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Pharmacology of Antibacterial Drugs II - Coggle Diagram
Pharmacology of Antibacterial Drugs II
ß-Lactam
cell wall inhibitors
Inhibit the crosslinking in the peptidoglycan wall (causes cells to swell and lyse)
Almost all bactericidal drugs
Inhibits
transpeptidase
and blocks cross-linking of cell wall polymers
First discovered was penicillin
ß-lactam is a four membered ring functional group
Two families of ß-lactams (same mechanism)
Penicillins
Penicillin G and V
Narrow spectrum (
gram + organisms
)
Pen G is unstable (not good for oral)
Subject to inactivation by
ß-lactamase
producers
Also has short half life (<1h)
Sustained release was figured out by binding with
Benzathine
(Benthazine Pen G)
Penicillinase resistant penicillins
Dicloxacillin
Narrow spectrum (
gram+ organisms
)
Resistant to ß-lactamase (
methicillin like
)
unfortunately made the drug less reactive to make it resistant
Extended spectrum penicillins
Ampicillin
Amoxicillin
Used for broad spectrum infections (
gram+ and gram-
)
Gotta be aware of hypersensitivity and adverse effects
Extended spectrum (gram+ and some gram- organisms)
Are inactivated by ß-lactamase
This is overcome by adding
clavulanic acid
Clavulanic acid + amoxicillin = augmentin
Clavulanate basically sacrifices itself to the ß-lactamse because there is higher affinity binding than to the amoxicillin
Cephalosporins
The first generation was narrow spectrum (
gram+
)
The following generations were broader spectrum (
gram+ and gram-
)
Cephalasporinases
have appeared
Wide range of spectrums
Adverse effects
Allergic reactions
it is a
hapten
(it's too small to react by itself, but when it binds to something else it can serve as an antigen
Superinfectins
Vancomycin
(cell wall inhibitor)
Binds the D-ala-D-ala
to keep it from forming the peptidoglycan wallq
Narrow spectrum (
gram+
) -
same as pen G and V
Not given orally (is parenterally given)
Not sensitive to ß-lactamase
Used for treatment of
serious gram+ infections
Methicillin resistant gram+
C. diff
can be used in those with penicillin allergy
Anaphylactoid reaction if administered too quickly (red-man syndrome)
Folate Synthesis Inhibitors
Sulfamethoxazole
(is a sulfonamide)
Inhibits Dihydropteroate synthase (can't make purines, can't make DNA)
Trimethoprim
Inhibits Dihydropholate reductase (can't make purines, can't make DNA)
Folic acid is necessary to make amino acids and neucleotides
Bacteria need to make own folic acid from
PABA
(p-aminobenzoic acid)
Humans don't need PABA as much
Broad spectrum (
gram+ and gram-
)
Bacteriostatic
(inhibiting DNA won't kill them, just stop them from multiplying
Sulfamethoxazole and Trimethoprim are
synergistic
This allows for lower likelyhood of toxicity because lower concentrations are needed
Used very frequently for UTIs, ear infections, bronchitis
Resistances
Sulfonamides
altered dihydrojpterate synthase enzyme
Decresased accumulation of drug in bacteria
Trimethoprim
altered dihydrofolate reductase enzyme
Adverse effects
Hypersensitivity reaction (Stevens-Johnson syndrome)
Hemolytic anemia in patients with glucose-6-phosphate dehydrogenase deficiency
Kernicturus - brain damage in newborns due to high levels of unconjucated bilirubin
Renal toxicity - drug precipitation in renal tubules
Drug interactions - can potentiate action of other drugs
inhibit metabolism other drugs (CYP450)
Displaces drugs from albumin (increasing free-drug concentration of other drug)