intestine before GI surgery

usually given in combo with a beta lactam for gram neg therapy

Question 18

aminoglycoside excretion

Answer 18

renal - glom filtration

2-3 hour elimination half time increased 20-40x with renal failure

Question 19

aminoglycoside SE

Answer 19

ototoxicity, nephrotoxicity, skeletal muscle weakness

POTENTIATES NDMR BLOCKADE - reversal may not be sustained with calcium or neostigmine

Question 20

fluroquinolones (ciprofloxacin and moxifloxacin) use and MOA

Answer 20

Bactericidal, broad spectrum
good for gram neg and mycobac
complicated GI/GU infection

cipro - resp infections, TB, anthrax, bone/soft tissue infection

moxi - sinusitis, bronchitis, abd infection

Question 21

fluroquinolones PK

Answer 21

rapid GI absorption
penetration to body fluid and tissue = excellent
renal excretion - required renal dosing
CYP450 inhibitor

Question 22

fluroquinolone SE

Answer 22

TENDON RUPTURE
muscle weakness in MG
dizzy, insomnia, N/V

moxi = qt prolongation and SJS

Question 23

Sulfonamides (sulfamethoxazole and trimethoprim) MOA/use

Answer 23

bacteriostatic - prevent bacteria from being able to synthesize folic acid

good for UTIs, IBS, Burns

Question 24

sulfonamides PK and SE

Answer 24

liver acetylated and renal excretion - needs renal dosing

skin rash to anaphylaxis
hepatotoxicity - thrombocytopenia, increase coagulant effects, hemolytic anemia
allergic nephritis
photosensitivity
drug fever

Question 25

Metronidazole - MOA/use

Answer 25

bactericidal ``` good fore anaerobic gram neg CNS - crosses BBB c-diff endocarditis abd sepsis preop prophylaxis for colorectal ```

Question 26

metronidazole side effects

Answer 26

dry mouth metallic taste nausea avoid alcohol

Question 27

antimycobacterial first line agents

Answer 27

CSF penetration!! - used in combo therapy Rifampin - bactericidal Isoniazid - bacteriostatic (cidal with cell dividing) Pyrazinamide - bateriostatic Ethambutol - bacteriostatic used in combo therapy for 2 months of 3-4 agents and then a minimum of 4 more months with 2 of them

Question 28

name the statics

Answer 28

``` sulfonamides clindamycin macrolides (dose dependent) isonazid (non-rapid dividing) pyrazidimide ethambutol ```

Question 29

abx that cross BBB

Answer 29

Vancomycin Metronidazole Antimycobacterials

Question 30

Non-renal excretions abx

Answer 30

``` clinda = liver sulfonamides = liver and renal macrolides = excreted in bile ```

Question 31

abx that effect NDMR

Answer 31

``` aminoglycosides = potentiate blockade clindamycin = potentiate blockade vancomycin = return of blockade ```

Question 32

ABX that act like cyp450 inhibitors

Answer 32

macrolides | fluroquinolones

Question 33

Antifungals - Amphotericin B

Answer 33

given for yeast/fungi poor PO absorption slow renal excretion - impairs renal function in 80% of patients on the drug (monitor plasma creatinine levels) Side effects - fever, chills, hypotension with infusion, hypokalemia, allergic reactions, seizure, anemia, thrombocytopenia not compatible with saline

Question 34

how do antivirals work

Answer 34

there are some cell surface receptors unique to viruses and this gives a location for potential drug therapies it is difficult to kill virus and not host

Question 35

acyclovir

Answer 35

used to treat herpes may cause renal damage thrombophlebitis patients may complain of headaches during IV infusion

Question 36

interferons

Answer 36

bind to receptors on host cell membranes and induce the production of enzymes that inhibit viral replication - degrade viral mrna treatment for hep b/c side effects: flu like symptoms, autoimmune conditions, changes in CV, thyroid, and hepatic functions, alopecia, decreased mental concentration, depression, irritability

Question 37

antiretroviral drugs

Answer 37

TRIPLE THERAPY chosen from 6 classes - nucleoside/non-nucleotide reverse transcriptase inhibitors - protease inhibitors - fusion inhibitors - CCR5 receptor antagonists - integrase inhibitors CRNAs should note that there are adverse effects with these drugs = liver toxicity, peripheral neuropathy, nephro-toxicity, neuromuscular weakness inhibit cyp450

Question 38

goals of antimicrobial therapy

Answer 38

- inhibit microorganisms at concentrations that are tolerated by the host - seriously ill/immunocompromised select bacteriocidal - narrow spectrum before broad spectrum or combo therapy to preserve normal flora

Question 39

surgical site infections outcomes

Answer 39

SSIs develop in 2-5% or 30million surgical patients that cost 1 billion dollars/year cause increased re-admissions, increased length of stay, and increased hospital cost

Question 40

SSI definition

Answer 40

an infection related to an operative procedure that occurs at or near the surgical incision within 30 days of the procedure purulent drainage from site positive culture obtained from surgical site that was closed initially surgeon's diagnosis of infection surgical site that requires reopening due to tenderness, swelling, redness, or heat

Question 41

surgical risks for ssi

Answer 41

procedure type skill of surgeon Use of foreign material or implantable device or implantable device degree of tissue trauma

Question 42

patient risks for ssi

Answer 42

diabetes, smoking, obesity, malnutrition, steroid use, immunosuppressive therapy, intraoperative hypothermia, trauma, prosthetic heart valves

Question 43

anesthesia impact on SSI

Answer 43

timely and appropriate use of abx maintain normothermia proper med admin

Question 44

SCIP goals

Answer 44

``` give abx one hour prior to incision discontinue within 24 hours after surgery end time glucose control periop temp management VTE prophylaxis ```

Question 45

dose of amoxicillin

Answer 45

2 gram po

Question 46

dose of ampicillin

Answer 46

2 gram IV

Question 47

clindamycin dose

Answer 47

600 mg IV

Question 48

cefazolin dose

Answer 48

1 gm IV