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for infection less than 3 days use what drug?
for infection less thang 3 days in an immune compromized patient use?
for an infection less than 3 days (early infection) that has a penicillin allergy use?
if the infection is less than 3 days old then what are the majority of the bacteria?
if the infection is greater than three days what bacteria are seen?
gram + and anerobic bacteria
for an infection that is greater than 3 days old what should you give the patient?
clindamycin, azithromycin, clarithromyscin, penicillin VK + metronidazole, Amoxicillin + metronidazole (for the immune compromized patient)
If an infection presents as an abcess what should pre Rx the patient?
- Nothing!!! incise or drain the abcess and give pain meds if necessary and remove to source of the infection ie EXT the tooth ect.
- Rx antibiotic only if fever or cellunlitis (facial swelling) is presented
What decreases antibiotic effectiveness?
- Pus- binding of the drug by cell debris and phagocytes which inactivate drug
- Hematomas- Ig accumulations of Hb can bind drugs ex panicillins and tetracyclines
- Abscess cavites- Lower the pH in the region and inactivate drug.
- Foreign body- these are the cause of the local infection and thus since it's not bacterial drug wont bind therefor no useful in this situation.
Define MIC and MBC
- MIC-> minimum inhibitory - the lowest  of antibiotic that STOPS growth
- MBC->minimum bactericidal - lowest  that KILLS bacterium in liquid broth
Things to konw about your patient
- current liver and kidney status
- know if antibiotic is affected with food
- know if taking oral contraceptives (drug might cause vomiting or diarrhea) if it does use barrier method!
what is the general duration of antibiotic in dentistry and why?
7 days vs 10 in medicine b/c of the rich blood supply to the head. there is more rapid healing.
for penicillin the dose is doubled from what to what in mg?
Dose doublled from 250mg--> 500mg q6h
What is selective toxicity?
What the drug does to the pathogen
Describe the general structure of penicillin
it has a 5 membered dihydrothiazine ring, a 4 membered beta lactam ring (this site is susceptible to beta lacamase drug activity can be cleaved) , and an amide off of the beta lactam ring. The R group on the amide can be modified giving penicillin different characteristics.
where in the structure of penicillin does beta-lactimase activity occur and what is the result of the activity?
beta-lactimase cleave the beta lactam 4 membered ring in penicillin and renders the penicillin inactive and it converts into prnicilloic acid.
what is the original penicillin and what are its 4 deficiencies?
- Penicillin G--> original
- 1.not acid stable aka not stable orally
- 2. sensitive to beta-lactimase enzyme
- 3. not broad spectrum
- 4. can not treat pseudomonas
for each deficiency what was done to over come it?
1. Acid stability->Penicillin V over comes this is acid stable issue with addition of oxygen, same spectrum of action, penicillin VK oral stable form
2. beta-lactimase sensitivity-> addition of a bulky group to to overcome beta lactimase activity...methacilllin, nafcillin, isoxazolyl panicillin, oxacillin... these are penicillinase- resistant penicillins Their ONLY PURPOSE is to Tx staphylococcus infections b/c they produce beta-lactimase
3.Not broad spectrum-> the addition of an amino group to create ampicillin and amoxicillin, allow for gram (-) pour passage and this makes it extended spectrum
4. Can't Tx pseudomonas-> production of anti-pseudomonal penicillins, Carboxypenicilins- tricacillin carbenicillin and Ureidopenicillins- piperacillin, aziocillin, meziocillin. Ureidopenicillins are derivatives of ampicillin therefore they extend the spectrum of apicillins .
Penicillin V or G are used to treat what?
both have same spectum of action and do the same thing the only difference is that one is acid soluble and therfore can be taken orally aka penicilln V has these properties.
- They treat->streptococcal infections
- -S. pyrogens (pharyngitis, oitis media, pheumonia, bactermia, scarlet fever, chiils scarlet rashe, sore throat, nephrits)
- -endocarditist (if it's enterococcal endocarditis) use penicillin G + amino-glycoside
- -Meningitis-> Pen. G won't cross BBB but it will when the BBB is inflamed.
Penicillin V or G is what spectrum of drug? what is it used for?
- narrow spectrum
- -gram + cocci and bacilli
- -Treponema pallidum (syphillis spirochete)
- -actinomyces (lumpy tumors of jaw and tongue, lose weight and strength)
- -Antrax (can Tx with pen G but mainly with ciprofloxacin)
- -clostridial infections ( tetanus, gas gangrene)
what are the 5 names for Penicillinase- resistant Penicillins?
- the are a class of penicillins that have big bulk groups added to them so that they can be beta-lactamase resistant. and only used to Tx beta lactamase producing staphalycocus
- 1. methicilin
- 2. nafcillin
- 3. cloxacillin
- 4. dicloxacillin
- 5. oxacillin
what is the spectrum of the penicillin-resistant penicillinases? and what is it used for?
- Narrow spectrum
- only used to Tx infections of beta-lactamase producing S. Aureus.
If S. Aureus is methacillin resistant aka MRSA then what is the alternative treatment?
- usually the infections that are resistant to methicillin are also resistant to other beta-lactam drugs as well.
What are the aminopenicillins and what is there addition and specturm to penicillin G?
they have an addition of an amine group and they are extended specturm (no have acces to some gram - bacteria)
what are the two examples of the aminopenicillins? and what do they not work against?
- -ampicillin and amoxacilin
- -they Tx infections of gram + and some gram - bacteria.
- -ex p. mirabilis, salmonella, Shigella, E.coli
- -Not active against pseudomonas, and are sensitive to beta-lactamase
what do you combine aminopencillins with to combat beta-betalactimase? and what are 3 examples? finally what is a common drug name for amoxicillin + clavulanic acid called?
- combine with beta-lactimase inhibitors
- -clavulanic acid
what are aminopenicillins used to treat?
- -Upper respiratory infections (sinusitis, otitis media, bronchitis)
- -Uncomplicated UTI
- -Prophylaxis prior to dental Tx.
Where are the beta-lactamase's in gram + bacteria and what about gram - bacteria?
gram +--> external to the cell (outside the peptidoglycan layer)
Gram (-)-->internal to the cell inbetween the outer cell wall and inner cell wall.
antipseudomonal penicillins have two classes. What are they and what are the subclasses within them?
Carboxypenicillins- active against P. aeruginosa and some proteus
Uridopenicillins- extends spectrum of ampicillinto included pseudomonas.
Since the antipseudomaonal penicillins are sensitive to beta-lactamase what should you do to correct this? What is the broadest antibacterial spectrum of penicillins? Finally what are they used for?
-must use with beta-lactimase inhibitor
-piperacillin-tazobactam is the broadest antibacteral specturm of penicillins
-used to Tx serious infections caused by gram -, bacterimia, pneumonias, infections following burns, UTI resistant to Pen G
What is the MOA for penicillins? and which one is the main mech of the penicillin?
- Inhibition of cell wall synthesis! (main mechanism)
- -Does this by binding to the PBP or transpeptidase and inhibiting it from cross linking and making the cell wasll
Also induce holing-like proteins in bacterial membrane that cause the collapse of the membrane potential
What site on the cross linking of bacteria does the penicillin mimic in order to bind PBP aka the transpeptidase and render it inactive?
C-O-N bond more specifically the beta lactam ring in the penicillin is what mimics it and is able to bind to the PBP.
How are the different penicillin's administered? IV, IM, Orally,
- -Penicillin G- im or IV b/c not acid stable and so it's inactivated in the stomach
- -antipseudomonial penicillins (mezlocillin, piperacillin) also inactivated by acid. ticarcilllin as well
- Procaine, benzathine penicillin are IM slow release
- -Penicillin V
- all are acid stable and given orally.
what % of penicillin is protein bound, and what about beta-lactimase resistant agents?
20-50% bond and beta-lactamase agents are 90-95% bound.
How do penicillins affect pregnant mothers and their babies?
penicillin can cross the placental barrier and is distributed into breast milk.
can penicillin cross the BBB? if so give an example or condition of when it can.
normally it can not cross the BBB and enter in the CSF. but in cases of meningitis where the BBB is inflamed and has altered permeability then penicillin can enter the BBB.
What is the primary method of metabolisim of penicillin? and how would you prolong it in the system ?
- -excretion from the kidney.
- -by giving with probenecid you would increase the time that penicillin stayed in the system aka elevated the blood levels of penicillin because it competes for binding in the kidney.
Penicillin V is acid soluble and there for able to be taken orally what is it's method of excretion?
also excreted by the kidney but only 50% the other 50% is metabolized in the liver.
not all metabolim of penicillin is by the kidney. where else is it metabolized?
- -nafcillin, and oxacillin are excreted via billiara significantly.
- -piperacillin is also pertially excreted via biliary
what is the most common adverse effect of penicillin?
- hypersensitivity->skin rashes
- acute anaphylactic rxns rare! and may be fatal
- -Tx with eli.
- Superinfection by resistant organisms
- -pseudomembranous colitis due to C. difficile
- Electrolyte disorder
- -rapid IV infusion of potassium salt of penicillin G can cause Hyperkalemia-->arrhythmias and cardiac arrest.
what should you do with regards to renal compromised patients?
decrease dose of penicillin or decrease the dose interval. or use clindamycin or azithromycin
clindamycin and azithromycin have minimal urinary excretion.
take penicillin either 1 hour before a meal or 1 hour after a meal to decrease binding of penicillin with food.
amoxicillin vs penicillin VK
amoxacillin is given rid or q8h due to longer t1/2. pen VK is q6h
compensated cirrhosis vs decompensated cirrhosis and amoxicillin.
in compsnsated give as usual but in decompensated avoid use!
Can amoxacillin be used in a patient with both liver and kidney disease?
yes, just adjust the dose according to renal guidelines.
which penicillin decreases the effectiveness of warfarin?
when there is a change ins the PBP and resistance is obtained what is the significance in saying that the bacteria is methicillin resistant.
if a bacteria is resistant to methicillin it is resistant to all beta-lactam antibiotics including cephalosporins.
What are the mechanisms of resistance against penicillin?
1. change in PBP->binds less to penicillin but still does cross linking
2. increase production of beta-lactamase-> can't bind to them all and if you increae drug can reach toxic levels
3. development of tolerance by loss of the autolysis mechanism. (agents become bacteriostatic)
4. Eflux pump
In Dentistry when would you prescribe a penicillin antibiotic?
- 1. post EXT infection
- 2. postsurgical infection
- 3. periocornitis
- 4.dentoalveolr abcesses
- 5. osetomyleitis (bone infection)
- 7.ulcerative gingivitis
- 9.prophylaxis (amoxicillin, ampicillin)
What two groups of patients REQUIRE antibiotic prophylaxis?
1. Heart conditions that may predispose infective endocarditis
2. total joint replacement patients that may be at risk for developing blood-borne infections.
Conditions that require a prophylaxis (lots of them)
- -artificial heart valve
- -history of infective endocarditis
- -cardiac transplant that develops a heart problem
- -unrepaired or incompletely repaired cyanotic congenital heart disease (palliative shuts and conduits, completely repaired congenital heart defect with prosthetic material basicallly anything to do with a heart condition)
Patients that NO LONGER need antibiotic prophylaxis.
- -mitral valve prolapse
- -Rhematic heart disease
- -bicuspid valve disease
- -calcified aortic stenosis
- -congenital heart condition
- -ventricular septal defect
- -atrial septal defect
- -hypertrophic cardiomyopathy
what two drugs are carbapenems?
Imipenem/cilistatin (given in conjuction)
What spectrum are the carbapenems?
- broad spectrum
- -act on both gram + and gram - bacteria don't work on MRSA or VRE.
Which drug is the choice for enterobacter infections?
what Tx are Carbapenems good for?
pumlonary infections, intra-abdominal infections, soft tissue infections that are caused by mixed bacteria (since it's broad spectrum)
-remember also the choice for enterobacter infections as well.
what is the MOA for carbapenems?
Bind to PBP 1 and 2, they are small in size and easily penatrate gram - porins.
how do carbapenems get metabolized?
they are not absobed from the GI tract so they must be IM or IV dispersed, carbapenems are excreted by the kidney.
imipenem is rapidly hydrolyzed by dehydropeptidase 1 which is why it is administerd with cilistatin to inhibit the binding and degredation of imipenem
Meropenem is resistant to degration by dehydropeptidase 1.
what are the adverse effects of Carbapenems?
- -@ high doses->seizures, less with meropenem
- -GI disturbances via N,V,D, skin as he and rare neutopenia
what are bacterial resistances to Carbapenems?
Alteration of porins so drug cannot access periplasmic space. (can't enter bacteria)
What is the preferred oral prophylaxis drug?
What is the preferred prophylaxis drug if patient can not take oral medication?
ampicillin or cefazolin or ceftriaxone (IM or IV)
What is the preferred prophylaxis drug if allergic to penicillins or ampicillin oral?
Cephalexin or clindamycin, azithromycin, or clarithromycin.
What is the preferred prophylaxis drug if allergic to penicillins or ampicllin and unable to take oral medication?
Cefazolim or ceftriaxone or clindamycin IV or IM
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