Misc. Abx Flashcards Preview

Pharm > Misc. Abx > Flashcards

Flashcards in Misc. Abx Deck (36)
Loading flashcards...

Although tetracyclines are cross-reactive, ____________ is resistant to this because it is in the tetracyclin derivative category known as ____________.

*Tigecycline - Glycylcylins


What classes of microbials can tetracyclines be used against? (list some of the major targets) What 2 general conditions are they commonly used to treat?

- Gram-pos aerobes (*MSSA) - Gram-neg aerobes - Anaerobes - bacteroides spp. - Misc. bacteria. - legionella, chlamydophila, chlamydia, mycoplasma, ureaplasma, rickettsia (sketchy) - Often used for STI infections and dz's caused by tick bites!


Does tigecyclin have a more or less broad spectrum of activity vs. tetracyclins? Which organism is tigecyline notably not active against?

- Broader * Pseudomonas


Besides being inactive vs. pseudomonas, what 2 other conditions does tigecycline NOT treat?

*UTIs and *bacteremia


*What type of meds are tetracyclines and glycylcyclines contraindicated with?

Di and tri-valent cations (they should even avoid dairy due to Ca2+) - Must separate administration by a few hours


What are the major serious side effects a/w tetracyclines/tigecycline?

- Severe N/V - Photosensitivity (should avoid sun)


What can occur if expired tetracyclines are prescribed?

Fanconi-like syndrome a/w renal failure


What drug acts synergistically w/sulfas?

Trimethoprim (also inhibits folate/purine synth pw but at a different enzyme--dihydrofolate reductase)


What is the precursor of purine synthesis? - How is it affected by purine synthesis pw inhibitors?

PABA - Builds up


What drugs are in the combination Bactrim?

Trimethoprim-Sulfamethoxazole (TMP-SMX)


Explain the target organisms (only) of the broad-spectrum antibiotic TMP-SMX (Bactrim).

gram-pos: *staph aureus (MRSA, CA-MRSA) Gram-neg: - Stenotrophomonas maltophilia. Other: - Pneumocystis carinii. Plus many more (broad spectrum)


When giving Bactrim, what lab level should be monitored and why?

CrCl (kidney function; eliminated partially by kidney)


*What are the (3) major clinical uses of TMP-SMX?

1. Acute, chronic, or recurrent UTIs 2. Acute or chronic bacterial prostatitis 3. Skin infections due to CA-MRSA


What are the major adverse effects a/w TMP-SMX/Bactrim?

- Leukopenia - Thrombocytopenia - Rash/hypersensitvity - Renal impairment (crystaluria)


Are dose adjustments required in renal failure when giving chloramphenicol?

No, metabolized by liver


*What 2 major adverse effects are the reason that chloramphenicol isn't available in the U.S.?

- Gray Baby Syndrome (resp failure, death) - Aplastic anemia (no RBC production)


What are the 2 urinary tract agents that we need to know?

- Nitrofurantoin - Methenamine


What is nitrofurantoin used for? What is methenamine used for?

- Nitrofurantoin: used solely for UTIs - Methenamine: used solely as prophylaxis for UTIs if they’ve had recurrent UTIs


Which of the enterobacteriacea are lactose fermenters and which are non-lactose fermenters? (All ferment glucose, oxidase negative, reduce nitrate, and use MacConkey)

- Lactose fermenters: E. coli, klebsiella, Enterobacter, Citrobacter, Serratia - Non-lactose fermenters: Salmonella, Shigella, Proteus, Yersinia


Distinguish the characteristics of the 5 types of E. coli.

o Enterotoxigenic E. coli (ETEC): Profuse watery diarrhea (Traveler’s diarrhea) o Enteropathogenic E. coli (EPEC): infants; diarrhea w/mucus but no gross blood o Enteroinvasive E. coli (EIEC): blood, mucus, and many leukocytes in stool o Enterohemorrhagic E. coli (EHEC): Bloody diarrhea w/o pyuria. May progress to HUS. ♣ Shiga-toxin producing E. coli (STEC) via E. coli O157:H7 o Enteroaggressive E. coli (EAggEC): Watery diarrhea w/blood and mucus


MoA for tetracyclines/glycylcyclines? - Static or cidal?

Reversibly bind 30S ribosomal subunit to inhibit ptn synth. - Bacteriostatic.


Mech of resistance for tetracyclines/glycylcyclines? (Which drug is more resistant to these mechs?)

- Efflux pumps - Ribosomal protection proteins - Enzymatic inactivation (Tigecycline more resistant to these mechs)


Where's an important body areas that Tetracyclines/Glycylcyclines, distribute to? - What about Bactrim?

Prostate - Same for bactrim


What 2 tetracyclines/glycylcyclines are excreted, unchanged, in the urine?



Do tetra/glycylcyclines have to be modified w/renal disease?

No - Doxycycline, minocycline (metab) and tigecycline (biliary) - excreted mainly by non-renal routes


What is tigecycline often used to treat?

Polymicrobial infections


Which demo is tetra/tigecycline contraindicated in?

Pregnant (category D) - Affects their children (e.g. teet


What's the MoA of sulfonamides? - Static or cidal?

Inhibits dihydropterate reductase (folate/purine synthesis) - Bacteriostatic.


What's the MoA of trimethoprim? - Static or cidal, when combined w/sulfas?

Inhibits dihydrofolate reductase - Becomes cidal w/bacteriostatic sulfas


What is another name for Trimethoprim-Sulfamethoxazole (TMP-SMX)? - How is the spectrum of activity/resistance affected when the drugs are combined?

Bactrim - Broader spectrum, decreased resistance