Beta Lactams Flashcards

1
Q

What is the function of beta lactam drugs?

A

Bacterial cell wall

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2
Q

What does a beta lactam ring look like?

A
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3
Q

What is the target enzyme of beta-lactam drugs?

A

Transpeptidase enzymes (stops peptidoglycan layer synthesis)

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4
Q

What type of bond is the bond between an antibiotic and the active site?

A

Covalent bond (very strong, makes beta lactams very effective!)

Renders the enzyme inactive

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5
Q

What are the four common pathogens we use beta-lactam drugs for?

A
  1. Strep pyogenes (pharynx and skin) - penicillin G
  2. Strep pneumo (respiratory infections, meningitis, sepsis) - amoxicillin and ampocillin
  3. Staph aureus (skin and soft tissue) - methicillin
  4. Pseudomonas aeruginosa (UTI, sepsis) - piperacillin
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6
Q

Are beta lactam drugs bactericidal or bacteriostatic?

A

Bactericidal

(kills cell due to osmotic rupture)

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7
Q

What are the four classes of penicillins?

A
  1. Natural
  2. Amino-penicillins
  3. Anti-staphylococcal
  4. Extended Spectrum
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8
Q

What must you do for treatment if a patient has a penicillin allergy?

A

Use a drug from a completely different class

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9
Q

What two drugs belong to the natural penicillin class? What routes are they given?

A
  1. Penicillin G (IV, IM) (almost unusable due to bacterial resistance)
  2. Penicillin V (PO)
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10
Q

What can natural penicillins treat?

A
  • Strep pyogenes (throat and skin) (strep throat & impetigo)
  • Oral/dental infections (oral anaerobes)
  • Syphilis
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11
Q

What helps penicillins not degrade in stomach acid?

A

Carbon ring

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12
Q

What two drugs belong to the aminopenicillin class?

A
  1. Ampicillin (IV)
  2. Amoxicillin (PO)
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13
Q

What can amino-penicillins treat?

A
  • Common respiratory tract infections (STREP PNUEMO, Moraxella, Haemoophilus)
  • UTIs
  • Most E. coli strains
  • Same things natural penicillins can treat also
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14
Q

What do you not want to treat with amino-penicillins?

A

MRSA

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15
Q

What three drugs belong to the class anti-staphylococcal penicillins? And what route are they given?

A
  1. Methicillin (IV)
  2. Nafcillin (IV)
  3. Dicloxacillin (PO)
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16
Q

What can anti-staphylococcal penicillins treat?

A
  • Staph aureus (skin and soft tissue, internal infections)
  • MSSA skin infections (never MRSA)
  • Surgical skin prophylaxis (ortho pre-op)
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17
Q

Why are anti-staphylococcal penicillins fairly ineffective?

A
  • Staph aureus did not have great susceptibility to penicillin G….therefore anti staph drugs were developed
  • Important historically but due to MRSA, they are ineffective
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18
Q

Why does dicloxacillin have a horrible taste?

A

It has a chlorine on it

19
Q

What two drugs are extended spectrum penicillins?

A
  1. Piperacillin (IV)
  2. Ticarcillin (IV)
20
Q

What can extended spectrum penicillins treat?

A

-Gram NEGATIVE infections (NOT gram +)
*Only used in hospital for tough to kill Gram - bacteria
*Only penicillin used for gram - (the other three types treat only gram +)
-UTI, intra-abdominal/pelvic infections

21
Q

What are the 5 classes of cephalosporins?

A
  • 1st generation
  • 2nd generation
  • 3rd generation
  • 4th generation
  • 5th generation
22
Q

What is the MOA of cephalosporins?

A

Inhibits transpeptidation - blocks cell wall synthesis (same as penicillins)

23
Q

T/F cephalosporins are beta lactams?

A

True

24
Q

What 3 drugs are 1st generation cephalosporins?

A
  1. Cefazolin (ancef) - IV only
  2. Cephalexin (keflex) - PO
  3. Cefadroxil (duracef) - PO
25
Q

Do 1st generation cephalosporins treat gram - or gram +?

A

ONLY Gram +

26
Q

What do 1st generation cephalosporins best treat?

A
  • MSSA and Strep pyogenes
  • Impetigo and cellulitis
27
Q

Why do orthopedic surgeons like to use 1st generations?

A

Ortho surgeons give these to patients before surgery to prevent the wound from being contaminated (pre-op orthopedic surgery prophylaxis) - covers staphylococcal skin flora very well

28
Q

What 2 drugs are 2nd generation cephalosporins?

A
  1. Cefotetan (cefotan) - IV
  2. Cefoxitin (mefoxin) - IV
29
Q

What are 2nd generation best used for?

A

Anaerobic prophylaxis
-MSSA and strep pyogenes

30
Q

Why do general surgeons like to use 2nd generations?

A
  • Covers intra-abdominal/pelvic flora very well
  • Given pre-op for surgery involving viscera
31
Q

Do 2nd generations treat gram + or gram -?

A

ONLY gram +

32
Q

What 7 drugs are 3rd generation cephalosporins?

A
  1. Cefotaxime (claforan) - IV
  2. Ceftriaxone (rocephin) - IV
  3. Ceftazidime (fortaz) - IV
  4. Cefdinir (omnicef) - PO
  5. Cefixime (suprax) - PO
  6. Cefpodoxime (vantin) - PO
  7. Cefuroxime (zinacef) - PO
33
Q

What do oral 3rd generations most commonly treat?

A

-Respiratory tract (strep pneumo +, moraxella -, heamophilus-)
-Urinary tract (E. coli -, enterobacteriacae -)
-Skin (MSSA +, strep pyogenes +)
*highest use for suspected or known penicillin-resistant strep pneumo

34
Q

Which 3rd generation oral abx is used to treat gonorrhea?

A

Cefixime

35
Q

What do IV 3rd generations most commonly treat?

A

-Respiratory (strep pneumo+, moraxella-, haemophilus-)
-Urinary tract (E. coli -, enterobacteriacae -)
-Skin (MSSA +, strep pyogenes +)
-CSF (strep pneumo+, neisseria meningitis-)
*Used for more sick patients - very good coverage for these infections in hospitalized patients

36
Q

Which 3rd generation has the longest half life? What does this mean?

A

Ceftriaxone, means you only need to dose ~1xday

37
Q

What 3 diseases can be treated with a one time IM ceftriaxone injection?

A
  1. Otitis media (save this for kids who cannot take oral)
  2. Gonorrhea (best overall tx)
  3. Strep throat (would rather use penicillin G)
38
Q

What one drug is a 4th generation cephalosporin?

A

Cefepime (maxipeme) - IV only

39
Q

When is cefepime commonly used?

A

Used as an “empiric” treatment when gram negative infection is suspected

40
Q

Why was cefepime developed?

A

To enhance effect against pseudomonas (gram -) and gram negatives

(can tx gram + but much better at gram -)

41
Q

What one drug is a 5th generation cephalosporin?

A

Ceftaroline (teflaro) - IV

42
Q

What is the sole purpose of ceftaroline?

A

ONLY beta lactam that antibiotic that works against MRSA

43
Q

What are the four carbepenems?

A
  1. Imipenem
  2. Meropenem
  3. Doripenem
  4. Ertapenen
44
Q

What are carbepenems used for?

A
  • SICK inpatients only - sepsis/resistant infections
  • Wide spectrum including gram - and anaerobes
  • Intra-abdominal, pelvic infectinos
  • IV only