Antibiotics

Question 1

What organisms can you treat with aminopenicillins (amoxicillin, ampicillin)

HEELPS

Answer 1

gram positives
Also, gram negative rods including HEELPSS
h. influenzae
h. pylori
e. coli
listeria monocytogenes
proteus mirabilis
salmonella
shigella
enterococci

Question 2

Antipseudomonal penicillins

Answer 2

ticarcillin
carbenicillin
piperacillin

Question 3

bacterial resistance against penicillin agents

Answer 3

production of beta- lactamase (hydrolyzes the beta- lactam ring)
alteration of beta lactamase targets

Question 4

beta- lactamase inhibitors

Answer 4

sulbactam
clavulanic acid
tazobactam

Question 5

clinical use of dicloxacillin, nafcillin, oxacillin

Answer 5

these are penicillinase- resistant penicillins. THey have a bulky R group that blocks access of beta- lactamase to beta- lactam rings.
Used for s. aureus (but only methicillin sensitive strains)

Question 6

side effects of penicillin

Answer 6

hypersensitivity reactions, hemolytic anemia, thrombocytopenia

Question 7

side effects of amoxicillin and ampicilin

Answer 7

hypersensitivity, rash, pseudomembranous colitis

Question 8

ampicillin and amoxicillin- what are they?

Answer 8

extended- spectrum penicillins. Combine with clavulanic acid to protect against destruction by beta lactamase.
Amoxicillin is PO and has greater oral bioavailability than ampicillin, which is given by IV.

Question 9

cephalosporins

Answer 9

like penicillins in that they inhibit cell wall synthesis and are therefore bactericidal
but they are less susceptible to penicillinases and have more gram + and gram - coverage.

Question 10

organisms not covered by cephalosporins are LAME

Answer 10

listeria
atypicals (chlamydia, mycoplasma)
MRSA
Enterococci

Exception: ceftaroline covers MRSA

Question 11

1st generation cephalosporins

Answer 11

cefazolin, cephalexin 
PEcK
proteus mirabilis
E. coli
Klebsiella pneumoniae

cefazolin (ancef) used prior to surgery to prevent s. aureus wound infections

cephalexin commonly used for UTI

Can be used against URIs
Prophylaxis against viridans endocarditis

Question 12

2nd generation cephalosporins

Answer 12

cefoxitin, cefaclor, cefuroxime, cefprozil
HENS PEcK

Haemophilis influenzae
Enterobacter aerogenes
Neisseria spp (gonorrhea resistance is growing so we generally don’t use cephalosporins to treat gonorrhea)
Serratia marcescens

Proteus mirabilis
E. coli
Klebsiella pneumoniae

Question 13

3rd generation cephalosporins

Answer 13

ceftriazone, cefotaxime, ceftazidime, cedinir

coverate of serious gram neg infections that would be resistant to other beta lactams

E. coli
Proteus mirabilis
Klebsiella
Enterobacter
Serratia
Citrobacter
Neisseria
Haemophilus influenzae

Strep pneumoniae!! still!

choice for gram negative meningitis

Question 14

Ceftriaxone IV

Answer 14

3rd generation cephalosporin,
choice for neisseria gonorrhea, meningitis, disseminated Lyme

safety increased because it is excreted in the bile

Question 15

3rd generation cephalosporin with pseudomonas coverage

Answer 15

Ceftazidime

Question 16

3rd generation PO cephalosporin used for resistant otitis media

Answer 16

Cefdinir

Question 17

Big gun 4th gen cephalosporin

Answer 17

Cefepime- 4th generation, gram negative organisms with increased activity against Pseudomonas and gram- positive organisms

Question 18

5th generation cephalosporin that covers MRSA

Answer 18

ceftaroline
Broad gram positive and gram negative organism coverage including MRSA.
Does not cover Pseudomonas

Question 19

Cephalosporins are LAME against

Answer 19

Listeria
Atypicals (mycoplasma, chlamydia)
MRSA (except ceftaroline)
Enteroccoci

for PNA (CAP), azythromycin can be added on for atypicals. 
Ceftriaxone and azythromycin are a common combination

Question 20

Caphalosporin hypersensitivity reaction

Answer 20

5-10% cross- reactivity with PCNs

nephrotoxicity risk if used with aminoglycosides

example- gentamycin

disulfiram- like reaction seen with alcohol when combined with some cephalosporins

Question 21

broad spectrum coverage for appendicitis

Answer 21

imipenem/cilastatin or meropenem

Question 22

cell wall inhibitors effective against pseudomonas

Answer 22

cefepime
axtreonam
carbapenems
carboxypenicillins (eg ticarcillin)

Question 23

resistance to vancomycin

Answer 23

D-ala D-ala is converted to

D-ala D-lac

Question 24

Aztreonam

Answer 24

monocyclic beta lactam resistant to penicillinases, inhibits cell wall synthesis, binds to penicillin binding protein 3.

gram negative rods ONLY

for PCN- allergic patients and those with renal insufficiency

"aminoglycoside pretender"
covers gram negative
E. Coli
Klebsiella
Pseudomonas
Serratia

Usually nontoxic (few side effects), no cross- sensitivity to PCNs

Question 25

Vancomycin

Answer 25

inhibits cell wall formation by binding D-ala D-ala cell wall precursor. Not susceptible to beta- lactamases use for gram positive bugs, including MRSA S. epidermidis, enterococcus, clostridium difficile (PO for pseudomembranous colitis, but use metronodozile instead possible) Side effects: Nephtoxocity, Ototoxicity, Thrombophlebitis Red man is diffuse flushing. When this happens, treat with antihistamines and a slower infusion rate Reisistance via D-ala D-lac

Question 26

Carbapenems

Answer 26

imipenem (broad spectrum, must be used with cilastin) meropenem ertapenem doripenem Gram positive cocci, gram negative rods, wide spectrum but significant side effects limit use to life- threatening infections (empiric threatment) Won't cover MRSA. Meropenem has decreased risk of seizures Toxicity- GI distress, skin rash, CNS toxicity (seizures) at high plasma levels Imipenem is more neurotoxic than meropenem which has a decreased risk of seizures, won't be inactivated in the renal tubules

Question 27

but AT 30, CCEL at 50

Answer 27

protein synthesis inhibitors 30S inhibitors Aminoglycosides (bactericidal) Tetracyclines (bacteriostatic) 50S inhibitors Chloramphenical, Clindamycin (bacteriostatic) Erythromycin (macrolides, bacteriostatic) Linezolid (variable)

Question 28

Tetracyclines- how do they work and what do they cover? - tetracycline - doxycycline - minocycline

Answer 28

Bacteriostatic, binds 30S and prevents tRNA interaction. limited CNS penetration. Fecally eliminated, which makes amenable to patients who have renal failure. Divalent cations block absorption ion the gut; not to be combined with milk or iron. Side effects: GI distress (don't use antacids- then the antibiotic won't be absorbed at all!), discolored teeth, inhibited bone growth in children, photosensitivity, contraindicated in pregnancy Minocycline can give blue discoloration after prolonged use ``` VACCUUM THe BedRoom Vibrio cholerae Acne Chlamydia Ureaplasma urealyticum Mycoplasma pneumoniae Tularemia Helicobacter pylori Borrelia burgdorferi Rickettsia ``` resistance via decreased uptake or increased efflux out of bacterial cells by plasmid- encoded transport pumps

Question 29

Oxazoladinone- Linezolid

Answer 29

binds 23S RNA component of 50S large ribosomal subunit, interacts with and inhibits formation of bacterial initiation complex used against MRSA, VRE, and is used orally against MRSA! Outpatient MRSA therapy is possible with linezolid if well controlled Toxicity- bone marrow suppression, thrombocytopenia, peripheral neuropathy, serotonin syndrome for pts who are on SSRIs resistance via point mutation on RNA

Question 30

AminO2glycosides - gentamycin - neomycin - amikacin - tobramycin - streptomycin

Answer 30

binds 30S ribosome bactericidal IRREVERSIBLY inhibits formation of initiation complex, causes mRNA misreading, ineffective against anaerobes (requires oxygen) These are for severe gram neg rod infections, and work synergistically with beta lactam antibiotics (eg am+gent) neomycin for bowel surger Toxicity: NNOT nephrotoxicity (especially when used with cephalosporins) neuromuscular blockade ototoxicity (especially if combined with loop diuretics) Teratogen resistance comes with bacterial transferase enzymes capable of acetylating, phosphorylating, or adenylating the aminoglycoside

Question 31

Macrolides. macroslides - erythromycin - azithromycin - clarithromycin

Answer 31

inhibit protein synthesis by blocking translocation (macroslides) at the 23rRNA of the large 50S ribosomal subunit. Bacteriostatic used for PUS PNA (atypical especially- mycoplasma, chlamydophila, legionella) b. pertussis URI (strep pneumoniae, strep pyogenes) STD (chlamydia, gonorrhea) Toxicity: MACRO: GI motility issues, Arrythmia due to prolonged QT, acute Cholestatic hepatitis (with erythromycin estolate), Rash, rare cases of eOsinophilia increases serum concentration of theophyllines and oral anticoagulants (warfarin) mostly safe in pregnancy -azythromycin Resistance via methylation of 23S rRNA binding site (prevents drug from binding)

Question 32

chloramphenicol

Answer 32

inhibits 50S subunit of ribosomal RNA, thereby inhibiting peptidyltransferase activity. Bacteriostatic treats meningitis: haemophilus influenzae neisseria meningitidis, streptococcus pneumoniae RMSF unpopular due to toxicity: dose- dependent anemia grey baby syndrome (babies need UDPGT to metabolize chloramphenicol, and they experience a buildup of toxic metabolites) symptoms include vomiting, ashen gray skin tone, poor muscle tone, cyanosis, CV collapse stop the chloramphenicol and do an exchange transfusion to treat this try phenobarbitol to induce UDPGT resistance: plasmid- encoded acetyltransferase can inactivate the drug

Question 33

Clindamycin

Answer 33

Clindamycin blocks peptide bond formation with the 50S ribosomal subunit. It is bacteriostatic. Use: ANAEROBES (bacteriodes, clostridium perfringens) in aspiration PNA, lung abscesses, oral infections, invasive GAS - above the diaphragm (versus metronidazole which is used below the diaphragm) Can also be used against MRSA skin abscesses (oral clindamycin is a nice outpatient option), protozoal infections topical use for acne treatment Toxicity:pseudomembranous colitis (C. Diff), fever, diarrhea

Question 34

Streptogramins | -Quinupristin/Dalfopristin (Synercid)

Answer 34

mechanism: binds to the 23S portion of the 50S ribosome (synthesized by the bacteria streptomyces virginiae) Use: MRSA, VRE, Staphylococcus and streptococcus skin infections that are very serious- this drug has a lot of side effects Side effects: hepatotoxicity pseudomembranous colitis, arthralgia, myalgia inhibits CYP450

Question 35

Sulfonamides - sulfamethoxazole (SMX) - sulfdiazone

Answer 35

bacteria need to absorb folic acid- they can't make their own Sulfonamides inhibit folate synthesis Para-aminobenzoic acid (PABA) antimetabolites inhibit dihydropteroate synthase Bacteriostatic (bactericidal when combined with trimethoprim)= TMP SMX Dapsone, used to treat lepromatous leprosy is a closely related drug that also inhibits folate synthesis Covers gram positives AND negatives Nocardia Chlamydia UTIs like E Coli Skin infections Toxicity- hypersensitivity reactions hemolysis if G6PD deficient nephrotoxicity (tubulointerstial nephritis) photosensitivity kernicterus in infants- do not give to pregnant females who are about to deliver SJS displace other drugs from albumin (warfarin) Resistance to the drug altered bacterial dihydropteroate synthesis decreased uptake increased PABA synthesis (if this were the case you could give a bigger dose?)

Question 36

Sulfa Pills Frequently Cause Terrible Acute Symptoms drugs that cause sulfa allergy

Answer 36

Sulfa Pills Frequently Cause Terrible Acute Symptoms ``` Sulfasalazine Probenecid Furosemide Celecoxib Thiazides/TMP-SMX Acetazolamide Sulfonylureas ```

Question 37

Drugs that cause SJS

Answer 37

``` Penicillin drugs Sulfa drugs Seizure drugs -ethosuximide -lamotrigine -carbamazepine -phenobarbital -phenytoin Allopurinol ```

Question 38

Trimethoprim

Answer 38

Dihydrofolate reductase inhibitor bacteriostatic ``` combine with sulfonamaides to cause sequential block of folate synthesis. TMP-SMX can be used for UTIs shigella salmonella pneumocystis jirovecii pneumonia treatment and ppx when CD4 ```

Question 39

Drugs that inhibit dihydrofolate reductase

Answer 39

methotrexate trimpethoprim pyrimethamine

Question 40

nitrofurantoin

Answer 40

bacteriocidal reduced by bacterial proteins to a reactive intermediate that inactivates bacterial ribosomes It has be reduced in the presence of bacteria to be effective- only effective in the URINE useful only for mild UTI (so, not pyelonephritis) -e.coli staphylococcus side effects: rarely nausea, HA, diarrhea safe in pregnancy

Question 41

Fluoroquinolones - levofloxacin - ciproflozacin - norfloxacin - levofloxacin - ofloxacin - moxifloxacin - gemifloxacin - enoxacin - gatifloxacin - nalidixic acid

Answer 41

inhibits DNA gyrase (aka topoisomerase I) absorption inhibited if taken with antacids used for gram negative infections, UTIs, GI tract infections, pseudomonas varying amounts of gram + coverage ok for CF children if they are getting a lot of lung infections ``` toxicity: GI upset cartilage damage in children tendinitis and tendon rupture QT interval prolongation ``` Resistance: chromosome-encoded DNA gyrase mutation

Question 42

Metronidazole

Answer 42

absorbed by micro-organisms, forms toxic ROS that damage DNA ``` use for GET GAP on the Metro Giardia lamblia Entamoeba histolytica Trichomonas Gardnerella vaginalis Anaerobic bacteria (c. diff, perfringens, tetani, bacteriodes species) Pylori (helicobacter pylori) ``` Can cause a disulfiram-like reaction with alcohol (sweating, nausea, hypotension)

Question 43

Polymyxins | Polymyxin E, polymyxin B

Answer 43

Cationic detergents that attack and disrupt cell membranes and also inactivate endotoxin Use for last resort therapy against gram- negative infections (give by IV) toxicity: neurotoxicity, nephrotoxicity (ATN) almost always used topically

Question 44

ppx meningococcal meningitis

Answer 44

ciprofloxacin, rifampin, ceftriaxone

Question 45

ppx h. influenzae meningitis

Answer 45

rifampin

Question 46

Gonorrea

Answer 46

ceftriaxone, especially after sexual assault

Question 47

syphilis

Answer 47

benzathine penicillin G

Question 48

recurrent UTI

Answer 48

TMP-SMX, nitrofurantoin, amoxicillin, cephalexin

Question 49

prevent pneumocystis jirovecii

Answer 49

TMP-SMX, when CD4

Question 50

endocarditis from dental procedure

Answer 50

penicillin, amoxicillin, cephalexin, azythromycin | Target= viridans strep

Question 51

GBS

Answer 51

ampicilin during labor

Question 52

gonocccal/ chlamydial conjunctivitis

Answer 52

erythromycin ointment

Question 53

SAFe Children Take Really Good Care

Answer 53

``` Sulfonamides-kernicterus Aminoglycosides-ototoxicity Fluoroquinolones- cartilage damage Clarythromycin- embryotoxic Tetracyclines- discolored teeth, inhibition of bone growth Ribavirin (antiviral)- teratogenic Griseofulvan (antifungal)- teratogenic Chloramphenicol- gray baby syndrome ```