Pharm 2 - Antimicrobials 4

isabellepjk's version from 2017-10-11 15:10



Question Answer
***All protein synth inhibitors are bacterio___, EXCEPT ____ which is bacterio___.All static, except Aminoglycosides, which are cidal. (Ami did not go to the pool w/ Mac & Lin)
What is the mechanism by which prot synth inhibitors work?They are specific to the 70s (30S & 50S) ribosomes responsible for making bacterial proteins → they interfere w/ initiation & elongation
Toxicities of the 30S'sNephro, Oto & Photo (lol)
**What are the 30S drugs? The 50S?(AT 30 you have 50 mean little cats OR 30 is where it's AT & 50 is CaLM)
30 = Aminoglycosides & Tetracyclines
50 = Macrolides, Lincosamides, Chloramphenicol


Question Answer
*Aminos Type _________ killing?1, Concentration-Dependent
and PAE (ami thinks she is #1) (even tho it has some post antibiotic effect. whatever.)
Aminos are bacterio___CIDAL! (All other protein synths are static)
*Aminos spectrum?Narrow (remember: Ami's B was Myxed-up in her Colon, isn't wasn't a narrow escape)
Aerobic, G-
**Why do owners like aminos?Single daily dose – equally efficient as the same dose divided over 24 hours
What are aminos effective against? Not effective against?Effective = G- & G+ aerobic... NOT EFFECTIVE AGAINST ANAEROBES (ami is only human, she has to breathe)
What are Aminocyclitols? How does this affect the distribution?The source for Aminoglycosides, they are polar organic bases w/ low lipid solubility (so cant get through cell membrane so they hang out extracellularly)
What are the 7 aminos?GPSNATK
Gentamicin (most renal toxic)
Neomycin (topical)
Amikacin (broadest spectrum)
Paromomycin (G+, G-, & protozoans)
Apramycin - feed additive
(Ami Kan Genta-ly Strep the paro Neo & Tob-y naked)
Which amino is the most renal toxic?Gentamicin (Gentamicin is not so GENTLE on your kidneys. harhar)
Which amino is used topically?Neomycin (think Neosporin)
*Which amino has the broadest spectrum?Amikacin (of course ami would be the best ami, what a broad)
*Which amino works against G+, G- & PROTOZOA?Paromomycin (start w/ P)
---How do bact resist aminos?*Enzymatic inactivation
Ribosomal alterations
Reduced permeability of abx
What is the special way aminos penetrate bact?BIPHASIC penetration enter bacteria by:
(1) Passive/Concentration-Dependent
(2) Active xport/oxygen dependent (That's why it only works on aerobics)
MOA for the aminos?Aminos bind irreversibly to receptor protein on the 30S ribosomal subunit & interferes w/ the mRNA translation process
Yields a non functional protein and has an irreversible lethal effect
The Concentration-Dependent effect & having post-antibiotic effect means what for the amount of doses needed to be given in a day for Aminoglycosides?Only need a single daily dose (not Time-Dependent!) so can ↓ frequency of administration (owners like this)
How does the pH affect aminos?↑ the pH (more basic) will ↑ the antimicrobial activity (acidic pH will ↓ activity) (Ami is a Basic bitch, she likes the basic shit)

presence of Ca or Mg cations also decrease
**How do you administer aminos?100% PARENTERAL ABSORPTION! (Oral absorption is shitty) (AMI is like the sultan → she is special, so only takes the strange ways into a building)

complete and rapid absorption in ear and eyes
Where do aminos accumulate? (Intra or extra cellularly?)Extra (Ami likes extra things)
Where are aminos metabolized?They arent metabolized (lol Amy has no metabolism, I guess she's fat then)
How is the distribution of aminos in lean versus fat animals?↑ distribution in lean animals (I'm not clear on WHY but she & all the textbooks say this is right)
slow tissue depletion
**What are the toxicities caused by aminos? (3)(1) Nephrotoxicities
(2) Ototoxicity inner ear, irreversible --> Perilymph and endolymph
(3) Neuromuscular blockade
(Ami's kidneys are probably shot, as well as her hearing, & by the way she dances youd think she had a neuromuscular problem too)
*Where are aminos excreted?Kidney → look out for nephrotox (drug accumulation in renal cortex)
Glom filtr and reabsorp
What makes the nephrotox of aminos worse?Dehydration


Question Answer
Are Tetracyclines cidal or static?Static
Spectrum of tetras?Broad
Which tetras can go into brain/spinal fluid/prostate?The semisynths (high lipid solubility)
*Tetras are Type _________ killing3 → Time-Dependent w/ post-antibiotic effect (the #3 is closest to tetra, the word for 4)
How do tetras penetrate the cell? Exceptions?Usually biphasic, a passive diffusion & an active xport phase. EXCEPTION is Doxycycline only enters via passive diffusion
*Which tetra only does passive diffusion & no active transport?Doxycycline (doxys are so cute, they dont have to try!)
What are the 2 main groups of tetras?Natural & Semi-Synthetic
How are tetras metabolized?VERY LOW METABOLISM, except Mino & Doxy are OXIDIZED in the LIVER!!!
What are the 3 main natural tetras?Chlortetracycline
(taking 4 oxys is like eating chlorine, it's so natural)
**What treats Equine Monocytic Ehrlichiosis???Oxytetracycline (although oxy's will kill a horse's GI, it's the heavy hitter to kill EME!!! so get that horse high to kill the blood shit)
Which natural Tetracycline has the lowest protein binding? What are the various formulations of this drug?Oxytetracycline! Conventional formulation can be IV or IM, & the long acting formula is IM only (oxys dont last too long)
Of the natural & the semi-synthetic tetras, which has a better distribution, & why?Semisynths are better, bc they are more lipid soluble
What are the 2 semi-synthetic tetras?Minocycline & Doxycycline
How are Minocycline and doxycycline metabolized?Oxidation (liver)
Where is Doxycycline absorbed from? Metab? ExcretedAbsorbed from GI, Metabolized in Liver via oxidation & excreted via feces.
How should you administer tetras?ORAL preferred, NEVER SC (the tetra fish goes in the mouth)
**What drugs chelate w/ cations & what happens bc of this?Semisynths (Doxy & Mino) ↓ absorption & deposit at sites of calcification (fuck up teeth) (mina the doxy has really bad teeth)
**Adverse effects of tetras?GI Upsets
irritation (if IM), chelates w/ Ca, so give slowly IV or it will collapse the heart
anaphylactic shock if IV,
can mess w/ the GI flora of ruminants so give slowly,
tooth mottling(tetra, teeth),
renal tubular damage,
**Which drug causes esophageal lesions in cats?Doxycycline (hyclate) (doxys are dogs, so they want to rip out a cat's throat)
Down side to IM injxn of tetras?Local irritation (tetra fish in my muscles would be really irritating)
Risks associated w/ IV injxn of tetras? (2)(1) Rapid IV injxn → chelates calcium in blood → ↓ Ca++ availability for heart contraction → collapse
(2) Anaphylactic shock in dogs
How can bacteria resist tetras?They ↑ the efflux of the drug
*Which tetra has complete oral absorption?Doxycycline (doxy likes to eat! A lot! Silly puppy)
Which tetra has long-acting deep IM action?Oxytetracycline (OXYgen DEEP in your MUSCLES means you can go a LONG time running)
Why are semisynth more effective?Bc highest protein bound, so more effective (& more lipid soluble)
Preferred drug for renal function impaired PTxs (tetras)DOXYCYCLINE bc excretion in bile & by diffusion into the large intestine (excreted in the feces)
Excretion of tetras? Exceptions?60% in urine & 40% in feces, exception is DOXY (biliary)
Doxycycline (IV) is risky in who, why?Horses – fatal cardiac arrhythmia/collapse (Short little thing like a doxy could spook a horse to death)
Oxytetracycline's bad effect?Alters GI microflora in horse butt (don't give oxy's to your horse. They are high enough on stupidity)
**The absorption of Tetracyclines is affected by cations, which means you should restrict...NO FOOD/MILK
Chelation w/ cations renders the drug useless
**Which tetra is safe for kidney PTxs?Doxycycline, bc excreted in bile!! (my doxie would never hurt your kidneys!)
**What are the lipid soluble, broad spectrum tetras?The semisynths → Doxy/Minocycline (mina the doxy)
**What should you know about horses & tetras?NEVER give Tetracycline PO to a horse!
Why? Superinfxn (GIT) – destruction of normal GIT flora (dont kill GI flora by putting the abx in the GI. derp.)
Chlamydia is treated in birds by what?Doxycycline (princess the doxy likes birdies)