Antibiotics

Question 0

Amoxicillin/ amoxil

Answer 0

Penicillin
Broad spectrum beta lactam, distributed everywhere but CSF
Used for- UTI, strep throat, otitis media, lower resp., skin infx
May cause- GI disturbances(less diarrhea than ampicillin), penicillin allergy or anaphylaxis

Question 1

Sulfamethoxazole/ Gantanol

Answer 1

Sulfanomide
Competitive inhibitor of emzyme that catalyze a the conversion of PABA to dihydropteroate- inhibits folate synthesis
Broad spectrum bacteriostatic- distributed throughout all tissues including CNS
Indicated for: UTI’s, otitis media, bronchitis
May cause- upset stomach, HA, skin rash, marked photosensitization

Question 2

Sulfamethoxazole with trimethoprim/ Bactrim

Answer 2

Sulfanomide
Interferes with folate production at 2 steps
Broad spectrum
May cause- HA, nausea, diarrhea. Poison bone marrow- megaloblastosis, leukopenia, thrombocytopenia
3x more common for hypersensitivity- STEVENS JOHNSON SYNDROME(toxic epidermal necrosis)
Indicated for: UTI, otitis media, bronchitis, pneumonia, pneumocytis prophylaxis, MRSA

Question 3

Penicillin G

Answer 3

Beta lactams
Used against bacterial cell wall- inhibits formation of peptidoglycan cross linkage
Bacteriocidal against gm+ cocci(strep) & gm-(neisseria)
does not work on beta lactamase producers
Used for UTI, strep throat, otitis media, lower resp., skin infx
May cause: hypersensitivity rxn’s, cross rxn with cephalosporins, possible neutropenia & nephrotoxicity

Question 4

Cephalexin/ keflex

Answer 4

Cephalosporin
Disrupts the synthesis of peptoglycan- destroys cell wall
Bacteriocidal- 4 generations- 1st against gm+, rest have added gm- with less affect on gm+
Used for- ENT infx, bronchitis, skin infx, prophylaxis in surgery, alternative to penicillin for allergic pts
May cause- GI disturbances, diarrhea, yeast overgrowth, hypersensitivity for those allergic to penicillin

Question 5

Amoxicillin and clavulanate/ augmentin

Answer 5

Similar to amoxil (Penicillin- broad spectrum- beta lactam)
But with the addition of clavulanatic acid = beta lactamase inhibition
250,500,750mg doses- all have the same amount of clavulanate, the difference is the amount of amoxil
May cause- inc GI distress from clavulanic acid, diarrhea, pseudo membranous colitis, abx associated colitis caused by C. Difficile overgrowth

Question 6

Azithromycin/ Zithromax

Answer 6

Macolides
Acts on protein synthesis- binds to 50s subunit of ribosome
Broad spectrum- bacteriaostatic
Distributed in all tissues except CSF
Long half life- 68hrs- Z pack: 6 tabs, 2 on day one, 1 tab day 2-5
Used for ENT, sinusitis, bronchitis, pneumonia, atypical infx, mycoplasma & chlamydia
May cause- far less GI digress than erythromycin, take with food to avoid yeast overgrowth

Question 7

Erythromycin

Answer 7

Macrolides
Affect protein synthesis- binds to 50s subunit- accumulate in leukocytes
Bacteriostatic, can be bacteriocidal in higher doses. Slightly wider spectrum than penicillin
SUBSTITUTE FOR PENICILLIN ALLERGIES
Used for- resp tract infx, chlamydia, syphilis, gonnorrhea. Works well against beta hemolytic strep, pneumococci, staph, enterococcus, mycoplasma, mycobacteria, some rickettsia
May cause- n/v, yeast overgrowth

Question 8

Gentamicin/ garamycin

Answer 8

Aminoglycoside
Inhibits protein synthesis at 30s & 50s ribosomal subunits
Bacteriocidal- aerobic, gm-, pseudomonas, often no used with other abx due to narrow spectrum
Used for- empirically for septicemia, complicated infx- UTI, nosocomial resp, meningitis, endocarditis, TB
May cause- potentially nephrotoxic

Question 9

Tetracycline/ sumycin

Answer 9

Tetracycline
Inhibits protein synthesis- 30s ribosomal subunit
Bacteriostatic, broad spectrum- resistance forming
MC used for- acne & rosacea
Also used for- oral & resp infx, chlamydia, Lyme, rocky mt spotted fever
May cause- GI distress, photosensitivity
Bound by Ca ions- accumulates in bones & teeth, avoid taking with dairy products/Ca supplements

Question 10

Ciprofloxin/ ciproxin

Answer 10

Quinolone
Inhibits DNA gyrase and replication/transcription
Easily enters host cell- resistance develops quickly
Chelates Ca- deposited in cartilage- increased risk of tendon rupture
Category x
Used for- gm - & +, UTI, ENT, upper & lower resp, anthrax
May cause- n/v, HA, insomnia, prolongs effect of caffeine

Question 11

Metronidazole/ flagyl

Answer 11

Imidazole
Disrupts DNA helical structure- inhibits further nucleic acid syn
Used for- trichomonas, bacterial vaginosis, gardnerella, acute gingivitis/ dental infx, endometriosis, tub ovarian abscess, pseudomembranous colitis, topically for rosacea.
Part of multi drug regime for H. Pylori
May cause- n/v, diarrhea, metallic taste, HA, thrush.
Disrupts acetaldehyde dehydrogenase= Disulfiram-like rxn with concurrent alcohol use

Question 12

Clindamycin/ cleocin

Answer 12

Lincosamide
Inhibits protein synthesis- 50s ribosomal subunit
Gm+ cocci, anaerobic gm- & + bacteria & Protozoa, many species strep(except entero)& staph- topical ance, MRSA, malaria, gardnerella
May cause- n/v, diarrhea, skin rash, oral thrush, yeast vaginitis, pseudomembranous colitis

Question 13

Nitrofurantoin/ macrobid

Answer 13

Nitrofurantoin
Acts on bacterial DNA
For lower UTI

Question 14

Neomycin

Answer 14

Aminoglycoside

Question 15

Rifampicin/ rifampin

Answer 15

Inhibits DNA transcription to RNA
Lipophilic- crosses BBB
Used for- mycobacterium(TB), hansen’s dz, prophylactic for neisseria meningitis
May cause- fever, chills, HA, malaise, n/v, diarrhea, abd. Cramps, rash, flushing, puritis, SOB
Turns urine & tears orange/red
Hepatotoxic

Question 16

Vancomycin/ vancocin

Answer 16

Glycopeptide
Inhibits synthesis of bacterial cell wall
Not used orally except for pseudomembranous colitis
Admin in dilute IV solution over 60 min to avoid high incidence of pain & RED MAN syndrome
Last resort drug- when all others fail

Question 17

Mupirocin/ bactroban

Answer 17

Binds to bacterial isoleucyl- tRNA. Halts incorporation of isoleucine into bacterial proteins
Effective against gm+
Topically used for- Skin infx(impetigo, boils, folliculitis, MRSA)
Originally isolated from pseudomonas fluorescens

Question 18

Bacitracin

Answer 18

Interferes with cell wall precursors from cell membrane
Targets gm +
Generally topical- superficial skin infx, eye

Question 19

Rifaximin/ xifaxan

Answer 19

Blocks translocation- binds to beta subunit of RNA polymerase
Poor bioavailability

Question 20

Polymyxin B

Answer 20

Binds to CELL MEMBRANE making it more permeable causing inc h2o uptake & cell death
Bactericidal- very effective against gm-

Question 21

Polysporin

Answer 21

Bacitracin- gm+

Polymixin B- gm-

Question 22

Neosporin

Answer 22

Bacitracin- gm+
Neomycin- gm+
Polymixin B- gm-

Question 23

MRSA

Answer 23

Resistant to beta lactams- penicillin, amoxicillin, cephalosporins