Exam 2 Antibiotics

Question 1

Term for antibiotic that INHIBITS bacterial growth

Answer 1

Bacteriostatic (antagonist) - ALL antibiotics are bacteriostatic

Question 2

Term for antibiotics that can KILL bacteria

Answer 2

Bactericidal (agonst) - not all antibiotics are bactericidal

Question 3

Narrow vs broad spectrum

Answer 3

Spectrum describes the range of bacteria an antibiotics can treat
Narrow - only effective against a SMALL number of bacteria (Penicillin)
Broad - effective against MANY types of bacteria (Tetracycline)

Question 4

The oral cavity contains normal flora which are gram + strep or staph. What causes oral/facial infections?

Answer 4

All resident microorganisms which are already in the mouth; any other bacteria found must have been introduced to oral cavity - like trauma

Question 5

T/F - NEVER combine a bactericidal antibiotic with a bacteriostatic antibiotic in the same person.

Answer 5

True

Question 6

T/F -Never give 2 antibiotics to the same person at the same time.

Answer 6

False - antibiotic synergism = 2 antibiotics work together for more positive effect. but usually there is antibiotic antagonism

Question 7

What is a minimum inhibitory concentration used for?

Answer 7

To determine bactericidal concentration of an antibiotic.
To reach MIC in a human, it may kill them
Therefore, we give less of the antibiotic to get an antibacterial effect

Question 8

Penicillin’s main route of elimination?

Answer 8

Excreted rapidly as an unchanged molecule (70% within first 4 hours)
- 90% via tubular secretion; active transport

Question 9

Why would you pretreat with probenecid prior to penicillin?

Answer 9

Probenecid (aka Benemid, tx for gout) competes(greater affinity for carrier) with penicillin for active transport mechanisms therefore slowing secretion of penicillin

Question 10

Which penicillin is first produced, natural, and commercially bactericidal, NARROW spectrum?

Answer 10

Penicillin G

Question 11

Which penicillin is the first semi-synthetic form, NARROW spectrum (G+ cocci), bactericidal?

Answer 11

Penicillin V

Question 12

Which penicillin is acid stable (more uniform absorption) = penicillinase-labile?

Answer 12

Penicillin V

Question 13

Which penicillin do you take orally (not broken down by gastric acid) take 1 hour before or 2 hours after meals to max. serum levels.

Answer 13

Penicillin V

Question 14

Which penicillin is acid-labile: broke down by gastric acid = incomplete and variable absorption also penicillinase-labile (broken down by penicillinase producing bacteria)?
Not effective if taken after meals

Answer 14

Penicillin G

Question 15

Which penicillin is treatment for STDs

Answer 15

Penicillin G

Question 16

What are some adverse reactions for penicillin V?

Answer 16

Nausea, mild diarrhea, oral candidiasis

Allergic reactions : typically delayed, rash erythema, bullous eruptions, angioedema

Question 17

Which penicillin V form has better bioavailability?

Answer 17

Potassium form of penicillin V - written penicillin V (not VK)

Question 18

When would you use a penicillinase resistant penicillin?

Answer 18

Only use if the patient has an infection caused by a penicillinase resistant microorganisms. (ex: cloxacililin, dicloxacillin, peperacillin, tazobactam sodium, ticarcillin, clavulante potassium)
Expensive, toxic, and PROMOTES RESISTANT MICROORGANISMS

Question 19

Which penicillin is acid stable, not penicillinase resistant, LARGER spectrum G-/G+?

Answer 19

Ampicillin (bactericidal)

Question 20

Which penicillin has better bioavailability, not penicillinase-resistant. Treats H. influenzae, sinus and inner ear infections?

Answer 20

Amoxicillin (Amoxil) - (less effective than penicillin VK for aerobic G+ cocci, similar for anaerobes)

Question 21

Which penicillin is mixed with clavulanic acid which increases spectrum?

Answer 21

Augmentin - inhibits penicillinase enzyme = beta lactamase

Used when pts do not respond to penicillin V within 36-48 hours

Question 22

What are the 4 the most common adverse effects of penicillin?

Answer 22

1. Allergic
2. OPPORTUNISTIC infection - oral or vaginal candidiasis
3. Black hair tongue with chronic use
4. Maculopapular rash - toxicity reaction

Question 23

What are two types of repository penicillin?

Answer 23

1. Procaine penicillin G - allows penicillin to be dissolved in oil
   - given IM (deltoid) for slower rate out of oil
   - released over 12-24 hour period
2. Benzathine penicillin G (Bicillin)
   - therapeutic blood levels last for 3 weeks!
   - takes longer to reach therapeutic level but doesnt reach peak level
   - Given IM aqueous penicillin G then Bicillin IM (buttocks)

Question 24

What does Procaine penicillin G treat?

Answer 24

TREATS TREPONEMA PALLIDUM, ANTHRAX

Question 25

What does Benzathine penicillin G (Bicillin) treat?

Answer 25

TREATS STDS

Question 26

Mechanism of action of penicillin?

Answer 26

Bactericidal
Beta-lactams blocks bacterial cell wall (peptidoglycan) synthesis by interfering with structural glycopeptides -> lysis causes bacterial cell death
(lethal to dividing bacteria)

Question 27

3 reasons someone might not respond to penicillin?

Answer 27

1. Pt. compliance
2. Production of penicillinase
3. Bacteria causing infection if outside of the spectrum - use broader spectrum drug

Question 28

What is penicillinase?

Answer 28

a beta lactamase (enzyme) that breaks down the beta lactam ring of the penicillin molecule. Without an intact beta lactam ring, penicillin is inffective

Question 29

What antibiotic is highly resistant to penicillinase. acid stable, inhibits bacterial cell wall synthesis, bactericidal, absorbed well through the GI tract, and is active against G+ aerobic, G- (klebsiella).

Answer 29

Cephalosporin (never the first choice for any orofacial infection)

Question 30

Who is cephalosporin contraindicated for?

Answer 30

Patients who had full blown type 1 (IgE anaphylaxis) to penicillin (cross-sensitive)

Question 31

What are 3 first generation cephalosporins?

Answer 31

Active against G+ cocci
1. cefazolin (parenteral only)
2. CEPHALEXIN (KEFLEX)
3 CEFADROXIL
(Most narrow spectrum)

Question 32

What are 2 second generation cephalosporins?

Answer 32

More active against G- than first generation

1. cefaclor (Raniclor)
2. cefuroxime (Ceftin)

Question 33

What is 1 third generation cephalosporins?

Answer 33

cefotaxime (Claforan)

Question 34

What is 1 fourth generation cephalosporin?

Answer 34

cefepime (Maxipime)