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pharmacology > MISC abx > Flashcards

MISC abx Flashcards

1
Q

Beta lactam- PCN: side chain impacts (4)

A

Spectrum
Stability to stomach acid
Cross-hypersensitivity
Susceptibility to bacterial degradative enzymes

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2
Q

adverse rxns to PCN (6)

A
  • Allergic rxns
  • GI side effects such as nausea, vomiting and diarrhea
  • Nephritis – acute interstitial nephritis (nafcillin)
  • Neurotoxicity – can cause seizures
  • Hematologic – with therapy > 2 weeks -decrease coagulation
  • Secondary infections: ex/ C. diff or vaginal candidiasis from suppressing normal flora
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3
Q

3 classes of PCNs

A

Penicillins AKA natural penicillins
Anti-staphylococcal penicillins
Extended spectrum penicillins

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4
Q

natural PCNs and how you administer

A

Penicillin G is given parenterally
Penicillin Benzathine is given IM
Penicillin V is a potassium salt, is more acid-stable, and able to be given orally

“Natural Voluptuous Girls = Benza-yonce”

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5
Q

what is used for gangrene and syphilis treatment?

A

natural PCN

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6
Q

spectrum of natural PCN?

A

treats: Gram pos. cocci and rods, and anaerobes, Gram neg cocci, and spirochetes
Little activity against gram negative rods because penicillin can’t penetrate their outer membrane
Not effective for S. Aureus

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7
Q

PCN MOA

A

inactivate transpepsidase, disrupt cross-linking (PBPs) –> cell lysis. effect mostly cells that are growing/dividing

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8
Q

Anti-staph PCN MOA + spectrum

A

Same MOA as penicillin G, but are beta-lactamase (penicillinase) resistant penicillins

Spectrum
Staphylococcus aureus (MSSA)
Streptococcus Grp A, B

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9
Q

extended spectrum PCN - subgroups and general spectrum

A

Ampicillin/amox and pipercillin/ticarcillin- greater activity against gram neg. (diff. side chain allows to better penetrate outer wall)

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10
Q

ampicillin/amox spectrum

A

Spectrum: Same as natural penicillins PLUS: gram pos and gram neg.
Not effective for pseudomonas aeruginosa or MSSA or MRSA

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11
Q

pipercillin/ticarcillin spectrum

A

natural PCN spectrum + gram negs (including pseudomonas)

Spectrum: same as ampicillin PLUS
Pseudomonas + other gram pos.
Resistance can develop so save them for when you really need them.

Used in very ill patients often in combination with another antibiotic to prevent resistance & increase killing power

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12
Q

Anti-staph PCN subgroups (4)

A

Naficillin, Oxacillin, Dicloxicillin, Methacillin

drug test for staff? “Nah… Oxy + Meth Dictate (me)”

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13
Q

beta lactamase inhibitor MOA

A

Beta lactamase is an enzyme made by bacteria that breaks apart the beta lactam ring of the ABX.
Beta lactamases are a source of resistance.
If you give an inhibitor of the enzyme that is produced by the bacteria with the Abx, the bacteria will not be as resistant to the Abx

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14
Q

beta lactimase inhibitor subgroups

A

Clavulanic acid
Avibactam (combined with ceftazidime)
Sulbactam
Tazobactam

“CAST” -inhibits from being “betta…” or
“Clara, Avi, Sultan, Taz”

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15
Q

beta lactams: subgroups

A

PCNs, Beta-inhibitors, cephalosporins, carbopenems, monobactams

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16
Q

dosing for combo beta-lactam inhibitors and beta lactam

A

Available in fixed combinations (don’t use inhibitor on its own- only in combo)
The dose is based on the strength of the primary antibiotic – not the beta lactamase inhibitor.

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17
Q

cephalosporins: general features

A
  • beta lactam ring like penicillins, w/ diff base compound attached
  • Generally more stable in face of beta lactamases so overall broader spectrum than PCNs
  • Work similar (on bacterial cell wall) as PCN- similar resistance problems
  • Potential option for PCN-allergic patient
  • Bactericidal
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18
Q

cephalosporin: categorizing for generations

A

Five generations

  • Generations are based on when they are made & what they kill.
  • significant modification made to the group that really changed the spectrum = a new generation.
  • First generation the oldest
  • higher generations for deadlier bacteria species (more coverage of bacteria overall)
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19
Q

PK of cephalosporins: admin. distribution. elimination

A

Administration
-Many IV, fewer oral due to poor oral absorption
Distribution:
-Good, but CSF penetration limited to Ceftriazone, cefotaxime. All cross placenta
Elimination
-Tubular secretion and or glomerular filtration
Exception: ceftriaxone – eliminated in bile/feces

20
Q

4 combos of Beta lactamase inhibitor w/ Abx

A

Amoxicillin + clavulanic acid = Augmentin
Ampicillin + sulbactam = Unasyn
Ticarcillin + clavulanic acid = Timentin
Piperacillin + tazobactam = Zosyn

21
Q

adverse rxns to cephalosporins: hypersensitivity rxns most significant between what two types of Abx?

A

PCN and 1st gen cephalorsporins
*Allergy to cephalosporin = 10 % chance of allergy to PCN
Allergy to PCN = 5% change of allergy to cephalosporin

22
Q

adverse rxns to cephalosporins

A

Hypersensitivity reactions:
GI
Superinfections: (C. difficile and vaginal candidiasis, thrush
Hypoprothrombinemia (low prothrombin level) with some cephalosporins)

Give vitamin K twice a week to prevent bleeding if giving antibiotic long term

Disulfiram-like reaction with cefotetan- (induced vomitting)
Increase nephrotoxicity of aminoglycosides

23
Q

1st gen cephalosporins

A

Cef-azolin, Ceph-alexin

” Cefa’s PEcK” - all 1st gen only use Cefa- (except 2nd gen cefaclor)

gram + cocci: Streptococci, staphylococci
PEcK: Proteus mirabilis, E. coli, Klebsiella
Doesn’t cover: MRSA, Pseudomonas

24
Q

2nd gen cephalosporins

A 
Ce-foxtin
Ce-furoxime
Ce-fote-tan
Cefacl-or
Cef-prozil

“Fox Fur For Tan Or Prozac”

25
Q

2nd gen cephalosporins Spectrum

A

First generation spectrum
gram + cocci: Streptococci, staphylococci
HENS PEcK

PEcK
Proteus mirabilis
E. coli
Klebsiella
PLUS:
	H. Influenzae
	Enterobacter aerogenes
	Neisseria spp.
	Serratia marcescens

Don’t get: enterococcus, Pseudomonas, or MRSA

26
Q

what is cephalexin used for?

A

UTIs (b/c kills some gm-rods)
Skin infections (abscess and cellulitis b/c kills staph)
Otitis media, pharyngitis (b/c kill strep).

27
Q

clinical uses for 2nd gen cephalosporins

A 
Sinusitis & otitis if mildly allergic to PCN
 ( but Extended spectrum PCN preferred)
 Lower respiratory tract infections
Pneumonia
H. flu
Moraxella catarrhalis

Cefuroxime is special for community acquired pneumonia (CAP)
b/c kills resistant H flu, strep pneumonia well

28
Q

special characteristics of 3rd gen Cephalosporins

A

increased gram neg. coverage and only ceph.
that crosses blood brain barrier (BBB)

“Ceftaz as tazmanian devil- potent and only one that gets pseudamonas)

29
Q

3rd generation cephalosporins

A 
Cef-dinir 
Ceftri-axone 
Cef-tazidime 
----(Ceftazidime/azobactam) 
Cefo-taxime 
Cef-podoxime

cephalosporins in 3rd gen all w/ suffix “-ime”
PLUS “Dine Alone” -CefDinir CeftriAzone “

30
Q

3rd gen ceph spectrum

A

Spectrum:Great gram neg. coverage

Ceftriaxone:
Meningitis
Gonorrhea
Lyme disease

Ceftazidime
Pseudomonas coverage

Do NOT use for MRSA

31
Q

clinical uses for 3rd gen cephalosporin

A

Clinical Uses:
Multidrug resistant gram negative organisms
HAP – Ceftazidime only
CAP
(hospital and community acquired pneumonias)
Gonorrhea

32
Q

4th generation cephalosporins

A

Cefepime “Pi me”

Like 3rd generation more resistant to more beta lactamases
Spectrum:
Combines gram + (Streptococci & staphylococci) activity of 1st generation with wider gram – (Enterobacter, E. coli, Klebsiella) spectrum of 3rd generation
Increased activity against pseudomonas

Use: Similar to 3rd generation

33
Q

5th generation Cephalosporin

A

Ceftaroline

Broad Spectrum:Gram positive and negative

PLUS
LAME (1st-4th generation don’t cover)
Listeria
Atypical (Chlamydia, Mycoplasma)
MRSA
Enterococcus faecalis

NO Pseudomonas

34
Q

monobactams: name, spectrum, adverse effects

A

Aztreonam

Less susceptible to beta-lactamases
Spectrum:
No gm + or anaerobe coverage
Great Gram – aerobic rods & Pseudomonas aeruginosa
Hospital drug for serious gm – infections that are resistant to other drugs or if PCN allergic and can’t use other drugs

Renally cleared – prolonged t1/2 in renal failure

35
Q

Carbapenems: names,

A

“DIME”
Doripenem, Imipenem, Meropenem, Ertapenem
Bactericidal
“DIME” for life-threatening infections
takeaway: great broad spectrum, one of the agents (imipenem) needs to be given with cilastin to inhibit other enzyme so you can keep imipenem around . others are resistant to that enzyme

36
Q

Cell Wall Antibiotics- Target PBPs

A

No beta lactam ring, but work on the cell wall: These work on cell wall but DONT have Beta Lactam Ring - target proteins - polypeptides

Glycopeptides
-Vancomycin- most important one

Cell membrane active agents

  • Daptomycin
  • Polymyxin B & Polymyxin E (Colistin)

-Fosfomycin

37
Q

Vancomycin MOA

A

MOA:
Inhibits cell wall synthesis by binding to D-Ala-D-Ala portion of the growing peptide during cell wall synthesis
–> inhibition of transpeptidase preventing further elongation and cross-linking
Same result as beta-lactams, but targets a different site

Bactericidal
Time-dependent killing

Spectrum:
Great gm + coverage
MRSA, S. epidermidis, sensitive enterococcus, C. diff.
NO gm- anaerobes or gm-
There is now VRE (vancomycin resistant enterococcus), a bad resistant bug

38
Q

Vancomycin PK: absorbtion, admin, excretion

A

Not absorbed from GI tract, given IV
If given orally it is not being absorbed and giving it to act topically in the GI tract (C. diff)

Slow administration – 1 hour

Renal excretion - dosage adjust in renal failure
Increased nephrotoxicity when given with other nephrotoxic drugs
Follow hospital protocol for drug dosing

39
Q

vancomycin Adverse Rxns

A

“Well tolerated but NOT trouble free”
Nephrotoxicity – especially if given with other nephrotoxic drugs (aminoglycosides)
Ototoxicity - especially if given with other ototoxic drugs (aminoglycosides)
Thrombophlebitis- Irritates tissue at site of injection

And-redman’s syndrome
skin flushing low BP from histamine release when give IV too fast

40
Q

Clinical Uses for Vancomycin

A

Serious MRSA infections
if MSSA, methicillin sensitive staph aureus, use antistaph penicillins
Pseudomembranous enterocolitis due to C. diff.
Endocarditis
Patients allergic to beta-lactams

41
Q

Daptomycin MOA

A

MOA:
Binds to cell membrane of organism leading to rapid depolarization, potassium efflux and cell death
Inhibits DNA, RNA, & protein synthesis
Bactericidal
Concentration-dependent killing

42
Q

Daptomycin Spectrum + adverse effect

A

Spectrum
Staphylococcus (MRSA), Enterococcus (including VRE)
NO gram negative activity
use: sepsis
Toxicity: skeletal muscle myalgia & weakness

43
Q

Polymixin B and E: MOA

A

MOA:
Bind to phospholipid of gram neg and act like a detergent
(Disrupts membrane integrity)
Leads to leakage of cellular components and cell death
Bactericidal – time-dependent killing

44
Q

Polymixcin B and E uses

A

Used for salvage therapy for multi-drug resistant gram negative
Pseudomonas, E. coli, Klebsiella
Nephrotoxic and Neurotoxic (weakness, slurred speech)

45
Q

Fosfomycin MOA + excretion

A

MOA:
Inhibits early cell wall synthesis in gm + and gm- in urine only

Bactericidal
Excreted unchanged by kidneys
Uncomplicated lower UTI only
only for UTIs , if infection has moved further up, this drug wont be effective

pharmacology (24 decks)

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