Walters-Penicilins Flashcards
what do penicillins (PCNs) inhibit?
they inhibit transpeptidase. important because gram (+) bacteria undergo cross-linkage reactions. without transpeptidase the D-alanine will not be removed, which inhibits cell wall synthesis-> LYSIS
are PCNs static or cidal?
cidal because they disrupt the sythesis of cell wall synthesis, which causes lysis
what defense have microbes evolved to destroy PCNs?
beta lactamase enzymes that destroy the beta lactam ring in PCN
how is PCN G administered and why?
cannot be taken orally (acidity would inactivate it) and only distributes into the CNS if the meninges are inflammed
what are the 3 forms of PCN G drugs?
aqueous, procaine and benzathine
why are people usually allergic to procaine?
it is an ester and some patients are allergic to esters
which PCN G drug is the longest lasting?
benzathine
What two drugs are combined to form Bicillin C-R?
procain and benzathine
what is the difference between PCN G and PCN V?
PCN V can be taken orally (acid stable), food will decrease absorption and it is dosed in mgs (not units like PCN G)
when would you use Penicillinase (beta-lactamase) resistant PCNs?
only if PCN G and PCN V are ineffective
what are the three type of Penicillinase resistant PCNs?
dicloxacillin (taken orally), oxacillin (parenteral) and nafcillin (parenteral)
how are Penicillinases eliminated?
eliminated by biliary and renal excretion an advantage in hepatic or renal disease
what are Aminopenicillins useful for?
increased coverage for gram negative bacteria but they are still susceptible to PCNases
how is ampicillin delivered?
oral or IV
what is sulbactam?
is a beta-lactamase (PCNase) inhibitor that protects ampicillin from metabolism, which enhances activity
