6
a. Penicillin V vs. penicillin G: the latter is more sensitive to acid
degradation and thus is usually injected rather than taken
orally
(Certainly no one in dentistry uses Pen G, so I
would think they would not use too many of these
questions)
b. Which penicillin has the best gram-negative spectrum:
ampicillin
c.
Which drugs from a list are or are not cross-allergenic with
penicillin: most usually asked about ones are: cephalosporins
and ampicillin are, erythromycin isn't
d. Which penicillin is useful against penicillinase-producing bugs
such as staphylococcus: dicloxacillin
e. Which is specific for Pseudomonas infections: an extended
spectrum such as carbenicillin
f.
Which combination of agents should be used prophylactically
for patient with heart valve to prevent bacterial endocarditis:
ampicillin and gentamycin (1988- according to latest
recommendation of AHA and ADA, although use the latest
guidelines that you have heard about)) (
here’s a big change
obviously, since combinations are no longer used, and
neither are doses given before and after treatment –
review your latest prophylaxis guidelines)
Prophylaxis Regimens For SBE (AHA 1997 Guidelines)
1
st
choice:
Amoxicillin: 2 g (4 X 500 mg), PO 1 hr before
treatment. # of pills to be dispensed depends on # of
appointments Children: 50 mg/kg 1 hr prior
For PCN allergic
: Clindamycin: 600 mg (4 X 150 mg)
PO 1 hr before treatment. . # of pills to be dispensed
depends on # of appointments
non-oral:
Ampicillin IV/IM 2 g, 1/2 hr before (Kids: 50 mg/kg)
Clindamycin (for PCN-allergic) 600 mg IV 1/2 hr prior,
kids (20 mg/kg)
Prophylaxis for the patient with a prosthetic joint
Keflex, 2 g, (4 X 500mg), PO 1 hr before treatment . # of
pills to be dispensed depends on # of appointments
Examples of patient cardiovascular conditions that
require prophylaxis and some that don’t
(AHA 1997 Guidelines)
Prophylaxis
Required
Prophylaxis Not Required
Prosthetic valves
Cardiac pacemakers
Previous
endocarditis
Rheumatic fever without valvular
dysfunction
Pulmonary
shunts
Mitral valve prolapse without
valvular regurgitation
Examples Of Dental Procedures That Require Prophylaxis
And Some That Don’t
(According to AHA 1997 Guidelines. Caveat: our clinic
guidelines, should they differ from these, are also
considered correct answers)
Required
Not Required
Extractions
Restorative Procedures
Periodontal Surgery
Intracanal endodontic treatment
Implants
Taking Of Impressions
Common Prescription Regimens For Treating An Infection:
Penicillin VK
250-500mg, dispense 30, take 2 tablets at once*,
then 1 tab every 6 hrs until gone (7 days)
*some sources do not indicate loading
dose, so dispense 28, take 1 q6h until
gone
Kids (less than 12 yrs): 20-50 mg/kg qid
Clindamycin
150-300 mg, dispense 21, take 1 capsule every 8
hrs until gone (7 days)
Kids: 8-12 mg/kg tid or qid
Amoxicillin
500 mg, dispense, 21, take 1 capsule every 8 hrs
until gone (7 days)
Kids (under 20 kg): 20-40 mg/kg tid
2. The 2nd largest category expects you to know the mechanism of
action of the various antibiotics:
a. Bactericidal agents such as penicillin kill rapidity growing cells by
inhibiting cell wall synthesis
b. Bacteriostatic agents such as tetracycline limit population
growth, but do not kill bugs by interfering with protein synthesis
on bacterial ribosomes
c. Antifungals such as nystatin bind to ergosterol in fungal cell
walls to weaken the wall
d. Bacteriostatic agents such as the sulfonamides compete with
PABA in folic acid synthesis, thus resulting in folic acid
deficiency
3. Many questions are asked regarding side effects or toxicities of
penicillins, tetracyclines, clindamycin, etc:
a. What are symptoms seen during allergic reactions to penicillins:
dermatitis, stomatitis, bronchoconstriction and cardiovascular
collapse
b. What agent produces GI upset and pseudomonas colitis:
clindamycin
c. Which agents are most likely or least likely to cause
superinfection: most: broad spectrum agents such as
tetracyclines; least: narrow spectrum agents such as penicillin G
d. Aplastic anemia is associated with chloramphenicol
e. Liver damage or hepatotoxicity is associated with tetracycline
f. Erythromycin estolate associated with allergic cholestatic
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