Antibiotics - B-lactams Flashcards
Which penicillin is more stable in stomach
Penicillin V
What catalyzes pen degradation
heavy metals
Best pH to store pens
6-8
Majority of pen excretion and breakdown
renal 90% secreted 10% filtered
How to prolong pen concentration in body
Give probenecid (cation) to compete for excretion
Benzylpenicillin (penG) Txs what
Gram +
N. gonorrhoeae and H. inf
PenG B-lac sensitive?
yes
Methicillin advantage
steric hinderance via 2x methoxy substituents on ortho position. protects from B-lac
Methicillin B-lac sensitive?
no
Methicillin acid stable? Compared to other pens
No. its worse - t1/2 is 5min in stomach
Methicillin admin route
IV
Methicillin spectrum
narrow - mainly S. aureas
Methicillin induce B-lac?
yes
MRSA gets resistance how
mecA gene (mutation in pen binding protein)
Cephapirin ring description
6 member instead of 5 member
Ceph inactivation occurs via
host esterase - hydrolyze the acetate
Imipenem structure difference
methylene group replaces sulfur in thiazolide ring - greater ring strain
Imipenem does what to B-lacs
inactivates them
Imipenem degradation occurs via
renal dehydropeptidase - 1
Prolong Imipenem in body how
give cilastatian to inhibit renal dehydropeptidase - 1
Imipenem spectrum includes
G+ and G-; very broad spec; magic bullet
Imipenem and B-lac
induces it
Imipenem main uses
serious infection of gut, GU, bone, skin, and endocardium
Aztreonam spectrum
total G- NO G+
Aztreonam allergenicity
can give to those with pen allergy (except ceftazidime which has identical side chain)
