pharm 3B: topical ABX + anti-TB Flashcards
what is the MOA for bacitracin?
it clogs the channels and prevents intracellular proteins from going from cell to intracellular space
what is the spectrum/pharmacokinetics/ s/e for bacitracin?
what is bacitracin often combined with?
spectrum - KILLS GRAM POSTIVES
pharmacokinetis - topically for derm, opthalmically
often combined with neomycin or polymyxin
S/E: nephrotoxicity if given systemically
what is the two polymyxin bacterias and what is the MOA?
- colistin (polymyxin E) and polymxin B
MOA - the abx kills the hydrophobic and hydrophillic compoentns of the bacteria cell wall and casuesing its destruction
what is the spectrum and pharmaokineitcs and S/E for polymyxin?
KILLS GRAM NEGATIVES
given topically, often combined w bacitracin
S/E: polymyxin E is nephrotoxicity when given IV so dont give it with other nephrotoxici drugs like vancomycin
what is mupirocin MOA, spectrum and pharmokinetics?
MOA - inhibits bacterial tRNA syntheases so it cannot make new proteins
kills MOST - AND +
given topically for skin infections and lesions
what are the two cell walls for mycobacterium and what is the importance?
- mycolic acid - it has 90C atoms in the molecules and its a waxy cell wall
- arabinogalacton - stabzlies the mycolic acid and cell wall
whats so imp about the arabinogalactan cell wall?
its part of the mycobacterium
- the arabinogalactan cell wall has arbinosyl transferase III
- this enzyme syntehsizes arabinogalactan
- since mycobacteria has a thick wall it protects the BUG FROM degradation
what happens when theres a TB in your body?
- TB will enter the alveolus and macrophages will engulf it
- normally macrophaes will shuttle it to lysosome to get it kills but bc the mycobacteria has this thick wall it prevents it from being hydrolyzed by the macophages
- the WAXY cell also inhibits + stops enzymes that porduces the molecules in the first place
- it also stops the macrophages from releases enzymes that helps w degradation
how is a granuloa formed with TB infection?
- since the bug cannot be killed, the immune system WALLS off the infection and forms a granuloma
- the macrophages with the TB will go under activation and is now called **epitheloid cell **
- some of the activated macrophages will fuse tg to form the CORE of ganuloma
what happens around the granuloma in the lungs for TB?
- since now we have a macrophage with latent TB in, the fiberglass secretes fibrotic tissues to WALL OFF the entire area of infection since the bug cannot be killed
how is caseous necrosis formed?
- overtime TB will secret TB TOXINS and it will kill the macrophages
- it will then kill the alveolar cells and when it kils the macriophages it will form a **caseous necrosis **
how many bugs live in the a TB granulmona?
107-109
what is milliary tB?
when it spreads to other orgran, skeletal and musucles
what is methy methacrylate balls?
they used this to tx TB in the 20th centry, they would put the balls in the upper lobe lung to have it collaspe to to prevent the spread of the DZ
what rx would u use for 4 month tx for TB?
RIP
rifampam, isoniazid, pyramizide
what type of rx happens with the TB test?
hypersensitvity TYPE 4 RX
explain if TB test is >5, >10, >15?
> 5 = immunocomprised ppl, HIV ppl, fibrotic changes should get TX
> 10 - iv drug users, hospital people, children exposed, immigrants - needs tx
> 15 - everyone like u doesnt need tx
what is the MOA for rifamycins and how does the bacteria become resisitant?
- it inhibits the beta subunit of the BACTERIAL RNA polymerase –> prevents the RNA from making protein
- the bacteria become reisistacne by mutating the beta subunit so that rifamycin cannot bind to it
what does rifamycin kill?
- TB, other mycobacterias
- gram +
gram -
what is the pharmokinetics for rifamycin?
it was a STRONG CYP INDUCER through heptatic metabolism so be careful with other drugs ,
main one: HIV drugs
very little in the kidney
what are the S/E to rifamycin?
- orange color discoloration
- rash fever flu sx
- hepato toxic - liver failure can happen
- GRAVID - AVOID
- hypersensitivty - can lead to hematuria or hemolysis
- DRUG DRUG INTERACTION
rifampin > rifapentine > rifabutin
really bad for HIV medications
what is INH?
INH is isoNICOTINYLhydrazide which is an isoniaid PRODRUG that is taken up by mycobacteria when given
what is the MOA for isonizaid ?
MOA - mycobacteira takes up isoniazid and in the bacteria there is KATG enzyme that changes the isonaizid pro drug into active drug
this allows iso to bind to NAD and NADH
NAD binding - allows to inhibit mycolic acid
NADH binding allows it to inhibit dihydrofolate reductase so it cannot make any more DNA
what is the resisitane for isoniazid?
the bacteria is able to mutate KATG so that iso cannot turn into its active form
