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Which class of penicillins do Penicillin G and V fall into?
Natural Penicillins
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How must Penicillin G be administered and why?
IM/IV, because acid labile, so unstable in the GI
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What are the usual indication for Penicillin G?
Endocarditis or syphilis
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Is penicillin G usually used prophylactically or for acute treatment?
Prophylactically
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What does it mean to be an intramuscular repository formulation?
Given intramuscularly and deposit enters blood stream slowly over a matter of weeks
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If high levels of Penicillin G are needed, by what route would you give it?
IV
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What are the intramuscular repository formulations of Penicillin G?
Benzathine and Procaine
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What are the benefits for Benzathine penicillin G?
Anesthetic effect and long duration of 2-3 weeks
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Benzathine penicillin G is usually used prophylactically or acutely?
Prophylactically
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What are the benefits of Procaine penicillin G?
Painless and extended duration with a high conc. at 24 hours
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What are the cons of Procaine penicillin G?
Some may be allergic
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How do procaine penicillin G mixtures work to reduce rate of absorption of Penicillin?
Procaine is positively charged and Penicillin is negatively charged, they bind together to act as a repository
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Penicillin V has been stabilized to withstand what?
Acid in the stomach
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How is penicillin V given?
Orally
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What is the main indication for Penicillin V?
Dental abscesses or infections
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What is the downside of Penicillin V?
Very frequent dosing
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By what route is Penicillin V excreted?
Renally
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What is the t1/2 of penecillins?
½ hour
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What percent of penicillin clearance is tubular secretion and what is glomerular filtration?
tubular secretion: 90% glomerular filtration: 10%
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What is probenecid?
Gout treatment
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Why should penicillin and probenecid not be given together?
Probenecid reduces the clearance of Penicillin, causing a higher blood level
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Penicillin distributes well to what tissues?
Most everywhere except the CNS (meningitis is exception to this) and humor of the eye
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Why can penicillin enter the CNS with meningitis?
B/c the membranes become inflamed and allow Penicillin to enter
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Would you choose a natural penicillin to treat Streptococcus or a Staphylococcus infection better and why?
Streptococcus, penicillin does not treat Staph because there are B-lactimases and penicillinases in the Staph
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Does natural Penicillin treat gram-positive or negative better?
Positive, poor to no treatment of gram negatives
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What gram negative bacteria can natural Penicillin treat?
Neisseria meningitides and non-penicillinase producing N. gonorrhoeae
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What gram positive cocci can be treated with natural Penicillin?
Streptococcus pneumonae and viridians
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What gram positive bacilli can be treated with natural Penicillin?
Clostridium perfringens(gangrene), Clostridium tetani, bacillus anthracis (anthrax)
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If you have heart issues and you visit the dentist, what drug might you be given prophylactically and why?
Natural Penicillins to prevent Strep viridians causing endocarditis
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What spirochete can be treated with natural Penicillin?
Treponema pallidum (syphilis)
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Is syphilis resistant to natural penicllins?
No, not usually
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Do natural penicllins treate gram negative rods?
No
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Do natural penicillins treat Pseudomonas aeruginosa?
No, because it is a gram negative rod
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Can you treat enterococci with natural penicillins?
Yes
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Can Cephalosporins treat enterococci?
No
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What is another term for Penicillinase resistant penicillins?
Antistaphylococcal penicillins
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Are natural penicillins or Penicillinase resistant penicillins more efficient at killing gram positive bacteria?
Natural penicillins
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Are Penicillinase resistant penicillins or natural penicillins more narrow spectrum?
Penicillinase resistant penicillins
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Penicillinase resistant penicillins have what feature that helps inhibits penicinillinases?
Large hydrophobic group
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Do Penicillinase resistant penicillins have high or low activity?
Low
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What group do Penicillinase resistant penicillins have no activity against?
Gram negative rods
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Will Penicillinase resistant penicillins treat an MRSA infection?
No
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Nafcillin, oxacillin, isoxazolyl penicillins, and methicillin all below to what class of penicillins?
Penicillinase resistant penicillins
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What were Penicillinase resistant penicillins developed and used for?
To treat Penicillin resistant strains of Methcillin susceptible staph aureus (MSSA) with Beta-lactimases
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Why don't we use methicillin anymore?
Greater toxicity than other Penicillinase resistant penicillins, causes interstitial nephritis
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If a bacteria is resistant to methicillin, will it be resistant to other Penicillinase resistant penicillins?
Yes
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Which Penicillinase resistant penicillins are given IV and can cause phlebitis?
Nafcillin and oxacillin
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Which Penicillinase resistant penicillins are given orally and cause GI effects?
Isoxazolyl penicillins
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Which Penicillinase resistant penicillins can cause interstitial nehritis?
Methicillin
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What is the advantage of Aminopenicillins over natural and penicillinase resistant penicillins?
Broader spectrum, mainly because they are able to be effective on more gram negative bacteria (some bacilli)
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The positively charged amino group on the R side chain of Aminopenicillins enhances what activity?
Activity against gram negative bacteria, by allowing them penetration into the porins of the membrane
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Is amoxicillin oral or IV and why?
Oral, not sensitive to acid degradation
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Is ampicillin oral or IV and why?
IV, sensitive to acid degradation
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How can you increase the activity of Aminopenicillins?
Add aminoglycoside
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What limits the spectrum of Aminopenicllins?
B-lactimases
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How can the issue of B-lactimases be resolved with Aminopenicillins?
Use of B-lactimase inhibitors
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What do Aminopenicillins have no or poor activity against?
No: Pseudomonas aeruginosa, Poor: Staph and obligatory anaerobes
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Other than the enhancement of Gram negative activity, in what other ways is the spectrum of Aminopenicillins enhanced?
Improved G+ activity against streptococci, enterococci
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Primarily, what gram negative bacteria are Aminopenicillins more active against than lower generation penicillins?
E. coli and H. influenza
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Why are Aminopenicillins not active against Staph infections?
B-laactimases are present
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Is Piperacillin or Ticarcillin more potent?
Piperacillin
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Which antipseudomonal penicillin has an amine group with apositve charge?
Piperacillin
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By what route are antipseudomonal penicillin given?
IV
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Piperacillin and Ticarcillin are what class of penicillin?
antipseudomonal penicillin
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What is the charge of Ticarcillin and why?
Negative, due to COOH
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What is the charge of Piperacillin?
Neutral because of COOH and amino group
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Do antipseudomonal penicillin have activity against Pseudomonas aeruginosa?
Yes
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