Antimicrobials 1 H&D Flashcards
Name the primary class of drugs that affect cell wall synthesis.
Beta lactams
What are the four subclasses of beta lactam antibiotics?
Penicillins (4 categories)Cephalosporins (5 generations)CarbapenemsMonobactams
To be effective, what four criteria must be met for beta lactams to be effective?
- evade bacterial defenses 2. penetrate outer cell layers to inner cytoplasmic membrane 3. keep the beta lactam ring intact 4. bind to transpeptidase
What is the ultimate method of action of beta-lactams?
They bind to active site of the PBP enzyme to prevent transpeptidation (terminal step in cell wall synthesis)
What is the only true naturally occurring penicillin?
Penicillin G
What two antimicrobials are natural penicillins?
Pen G, Pen V (aka Pen VK)
What are natural penicillins effective against?
sensitive strains of Gram + cocci (Pen G also active against some gram - Neisseria and anaerobes)
Are Natural penicillins narrow or broad spectrum?
Narrow spectrum
What are two Aminopenicillin antimicrobials?
Ampicillin, Amoxicillin
Since activity is extended compared to natural penicillins, aminopenicillins are referred to as what?
Extended spectrum penicillins(better Gram negative coverage than natural penicillins)
Aminopenicillins are administered with B-lactamase inhibitors such as? (3 names)
Clavulanate, Sulbactam, or Tazobactam
What is augmentin?
Amoxicillin + Clavulanate
Ampicillin should not be consumed with?
food, because the food binds to the drug and disables it
What are aminopenicillins effective against?
Sensitive Gram + and sensitive Gram - bacteria like H. flu, E. coli, Salmonella, Shigella
What is the drug of choice for standard prophylaxis for infective endocarditis?
Amoxicillin(if allergic, can take cephalexin, or non-B-lactams)
What three things interact with Ampicillin activity?
Hydrocortison (inactivates ampicillin), Oral contraceptives (inactivates contraceptive), and Probenecid (slows clearance of ampicillin)
What four antimicrobials are Penicillinase-resistant Penicillins (PRPs)?
methicillin, nafcillin, oxacillin, and dicloxacillin
PRPs are effective against what?
staphylococci, streptococci(NOT enterococci, anaerobic bacteria, gram - cocci or rods)
What two PRPs are normally acid stable (given PO) with a reduced risk of interstitial nephritis?
Oxacillin, Dicloxacillin(also undergo biliary excretion, not renal)
What is the drug of choice for serious Staphylococcus aureus infections that are non-methicillin resistant (non-MRSA)?
Nafcillin(Naf for Staph)
What does probenecid do that causes it to increase drug half-life and prolong clearance?
Probenecid inhibits organic anion transporters in the proximal tubule, causing the drug to remain in the blood.
What three drugs aren’t effected by probenecid?
Nafcillin, oxacillin, dicloxacillin (¾ of penicillinase-resistant penicillins)
Carboxypenicillins, ureidopenicillins, and monobactams are what kind of B-lactam?
Anti-pseudonomal penicillins
How are anti-pseudonomal penicillins administered?
either intramuscular (IM) or intravenously (IV)NOT perorally (PO)
What kind of anti-pseudonomal penicillin are Indanyl carbenicillin and Ticarcillin?
Carboxypenicillins
What must be administered with ticarcillin?
Clavulanate (two are put into one dose in America - drug called Timentin)
What are anti-pseudonomal penicillins effective against?
Everything Pen G is effective against, plus Gram negative bacteria like Pseudonomas aerugenosa
What is Piperacillin?
An Ureidopenicillin (also broadest spectrum Penicillin)
Aztreonam is what?
A monobactam (an A-PP)(and great for pts with IgE-mediated penicillin allergy)
Anaphylactic reactions are more common when penicillin is administered __________?
Parenterally (other route than mouth/GI)
Name three allergic reactions to penicillin/B-lactams.
Anaphylactic (immediate - IgE mediated), Accelerated onset (30’ - 48” after admin), Delayed onset (2+ days - 80-90% of rxs)
What are some signs/symptoms of anaphylaxis?
headache; lightheadedness; swelling of tongue, nose and/or throat; low BP; flushed skin; SOB; stridor; swelling of conjunctiva; etc
Large doses of Pen G may produce _____, confusion, twitching, ________, kidney failure, and _____.
lethargy, seizures, coma
10% of people are allergic to what?
Penicillins, and probably cross sensitive to all other B-lactams, including cephalosporins
What difference is there between the 5 generations of cephalosporins?
From gen 1 to 5, they increase in spectrum size and B-lactamase resistance. Moderate to broad.
All cephalosporins are bacteri____.
bactericidal
Which generation cephalosporin is active against MRSA?
Gen 5 (ceftaroline)
Cefazolin is which gen cephalosporin?
1 (don’t penetrate CNS)
Cefaclor, Cefoxitin, Cefuroxime are which gen cephalosporin?
2 (good activity against E. coli, H. flu, and Klebsiella)
Cefoxitin is a ______ and is effective against mixed ________ infections, like peritonitis and pelvic inflammatory disease.
cephamycin, anaerobe
What cephalosporin crosses the blood brain barrier?
Cefuroxime
Cefotaxime, Ceftazidime, and Cefdinir are which gen cephalosporin?
3 (all of these penetrate CNS to treat meningitis)
Which cephalosporin is the highest selling and used to treat strep throat?
Cefdinir
Cefepime is which gen cephalosporin?
4 (good against Enterobacter, but poor against anaerobes)
Ceftaroline is which gen cephalosporin?
5
Ceftaroline is most commonly used to treat what three things?
MRSA, Pseudomonas and community-acquired pneumonia
What antimicrobial has the broadest spectrum known to man?
Imipenem (except MRSA and mycoplasma are resistant)
Imipenem is what class of B-lactam, and is always coadministered with _______?
Carbapenems, cilistatin (to prevent rapid renal clearance of drug)
What are some non-B-lactam antibacterials that prevent cell wall synthesis?
Vancomycin (covers all Gram +), Bacitracin (covers multi drug resistant Gram - )
Name two non-B-lactams that disrupt cell membranes.
Bacitracin, Daptomycin (active against MRSA and VRE)
How does Daptomycin disrupt bacterial cell membranes?
It inserts into the membrane and comes together to form a pore that ions freely pass through
What drug MUST be administered topically?
Bacitracin, because another route is high enough concentration to cause kidney damage
