Antimicrobials

Question 1

If a patient is severely immunocompromised, what type of antibiotic should you give them?

Answer 1

Bactericidal

Question 2

Without our normal flora, we can be exposed to

Answer 2

Superinfections. Our normal flora competes with pathogens for nutrients and secrete substances that can kill opportunistic bacteria

Question 3

When might you not want to give antibx?

Answer 3

If the person is allergic and the surgery has low risk for infection

Question 4

The prophylactic antibiotic should be given no earlier than _____

Answer 4

1 hour before surgery

Question 5

Does a brief course of antibiotics result in resistant organisms?

Answer 5

There is no evidence of this. Peri-operatively we usually only give 1 dose, but may be continued up to 48 hours post-op

Question 6

Do we usually give broad or narrow antibx?

Answer 6

Anesthesia usually gives broad. The antibx will depend on pt tolerances and location of the surgery

Question 7

Do antibiotics cross the BBB?

Answer 7

Highly variable

Question 8

When might the surgeon want you to hold off on the antibiotics?

Answer 8

If pt is in OR for a wound cleaning (remember that antibiotics are more effective if infected material is removed!)

Question 9

Are hypersensitivity reactions from antibiotics dependent or independent of dose?

Answer 9

Independent

Question 10

Things to keep in mind with parturients

Answer 10

Most antimicrobials cross the placenta and enter breast milk. Also concern for teratogenecity.

Question 11

Considerations for the elderly

Answer 11

Renal and liver impairment
Decreased plasma protein (higher free fraction)
Reduced gastric motility and acidity
Increased body fat

Question 12

Which is better absorbed from the GI tract, ampicillin or amoxicillin?

Answer 12

Amoxicillin! (think of Moxi)

Question 13

Renal excretion of Penecillin

Answer 13

90%

Question 14

MOA for penicillin?

Answer 14

Interferes with cell wall synthesis and stability

Question 15

These antimicrobials belong to the beta-lactam family

Answer 15

Penicillins, cephalosporins,

Question 16

Only these antimicrobials are bacteriostatic

Answer 16

Tetracyclines, macrolides (can be either), lincomycins, and sulfonamides

Question 17

How are viruses classified?

Answer 17

By if they contain DNA or RNA. They never contain both!!

Question 18

This HIV protease inhibitor is the most potent inhibitor of the cytochrome P-450 system

Answer 18

Ritonavir

Question 19

Acyclovir and Valacyclovir

Answer 19

Antivirals for herpes. Excreted by the kidneys.

Question 20

Vidarabine

Answer 20

Antiviral for cytomegalic inclusion disease and HSV encephalitis. This antiviral is mutagenic and carcinogenic.

Question 21

Famciclovir

Answer 21

Antiviral for acute herpes zoster (shingles)

Question 22

Ganciclovir

Answer 22

Antiviral for CMV. Risk of hematologic toxicity

Question 23

Amantadine

Answer 23

Antiviral for Influenza A. Renally excreted.

Question 24

Antibiotic that inhibits the P-450 system

Answer 24

Cipro (fluoroquinolone)

Question 25

Antibiotic that induces the P-450 system

Answer 25

Rifampin

Question 26

Antibiotic whose MOA is bactericidal by acting on DNA and RNA polymerase

Answer 26

Rifampin

Question 27

This antibiotic has the most potent effect at the NMJ

Answer 27

Polymyxin B and Colistimethate. These are mostly prejunctional, and potentiate with NDNMBs. Not reliable reversed with neostigmine or calcium.

Question 28

This antibiotic can cause pseudomembranous colitis

Answer 28

Clindamycin

Question 29

This antibiotic can treat pseudomembranous colitis

Answer 29

Flagyl (even when caused by clinda)

Question 30

Example of an antifungal

Answer 30

Amphotericin B.

Question 31

Biggest risk of amphotericin B

Answer 31

Renal impairment. 80% of people will experience renal impairment. Most recover, but some have permanent reduction in GFR. Follow plasma creatinine. Amphotericin B is a terrible bitch to your kidneys

Question 32

Method of action for antivirals (interferons)

Answer 32

1) Binds to receptors on host cell membranes, causing production of enzymes that inhibit viral replication and degrade viral RNA 2) Enhances tumoricidal activity of macrophages

Question 33

Biggest symptom of interferons

Answer 33

Flu-like symptoms

Question 34

Three different mechanisms of antivirals for AIDS

Answer 34

1) Nucleoside reverse transcriptase inhibitors (impostor host cells) 2) Non-nucleoside reverse transcriptase inhibitors (inhibits the function of enzymes used by the virus) 3) Protease inhibitors (binds to HIV protease)

Question 35

Effect of protease inhibitors on the P-450 system

Answer 35

Inhibits the P-450 system.

Question 36

Which protease inhibitor is the most potent inhibitor of the P-450 system?

Answer 36

Ritonavir

Question 37

MOA of penicillins

Answer 37

Interferes with enzymes responsible for cell wall construction and stability

Question 38

Main method of excretion of macrolides

Answer 38

Bile

Question 39

How to remember macrolides.

Answer 39

Remember the erythromycin is a macrolide. We used this to increase gastric emptying. Therefore, the main SE of this is GI intolerance (Cramping, N/V/D, especially with IV infusion). Also with GI stuff, it is excreted through bile and is metabolized by the P-450 system.

Question 40

SE of erythromycin

Answer 40

GI intolerance (cramping, N/V/D) especially with IV infusion, QT prolongation, and thrombophlebitis with prolonged IV use.

Question 41

Ciprofloxacin has a ________ effect on the P-450 system and has an elimination half time of _____

Answer 41

Inhibitory | 3-8 hours

Question 42

SE of Cipro

Answer 42

Minimal SE. Mild GI disturbance

Question 43

All GPCRs will undergo _____

Answer 43

Desensitization

Question 44

MOA of ciprofloxacin

Answer 44

Interfering with the enzyme responsible for maintaining the helical structure of DNA

Question 45

Adverse effects of sulfonamides

Answer 45

Increases the effects of PO anticoagulants, skin rash to anaphylaxis, drug fever, hepatotoxicity, and rare incidence of hemolytic anemia

Question 46

Polymyxin B and Colistimethate have mostly (pre/post) junctional effects on the NMJ

Answer 46

Mostly prejunctional ("B"efore the synapse!)

Question 47

With what antibiotic class do you want to measure coags?

Answer 47

Sulfonamides

Question 48

Is rifampin able to cross the BBB?

Answer 48

Hellz to the yea