PHARM: EXAM #1 (LEC 1)

what is the post antibiotic effect?

Persistent suppression of bacterial growth after limited exposure to an antimicrobial agent

penicillin MOA

1. beta lactam ring mimcs the 2-D-ala on bacterial cell wall synthesis and takes the place
2. chains are made but cannot be cross linked
3. cell wall inhibition

drugs that are hepatically excreted

penicillinase-resistant penicillins
Ceftriaxone
Moxifloxacin
Tigecycline

Gram negative resistant bacteria

klebsiella
E. coli
pseudomonas aeruginosa

Risk factors for development of bacterial resistance

1. indiscriminate antimicrobial use (double covering one bacteria, prolonged tx, not de-escalating therapy)
2. greater than 7 days on mechanical ventilation
3. prolonged hospitla stays
4. recent abx use

Concentration-dependent vs time-dependent abx

concentration dependent: the higher the concentration the higher the killing
time-dependent: the more time above the MIC, the more killing

how to keep time-dependent concentration

continuous or frequent infusions of antibiotics

what structure does beta lactam ring mimic on bacteria

2 D-Ala

Natural penicillins are good against what type of bacteria

Gram positive
cocci
ok with anaerobes

Penicillin V Potassium is given what route

oral

Penicillin G Benzathine is given through what route?

IM
long acting

Penicillin G (Benzylpenicillin) is given through which route

IV only

Natural penicillins (G and V) are useful for what diseases

1. syphillis
2. gas gangrene
3. meningococcus

natural penicillins

Penicillin G
Penicillin V

which drugs are aminopenicillins

Ampicillin
Amoxicillin

am- + -illin

aminopenicillin

aminopenicillin side effects

- abnormal prolongation of PT with anticoagulation
- decrease effectiveness of oral contraception
- hepatic dysfunction
- increased risk for C. diff
- nephritis, hematuria, crystalluria
- anemia, thrombocytopenia

contraindications for aminopenicillins

past medical hx of
1. cholestatic jaundice
2. hepatic dysfunction
(LIVER PROBLEMS)

adverse reactions to penicillin

hypersensitivity
rash
diarrhea

special consideration for penicillins

renal function because penicillin is renally excreted

what do the beta lactamase inibitors do

irreversibly inactivate beta lactamase produced by bacteria that is used WITH beta lactam antibiotic to prevent the breakdown of beta lactam antibiotics

What are the beta-lactamase inhibitors?

CAST:
Clavulanic Acid
Sulbactam
Tazobactam

Unasyn comprised of

ampicillin + sulbactam

Zosyn comprised of

pipercillin + tazobactam

Augmentin comprised of

amoxicillin + clavulanic acid

Beta lactamase inhibitors increase what when added to beta lactam abx?

anaerobic coverage
Gram - coverage
Staph coverage!

drugs used specifically to kill S. Aureus

penicillinase-resistant penicillin
NOD: Nafcillin, oxacillin (Bactocill), dicloxacillin

special dosing considerations for penicillinase-resistant penicillins?

hepatic dosing

drugs of choice for pseudomonals

piperacillin (Pipracil)
piperacillin/tazobactam (Zosyn)

-cillin

class of penicillin

what is special about cephalosporins?

good CSF penetration

cef-

cepahlosporin

as cephalosporin generation increases...

gram negative activity increases

gram negative coverage for 2nd generation cephalosporins

E. coli
Klebsiella
enterobacter
neisseria
proteus
H. influenza

T or F: some cephalosporins have enterococcus activity

False

why is ceftriaxone easy to dose?

hepatic elimination
only one IV dose per day

ceftriaxone (maxipime) is the drug of choice for

strep

ceftotaxime is drug of choice for what population

neonates

4th gen cephalosporin

cefepime (Maxipime)

5th gen cephalosporins

used rarely
ceftaroline (Teflaro)
ceftolozane/tazobactam (Zerbaxa)

monobactams are useful against

gram negative
pseudomonas aeruginosa

which drug is a monobactam

aztreonam (Azactam)

carbapenems cover...

everything except MRSA.

List of things that carbapenems kill

gram +
gram -
anaerobes (including enterococcus)
extended sprectum beta lactamase inhibitors (ESBL)
nosocomial infections
meningitis

-penem

carbapenem

which carbapenem may cause seizures?

imipenem

gram positive aerobic cocci

Staphylococcus
Streptococcus
Enterococcus

gram positive anaerobes

Peptostreptococcus
Clostridium difficile
Clostridium perfringens

List some gram negative bacilli

Enterobacteriaceae
pseudomonas aeruginosa
others too

atypical bacteria include

chlamydia trachomatis
chlamydia pneumoniae
legionella pneumoniae
mycoplasma pneuomniae

skin and soft tissue harbor a lot of what type of bacteria

gram positive

bones and joint harbor what types of bacteria

gram negative rods
gram positive

abdomen harbors a lot of what type of bacteria

anaerobic gram negative

urinary tract harbors a lot of what type of abcteria

gram negative

nosocomial infection bacteria

MRSA
psuedomonas aeruginosa
enterobacter bacilli
k. pneumoniae
serratia spp.

spp stands for

bacilli

2 types of tests used to determine whether an antibiotic is effective to a particular bacteria?

E test
antibiotic sensitivity testing

what is empiric therapy

going broad initially and scaling down when organism is narrowed down

what kind of antibiotic is vancomycin

glycopeptide antibiotic

MOA for vancomycin

binds to 2 D-Ala on peptide to inhibit cell wall synthesis - just like penicillins, but does not have a beta lactam ring, so is more resistant to bacteria

vancomycin kills what types of bacteria

gram positive

vancomycin is good for

MRSA
C. Diff (PO)
endocarditis or osteomyelitis
surgical prophylaxis

how do you renally dose

by changing frequency of administration, rather than dose

what causes red man syndrome

too high of a drip rate of vancomycin

vancomycin risks

ototoxicity
nephortoxicity
(just like aminoglycosides)

drugs that inhibit protein synthesis

Aminoglycosides
Tetracyclines
Chloramphenicol
Macrolides
clindamycin
streptogramins
tigecycline

how to remember the macrolides

ACE!
azithromycin
clarithomycin
erythromycin

what is special about macrolide coverage

covers a lot of atypical bacteria like
legionella
mycoplasma pneumoniae
chlamydia pneumoniae
chlamydia trachomatis

Macrolides coverage

- gram positive
- SOME gram negative
H. influenza
M. catarrhalis
N. maningitides
N. gonorrhea

side effects of macrolides

MACCRo
motility of the GI
arrhythmia
CYP inhibition
Cholestatic hepatitis
Rashes

If CYP enzyme is not working, what happens?

CYP drugs are not metabolized

MOA for tetracyclines

prevent tRNA from binding on A site

-cycline

tetracycline antibiotic

tetracycline treatments useful for

acne
atypical pneumonia
Rocky mountain spotted fever
Lyme disease
MRSA!
bubonic plague

adverse effects of tetracyclines

Binds with iron and calcium containing products
- photosensitivity
- discoloration of teeth (calcium)
- skeletal growth inhibition

what kind of foods need to be avoided with tetracyclines?

iron and calcium containing foods

tygecycline belongs to what drug class

glycylcycline

tigecycline is most useful for

complicated skin and intra-abdominal infections

tigecycline is excreted via what pathway

hepatic

List of aminoglycosides

Gentamicin
Tobramycin
Amikacin
(GTA - grand theft auto)

aminoglycosides specifically target

gram negative bacteria

aminoglycosides are good treatment for what type of pathogens

nosocomial bacterial infections

pseudomonas
E coli
enterobacter aerogenus
klebsiella penuomniae
proteus
serratia

why do we need to therapeutically monitor aminoglycosides?

narrow therapeutic index

when should peaks be drawn in TDM?

30 minutes after infusion

When should troughs be drawn in TDM?

15-30 minutes before next scheduled dose

trough of gentamycin and tobramycin should not be higher than

1

trough of amikacin should not be higher than

5

When should you use linezolid

to treat MRSA when vancomycin does not work
(vancomycin resistant enterococcus)

Side effects of linezolid

thrombocytopenia
serotonin syndrome

what foods should be avoided when taking linezolid

tyramine containing foods

Daptomycin (Cubicin) MOA

causes increased bacterial depolarization inhibiting DNA, RNA, and protein synthesis

side effects of daptomycin

myalgias and elevated CPK

daptomycin coverage

Gram + only

2 drugs for vancomycin resistant enterococcus?

linezolid
daptomycin

Fluoroquinolones include

Ciprofloxacin 2nd gen
Levofloxacin 3rd gen
Moxifloxacin 3rd gen

Fluoroquinolones MOA

inhibits DNA gyrase (topoisomerase II) to induce DNA cleavage

Preferred places to use fluoroquinolones

eyes and ears

adverse reactions for fluoroquinolones

QTC interval changes
CNS changes
warfarin interactions
interactions with iron, antacids, multivitamins, calcium (dairy)

BACIC - bleeding, arrhythmias, CNS changes, iron, calcium

what is different about moxifloxacin compared to the other FQs

hepatic elimination

order of pseudomonas coverage of FQs (from strongest to weakest)

moxi
levo
cipro