Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
113 Cards in this Set
- Front
- Back
What are the different sites of action for antibiotics?
|
-cell wall syntheiss
-DNA replication -DNA dependent RNA poymerase -protein synthesis (30 or 50s) -cell membrane -folic acid metabolism |
|
Mechanisms of bactericidal activity
|
-cell wall synthesis inhibition
-inhibition of DNA synthesis -inhibition of DNA gyrase -inhibition of protein synthesis |
|
Penicillins, cephalosporins, vancomycin
|
cell wall synthesis inihibition
|
|
aminoglycosides
|
inhibition of protein synthesis
|
|
quinolones
|
inhibition of DNA gyrase
|
|
inhibition of DNA synthesis
|
metronidazole
|
|
What do antifungals bind to?
|
ergosterol
|
|
what do sulfonamides target?
|
folic acid synthesis
|
|
What are the therapeutic uses of antibiotics in dentistry?
|
-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 |
|
what are a few examples of compromised host defences?
|
anaemia or diabetes
transplant patients on immunosuppressants AIDs patients or patients taking cytotoxic drugs |
|
according to AHA guidelines, what patients have taken prophylactic antibiotics routinely in the past but no longer need them?
|
-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 |
|
A patient asks you why the guidelines have been revised about antibiotic coverage, what do u say?
|
-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 |
|
so what situations would prophylaxis be reasonable?
|
prosthetic cardiac valve or prosthetic material used for cardiac valve repair
-previous infective endocarditis -congenital heart disease -cardiac transplantation |
|
What are examples of procedures that do not need prophylaxis?
|
LA injections, shedding of primary teeth , bleeding from trauma to lips or mucosa
|
|
What is the prophylaxis regime for amoxicillin oral?
|
2 grams 30-60 minutes before procedure for adults
50 mg/kg for children |
|
what is the prophylaxis regime for a patient unable to take oral medications?
|
ampicillin
-2g IM or IV OR cefazolin or ceftriaxone -1g IM or IV *50 mg/kg IM for kids |
|
What is the prophy regime for a patient allergic to penicillins or ampicillin
|
cephalexin 2g (kids=50 mg/kg) OR
clindamycin 600 mg (20 mg/kg) OR azithromycin or clarithromycin 500 mg (15 mg/kg) |
|
What is the prophy regime if a patient is allergic and cannot take oral?
|
cefazolin or ceftriaxone 1g IM (kids=50 mg/kg)
clindamycin 600 mg IM (20 mg/kg) |
|
5 goals in management of oral infection
|
-assess severity of the infection
-assess host defense mechanism -incision and drainage -selection of antibiotic -eliminate etiology of infection |
|
most odontogenic infections such as streptococci
|
penicillin
|
|
skin infection are usually caused by staphylococcus aureus. First choice antibiotic?
|
Flucloxacillin
|
|
sinus infection mainly cause by H influenzae. what is first choice?
|
amoxicillin
|
|
what are the best for most orofacial infections that are primarily aerobic gram + type bacteria?
|
penicillin and amoxicillin
|
|
what will extend the spectrum to cover anaerobic infections as well?
|
penicilin + metronidazole
|
|
Perio infections are usually best handled with ?
|
tetracyclines given locally
|
|
staph infections benefit from?
|
Augmentin
-Augmentin contains a combination of amoxicillin and clavulanate potassium |
|
what antibiotics have a broad spectrum ?
|
chloramphenicol
sulfonamids tetracyclines trimethoprim |
|
what are the 4 factors that affect patient compliance?
|
cost
regimen preparation tolerance to adverse side effects |
|
why arent bacteriostatic drugs used in immunocompromised patients?
|
they only slow the growth of bacteria population and you need the immune system to do the actual killing
|
|
your patient has renal function, what do you avoid>?
|
penicillins
cephalosporins clarithromycin |
|
your patient has liver dysfunction, what do u avoid?
|
erythromycin
tetracycline metronidazole clindamycin |
|
your patient has intestinal problems, what do you avoid?
|
clindamycin
|
|
what is the dangerous interaction between erythromycin and clarithromycin?
|
can cause dangerous heart rhythm bc both increase Qtc interval.
-via the cyp3A4 metabolism |
|
what should patients avoid if they take metronidazole?
|
alcohol
|
|
what potentiates the anticoagulant effects of warfarin?
|
tetracycline
|
|
What is the interaction between macrolides with terfenadine(h1 receptor antagonist), hismanal or propulsid. (releaves constipation)
|
Failure to metabolize prodrug leading to dangerous cardiac arrythmias (increase Qt interval)
|
|
what is the interaction between macrolides and protease inhibitors?
|
the duration of action will be increased by the macrolides. They also inhibit the H-1 antagonist drugs mentioned in the previous slides
|
|
what is an example of a synergistic interaction?
|
penicillin and gentamicin
-the combination is more effective than predicted |
|
what is the interaction between tetracyclines and metal ions?
|
the tetracyclines will not be absorbed from the GI tract
|
|
what happens with anticoagulants and tetracyclines or cephalosporins.
|
increased bleeding due t oeffects on vit K synthesis
|
|
what are the B drugs that are safe to use in pregnancy?
|
-penicillin
-erythromycin -azithromycin -cephalosporins -amphotericin B |
|
what is the drug in category D?
|
-tetracycline
* can also cause ttooth discoloration in developing teeth |
|
what can cause cartilage damage in children?
|
quinolones
|
|
why is tetracycline useful for perio infections?
|
it concentrates in gingival fluid
|
|
what are useful for bone infections?
|
clindamycin and cephalosporins
|
|
what kind of drugs are good especially for prophy and list a few
|
bacteriocidal
-penicillins -cephalosporins -metronidazole -aminoglycosides -vancomycin -quinolones -clindamycin |
|
why is cidal better than static?
|
less reliance on the host defense mechanisms
bacteriostatic take longer to resolve the infection also, the cidal drugs have a "post-antibiotic effect" |
|
do cell wall synthesis inhibitors effect viruses,fungi or protozoa
|
no
|
|
does the cell wall inhibitor (cidal) antibiotic drug work on mature infections?
|
no bc it needs growing bacteria that are synthesizing cell walls
|
|
protein synthesis inhibition is an example of?
|
bacteriostatic mechanism of action
-stops the bacteria from rapidly dividing so immune system can kill |
|
what are some examples of bacteriostatic bacteria?
|
macrolide
tetracycline clindamycin (low doses) sulfonamides chloramphenicol |
|
so which drug requires a functioning immune system?
|
static
|
|
what is a useful pneumonic to remember static drugs?
|
"Those Mean Cock Suckers"
Tetracyclines macrolides clindamycin (low doses) sulfonamides |
|
why is penicillin and tetracycline a bad combination?
|
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)
|
|
So what are 3 examples of good combinations of antibiotics?
|
1. amoxicillin and clauvulanic acid (augmentin)
2. penicillin and metronidazole 3. ampicillin and gentamicin |
|
why is augmentin a good combo?
|
clavulanic acid is an inhibitor of beta lactamase enzymes so it extends the spectrum of amoxicillin to include penicillinase producing organisma
|
|
why is metronidazole and penicillin a good combo?
|
extends penicillin spectrum to anaerobes.
"poor mans augmentin" |
|
why is ampicillin and gentamicin a good combo?
|
aminoglycosides penetrate better with cell wall inhibitors
|
|
inherent resistance
|
the resistance provided by the thick cell wall layers of gram - mos
*beta lactamases |
|
why is staph aureus resistant to penicillin?
|
beta lactamase production
|
|
tetracyclines and clindamycin. adverse effect?
|
superinfection
|
|
aplastic anemia adverse effect
|
chloramphenicol
|
|
nephrotoxicity
|
sulphonomides
aminoglycosides amphotericin B vancomycin |
|
amphotericin b
|
antifungal
|
|
what is the drug choice for dentistry covering almost all bacteria in the mouth
|
penicillin
|
|
what does it effect?
|
usual doses effect gram + aerobic primarily and facultative
*gram + cocci and gram + rods *limited activity against gram - rods (beta lactamases) |
|
dosage for PenVK oral form
|
600 mg Q6H
(kids 50 mg /kg in 4 divided doses) |
|
what is an advantage of PenVK
|
cheap
wide therapeutic index |
|
what are the pediatric dosages for penicillin , amoxicillin and erythromycin?
|
pen- 50 mg/kg (4 divided doses)
amox-20-40 mg/kg day q 8hr eryth-40-50 mg/kg/day in 4 doses |
|
why do u reduce penicillin dose in renal failure?
|
inadequate clearance and increased risk for toxic levels and neurotoxicity
|
|
what % of px show hypersensitivity?
|
3-5%
|
|
What patients are more likely to be allergic to pen?
|
hx of allergies in general (hay fever, asthma, eczema)
|
|
what are the 3 classifications of Pen allergic reactions?
|
1. acute allergic reaction (within 30 mins)
2.accelerated allergic reactions (30mins -48hrs) 3. delayed allergic reactions (>2 days)*most common |
|
when would u use a penicillinase-resistant penicillin?
*cloxacillin /dicloxacillin |
infections caused by penicillin resistant staph cocci
|
|
do u need to reduce these drugs in impaired renal function patients?
|
no bc its hepatic and biliary
|
|
when would u use extended spectrum penicillins? (ampicillin)
|
gram - rods or mixed gram+/- infections
|
|
what patients might need gentamicin and ampicillin?
|
a prophy for endocarditis at risk patients such as those with prosthetic heart valves
|
|
what is the dosing for amoxicillin?
|
250-500mg q8h (child 20-40mg/kg q 8h)
|
|
what is the current drug of choice for subacute bacterial endocarditis regime?
|
amoxicillin
|
|
is amoxicillin cross allergenic w penicillin?
|
yes
|
|
what is the most frequent cephalosporin used in dentistry?
|
Keflex (1st generation)
|
|
Keflex dose?
|
250-500 mg q6hr
|
|
when would u use keflex?
|
for surgical prophy when cutting through skin
prosthetic joint prophy |
|
what should u watch out for when prescribing keflex?
|
interference with vit K synthesis thus increasing risk of hemorrage
|
|
when would u prescribe erythromycin (50s ribosome binding)?
|
patients with significant renal impairment and mild to moderate infections in pen sensitive patients
|
|
erythromycin dose
|
250 mg q6h
(kids 30-50 mg/kg/day in 4 doses) |
|
what are the main drug interactions with erythromycin?
|
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) |
|
gram + and gram - anaerobic bacteria
prophy drug of choice for pen allergic good treatment for osteomyelitis (bone penetration) |
clindamycin
|
|
dose of clindamycin
|
150-300 mg q6h
|
|
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) |
tetracycline
*dnt give to kids 8 and under |
|
minocycline
|
cause greysh brown staining of the incisal of teeht rather than the gingival 1/3rd like tetracycline.
|
|
bacteriocidal via nucleic acid synthesis inhibition
narrow spectrum (anaerobes) |
metronidazole
|
|
what are metronidazole's uses?
|
c. difficile following clindamycin
poor mans augmentin(pen+metron) perio |
|
poor mans augmentin dosing
|
250 mg metronidazole
250 mg amoxicillin q 8hr for 7-10 days |
|
metronidazole dosing for perio
|
250mg tid 7-10 days
|
|
vancomycin
|
bacteriocidal and interferes with cell wall synthesis different than pens
all gram + |
|
uses for vanco in dentistry
|
parental use for allergic patietns to pens and cephalosporins
prophy for subacutre endocarditis in pen allergic px |
|
adverse effects
|
deafness
renal toxicity red man syndrome in iv infusion |
|
vanco dosing
|
500 mg IV over 1 hour Q 6h
|
|
when would u use Linezolid?
|
infections caused by vanco resistant
effective for staph aureus, strep pneumonia, strep pyogenes |
|
polyene antifungal agents
|
nystatin and amphotericin B
|
|
which one is for serious maxillofacial fungal infections, and fungal infections in immunosuppressed patients?
|
amphotericin B
|
|
what is the topical treatment for candidiasis?
|
clotrimazole 1st choice
nystatin 2nd choice (but first for liver disease px) |
|
what is the systemic treatment for candidiasis?
|
ketoconazole or fluconazole (200 mg/day)
|
|
what is the dosing for nystatin?
|
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 |
|
what is the dose for clotrimazole?
|
-topical of 10 mg 5 x daily for 2 weeks. It dissolves slowly in mouth
*drug of choice for AIDs patients |
|
what has drug interactions similar to those seen in erythromycin due to its CYP450 3A inhibition?
|
Ketoconazole.
increased cyclosporin, phenytoin, digoxin and warfarin plasma levels will be increased. |
|
when would u use antivirals in dentistry?
|
Herpes Simplex type 1
varicella zoster |
|
what dose of acyclovir is effective against mild herpes?
|
oral 200 mg
|
|
what antibiotics require no change in dosing in patients with renal disease?
|
erythromycin
metronidazole clindamycin doxycycline and cefaclor |
|
there is a potential for overdosage of these antibiotics in patients with renal disease
|
-pen, amox, ampi
-cephalosporins -clarithromycin -tertracyclines except doxi and mino -ciprofloxacin (quinolone) -acyclovir |
|
what antibiotics can u use in liver disease px?
|
penicillin
cephalosporin ciprofloxacin |
|
what antibiotics should be reduced in px with liver disease?
|
-clindamycin
-erythromycin, azithromycin -tetracyclines |