Anti-biotics Flashcards
What antibiotic drug classes are naturally derived (5)
Penicillins Cephalosporins Macrolides Tetracyclines Aminoglycosides
What is “sensitivity”
degree to which microbial organisms are killed or their proliferation arrested by the drug
What drug class is sulfamethoxazole
sulfonamide antibiotic
What is the MOA of sulfamethoxazole
Competitive antagonist of para-aminobenzoic acid (PABA) which blocks bacterial production of folic acid
What is the MOA of Sulfamethoxazole + Trimethoprim combination drug (TMP/S)
inhibits two different step of bacterial folic acid production
What are the indications of Sulfamethoxazole + Trimethoprim combination (TMP/sulfa)
UTI, pneumocystis prophylaxis, susceptible MRSA infection
what sort of creatures are susceptible to TMP/S?
mostly microbial: Streptococcus, Staphylococcus aureus, Escherichia coli, Haemophilus influenzae, and oral anaerobes.
But also some fungi, thus use in pneumocystis prophylaxis
What is the worst reaction to TMP/S
Stevens Johnson syndrome
What are the most common reactions to TMP/S
Skin reactions like rash, photosensitivity. And of course nausea and diarrhea
What drug class are penicillins
Beta-lactam antibiotics
What is the MOA of penicillins
Bind to penicillin binding proteins (Peptoglycans) on the bacteria which inhibits the formation of peptidoglycan cross-linkage in the bacterial cell wall, which causes cytolysis and cell death.
What sort of bugs are susceptible to penicillins
mostly gram positive bugs
What type of anti-biotic causes the most severe allergic response
penicillins!
When is penicillin G indicated
for use against strep throat and some gram negs like Neisseria. Plus it is cheap!
How is the half-life of penicillin G extended
Procaine and benzathine are added to IM injection to decrease pain and increase half-life
When is amoxicillin used
it is a broad spectrum bactericidal drug used against gram pos, UTI, ENT, skin infxn. Not really for severe stuff
What is advantageous about penicillin’s range over amoxicillin’s range
penicillin can cross the BBB, and thus is used for meningitis whereas amoxicillin cannot.
how can amoxicillin’s effect be improved
By adding clavulanic acid added to prevent β lactamase inhibition. This is called Augmentin
What is augmentin’s (amoxil + calvulanic acid) MOA
binding to penicillin binding protein and inhibiting protein synthesis in the bacterial cell wall
what is the most severe common side effect of augmentin (amoxil + clavulanic acid)
The most severe cause of antibiotic induced diarrhea is pseudomembranous colitis.
How much clavulanic acid is in the 250, 500, and 750mg doses of Augmentin
The dosage applies to the amoxicillin portion only. They all contain the same amount of clavulanic acid.
What is the MOA of cephalosporins
Same as other beta-lactam antibiotics: Bind to penicillin binding proteins (Peptoglycans) on the bacteria which inhibits the formation of peptidoglycan cross-linkage in the bacterial cell wall, which causes cytolysis and cell death.
What is a first generation cephalosporin useful for
It has very good activity against gram positive, but poor gram neg coverage
What generation is cephalexin (Keflex)
1st generation cephalosporin (all 1st gen start with “ceph”)
