Misc. antibiotics

Question 1

What is the MOA of tetracyclines?

Answer 1

REVERSIBLY binds to the 30S ribosomal subunit (inhibits protein synthesis - no binding of tRNA to acceptor site)

Question 2

Tetracyclines ____________ bind to the 30S subunit while aminoglycosides _______________ bind to the 30S subunit

Answer 2

REVERSIBLY

IRREVERSIBLY

Question 3

Are tetracyclines bacteriocidal or static?

Answer 3

STATIC (cidal at high concentrations against susceptible organisms)

Question 4

What are 3 big MOR for tetracyclines?

Answer 4

1) efflux pumps
2) ribosomal protection proteins
3) enzymatic inactivation

Question 5

Do you see cross-resistance at all for tetracyclines?

Answer 5

YES but not for minocycline

Question 6

Which tetracycline is resistant to the MORs?

Answer 6

tigecycline

Question 7

Describe the spectrum of activity for tetracyclines

Answer 7

GRAM POS: MSSA, PSSP, bacillus, listeria, nocardia

GRAM NEG: burkholderia pseudomallei, neisseria, H. flu

Aerobes: actinomyces, proprionibacterium

MISC: legionella, chlamydophila, chlamydia, mycoplasma, ureaplasma, rickettsia

Question 8

What are the miscellaneous bacteria covered by tetracylcine

Answer 8

legionella 
chlamydophila
chlamydia
mycoplasma
ureaplasma
rickettsia

Question 9

What is a special inclusion and exemption of tigecycline?

Answer 9

INCLUDED: bacteroides

OMISSION: proteus and pseudomonas

Question 10

True or false: tigecycline has pseudomonas activity

Answer 10

FALSE (big hole in activity)

Question 11

Why can you not use tigecycline for bacteremias or UTIs?

Answer 11

cannot maintain good levels in the blood and does not concentrate in the bladder

Question 12

What is the route of admin for tigecycline?

Answer 12

IV

Question 13

What impairs absorption of tetracyclines?

Answer 13

di and trivalent cations

Question 14

Where is a big site of distribution of tet?

Answer 14

prostate

Question 15

What 3 drugs are not eliminated via the kidney? andwhat 2 are?

Answer 15

renal: tetracycline, demeclocycline

non renal: doxy, mino, tige

Question 16

what do you use tet/glycylcyclines for?

Answer 16

RMSF, CA pneumo, STDs

Question 17

What is demeclocycline particularly useful for?

Answer 17

SIADH

Question 18

Name 5 adverse effects of tetracyclines

Answer 18

1) GI (nausea and vomiting)
2) hypersensitivity
3) PHOTOSENSITIVITY (exaggerated sunburn)
4) renal (fanconi-like syndrome with expired tets)
5) PREGNANCY CAT D

Question 19

What can you get with expired tet?

Answer 19

fanconi like syndrome (renal failure)

Question 20

What effects do tetracylcines have on pregnancy?

Answer 20

discoloration of teeth and decreased bone growth

Question 21

What is the MOA of sulfonamides?

Answer 21

INHIBITS dihydropteroate synthetase (so PABA cannot be incorporated into tetrahydropteroic acid)

Question 22

Are sulfonamides bacteriocidal or static?

Answer 22

STATIC

Question 23

What is the most common short acting sulfonamide?

Answer 23

sulfamethoxazole

Question 24

What does Trimethoprim do?

Answer 24

inhibits dihydrofolate reductase

Question 25

____________ blocks conversion of PABA ---> dihydrofolic acid while __________ blocks dihydrofolic acid ----> tetrahydrofolic acid

Answer 25

sulfamethoxazole trimethoprim (both result in no purines produced)

Question 26

Is resistance common to sulfonamides?

Answer 26

YES (structural change of enzyme)

Question 27

What is the big gram positive and big gram negative bug TMP-SMX targets?

Answer 27

``` + = staph aureus - = stenotrophomonas maltophilia ```

Question 28

TMP-SMX is prophylaxis of choice for what bug?

Answer 28

pneumocystis carinii

Question 29

Where do TMP-SMX get good distribution?

Answer 29

prostate

Question 30

Where are TMP-SMX eliminated?

Answer 30

liver and kidney - need to adjust dose in patients with CrCl

Question 31

Name 5 clinical uses for TMP-SMX

Answer 31

1) acute, chronic, or recurrent infections of the urinary tract 2) acute/chronic bacterial prostatitis 3) skin infections due to CA MRSA 4) bacterial sinusitis 5) NOCARDIA

Question 32

Name 4 adverse effects associated with TMP-SMX

Answer 32

1) leukopenia 2) thrombocytopenia 3) hypersensitivity (rash) 4) crystalluria also get tubular necrosis and interstitial nephritis

Question 33

Name 3 drug interactions common of TMP-SMX

Answer 33

1) phenytoin 2) warfarin 3) methotrexate

Question 34

How is TMP-SMX administered?

Answer 34

oral (single or double strength) or IV

Question 35

What is the MOA of chloramphenicol?

Answer 35

binds to 50S subunit of 70s ribosome

Question 36

For which 3 bugs is chloramphenicol bacterioCIDAL (not static) for?

Answer 36

1) H. flu 2) strep pneumo 3) N. meningitidis

Question 37

What are 3 resistance mechanisms for chloramphenicol?

Answer 37

1) reduced permeability/uptake 2) ribosomal mutation 3) acetyltransferase inactivation

Question 38

You should decrease chloramphicol dose in what kind of failure?

Answer 38

liver (adjustment not required in renal failure)

Question 39

Is chloramphenicol used for pseudomonas?

Answer 39

NO

Question 40

What 4 bugs does chloramphenicol treat?

Answer 40

Ricketssiae Spirochetes Chlamydia Mycoplasma IN DEVELOPING WORLD

Question 41

What are the 2 main adverse effects of chloramphenicol?

Answer 41

1) Aplastic anemia | 2) Gray baby syndrome

Question 42

What are the 2 UTI agents?

Answer 42

Nitrofurantoin | Methenamine

Question 43

Which UTI agent is converted to formaldehyde in acidic pH?

Answer 43

Methenamine

Question 44

Which UTI agent is used to suppress UTIs and which to treat?

Answer 44

Methenamine --> suppress Nitrofurantoin --> treat

Question 45

How are the UTI agents administered?

Answer 45

orally

Question 46

What are some adverse effects of nitrofurantoin?

Answer 46

GI intolerance | rashes