Anit-Infectives Part I

Question 1

What two things must a provider know when prescribing antibiotics?

Answer 1

1. What abx covers what bacteria

2. What bacteria typically lives in the infected area

Question 2

What makes Gram neg bacteria non-staining and why is this clinically relevant?

Answer 2

Gram neg bacteria have an extra polysaccharide layer. This makes them more difficult to kill.

Question 3

What is the most pathogenic Gram neg bacteria?

Answer 3

Pseudomonas

Question 4

What is the most pathogenic Gram pos bacteria?

Answer 4

Enterococcus

Question 5

What was the first abx and what bacteria does it cover?

Answer 5

PCN –> covers Gram pos bacteria

Question 6

Differentiate between the two main types of PCN.

Answer 6

Penicillin G (IV) and Penicillin V (PO)

Question 7

What abx treats syphilis and how is it administered?

Answer 7

Benzathine LA - Thick suspension given IM in gluteus maximus (painful injection)

Question 8

What abx treats strep pneumonia and how is it administered?

Answer 8

Procaine - IM

Question 9

PCN remains the drug of choice for what common infection?

Answer 9

Strep Throat (Group A Streprococcus)

Question 10

What are the instructions given for taking PCN and what are the cautions?

Answer 10

Best taken around the clock and on an empty stomach. Cautions are diarrhea (may cause C-diff) and rash (antigenic - increased risk of allergic rxns)

Question 11

How is PCN eliminated and what is the clinical significance?

Answer 11

Renally –> adjust dose if CrCl < 50

Question 12

List the PCNs used to treat staphylococcus and state how they are administered.

Answer 12

IV: Methicillin, Oxacillin, Nafcillin
PO: Cloxacillin, Dicloxacillin

Question 13

T/F: Methicillin is the only PCN that cannot be used to treat MRSA.

Answer 13

False: MRSA is resistant to all PCNs and almost all cephalosporins

Question 14

What drugs can be used to treat MRSA and which is most common?

Answer 14

Most common: Vancomycin

Other: Ceftaroline (only cephalosporin that treats MRSA),

Question 15

Dicloxacillin is the drug of choice for what type of infection and what are its cautions?

Answer 15

Cellulitis or any MSSA (Staph and Strep). Cautions: causes GI and taste issues

Question 16

What are the two amino penicillins and what is the difference between the two?

Answer 16

Ampicillin: low Vd - must be taken on empty stomach
Amoxicillin: high Vd

Question 17

What infections are covered by amoxicillin?

Answer 17

Everything PCN covers other than MSSA plus three Gram neg organisms - E. Coli, H. Flu, M. Cat.

Question 18

What infections do E. Coli, H. Flu, and M. Cat most commonly cause?

Answer 18

E. Coli = UTIs
H. Flu = CAP pneumonia, otitis media, and sinusitis
M. Cat = sinusitis

Question 19

What infections are covered by ampicillin? (2 zebras)

Answer 19

Enetrococcus and Listeria (Neonatal Meningitis)

Question 20

What infection does listeria commonly cause?

Answer 20

Meningitis in newborns

Question 21

What is the mechanism of action of a beta lactamase inhibitor?

Answer 21

Beta lactamase chews up beta lactam abx. Beta lactamase inhibitors keep the abx around longer.

Question 22

What abx are beta lactams?

Answer 22

Amoxicillin, Ampicillin, all PCNs, Cephalosporins

Question 23

List two combination drugs that have a beta lactamase inhibitor and state how they are administered.

Answer 23

Augmentin: Amoxicillin + Clavulanic Acid - PO
Unasyn: Ampicillin + Sulbactam - IV

Question 24

In what patients would a combination of an abx + beta lactamase inhibitor be most useful?

Answer 24

Patients with > 1 infection that have shown resistance to the abx alone or patients with comorbidities in whom you don’t want to risk the abx failing.

Question 25

What is the main difference between PCN and Extended Spectrum PCNs?

Answer 25

PCNs cover Gram pos while Extended Spectrum PCNs suck at Gram pos infections but cover Gram neg, including pseudomonas.

Question 26

State two facts about the formulation of Extended Spectrum PCNs.

Answer 26

1. Always combined with a beta lactamase inhibitor | 2. Only available IV

Question 27

List two combination Extended Spectrum PCN and state which is most commonly used.

Answer 27

Timentin: Ticarcillin + Clavulonate Zosyn: Piperacillin + Tazobactam --> most used

Question 28

Describe the interaction of PCNs with oral contraceptives.

Answer 28

Oral contraceptives are activated by bacteria in the gut. PCNs disrupt normal gut bacteria and make oral contraceptives less effective.

Question 29

Describe the treatment for C. Diff brought on by PCN.

Answer 29

1. Stop the antibiotic 2. No anti-diarrheals - prolongs contact time with the toxin that is causing the C. Diff 3. DOC = PO Vancomycin

Question 30

How are cephalosporins related to PCNs and what is the clinical significance?

Answer 30

Cephalosporins, like PCNs, are beta lactams meaning there can be cross reactivity between the two.

Question 31

List the drugs that are used to treat pseudomonas.

Answer 31

Extended Spectrum PCNs Two cephalosporins - Ceftazidime and Cefepime All Carbapenams EXCEPT Ertapenam Ciprofloxacin (Only PO drug)

Question 32

What PCN drugs are 1st generation cephalosporins most like and what do they cover?

Answer 32

Similar to amino-PCNs. They cover mostly gram pos. plus E. Coli and Klebsiella (Pneumonia)

Question 33

List two 1st generation cephalosporins and state the use of each.

Answer 33

Cefazolin: IV admin to cover MSSA in PCN allergy Cephalexin: PO cephalosporin

Question 34

What do 2nd generation cephalosporins cover?

Answer 34

Hodge-podge of gram pos and neg.

Question 35

What do third generation cephalosporins cover?

Answer 35

Gram negative

Question 36

What type of drug is ceftriaxone and what are its uses?

Answer 36

3rd generation cephalosporin. Uses include: - qd injection - treatment of meningitis (double the dose) - Lyme disease (late - when arthritic pain presents) - treatment of gonorrhea (paired with chlamydia drug)

Question 37

What are the two drugs administered to treat chlamydia and gonorrhea?

Answer 37

Azythromyocin and Ceftriaxone

Question 38

What kind of drug is Ceftazidime and what is its primary use?

Answer 38

Third generation cephalosporin used to cover pseudomonas.

Question 39

What type of drug is cefepime and what is its primary use?

Answer 39

Fourth generation cephalosporin used to cover pseudomonas.

Question 40

What type of drug is ceftaroline and what is its primary use?

Answer 40

Fifth generation cephalosporin used to treat MRSA

Question 41

T/F: Cephalosporins are made in combination with a beta lactamase inhibitor and are used frequently.

Answer 41

False: Cepahlosporins are coformulated with beta lactamase inhibitors but they are NOT used often.