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Cellular Week 3 > Antibacterials II > Flashcards

Antibacterials II Flashcards

1
Q

inhibitors of nuclei acid synthesis?

A

fluoroquinolones

common:
ciprofloxin (cipro)
levofloxacin (levaquin)
moxifloxacin (avelox)
gemifloxacin (factive)

double bonded O and COOH are important

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2
Q

fluoroquinolones:
MoA?
killing?
Mechanisms of resistance?

A

MoA - inhibit DNA gyrase and topoisomerase
- FQ’s form a complex with gyrase and topoisomerase IV, blocking DNA rep, resulting in DNA release, chromosomal disruption and cell death

BACTERICIDAL, CONCETRATION DEPENDENT KILLING!
(bigger doses less frequently)

mechanism of resistance: altered target site, efflux

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3
Q

fluroquinolones:
spectrum?
uses?
PK/PD?

A

spectrum - BROAD! (gram +, gram -, atypicals, TB)

Uses - RTI, UTI/prostatitis, GI, osteomyelitis, anthrax, TB

PK/PD - excellent oral absorption, tissue penetration (IV to PO switch)
- Al, Mg, Ca, Fe, Zn impair absorption (di/trivalents)

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4
Q

Fluroquinolones:
adverse SE - regular?
black box? (3)

A

GI: n, loose stools, altered taste
CNS: HA, lightheadedness, dizziness, nervousness, insomnia
Skin: photosensitivity

Black box:

  1. tendonitis/rupture, peripheral neuropathy, dysglycemia (blood glucose), QTc prolongation
  2. generally not recommended in children <18 yr or pregnant women unless benefit is greater than the risk (damage growing cartilage and cause arthropathy - disease of the joints)
  3. FDA (2016) should be reserved for complicated infections
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5
Q

Inhibitors of 50s ribosomal subunit

A
  • MACROLIDES (erythromycin, clarithromycin, AZITHROMYCIN, fidamicin); Ketolids (telithromycin)
  • OXAZOLIDINONES (LINEZOLID, TEDIZOLID)
  • LINCOSAMIDES (CLINDAMYCIN)
  • CHLORAMPHENICOL
  • streptogramins (quinopristin-dalfopristin)
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6
Q

inhibitors of the 30s ribosomal subunit

A

-AMINOGLYCOSIDES (GENTAMICIN, TOBRAMYCIN, amikacin, streptomycin, plazomicin)

  • TETRACYLCINES (tetracycline, DOXYCYCLINE, minocycline, omadacycline (2018), sarecycline (2018)
    - glycylcyclines (tigecycline)
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7
Q

chloramphenicol, macrolides, clindamycin, and streptogramins bind to the 50s subunit and block…

A

peptide bond formation!!

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8
Q

the tetracyclines and aminoglycosides bind to the 30s subunit and prevent….

A

binding of the incoming charged tRNA unit!

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9
Q

macrolides/ketolides structure is a ….

important one?

A

macrocyclic lactone ring!

ex. azithromycin (zithromax)

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10
Q

Macrolides inhibit protein synthesis…

killing?

A

usually bacteriostatic, concentration-independent killing; anti-inflammatory

block elongation and exit of peptides from 50s ribosomal subunit tunnel; produces a defective intermediate, unable to fold correctly

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11
Q

macrolides resistance…
low level?
high level?

A

low level - efflux pump

high level - target site modification

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12
Q

macrolides spectrum?

A

BROAD
gram +, neisseria, treponema
drug of choice for atypicals!!!! (mycoplasma, legionella, chlamydia)

**good for intracellular bad

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13
Q

macrolides pharmacology?

A

erhythromycin - many formulations; erratic absorption, acid labile, excreted in bile; take EMs with food to decrease GI upset

clarithryomycin, azithromycin - better absorbed, higher tissue levels and longer half life!!!!

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14
Q

clinical use of macrolides?

A

ALTERNATIVES IN PREGNANCY AND PEN ALLERGY!!!

STI - CHLYAMYDIA (azithromycin), gonorrhea!!!!
RTI - phyrungitis, otitis, CAP (azithromycin)!!!!
Treating gastroparesis - stimulates motilin receptors

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15
Q

Macrolide adverse effects?

A

GI - higher than most classes!!

  • erythromycin - 50% have bloating, cramping, n, d
  • somewhat less with clark-, lowest with azithromycin

MAY INCREASE QTc INTERVAL! - torsades, block cardiac K+ channels

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16
Q

erthyromycin drug interactions?

A

VERY POTENT CYP 3A4 INHIBITOR!
(theopylline, warfarin, triazolam, carbamazepine, cyclosporine, simvastatin, lovastatin, sildenafil, many others)

  • erthyromycin > clarithromycin > azithromycin
  • few or no drug interactions with azithromycin!!!
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17
Q

oxazolidinones (linezolid [zyvox, IV/PO]; tedizolid [sivextro, IV/PO])

relevant chemistry?
MOA?
Killing?
spectrum?
therapeutic use?
A

Relevant chemistry - totally synthetic; originally developed as a MAOI

MoA - inhibits early protein synthesis at initiation complex
- primarily BACTERIOSTATIC, TIME DEPENDENT KILLING

spectrum - narrow (gram +)

use - alt to vanco for MRSA; also used for VRE (vanco resistant enterococci)!!!!!

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18
Q

linezolid and tedizolid (oxazolidinones) Adverse side effects?

A

GI (most common)!!!
SKIN RASHES - dose related

hematologic (cytopenias; weekly CBC)
neuropathy, optic neuritis
SEROTONIN SYNDROME: a few cases in pts on SSRIs ANTIDEPRESSANTS due to inhibition of MAO by linezolid (FDA WARNING!)

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19
Q

Lincosamides ex.?

A

clindamycin

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20
Q 
lincosamides: clindamycin
MoA?
killing?
MoR?
Spectrum?
A

MoA - binds to 50s, inhibits protein synthesis

BACTERIOSTATIC, TIME-DEPENDENT!

MoR - altered target, decreased binding, efflux

spectrum - BROAD. ; gram positive anaerobes

21
Q

common uses of lincosamides (clindamycin)

A

SKIN, SOFT TISSUE, BONE (HIGH BONE LEVELS), INHIBITS TOXIN PRODUCTION
alternative in PEN-ALLERGY!
toxoplasmosis, pneumocytosis
topical for acne, rosacea

22
Q

adverse effects of lincosamides (clindamycin)

A

diarrhea, C.diff colitis

hypersensitivity, rash

23
Q 
chloramphenicol
Moa?
killing?
spectrum?
therapeutic uses?
PK?
A

Moa: reversibly binds to 50s ribosomal subunit preventing aa from being transferred to growing peptide chain

bacteriostatic for most

BROAD SPECTRUM! many trap +, - aerobes, anaerobes

use - alt in drug allergy!!! (meningitis, brain abscess)

PK - metabolism - extensive hepatic glucoronidation!! drug interactions too

serum monitoring - therapeutic - 15-20 ug/ml

24
Q

chloramphenicol adverse effects? (3)

A
  1. reversible bone marrow suppression (anemia, leukopenia, thrombocytopenia) - concentrations >25 ug/ml
  2. aplastic anemia
    idosncratic - NOT CONCENTRATION RELATED!
    may occur weeks to months after completing therapy - CBC twice weekly!
  3. Gray Baby syndrome!!!
    - circulatory collapse, cyanosis, acidosis, myocardial depression, coma, death
    - newborns lack effect glucoronic acid conjugation mechanisms to metabolize; associated with serum lvls >50ug/ml
25
Q

aminoglycosides ex.?

A 
gentamicin
tobramycin
amikacin
streptomycin
plazomicin
26
Q

aminoglycosides chemistry?

bacteriocidal!

A

hexose ring with various amino sugars attached by glycosidic bonds

water soluble, polar

active in alkaline pH (put pus is acidic)

27
Q 
aminoglycosides 
MoA?
killing?
MoR?
spectrum?
A

MoA - irreversibly binds to 30s ribosome

RAPIDLY CIDAL, CONCENTRATION DEPENDENT KILLING WITH LONG PAE - post antibiotic effect?

MoR - enzyme modification, altered 30s efflux

spectrum - primarily gram neg; SYNERGISTIC ACTIVITY with cell wall agents for GRAM POS!

28
Q 
aminoglycosides...
kinetics?
dosing (normal renal)?
monitoring?
uses?
A

kinetics: poor absorption, limited tissue, distribution, not metabolized, 100% renal elimination

dosing (normal renal): high dose, extended interval

REQUIRES SERUM CONCENTRATION MONITORING

uses: mainly in combination with other agents:
severe gram neg infections, synergy with gram pos infections, TB!

29
Q

aminoglycoside toxicity (3)

A
  1. nephrotoxicity!!
    - ACCUMULATION IN THE PROXIMAL TUBULE (SATURABLE)
    - USUALLY GRADUAL, MILD, REVERSIBLE
    - INCREASE IN SCR OR TROUGH ACCUMULATION AFTER 5-7 DAYS
    - requires dosage modification or d/c
    - increased risk with other nephrotoxins
  2. ototoxicity
    - 8th nerve damage, destruction of type II hair cells
    - VESTIBULAR (vertigo, ataxia) and HEARING (high frequency initially)
    - irreversible
  3. NEUROMUSCULAR BLOCKADE!
    - associated with rapid, bolus infusion in post surgical pts, neonates (calcium salts can reverse)
30
Q

tetracyclines and glycylcyclines
primary agents?
new in 2018?

A

primary agents: tetracycline, DOXYCLCINE, minocycline, TIGECYCLINE

New in 2018: eravacycline, omadacycline, sarecycline

31
Q

tetracyclines and glycylcyclines

MoA?
killling?
spectrum?
active against what? 
uses?
A

MoA:

  • bind to 30s ribosome, blocking formation of the initiation complex (same as amino glycosides)
  • tigecycline has 5 fold > binding to overcome resistance, not a substrate for efflux pump!

bacteriostatic, time dependent!!

BROAD SPECTRUM!

Tigecycline and new 2018 ervacycline and omadacycline active against many MDR isolates!!

uses: MANY TICK BORNE INFECTIONS!, travelers diarrhea, RTI, STI

32
Q

tetracyclines and glycylcyclines AE?

A

GI: n/d, epigastric distress

PHOTOSENSITIVITY

CONTRAINDICATED IN CHILDREN <8YR, PREGNANCY, BREAST FEEDING
- gray-brown to yellow discoloration of teeth and enamel hypoplasia in children; retards bone growth!!!!

TIGECYCLINE BOXED WARNING (2013) - INCREASED RISK OF DEATH!!!

33
Q

tetracycline and glycylcyclines: drug interactions

A

Ca, Mg, Al, Fe, NaHCo3, dairy products impair absorption!! (separate doses by > 2h)

MAY DECREASE THE EFFECTS OF ORAL CONTRACEPTIVES!

may potentiate effects of oral anticoagulants

34
Q

Sulfonamides and trimethoprim (a pyrimidine) are inhibitors of what?
killing???
blocks what?

A

folate inhibitors

synergisitc, bacteriacidal combination (NEVER USED ALONE! STATIC AND GREATER RESISTANCE)

BLOCKS PURINE PRODUCTION AND NUCLIC ACID SYNTHESIS!

35
Q

sulfonamides and trimethoprim…

spectrum?
use?

A

broad spectrum:
many gram pos, neg, pneumocystis, atypical mycobacteria, plasmodium, toxoplasma

common use - UTI!

36
Q

trimethoprim/ sulfamethoxazole…

PK?

A 
excellent absorption
widely distributed
hepatic metabolized (acetylation, glucuronidation)
long half-life
37
Q

trimethoprim/ sulfamethoxazole…

ADR?
Warning?
drug interactions?

A

ADR:

  • GI, SKIN (rash, urticaria, photosensitivity)
  • hypersensitivity (stevens-johnson, TEN)
  • hematologic (bone marrow suppression)
  • renal (hyperK+, AKI - acute kidney injury)

WARNING:

  • should NOT be used in 3rd trimester or newborns (KERNICTERUS)
  • bilirubin displacement from plasma proteins leading to brain damage

drug interactions: CYP 2C8/9 INHIBITOR!
-may increase effects of sulfonylureas, warfarin, anticonvulsants, cyclosporine, methotrexate

38
Q

nitrofurantoin

MOA?
resistance?
spectrum?
indications?

A

moa - inhibits several enzyme systems, including acetyl coA, inhibiting metabolism

resistance - low

spectrum - PRIMARILY GRAM NEG!! (E.COLI)

indications - UTI (CYSTITIS)

39
Q

nitrofurantoin

PK?

A

WELL ABSORBED! (macrodantin)

  • MACROCRYSTALS ABSORBED SLOWER, ALLOWING FEWER GI EFFECTS!
  • renal dose adjustment - do not use CrCl <40ml/min
  • Mg-containing antacids decrease absorption!!
40
Q

nitrofurantoin

ADR?

A
  • GI
  • RASH
  • PULMONARY (<1/100,000)

acute pulm: REVERSIBLE HYPERSENSITIVITY phenomenon
gradual onset of nonproductive cough, dyspnea, interstitial infiltrates on CXR; possible eosinophilia
rapid improvement after drug D/C

chronic pulm: 
S/Sx similar to acute
occurs after 1-6 mos of therapy
usually improvement after drug D/C
IRREVERSIBLE FIBROSIS, FATALITIES HAVE OCCURRED (VERY RARE)
41
Q

fluoroquinolones common SE?

A

GI
CNS stim
photosensitivity

warning - cartilage malformation, tendon rupture, neuropathy, prolonged QT, drug interactions

42
Q

macrolides common SE?

A

GI
warning - prolonged QT
drug interactions

43
Q

lincosamides (clindamycin) common SE?

A

GI

44
Q

chloramphenicol common SE?

A

anemia (conc-related and idiosyncratic aplastic anemia)
bone marrow suppression
gray baby syndrome

45
Q

oxazolidinones (linezolid) common SE?

A

GI
CNS
myelosuppression

46
Q

aminoglycosides common SE?

A

nephrotoxicity, ototoxicity

47
Q

tetracylces/glycylcyclines common SE?

A 
GI 
rash/allergy
photosensitivity
superinfection
warning! not in children - athropathy (disease of joints), teeth discoloration, drug interactions
48
Q

sulfonamides common SE

A 
GI
rash/allergy
photosensitivity
myelosuppression
warning!! do not use in third trimester or newborns, drug interactions
49
Q

nitrofurantoin common SE?

A

GI
rash
pulmonary

Cellular Week 3 (21 decks)

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