Overview of Exam 2 Flashcards
In transcription of DNA, what is the strand that is copied?
Noncoding (antisense) strand
Function of the 50S subunit of bacterial ribosomes
Biochemical tasks (does the actual synthesis of the new protein)
Function of the 30S subunit of bacterial ribosomes
Has to do with binding (and recognition of molecules and reading the code)
Peptidyl transferase
actual enzyme in the ribosome that has the catalytic activity to form the peptide bond
MOA of Aminoglycosides
1.) Interferes with initiation (where ribosome finds AUG start codon)
2.) Premature termination
3.) Causes wrong AA to be put in place
**Secondary action= might directly affect membrane permeability
BACTERIOCIDAL
Post-antibiotic effect
bacteria continue to die even after antibiotics have been stopped (residual antibiotic activity)
What’s special about doxycycline?
Only TC that can be dosed once/day (longer t1/2); is the only TC that covers CA-MRSA (not HA-MRSA)
What’s special about minocycline?
Can go over CSF since it is the most lipophilic of the tetracyclines; causes bluish-black pigmentation to skin in some pts; causes ototoxicity
MOA of tetracyclines
Bind to A site of 30S and blocks access of tRNA
BACTERIOSTATIC
What TC’s can you use in renal compromise?
Minocycline or Doxycycline
Important ADR’s of Tetracyclines
Teeth discoloration and bone effects!, Hepatotox, Nephrotox, Benign Intracranial hypertension (edema in the brain), Fanconi Syndrome (so don’t “save” you pills!)
MOA of Glycylcyclines
Blocks entry into A site of 30S (like TC’s) but are not affected by resistance mechanisms like TC’s are
Important ADR’s of Glycylcyclines
Teeth discoloration and bone effects (from chelation of metal); < elimination of Warfarin
MOA of Macrolides
Block the exit tunnel (DOES NOT INHIBIT RIBOZYME DIRECTLY)
Important ADR’s of Macrolides
Epidgastric distress, ototoxicity, cholestatic jaundice, metallic taste (only in Clarithro), Q-T prolongation/ torsades, 3A4 drug interactions
MOA of Telithromycin
Binds to 50S on 2 separate areas (exit tunnel like macrolides & other site nearby on 50S)
Important ADR’s of Telithromycin
Syncope (fainting), CYP interactions, Q-T prolongation, torsades
MOA of Lincosamides
Bind to exit tunnel of 50S and cause backlog
Important ADR’s of Clindamycin
Pseudomembranous Colitis (overgrowth of C. diff), > liver enzymes, < neurotransmission
MOA of Streptogramins
A binds to allosteric site on 50S and B binds to exit tunnel (same site as macrolides)
Important ADR’s of Streptogramins
CYP 3A4 interactions, arthralgia/myalgia
MOA of Chloramphenicol
Prodrug –> Inhibits peptidyl transferase (inhibits binding of tRNA to ribosome and prevents actual peptide bond from being made)
Important ADR’s of Chloramphenicol
Mostly related to the fact that human protein synthesis in mitochondria can also be inhibited: Bone marrow suppression, aplastic anemia, Gray Baby Syndrome
MOA of Oxazolidinones
Prevents initiation and not elongation!! (means no cross resistance with other abx) Binds to 50S and prevents 50S from coming into contact with 30S to form initiation complex
Important ADR’s of Linezolid
Myelosuppression, Pseudomembranous Colitis,
** Linezolid is a weak inhibitor of MAO so can also have enhanced effects of adrenergic agents that use this enzyme: Serotonin Syndrome (when administered with SSRI’s), Cheese Reaction (avoid food or drink high in tyramine)
MOA of Quinolones (Fluoroquinolones)
Inhibit topoisomerases= allows them to break the DNA but then binds and prevents them from re-sealing the nick DNA gyrase (Topoisomerase II)= Gram (-) Topoisomerase IV= Gram (+)
Important ADR’s of FQ’s
Achilles and Rotator Cuff Tendonitis and Rupture, Q-T prolongation/ torsades, CYP inhibition, chelation
Which FQ can you use in renal failure?
Moxifloxacin (since it is most excreted by liver)
MOA of Nitrofurantoin
Gets activated by having its NO2 group reduced by NADPH –> attacks sensitive enzymes
Important ADR’s for Nitrofurantoin
Hemolytic anemia (in pts with G6PD deficiency) Acute pneumonitis (if drug achieves tx conc in blood)
MOA for Metronidazole
PRODRUG –> activated when NO2 group is reduced by electron transport chain (ferrodoxins) –> attacks DNA
Important ADR’s for Metronidazole
Furry tongue/ metallic taste, Steven-Johnson’s Syndrome, Disulfiram-like effect (if you drink you become ill)
NO PREGO!
MOA of Rifamycins
Inhibit RNA Polymerase (transcription initiation)
Important ADR’s of Rifamycins
Red-orange color to body fluids, induction of P450
ADR’s specific to Rifabutin
Polymyalgia, pseudojaundice, Anterior uveitis (inflammation of undercoating of eye)
MOA of Sulfonamides
Act like PABA and inhibit dihydropterate synthase –> inhibit synthesis of folic acid (used in DNA synthesis)
Important ADR’s of sulfonamides
Crystalluria, hemolytic anemia (in pts with G6PD deficiency), SJS
MOA of Trimethoprim
Inhibits dihydrofolate reductase (DHFR)
Bactrim
Trimethoprim/ sulfamethoxazole 5:1 ratio
Important ADR’s for Trimethoprim
Megaloblastic anemia, hemolytic anemia (in pts with G6PD deficiency), jaundice
MOA of Fidaxomycin
same as Rifamycins, bind to RNA Pol and prevent initiation of transcription
MOA of Daptomycin
Needs calcium as a cofactor!; forms channels that leak ions
Can Daptomycin be used in Respiratory infections?
NO! b/c the surfactants in the lungs soak up the drug
Important ADR’s with Daptomycin
Eosinophilic pneumonia, reversible myopathy, peripheral NS disorders
MOA of polymixins
causes “leaks” in the membrane
Important ADR’s with Polymixins
Neurotox, Nephrotox
MOA of Glycopeptides
Inhibit polymerization of cell wall by binding directly to D-Ala/D-Ala and blocking addition of new NAG-NAM
Important ADR’s of Glycopeptides
REDMAN’S SYNDROME, ototoxicity, nephrotoxicity, Q-T prolongation, NO PREGO
