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(DIT) Rapid Fire + 4/5 Stars > Antibiotics > Flashcards

Antibiotics Flashcards

1
Q

Mechanism of beta lactams

  • Penicillins
  • Cephalosporins
A
  1. penicillins bind penicillin binding proteins (PBPs)
    - PBPs involved in synthesis of peptidoglycan binding –> cell wall synthesis inhibits –> lysis
  2. inhibit cross linking of peptidoglycan chains –> weak cell wall
  3. facilitate damageby autolysins d/t weakened/absent cell wall - may up regulate

bacteriocidal

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2
Q

Penicillin coverage and toxicity

A

b-lactam

PCN G - IV form
PCN V - oral form

Gram + cocci:
S. pneumo
S. pyogenes
Actinomyces
Grp B strep - neonatally
Spriochetes - syphilis

Gram + rods:
Clostridium
listeria
Bacillus

Gram - cocci:
Neisseris - if not penicillinase resistant

MC toxicity:
HSR
Hemolytic anemia
Thrombocytopenia

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3
Q

Resistance mechanisms to penicillin

A

Penicilinase - type b-lactamase
-produced in periplasm gram - organims
coded by plamids

alteration of b-lactam target - PBP

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4
Q

Penicilinase resistant penicillins

A

Bulky R group blocks penicillinase (b-lactamase) binding

Methicillin (lab use only)
Nafcillin
Oxacillin
Dicloxacillin

use: Staph aureus
MRSA - altered binding target site

Toxicity:
Methicillin - interstitial nephritis
Rest: HSR

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5
Q

Aminopenicillins

A

Ampicillin (IV)
Amoxicillin (PO)

Penicillinase (b-lactamase) sensitive
Broader spectrum: "HEELPSS"
H.flu
Ecoli
Enterococci
Listeria
Proteus mirabilis
Salmonella
Shigella

UTIs - kids
Neonatal infection s- ampicillin IV
Prophylaxis against Viridans strep endocarditis

SE:
HSR
Rash w/ mononucleosis caused pharyngitis
-full body rash

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6
Q

B-lactamase inhibitor

A

enhance spectrum of drug
used in combination:

Clavulanic acid + amoxicilin - resistant OM
Clavulanic acid + piperacillin
Sulbactam + ampicillin - IV, surgery
Tazobactam + piperacillin

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7
Q

Antipseudomonal abx

A

Ticarcillin
Carbenicillin
Piperacillin

Extended spectrum
Pseudomonas
gram - rods

susceptible to penicillinase
-add B-lactamase inhibitor

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8
Q

Cephalosporins general

A

B-lactam mechanism
Bactericidal
Less susceptible to penicillinases

LAME against:
Listeria
Atypicals - mycoplasma, chlamydia
MRSA - except 5th gen
Enterococci

Toxicity:
HSR - 5-10% cross reactivity to PCNs
Increased nephrotoxicity if used w/ aminoglycosides
Disulfam like rxn - rare

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9
Q

1st gen cephalosporins

A

Cefazolin
Cephalexin

Gram + cocci
Gram -  "PEcK"
Proteus mirabilis
Ecoli
Klebsiella

UTIs - cephalexin for prophylaxis
URIs
Prophylaxis against viridan strep endocarditis

Cefazolin - post op surgical infection - MSSA

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10
Q

2nd gen cephalosporins

A

Cefoxitin
Cefaclor
Cefuroxime
Cefprozil

Gram + cocci w/ 1st gen
Gram - "HENS PEcK"
Hflu
Enterobacter
Neisseria sp. (not urethritis gonorrhea tx)
Serratia marcescens

Proteus mirabilis
Ecoli
Klebsiella

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11
Q

3rd gen cephalosporins

A

Ceftriaxone (IV, IM)
Cefotaxime
Ceftazidine
Cefdinir

Serious Gram - infecitons, resistant to other b-lactams
“HENS PEcK” + Citrobacter

gram - meningitis
gram + S. pneumo only!

Ceftriaxone - longest t 1/2

  • Neisseria gonorrhoeae - IM
  • excreted in bile, good for renal failure pts

Ceftazidime - pseudomonas

Cefdinir - recurrent OM

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12
Q

4th gen cephalosporins

A

Cefepime

broad spectrum
-most gram + of 1st and 2nd gen
Gram -

Pseudomonas

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13
Q

5th gen cephalosporins

A

Ceftaroline

Broad spectrum
MRSA
No Pseudomonas coverage
Community acq pneumonia
complicated skin infections (MRSA)
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14
Q

Aztreonam

A

monocyclic B-lactam
inhibits cell wall synthesis - binds PBP3 “azTHREE-onam”

Synergicstic w/ aminoglycosides - gentamicin
no cross allergenisity w/ PCN

“Aminoglycoside pretender”

Gram - “PEcKS”
no gram + or anaerobe coverage

Can use in PCN allergy, renal insufficiency (no renal involvement)
non toxic

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15
Q

Carbapenems

A

Imipenem - cilastatin (inhibitor of renal dehydropeptidase 1 –> decreased inactivation)
Meropenem
Ertapenem
Doripenem

Broad spectrum:
Gram + cocci
gram - rods
anaerobes
Pseudomonas

B-lactamase resistant
binding PBPs

Empiric tx of life threatening infections - sick!
does NOT cover MRSA

meropenem - decrease risk of seizures, not inactivated in renal tubules

Toxicity:
GI distress
skin rash
some CNS toxicity - imipenem

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16
Q

Vancomycin

A

inhibit cell wall synthesis
inhibit cell wall mucopeptide formation by binding D-ala-D-ala moieties of cell wall precursors
inhibit cell wall glycopeptide polymerization
Bactericidal

Gram +
poor oral availability - IV for systemic

Use:
MRSA
Enterococci VRE
C. diff - oral - stays in GI
Coag - staph epidermidis endocarditis (R-side)

Toxicity: “NOT”
Nephrotoxicity
Ototoxicity
Thrombophlebitis

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17
Q

Vancomycin resistance mechanism

A

D-ala-D-ala to D-ala-D-lac

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18
Q

Red man syndrome

A

Vancomycin associated

diffuse flusing of whole body
non specific mast cell degranulation
avoid w/:
-antihistamine pretreatment
-slow down infusion
-can restart
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19
Q

30 S and 50 S inhibitors

A

“buy AT 30, CCELL at 50”

30S:
Aminoglycosides
Tetracyclines

50S:
Chloramphenicol
Clindamycin
Erythromycin (macrolides)
Lincomycin
Linezolid
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20
Q

Aminoglycosides

A 
"GNATS"
Gentamicin
Neomycin
Amikacin
Tobramycin
Streptomycin

MO: bind 30S
bactericidal
inhibits formation of initiation complex –> misreading mRNA

ineffective against anaerobes - needs O2 for uptake
“aminO2glycosides”

Use:
severe gr - rod infections
-work synergistically w/ b-lactam abx

neonatal infections: Ecoli pneumonia or sepsis
-ampicillin + gentamicin

Neomycin: bowel surgery and bowel infections

Toxicity: “NOT” (not same as Vanc)
Nephrotoxicity
Ototoxicity w/ loop diuretics
Teratogenicity

21
Q

Chloramphenicol

A

inhibits 50s peptidyltransferase activity
bacteriostatic

harmful side effects:
anemia - dose dependent –> aplastic anemia

Gray baby sn

Uses:
meningitis - H. flu, N. meningitidis, S. pneumo

22
Q

Gray baby syndrome

A

decreased UDPGT activity in neonates
–> build up toxic metabolites

about 9 days sx start
V, ashen skin color
poor muscle tone
cyanosis
CV collapse

Tx:
stop chloramphenicol
exchange transfusion
phenobarbital to induce UDP-GT

23
Q

Linezolid

A

binds 23 S RNA portion of 50S
interacts w/ bacterial initiation complex

Use: MRSA, VRE

can cause serotonin syndrome w/ SSRI med use

24
Q

Tetracyclines

A

Tetracycline
Doxycycline
Demeclocycline
Minocycline

Binds 30 S - inhibits attachment of aminoacyl t-RNA

bacteriostatic
less CNS penetration

Doxycycline fecally eliminated, good in renal failure pts

Avoid w/ milk or antacids - Iron, Ca2+, Mg2+
-divalent cations inhibit abx absorption

Toxicity: 
GI distress
discolored teeth in kids
inhibits bone growth in kids
photosensitivity - bluish skin w/ minocylcine, chornic use w/ acne

Contraindication in pregnancy

25
Q

Tetracycline clinical uses

A

“VACUUM THe BedRoom”

Vibrio cholerae
Acne
Chlamydia
Ureaplasma Urealyticum
Mycoplasma pneumoniae

Tularemia
H. pylori

Borrelia burgdorferi
Rickettsia

26
Q

Macrolides

A

Erythromycin
Azithromycin
Clarithromycin

Inhibit protein synthesis by binding 23 S RNA of 50S –> blocking translocation

Resistance: methylation of 23S RNA binding site

Bacteriostatic

Toxicity:
Prolonged QT interval
GI discomfort
rare acute cholestatic hepatitis (w/ erythromycin estolate)
rare cause of eosinophilia

Drug interactions: increased serum concentration of theophylline; oral anticoag (e.g. warfarin)

Safe in pregnancy - erythromycin and azithromycin safest

27
Q

Clinical uses of Macrolides

A

“PUS”
Pneumonia - atypical: mycoplasma, chlamydophila, legionella
URI - S. pneumo, H. flu
STD - Chlamydia, gonorrhea

28
Q

Streptogramins

A

Quinupristin/Dalfopristin combo drug

synthesized by bactera Stretpomyces virginiae

binds 23 S portion of 50S ribosome

Uses:
MRSA
VRE
Staph and strep skin infections

SE:
hepatotoxicity
pseudomembranous colitis
arthralgias
myalgias

inhibits CYP450

29
Q

Clindamycin

A

blocks peptide bond formation w/ 50S ribosomal subunit
bacteriostatic

Toxicity:
causes pseudomembranous colitis d/t C.diff overgrowth

Anaerobic infections
MRSA
protozoal infections
topically for acne

Bacterioides fragils
C. perfringens
MRSA skin abscess - oral

30
Q

Sulfonamides

A

Sulfamethoxaole (SMX) MC
Sulfadiazine

Folic acid inhibitors - competitively inhibit dihydropteroate synthase

Gram + some
Gram - some
Nocardia
Chlamydia

UTIs
Skin infections

Resistance: alt enzyme, decrease uptake, increase PABA synthesis

Tox:
HSR - MC
hemolysis in G6PD
Nephrotoxicity - tubulointerstitial nephritis
Kernicteris in infants
Dispace other drugs from albumin - warfarin

Stevens Johnson sn
Photosensitivity (“SAT”)

31
Q

Trimethoprim (TMX)

A

inhibits dyhydrofolate reductase

  • -> megaloblastic anemia, leukopenia, granulocytopenia
  • give folic acid supplement
32
Q

TMP-SMX uses

A 
UTIs
Shigella
Salmonella
MRSA skin infections
Prophyalxis for recurrent UTIs
AIDS - prophylaxis against PCP (CD4 under 200)
33
Q

Fluoroquinolones

A 
Levofloxacin (3)
Ciprofloxacin
Norfloxacin
Ofloxacin
Moxifloxacin (4)
Gatifloxacin

-quinolone: Nalidixic acid

Inhibits DNA gyrase (topoisomerase II)

don’t take w/ Ca2+ or Mg2+ supplements, inhibits absorption

resistance: change DNA gyrase

Use:
Gram - infections
Gram - rods
UTIs
GI infections
Pseudomonas
Vary gram + coverage (gen 2-4 better against S. pneumo)
Tox:
GI upset
Contra indicated in pregnancy
Kids - damage to articular cartilage
tendonitis/rupture in adults (CF pt long term tx)
QT prolongation
34
Q

Drugs to be avoided w/ sulfa allergy

A

“Sulfa Pills Frequently Cause Terrible Allergy Symptoms”

Sulfasalazine
Probenecid
Furosimide
Celecoxib
Thiazides/TMP-SMX
Acetazolamide
Sulfonylureas
35
Q

Drugs causing Stevens Johnson Syndrome (SJS)

A

“Steve Jobs made APPLE PCS”

Allopurinol
Phenytoin
Phenobarbital
Lamotrigene
Ethrosuximide
Penicillin
Carbamazepine
Sulfonamides
36
Q

Nitrofurantoin

A

Bactericidal
reduced by bacterial proteins to reactive intermediate that inactivates bacterial ribosomes

use:
mild UTI cystitis - not pyelo- by E. coli or S. saprophyticus
(DOES NOT COVER PROTEUS)

SE:
rarely N
HA,
D

safe in pregnancy

37
Q

Polymyxins B and E

A

Cationic detergens - attach to and disrupt bacterial cell membranes, inactivate endotoxin

IV: last resport for resistant gram - infections

Topical: used in may OTC abx ointments - OTC neosporin

Toxicity:
IV is NEUROTOXIC! and nephrotoxic (acute renal tubular necrosis)

38
Q

metronidazole

A

forms toxic free radicals –> DNA damage

Use: “GET GAP on the Metro”
Giardia lamblia
Entamoeba histolytica
Trichomonas

Gardnerella vaginalis
Anaerobic bacteria (Clostridium spp., Bacteriodes fragilis)
Pylori

Cause disulfam like reaction - don’t drink
increased acetylaldehyde –> flushing, sweating, N, HA, hypotension

39
Q

Prophylaxis coverage for meningococcal meningitis exposure

A

Ciprofloxacin
Rifampin
Ceftriaxone

40
Q

Prophylaxis coverage for H. flu meningitis

A

rifampin

41
Q

Prophylaxis coverage for gonorrhea - sexual assault

A

cetriaxone

42
Q

Prophylaxis coverage for syphilis

A

PCN G

43
Q

Prophylaxis coverage for recurrent UTIs

A

TMP-SMX
Nitrofurantoin
Amoxicillin
Cephaloxin

44
Q

Prophylaxis coverage for Pneumocystis jirovecii CD4 under 200

A

1: TMP-SMX

aerosolized pentamide
Dapsone

45
Q

Prophylaxis coverage for endocarditis

A

PCN
Amoxicillin
cephalexin
PCN allergy - Clindamycin, azythromicin

46
Q

Prophylaxis coverage for Group B Strep

A

ampicillin intrapartum

47
Q

Prophylaxis coverage for Gonorrococcal/chlamydial conjunctivitis

A

Erythromycin

48
Q

Antimicrobials to avoid in pregnancy

A

Clarithromycin - embryotoxic
Sulfonamides - kernicterus close to delivery
Aminoglycosides - ototoxicity
Fluoroquinolones - cartilage damage
Metronidazole - metagenesis in 1st trimester (neural tube)
Tetracyclines - discolored teeth, inhibition of bone growth
Ribavirin - teratogenic
Griseofulvin - teratogenic
Chloramphenicol - gray baby sn

(DIT) Rapid Fire + 4/5 Stars (162 decks)

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