Antibiotics Oral Surgery

Front 1

What are the different sites of action for antibiotics?

Back 1

-cell wall syntheiss
-DNA replication
-DNA dependent RNA poymerase
-protein synthesis (30 or 50s)
-cell membrane
-folic acid metabolism

Front 2

Mechanisms of bactericidal activity

Back 2

-cell wall synthesis inhibition
-inhibition of DNA synthesis
-inhibition of DNA gyrase
-inhibition of protein synthesis

Front 3

Penicillins, cephalosporins, vancomycin

Back 3

cell wall synthesis inihibition

Front 4

aminoglycosides

Back 4

inhibition of protein synthesis

Front 5

quinolones

Back 5

inhibition of DNA gyrase

Front 6

inhibition of DNA synthesis

Back 6

metronidazole

Front 7

What do antifungals bind to?

Back 7

ergosterol

Front 8

what do sulfonamides target?

Back 8

folic acid synthesis

Front 9

What are the therapeutic uses of antibiotics in dentistry?

Back 9

-prophylaxis in patients at risk of developing bacterial endocarditis from bacteremia from some dental procedures
-treatment of acute odontogenic infections
-prophylaxis in patients with compromised host defenses due to disease or drug therapy

Front 10

what are a few examples of compromised host defences?

Back 10

anaemia or diabetes
transplant patients on immunosuppressants
AIDs patients or patients taking cytotoxic drugs

Front 11

according to AHA guidelines, what patients have taken prophylactic antibiotics routinely in the past but no longer need them?

Back 11

-mitral valve prolapse
-rheumatic heart disease
-bicuspid valve disease
-calcified aortic stenosis
-congenital heart conditions such as ventricular septal defect, atrial septal defect and hypertrophic cardiomyopathy

Front 12

A patient asks you why the guidelines have been revised about antibiotic coverage, what do u say?

Back 12

-Infective endocarditis is much more likely to result from daily activities that cause frequent exposure to bacteremias
-the risk of antibiotic associated adverse events exceed the benefit , if any
-maitenence of oral health and hygiene may reduce the incidence of bacteremia of daily activities and is more important than prophylactic antibiotics

Front 13

so what situations would prophylaxis be reasonable?

Back 13

prosthetic cardiac valve or prosthetic material used for cardiac valve repair
-previous infective endocarditis
-congenital heart disease
-cardiac transplantation

Front 14

What are examples of procedures that do not need prophylaxis?

Back 14

LA injections, shedding of primary teeth , bleeding from trauma to lips or mucosa

Front 15

What is the prophylaxis regime for amoxicillin oral?

Back 15

2 grams 30-60 minutes before procedure for adults
50 mg/kg for children

Front 16

what is the prophylaxis regime for a patient unable to take oral medications?

Back 16

ampicillin
-2g IM or IV OR
cefazolin or ceftriaxone
-1g IM or IV

*50 mg/kg IM for kids

Front 17

What is the prophy regime for a patient allergic to penicillins or ampicillin

Back 17

cephalexin 2g (kids=50 mg/kg) OR
clindamycin 600 mg (20 mg/kg) OR
azithromycin or clarithromycin 500 mg (15 mg/kg)

Front 18

What is the prophy regime if a patient is allergic and cannot take oral?

Back 18

cefazolin or ceftriaxone 1g IM (kids=50 mg/kg)
clindamycin 600 mg IM (20 mg/kg)

Front 19

5 goals in management of oral infection

Back 19

-assess severity of the infection
-assess host defense mechanism
-incision and drainage
-selection of antibiotic
-eliminate etiology of infection

Front 20

most odontogenic infections such as streptococci

Back 20

penicillin

Front 21

skin infection are usually caused by staphylococcus aureus. First choice antibiotic?

Back 21

Flucloxacillin

Front 22

sinus infection mainly cause by H influenzae. what is first choice?

Back 22

amoxicillin

Front 23

what are the best for most orofacial infections that are primarily aerobic gram + type bacteria?

Back 23

penicillin and amoxicillin

Front 24

what will extend the spectrum to cover anaerobic infections as well?

Back 24

penicilin + metronidazole

Front 25

Perio infections are usually best handled with ?

Back 25

tetracyclines given locally

Front 26

staph infections benefit from?

Back 26

Augmentin
-Augmentin contains a combination of amoxicillin and clavulanate potassium

Front 27

what antibiotics have a broad spectrum ?

Back 27

chloramphenicol
sulfonamids
tetracyclines
trimethoprim

Front 28

what are the 4 factors that affect patient compliance?

Back 28

cost
regimen
preparation
tolerance to adverse side effects

Front 29

why arent bacteriostatic drugs used in immunocompromised patients?

Back 29

they only slow the growth of bacteria population and you need the immune system to do the actual killing

Front 30

your patient has renal function, what do you avoid>?

Back 30

penicillins
cephalosporins
clarithromycin

Front 31

your patient has liver dysfunction, what do u avoid?

Back 31

erythromycin
tetracycline
metronidazole
clindamycin

Front 32

your patient has intestinal problems, what do you avoid?

Back 32

clindamycin

Front 33

what is the dangerous interaction between erythromycin and clarithromycin?

Back 33

can cause dangerous heart rhythm bc both increase Qtc interval.
-via the cyp3A4 metabolism

Front 34

what should patients avoid if they take metronidazole?

Back 34

alcohol

Front 35

what potentiates the anticoagulant effects of warfarin?

Back 35

tetracycline

Front 36

What is the interaction between macrolides with terfenadine(h1 receptor antagonist), hismanal or propulsid. (releaves constipation)

Back 36

Failure to metabolize prodrug leading to dangerous cardiac arrythmias (increase Qt interval)

Front 37

what is the interaction between macrolides and protease inhibitors?

Back 37

the duration of action will be increased by the macrolides. They also inhibit the H-1 antagonist drugs mentioned in the previous slides

Front 38

what is an example of a synergistic interaction?

Back 38

penicillin and gentamicin
-the combination is more effective than predicted

Front 39

what is the interaction between tetracyclines and metal ions?

Back 39

the tetracyclines will not be absorbed from the GI tract

Front 40

what happens with anticoagulants and tetracyclines or cephalosporins.

Back 40

increased bleeding due t oeffects on vit K synthesis

Front 41

what are the B drugs that are safe to use in pregnancy?

Back 41

-penicillin
-erythromycin
-azithromycin
-cephalosporins
-amphotericin B

Front 42

what is the drug in category D?

Back 42

-tetracycline
* can also cause ttooth discoloration in developing teeth

Front 43

what can cause cartilage damage in children?

Back 43

quinolones

Front 44

why is tetracycline useful for perio infections?

Back 44

it concentrates in gingival fluid

Front 45

what are useful for bone infections?

Back 45

clindamycin and cephalosporins

Front 46

what kind of drugs are good especially for prophy and list a few

Back 46

bacteriocidal
-penicillins
-cephalosporins
-metronidazole
-aminoglycosides
-vancomycin
-quinolones
-clindamycin

Front 47

why is cidal better than static?

Back 47

less reliance on the host defense mechanisms
bacteriostatic take longer to resolve the infection
also, the cidal drugs have a "post-antibiotic effect"

Front 48

do cell wall synthesis inhibitors effect viruses,fungi or protozoa

Back 48

no

Front 49

does the cell wall inhibitor (cidal) antibiotic drug work on mature infections?

Back 49

no bc it needs growing bacteria that are synthesizing cell walls

Front 50

protein synthesis inhibition is an example of?

Back 50

bacteriostatic mechanism of action
-stops the bacteria from rapidly dividing so immune system can kill

Front 51

what are some examples of bacteriostatic bacteria?

Back 51

macrolide
tetracycline
clindamycin (low doses)
sulfonamides
chloramphenicol

Front 52

so which drug requires a functioning immune system?

Back 52

static

Front 53

what is a useful pneumonic to remember static drugs?

Back 53

"Those Mean Cock Suckers"
Tetracyclines
macrolides
clindamycin (low doses)
sulfonamides

Front 54

why is penicillin and tetracycline a bad combination?

Back 54

penicillin is a cidal agent, and tetracycline is a static agent. There fore, the static agent inhibits any benefit of the cidal agent bc it inhibits growth and cidal agents need growth (the cell wall inhibitors like penicillin)

Front 55

So what are 3 examples of good combinations of antibiotics?

Back 55

1. amoxicillin and clauvulanic acid (augmentin)
2. penicillin and metronidazole
3. ampicillin and gentamicin

Front 56

why is augmentin a good combo?

Back 56

clavulanic acid is an inhibitor of beta lactamase enzymes so it extends the spectrum of amoxicillin to include penicillinase producing organisma

Front 57

why is metronidazole and penicillin a good combo?

Back 57

extends penicillin spectrum to anaerobes.
"poor mans augmentin"

Front 58

why is ampicillin and gentamicin a good combo?

Back 58

aminoglycosides penetrate better with cell wall inhibitors

Front 59

inherent resistance

Back 59

the resistance provided by the thick cell wall layers of gram - mos
*beta lactamases

Front 60

why is staph aureus resistant to penicillin?

Back 60

beta lactamase production

Front 61

tetracyclines and clindamycin. adverse effect?

Back 61

superinfection

Front 62

aplastic anemia adverse effect

Back 62

chloramphenicol

Front 63

nephrotoxicity

Back 63

sulphonomides
aminoglycosides
amphotericin B
vancomycin

Front 64

amphotericin b

Back 64

antifungal

Front 65

what is the drug choice for dentistry covering almost all bacteria in the mouth

Back 65

penicillin

Front 66

what does it effect?

Back 66

usual doses effect gram + aerobic primarily and facultative
*gram + cocci and gram + rods
*limited activity against gram - rods (beta lactamases)

Front 67

dosage for PenVK oral form

Back 67

600 mg Q6H
(kids 50 mg /kg in 4 divided doses)

Front 68

what is an advantage of PenVK

Back 68

cheap

wide therapeutic index

Front 69

what are the pediatric dosages for penicillin , amoxicillin and erythromycin?

Back 69

pen- 50 mg/kg (4 divided doses)
amox-20-40 mg/kg day q 8hr
eryth-40-50 mg/kg/day in 4 doses

Front 70

why do u reduce penicillin dose in renal failure?

Back 70

inadequate clearance and increased risk for toxic levels and neurotoxicity

Front 71

what % of px show hypersensitivity?

Back 71

3-5%

Front 72

What patients are more likely to be allergic to pen?

Back 72

hx of allergies in general (hay fever, asthma, eczema)

Front 73

what are the 3 classifications of Pen allergic reactions?

Back 73

1. acute allergic reaction (within 30 mins)
2.accelerated allergic reactions (30mins -48hrs)
3. delayed allergic reactions (>2 days)*most common

Front 74

when would u use a penicillinase-resistant penicillin?
*cloxacillin /dicloxacillin

Back 74

infections caused by penicillin resistant staph cocci

Front 75

do u need to reduce these drugs in impaired renal function patients?

Back 75

no bc its hepatic and biliary

Front 76

when would u use extended spectrum penicillins? (ampicillin)

Back 76

gram - rods or mixed gram+/- infections

Front 77

what patients might need gentamicin and ampicillin?

Back 77

a prophy for endocarditis at risk patients such as those with prosthetic heart valves

Front 78

what is the dosing for amoxicillin?

Back 78

250-500mg q8h (child 20-40mg/kg q 8h)

Front 79

what is the current drug of choice for subacute bacterial endocarditis regime?

Back 79

amoxicillin

Front 80

is amoxicillin cross allergenic w penicillin?

Back 80

yes

Front 81

what is the most frequent cephalosporin used in dentistry?

Back 81

Keflex (1st generation)

Front 82

Keflex dose?

Back 82

250-500 mg q6hr

Front 83

when would u use keflex?

Back 83

for surgical prophy when cutting through skin
prosthetic joint prophy

Front 84

what should u watch out for when prescribing keflex?

Back 84

interference with vit K synthesis thus increasing risk of hemorrage

Front 85

when would u prescribe erythromycin (50s ribosome binding)?

Back 85

patients with significant renal impairment and mild to moderate infections in pen sensitive patients

Front 86

erythromycin dose

Back 86

250 mg q6h
(kids 30-50 mg/kg/day in 4 doses)

Front 87

what are the main drug interactions with erythromycin?

Back 87

Seldane,Hismanal,propulsid, and other drugs that rely on liver metabolism. It results in increased plasma levels of these drugs and exaggerated effects of toxicity
*also suppresses GI flora (digoxin toxicity)

Front 88

gram + and gram - anaerobic bacteria
prophy drug of choice for pen allergic
good treatment for osteomyelitis (bone penetration)

Back 88

clindamycin

Front 89

dose of clindamycin

Back 89

150-300 mg q6h

Front 90

bacteriostatic by binding to the 30s ribosomal subunits
wide activity with gram - and +
indicated for perio deep pockets
impregnate dressings to prevent dry socket
most common to cause superinfections (candida)

Back 90

tetracycline
*dnt give to kids 8 and under

Front 91

minocycline

Back 91

cause greysh brown staining of the incisal of teeht rather than the gingival 1/3rd like tetracycline.

Front 92

bacteriocidal via nucleic acid synthesis inhibition
narrow spectrum (anaerobes)

Back 92

metronidazole

Front 93

what are metronidazole's uses?

Back 93

c. difficile following clindamycin
poor mans augmentin(pen+metron)
perio

Front 94

poor mans augmentin dosing

Back 94

250 mg metronidazole
250 mg amoxicillin
q 8hr for 7-10 days

Front 95

metronidazole dosing for perio

Back 95

250mg tid 7-10 days

Front 96

vancomycin

Back 96

bacteriocidal and interferes with cell wall synthesis different than pens
all gram +

Front 97

uses for vanco in dentistry

Back 97

parental use for allergic patietns to pens and cephalosporins

prophy for subacutre endocarditis in pen allergic px

Front 98

adverse effects

Back 98

deafness
renal toxicity
red man syndrome in iv infusion

Front 99

vanco dosing

Back 99

500 mg IV over 1 hour Q 6h

Front 100

when would u use Linezolid?

Back 100

infections caused by vanco resistant
effective for staph aureus, strep pneumonia, strep pyogenes

Front 101

polyene antifungal agents

Back 101

nystatin and amphotericin B

Front 102

which one is for serious maxillofacial fungal infections, and fungal infections in immunosuppressed patients?

Back 102

amphotericin B

Front 103

what is the topical treatment for candidiasis?

Back 103

clotrimazole 1st choice
nystatin 2nd choice (but first for liver disease px)

Front 104

what is the systemic treatment for candidiasis?

Back 104

ketoconazole or fluconazole (200 mg/day)

Front 105

what is the dosing for nystatin?

Back 105

2-3 ml of 100 000 units/ml suspension are placed in each side of the mouth, swished and held for 5 min before swallowing (every 6 hours for at least 10 days)
-if lozenges, then one or two 4-5 times /day

Front 106

what is the dose for clotrimazole?

Back 106

-topical of 10 mg 5 x daily for 2 weeks. It dissolves slowly in mouth
*drug of choice for AIDs patients

Front 107

what has drug interactions similar to those seen in erythromycin due to its CYP450 3A inhibition?

Back 107

Ketoconazole.
increased cyclosporin, phenytoin, digoxin and warfarin plasma levels will be increased.

Front 108

when would u use antivirals in dentistry?

Back 108

Herpes Simplex type 1
varicella zoster

Front 109

what dose of acyclovir is effective against mild herpes?

Back 109

oral 200 mg

Front 110

what antibiotics require no change in dosing in patients with renal disease?

Back 110

erythromycin
metronidazole
clindamycin
doxycycline and cefaclor

Front 111

there is a potential for overdosage of these antibiotics in patients with renal disease

Back 111

-pen, amox, ampi
-cephalosporins
-clarithromycin
-tertracyclines except doxi and mino
-ciprofloxacin (quinolone)
-acyclovir

Front 112

what antibiotics can u use in liver disease px?

Back 112

penicillin
cephalosporin
ciprofloxacin

Front 113

what antibiotics should be reduced in px with liver disease?

Back 113

-clindamycin
-erythromycin, azithromycin
-tetracyclines