Bactericidal Antibiotics

Question 1

What is penicillins mechanism of action?

Answer 1

Block bacterial cell wall synthesis by interferring with structural glycopepties

Question 2

What is penicillinase?

Answer 2

A beta lactamase (enzyme) that breaks down the beta lactam ring of the penicillin molecule

Question 3

What are penicillinase-producing bacteria associated with?

Answer 3

• Immunocompromised
• Immunosuppressed
• Malnourished
• Institutionalized

Question 4

What is another name for penicillinase?

Answer 4

Beta lactamase

Question 5

How much of an oral dose of penicilin is excreted within the first 4 hours?

Answer 5

70%

Question 6

What can slow the rapid excretion of penicillin?

Answer 6

probenecid (Benemid) - a medication used to treat gout

Question 7

How does probenecid work to slow excretion of penicillin?

Answer 7

It stops the reabsorption of uric acid back into the bloodstream

It also has a greater affinity for the carrier than penicillin does (not excreted by active transport as fast)

Question 8

What does probenecid do to the blood levels of penicillin?

Answer 8

Elevates the level 3-4 times, and prolongs the effect of penicillin

Question 9

What is the drug of choice for orofacial infections?

Answer 9

penicillin

Question 10

What was the first penicillin produced, and the only natural penicillin available commercially?

Answer 10

Penicillin G

Question 11

What is penicillin G used to treat?

Answer 11

STDs

Question 12

How and when is penicillin G taken?

Answer 12

By injection, not after meals

Question 13

What is procaine penicillin G (repository form)?

Answer 13

Dissolved in oil, given by injection - slowly absorbed 12-24 hours

Question 14

What is procaine penicillin G (repository form) used for?

Answer 14

Treponema pallidum & anthrax

Question 15

What is the trade name of benzathine penicillin G?

Answer 15

Bicillin

Question 16

What produces therapeutic blood levels that last for 3 weeks?

Answer 16

Benzathine penicillin G - Bicillin

Question 17

Which penicillin produces the longest therapeutic blood level after parenteral administration?

Answer 17

Benzathine penicillin G

Question 18

What penicillin is acid stabile?

Answer 18

penicillin V

Question 19

When writing a prescription for penicillin V, what could you write?

Answer 19

penicillin V (Pen VK - brand name)

Just write penicillin V not Pen VK otherwise no generic!

Question 20

Describe penicillin V.

Answer 20

Bactericidal

Narrow spectrum

Acid stabile

Better bioavailability in potassium form

Question 21

What does the CDC say when treating an infection?

Answer 21

You much use the most narrow spectrum antibiotic available for that infection

Question 22

What is the best choice for orofacial infections?

Answer 22

penicillin V

Question 23

Can penicillin be effective in the midst of penicillinase-resistant microorganism?

Answer 23

Yes - other penicillins can resist penicillinase

Question 24

What type of antiobiotic is ampicillin?

Answer 24

Broad spectrum bactericidal

Question 25

What is one of the most commonly prescribed drugs in the United States?

Answer 25

amoxicilin (Amoxil)

Question 26

What is used to treat syphilis?

Answer 26

Principen with Probenecid (ampicillin with probenecid)

Question 27

What is the drug called that combines amoxicillin with clavulanic acid to broaden spectrum?

Answer 27

Augmentin

Question 28

When prescribing Augmentin, why do you want to prescribe 1 500mg capsule vs 2 250mg capsules?

Answer 28

There will be double (125mg) clavulanic acid = diarrhea

Question 29

What’s an adverse reaction to penicillin?

Answer 29

Opportunistic fungal infections

Question 30

What looks like, acts like and works like penicillin?

Answer 30

Cephalosporins

Question 31

What is cephalosprins mechanism of action?

Answer 31

Inhibits bacterial cell wall synthesis, similar to penicillin => bactericidal

Question 32

What are some of the adverse effects of cephalosporins?

Answer 32

• Gastrointestinal effects - nausea, vomitting, diarrhea
• Glossitis - inflammed tongue, smooth, shiny red
• Stomatitis - ulcerations on buccal mucosa
• Superinfection - candidiasis
• Nephrotoxicity

Question 33

If a patient has a full blown Type 1 (IgE) mediated allergic reaction (anaphylaxis) to penicillin, could you prescribe a cephalosporin?

Answer 33

No! They are contraindicated (up to 20% of these patients will be cross-sensitive)

Question 34

The higher the generation of cephalosporins, the more _________ the spectrum of kill.

Answer 34

Broad

Question 35

What are the 1st generation cephalosporin drugs?

Answer 35

• cefazolin - parenteral only
• cephalexin (Keflex)
• **cefadroxil (Duricef) **
• cephradine (Velosef)

Question 36

What type of of drug is NEVER the first choice for any orofacial infection?

Answer 36

Cephalosporins

Question 37

What are quinolones mechanism of action?

Answer 37

Inhibits DNA synthesis during bacterial replication

Bactericidal & broad spectrum

Question 38

Why are quinolones prescribed?

Answer 38

• Respiratory infections - **bronchitis, community-aquired pneumonia **
• UTIs
• Rarely used in dentistry

Question 39

What is the most common preparation of quinolones?

Answer 39

ciprofloxacin (Cipro) and levofloxacin (Levaquin)

Question 40

What is not an antibiotic, but is an antibacterial, bactericidal and a broad spectrum drug?

Answer 40

Metronidazole

Question 41

What is metronidazole used for?

Answer 41

To supplement other antibiotics when periodontal condition is not responding

Question 42

What drug is very effective against periodontal pathogens?

Answer 42

Metronidazole

Question 43

What are the adverse events of metronidazole?

Answer 43

• Hematopoietic system - leukopenia
• Metallic taste
• Circumoral paresthesia
• Oral ulcerations

Question 44

What should you avoid while taking metronidazole?

Answer 44

drinking alcohol - causes disulfiram-like reaction = nausea, vomitting, headache