First Aid: Antimicrobials

Front 1

Block cell wall synthesis by inhibiting peptidoglycan cross-linking.

Back 1

penicillin, ampicillin, ticarcillin, piperacillin, imipenem, aztreonam, cephalosporins

Front 2

Block peptidoglycan synthesis.

Back 2

bacitracin, vancomycin, cycloserine

Front 3

Block protein synthesis at 50S ribosomal subunit.

Back 3

chloramphenicol, erythromycin/macrolides, lincomycin, clindamycin, streptogramins (quinupristin, dalfopristin), linezolid

Front 4

Block protein synthesis at 30S ribosomal subunit.

Back 4

aminoglycosides, tetracyclines

Front 5

Block DNA topoisomerases.

Back 5

quinolones

Front 6

Block mRNA synthesis

Back 6

rifampin

Front 7

Bactericidal antibiotics.

Back 7

penicillin, cephalosporins, vancomycin, aminoglycosides, fluoroquinolones, metronidazole

Front 8

Disrupt bacterial/fungal cell membranes

Back 8

polymyxins

Front 9

Disrupt fungal cell membranes.

Back 9

amphotericin B, nystatin, fluconazole/azoles

Front 10

Unknown

Back 10

pentamidine

Front 11

Penicillin (G: IV form; V: oral form)

Back 11

M: binds PBPs, blocks transpeptidase cross-linking of cell wall, activates autolytic enzymes; C: bactericidal for gram + cocci, gram + rods, gram - cocci and spirochetes; T: hypersensitivity reactions, hemolytic anemia.

Front 12

Methicillin, nafcillin, dicloxacillin

Back 12

M: binds PBPs, blocks transpeptidase cross-linking of cell wall, activates autolytic enymes; narrow spectrum; penicillinase resistant because of bulkier R group; C: staphylococcus aureus; T: hypersensitivity reactions; methcillin - interstitial nephritis.

Front 13

Ampicillin, amoxicillin

Back 13

M: binds PBPs, blocks transpeptidase cross-linking of cell wall, activates autolytic enymes; wider spectrum, penicillinase sensitive, can combine with clavulanic acid (penicillinase inhibitor) to enhance spectrum; amOxicillin = Oral bioavailability; C: extended spectrum penicillin, certain gram + bacteria and gram - rods (ampicillin/amoxicillin HELPS kill enterococci - Haemophilus influenza, E. coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, enterococci); T:hypersensitivity reactions, ampicillin rash, pseudomembranous colitis.

Front 14

Carbenicillin, piperacillin, ticarcillin

Back 14

M: binds PBPs, blocks transpeptidase cross-linking of cell wall, activates autolytic enymes; extended spectrum; C: pseudomonas spp. and gram - rods; susceptible to penicillinase; use with clavulanic acid; T: hypersensitivity.

Front 15

Cephalosporin mechanism

Back 15

beta lactam drugs that inhibit cell wall synthesis, but less vulnerable to penicillinases; bactericidal

Front 16

1st generation cephalosporins: clinical use

Back 16

PEcK: gram + cocci, Proteus mirabilis, E. coli, Klebsiella pneumoniae

Front 17

2nd generation cephalosporins: clinical use

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HEN PEcKS: gram + cocci, Haemophilus influenza, Enterobacter aerogenes, Neisseria spp., Proteus mirabilis, E. coli, Klebsiella pneumoniae, Serratia marcescens

Front 18

3rd generation cephalosporins: clinical use

Back 18

serious gram - infections resistant to other beta lactams, meningitis (most penetrate the BBB); eg.: ceftazidime for pseudomonas, ceftriaxone for gonorrhea

Front 19

4th generation cephalosporins: clinical use

Back 19

increased activity against pseudomonas and gram + organisms

Front 20

Cephalosporin toxicity

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hypersensitivity reactions, + nephrotoxicity of aminoglycosides, disulfiram-like reaction with ethanol (in cephalosporins with a methylthiotetrazole group, eg.: cefmandole)

Front 21

Aztreonam

Back 21

M: monobactam resistant to beta lactamases, inhibits cell wall synthesis (binds to PBP3), synergistic with aminoglycosides, no cross-allergenicity with penicillins; C: gram - rods (Klebsiella spp., Pseudomonas spp., Serratia spp.), no activity agains gram + or anaerobes, for use in penicillin-allergic patients and those with renal insufficiency who can't tolerate aminoglycosides; T: usually non-toxic; occasional GI upset.

Front 22

Imipenem/cilastatin

Back 22

M: imipenem is a broad-spectrum, beta lactamase resistant carbapenem, always administered with cilastatin (inhibitor of renal dihydropeptidase I) to lower inactivation in renal tubules; C: gram + cocci, gram - rods, and anaerobes (drug of choice for Enterobacter); T: GI distress, skin rash, and CNS toxicity (seizures) at high plasma levels

Front 23

Imipenem/cilastatin mneumonic

Back 23

with imipenem, "the kill is LASTIN' with ciLASTATIN."

Front 24

Vancomycin

Back 24

M: block cell wall mucopeptide formation by binding D-ala D-ala portion of cell wall precursors, bactericidal, resistance occurs with amino acid change of D-ala D-ala to D-ala D-lac; C: used for serious gram + multi-drug resistant organisms, including Staph aureus and Clostridium difficile (pseudomembranous colitis); T: "well tolerated in general, does NOT have many problems." Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing ("red man syndrome" - can be largely prevented by pretreatment with antihistamines and slow infusion rate

Front 25

List the protein synthesis inhibitors

Back 25

"buy AT 30, CELL at 50": 30S inhibitors...Aminoglycosides ("TAGS" tobramycin, amikacin, gentamicin, streptomycin [bactericidal]), Tetracylines [bacteriostatic]; 50S inhibitors...Chloramphenicol, Erythromycin, Lincomycin, cLindamycin [all 4 are bacteriostatic]

Front 26

List the aminoglycosides and their mechanism of action

Back 26

TANGS: tobramycin, amikacin, neomycin, gentamicin, streptomycin; M: bactericidal, inhibit formation of initiation complex and cause misreading of mRNA, require O2 for uptake so ineffective against aerobes.

Front 27

Aminoglycosides: clinical use and toxicity

Back 27

C: severe gram - rod infections, synergistic with beta lactam antibiotics, neomycin for bowel surgery; T: Nephrotoxicity (esp. when combined with cephalosporins), Ototoxicity (esp. when combined with loop diuretics) "amiNOglycosides"

Front 28

List the tetracyclines and their mechanism of action

Back 28

TDDM: tetracyline, doxycycline, demeclocycline, minocycline; bacteriostatic, bind to 30S and prevent attachment of aminoacyl tRNA, limited CNS penetration; doxycycline is fecally eliminated and can be used in patients with renal failure; must NOT be taken with milk, antacids, or iron-containing prepartions because divalent ions inhibit gut absorption

Front 29

Tetracylines: clinical use and toxicity

Back 29

C: VACUUM you BedRoom: Vibrio cholerae, Acne, Chlamydia, Ureaplasma Urealyticum, Mycoplasma pneumoniae, Borrelia burgdorferi (Lyme disease), Rickettsia, tularemia; T: GI distress, discoloration of teeth and inhibition of bone growth in children, Fanconi's syndrome, photosensitivity.

Front 30

List the macrolides and their mechanism of action

Back 30

ACE: azithromycin, clarithromycin, erythromycin; M: inhibit protein synthesis by blocking translation, bind to the 23S rRNA of the 50S ribosomal subunit, bacteriostatic

Front 31

Macrolides: clinical use and toxicity

Back 31

C: URIs, pneumonias, STDs (gram + cocci; streptococcal infections in patients allergic to penicillin), Mycoplasma, Legionella, Chlamidia, Neisseria; T: GI discomfort (most common cause of noncompliance), acute cholestatic hepatitis, eosinophilia, skin rashes

Front 32

Chloramphenicol

Back 32

M: inhibits 50S peptidyltransferase, bacteriostatic; C: meningits (H. influenza, N. meningitidis, S. pneumoniae); T: use conservatively due to the toxicities - anemia (dose dependent), aplastic anemia (dose dependent), gray baby syndrome (in premature infants because they lack liver UDP-glucoronyl transferase)

Front 33

Clindamycin

Back 33

M: blocks peptide bond formation at 50S ribosomal subunit, bacteriostatic; C: treat anaerobic infections (eg.: Bacteroides fragilis, Clostridium perfringens); T: pseudomembranous colitis (C. difficile overgrowth), fever, diarrhea

Front 34

sulfonamides

Back 34

eg.: sulfamethoxazole (SMX), sulfisoxazole, triple sulfas, sulfadiazine

M: PABA antimetabolites inhibit dihydropteroate synthase; bacteriostatic

C: gram +, gram -, nocardia, chlamydia; triple sulfas or SMX for simple UTI

T: hypersensitivity rxn, hemolysis if G6PD deficient nephrotoxicity (tubulointerstitial nephritis), kernicterus in infants, displace other drugs from albumin (eg. warfarin)

Front 35

why is THF (tetrahydrofolic acid) important?

Back 35

cofactor in the production of purines and the amino acids thymine, methionine and glycine

Front 36

trimethoprim

Back 36

trimethoprim = TMP = "Treat Marrow Poorly"

C: combined with sulfas to cause sequential block of folate synthesis; combo used for recurrent UTIs, Shigella, Salmonella, Pneumocystis carinii pneumonia

T: megaloblasticanemia, leukopenia, granulocytopenia (can alleviate with supplemental folinic acid)

Front 37

fluoroquinolones

Back 37

"FluoroquinoLONES hurt attachments to your BONES"

eg.: ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin, moxifloxacin, gatifloxacin, enoxacin (fluoroquinolones), nalidixic acid (a quinolone)

M: inhibit DNA gyrase (topoisomerase II), bactericidal

C: gram - rods of urinary and GI tracts (incl. Pseudomonas), Neisseria, some gram + organisms

T: GI upset, superinfection, skin rashes, headache, dizziness; contraindicated in pregnant women and kids due to possible cartilage damage; tendonitis and tendon rupture in adults

Front 38

metronidazole

Back 38

GET on the METRO! Anaerobes below the diaphragm

M: forms toxic metabolites in the bacterial cell; bactericidal

C: antiprotozoal, Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, anaerobes (Bacteroides, Clostridium); used with bismuth and amoxicillin (or tetracyline) for "triple therapy" against H. pylori

T: disulfram-like reaction with alcohol, headache

Front 39

polymyxins

Back 39

eg.: polymyxin B, polymyxin E

M: bind to cell membranes of bacteria and distrupt osmotic properties; polymyxins are cationic, basic proteins that act like detergents

C: resistant gram - infections

T: neurotoxicity, acute renal tubular necrosis

Front 40

anti-TB drugs

Back 40

RESPIre. All are hepatotoxic.

Rifampin
Ethanmbutol
Steptomycin
Pyrazinamide
Isoniazid (INH)

cycloserine (2nd line therapy)

Front 41

isoniazid (INH)

Back 41

INH Injures Neurons and Hepatocytes. Different INH half lives in fast vs. slow acetylators.

M: - synthesis of mycolic acids

C: Mycobacterium tuberculosis. The only agent used as solo prophylaxis against TB.

T: Hemolysis if G6PD deficient, neurotoxicity, hepatotoxicity, SLE-like syndrome. Pyridoxine (vitamin B6) can prevent neurotoxicity.

Front 42

rifampin

Back 42

Rifampin's 4 R's:
RNA polymerase inhibitor
Revs up microsomal P-450
Red/orange body fluids
Rapid resistance if used alone

Front 43

block nucleotide synthesis

Back 43

sulfonamides, trimethoprim