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Flashcards in Antibiotics Deck (132)
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1
Q

Which penicillin is oral? IV/IM?

A

oral: pen V. IV/IM: pen G.

2
Q

Penicillin mech

A

1) bind PBPs (transpeptidases) 2) block transpeptidase cross-linking of peptidoglycan. 3) Activate autolytic enzymes.

3
Q

Clinical use of Penicillin

A

Gram + organisms (S. pneumoniase, S. pyogenes, Actinomyces). Also used for N. Meningitidis and T. Pallidum. Bactericidal for gram positive cocci, gram positive rods, gram negative cocci, and spirochetes. Penicillinase sensitive.

4
Q

Penicillin Toxicity

A

Hypersensitivity reactions. Hemolytic anemia

5
Q

Penicilin Resistance

A

Penicillinase in bacteria (a type of beta lactamase) cleaves beta lactam ring

6
Q

Ampicillin, amoxicillin (aminopenicillins, penicillinase sensitive penicillins) Mechanism?

A

Same as penicillin but wider spectrum; penicillinase sensitive. Also combine with clavulonic acid to protect against beta lactamase.

7
Q

Which has better oral bioavailability, ampicillin or amoxicillin?

A

amOxicillin (O for oral)

8
Q

What is the clinical use of Ampicillin, amoxicillin (aminopenicillins, penicillinase sensitive penicillins)?

A

Extended-spectrum penicillin : HELPSS kill enterococci: Haemophilus influenzae, E. Coli, Listeria monocytogenes (meningitis in the elderly) Proteus mirabilis, Salmonella, Shigella, enterococci

9
Q

Ampicillin, amoxicillin (aminopenicillins, penicillinase sensitive penicillins) SE?

A

Hypersensitivity reactions; rash; pseudomembranous colits

10
Q

Ampicillin, amoxicillin (aminopenicillins, penicillinase sensitive penicillins) Mechanism of resistance?

A

Penicillinase in bacteria (a type of beta lactamase) cleaves beta lactam ring

11
Q

Oxacillin, nafcillin, dicloxacillin (penicillinase resistance penicillins) mechanism?

A

same as penicillin. Narrow spectrum; penicillinase resistant because bulky R group blocks access of beta lactamase to beta lactam ring

12
Q

Oxacillin, nafcillin, dicloxacillin (penicillinase resistance penicillins) clinical use?

A

S. aureus ( except MRSA; resistant because of altered PBP target site). Use naf (naficillin for staph)

13
Q

Oxacillin, nafcillin, dicloxacillin (penicillinase resistance penicillins) toxicity?

A

hypersensitivity reactions, interstitial nephritis

14
Q

Ticarcillin, piperacillin mech?

A

Same as penicillin. Extended spectrum.

15
Q

Ticarcillin, piperacillin clinical use?

A

Pseudomonas spp. and gram-negative rods; susceptible to penicillinase; use with beta lactamase inhibitors.

16
Q

Ticarcillin, piperacillin toxicity?

A

hypersensitivty reactions

17
Q

What are the beta lactamase inhibitors?

A

Clavulanic Acid, Sulbactam, Tazobactam. Often added to penicillin antibiotics to protect the antibiotic from destruction by beta lactamase (penicillinase).

18
Q

what are cephalosporins

A

beta lactam drugs that inhibit cell wall synthesis but are less susceptible to penisillinases

19
Q

What organisms are typically not covered by cephalosporins?

A

they are LAME: Listeria, Atypicals (chlamydia, mycoplasma), MRSA, and Enterococci.

20
Q

What Cephalosporin will cover MRSA?

A

Ceftaroline

21
Q

What is the clinical use of 1st generation Cephalosporins?

A

gram positive cocci: PEcK : Proteus mirabilis, E. Coli, Klebsiella pneumoniae.

22
Q

What are the 1st generation Cephalosporins?

A

cefazolin, cephalexin

23
Q

which 1st generation cephalosporin is used prior to surgery to prevent S. aureus wound infections?

A

Cefazolin

24
Q

What are the 2nd generation cephalosporin drugs/indications?

A

cefoxitin, cefaxcor, cefuroxime (gram positive cocci): HEN PEcKS: Haemophilius influenzae, Enterobacter aerogenes, Neisseria spp., Proteus mirabilis, E. coli, Klebsiella pneumoniae, Serratia

25
Q

What are the 3rd generation cephalosporin drugs/indications?

A

Ceftriazone (meningitis and gonorrhea), Ceftazidime (Pseudomonas), Cefotaxime: Serious gram negative infections resistant to other beta lactams

26
Q

What is the 4th generation cephalosporin drug/indications?

A

Cefepime - increased activity against Pseudomonas (G-) and other gram positive organisms

27
Q

What is a 5th generation cephalosporin, and what is the indication?

A

Ceftaroline: broad gram positive and gram negative organism coverage including MRSA ; does NOT cover Pseudomonas

28
Q

What toxicites can cephalosporins cause?

A

Hypersensitivity reactions, vitamin K deficiency. Low cross reactivity with penicillins. Increased nephrotoxicity of aminoglycoside

29
Q

Aztreonam mechanism

A

A monobactam; resistant to beta lactamases. Prevent peptidoglycan cross linking by binding to PBP 3. Synergisitc with aminoglycosides. No cross allergenicity with penicillins.

30
Q

What is the clinical use of Aztreonam?

A

Gram negative rods only. no activity against gram positives or anaerobes. Used for penicillin allergic patients and those with renal insufficiency who cannot tolerate aminoglycosides.

31
Q

What is the toxicity of Aztreonam?

A

generally none. occasional GI upset

32
Q

What are the carbapenems?

A

Imipenem, meropenem, ertapenem, doripenem

33
Q

What is the mechanism of carbapenems, specifically imipenem?

A

broad spectrum beta lactamase resistance carbapenem.

34
Q

What drug is alway administered with Imipenem? Why?

A

Cilastin (inhibitor of renal dehydropeptidase I) to decrease inactivation of drug in renal tubules.

35
Q

The kill is lastin with cilastin!

A

haha

36
Q

What carbapenem has limited psuedomonas coverage?

A

ertapenem

37
Q

What is the clinical use of the carbapenems?

A

Gram-positive cocci, gram-negative rods (enterobacter cloacae, serratia marcescens, klebsiella pneumonia) and anaerobes. Wide spectrum, but significant SE limit use to life threatening infection or after other rgus have failed.

38
Q

What carbapenem has resistance to dehydropeptidase I?

A

Meropenem

39
Q

What carbapenem has a decreased risk of seizures?

A

Meropenem

40
Q

What are the SE/Toxicities of carbapenems?

A

GI distress, skin rash, and CNS toxicity (seizures) at high plasma levels.

41
Q

Vancomycin mech

A

inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors. Bactericidal.

42
Q

What is the use of Vancomycin?

A

Gram positive only. serious, multi-drug resistant organisms including MRSA, enterococci, and C diff - Oral dose for pesudomembrane colitis!

43
Q

What are the toxicites of Vancomycin?

A

Well tolderated in general but NOT trouble free: Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing (RED MAN SYNDROME)

44
Q

how can RED MAN syndrome be prevented?

A

Vanco + antihistamines and slow infusion

45
Q

What is the mech of resisitance to Vancomycin?

A

Ocurrs in bacteria via amino acid modification of D-Ala D-ala to D-ala D-lac.

46
Q

Protein synthesis inhibitors

A

Specifically target smaller bacterial ribosome 70S, made of 30S and 50S subunits, leaving human ribosomes 80s unaffected

47
Q

buy AT 30, CCEL at 50

A

1) 30s inhibitors: Aminoglycosides (bactericidal), Tetracyclines (bacteriostatic)
2) 50s inhibitors: Chloramphenicol, Clindamycin (bacteriostatic), Erythromycin (macrolide, bacteriostatic), Linezolid (variable)

48
Q

What are the Aminoglycosides?

A

Mean (aminoglycoside) GNATS caNNOT kill anaerobes. Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin

49
Q

Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin mechanism

A

Bactericidal; inhibit formation of initiation complex and cause misreading of mRNA. Also block translocation. Require O2 for uptake; therefore ineffective against anaerobes.

50
Q

Aminoglycoside mneumonic?

A

A INITIATES the Alphabet

51
Q

What is the SE’s of Aminoglycosides?

A

Mean (aminoglycoside GNATS caNNOT kill anaerobes. Nephrotoxicity (especially when used with cephalosporins), Neuromuscular blockase, Ototoxicity (especially with loop diuretics). Teratogen

52
Q

What is the mechanism of resistance to Aminoglycosides?

A

Bacterial transferase enzymes inactivate the drug by acetylation, phosphorylation, or adenylation

53
Q

What are the Tetracyclines?

A

Tetracycline, doxycline, minocycline

54
Q

Mechanism of Tetracyclines

A

Bacteriostatic: bind to 30S and prevent attachment of aminoacyl-tRNA; limited CNS penetration. Doxycycline is fecally eliminated and can be used in patient with renal failure.

55
Q

What should you NOT take with the Tetracyclines?

A

milk (Ca++), antacids (Ca++ or Mg++), or iron-containing preparations because divalent cations inhibit its absorption in the gut

56
Q

What is the clinical use of Tetracyclines?

A

Borrelia burgdorferi, M. pneumoniae, vibrio cholera, chlamydia urea plasm, urealyticum, francisella tularenesis, H pylori, rickettsia. Drugs ability to accumulate intracellulary makes it very effective against Rickettsia and Chlamydia. Also used to treat Acne

57
Q

Tetracycline Toxicities:

A

GI distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity.

58
Q

Who should NOT take Tetracyclines?

A

Pregnant Bitches

59
Q

mechanism of resistance to Tetracyclines

A

Decrease uptake or Increased efflux out of bacterial cells by plasmid-encoded transport pumps

60
Q

What are the Macrolides?

A

(MAC is an ACE) Azithromycin, Clarithromycin, Erythromycin

61
Q

Mechanism of the Macrolides?

A

Inhibit protein synthesis by blocking translocation (macroSLIDES); bind to the 23S rRNA of the 50s ribosomal subunit. Bacteriostatic.

62
Q

Clinical use of Macrolides?

A

Atypical Pneumonias (Mycoplasma, Chlamydia, Legionella), STDs (for Chlamydia), and gram positive cocci (streptococcal infections in patients allergic to penicillin)

63
Q

SE/Toxicities of Macrolides?

A

MACRO: Gatrointestinal Motility issues, Arrhythmia causing prolonged QT, acute Cholestatic hepatitis, Rash, eOsinophilia.

64
Q

Macrolides increase the serum concentration of what drugs?

A

Theophyllines, oral anticoagulants

65
Q

What is the mech of resistance to macrolides?

A

Methylation of 23S rRNA-binding site prevents binding of drug

66
Q

Chloramphenicol mech

A

blocks peptidytransferase at 50S ribosomal subunit. bacteriostatic.

67
Q

Chloramphenicol Use:

A

Meningitis (Haemophius influenze, Neisseria meningitidis, Streptococcus pneumoniae), and Rocky Mountain spotted fever (Rickettsia Ricketsii).

68
Q

What limits Chloramphenicol’s use?

A

toxicities; still used in developing countries because of low cost

69
Q

Toxicity/SE of Chloramphenicol?

A

Anemia (dose dependent), aplastic anemia (dose dependent), gray baby syndrome (in premature infant because they lack liver UDP glucuronyl transferase)

70
Q

What is the mech of resistance to chloramphenicol?

A

plasmid encoded acetyltransferase inactivates the drug

71
Q

Clindasidosin mech

A

Blocks peptide transfer (translocation) at 50S ribosomal subunit. Bacteriostatic.

72
Q

Clinical use of Clindaslidosin?

A

Anaerobic infections (Bacteroides spp., C. Perfringens) in aspiration pneumonia, lung abscess, and oral infections. Also effective against invasive Group A Strep (GAS) infection.

73
Q

Helpful tip for clinda

A

Treats anaerobes ABOVE the diaphragm vs Metrondiazole (anaerobic infections below the diaphragm)

74
Q

Toxicity of Clindamycin?

A

Pseudomembranous colitis (C. Diff overgrowth), fever, diarrhea

75
Q

What are the sulfonamides?

A

Sulfamethoxazole (SMX), Sulfisoxazole, Sulfadiazine

76
Q

Sulfonamides mech?

A

inhibit folate synthesis. Para aminobenzoic acid (PABA) antimetabolites inhibit dihydropteroate synthase. Basteriostatic.

77
Q

Clinical use of sulfonamides?

A

Gram +, Gram -, Nocardia, Chlamydia. Triple sulfas or SMX for simple UTI

78
Q

What are the SE/toxities of the sulfonamides?

A

Hypersensitivity reactions, hemolysis if G6PD deficient, nephrotoxicity (tubulointersitial nephritis), photosensiivity, kernicterus in infants, displace other drugs from albumin (i.e. warfarin)

79
Q

What is the mechanism of resistance to sulfonamides?

A

Altered enzyme (bacterial dihydropteroate synthase), decrease uptake, or increase PABA synthesis

80
Q

Trimethoprim mechanism

A

Inhibits bacterial dihydrofolate reductase. bacteriostatic

81
Q

What is the clinical use of Trimethoprim?

A

Used in combination with sulfonamides (TMP-SMX), causing a sequential block of folate synthesis. Combination used for UTIs, Shigella, Salmonella, Pneumocystis Jirovecii pneumonia treatment and phophylaxis, toxoplasmosis prophylaxis

82
Q

Trimethoprim SE/Toxicity

A

Megaloblastic anemia, leukopenia, granulocytopenia. (may alleviate with supplemental folinic acid).

83
Q

Trimethoprim mneumonic: TMP

A

Treats Marrow Poorly

84
Q

What are the Fluroquinolones?

A

Ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, sparfloxacin, moxifloxacin, gemifloxacin, enoxacin, nalidixic acid (a quinolone)

85
Q

mech of the Fluoroquinolones (floxacin):

A

Inhibit DNA gyrase (topoisomerase II) and topoisomerase IV. bactericidal.

86
Q

What should not be taken with the fluoroquinolones?

A

antacids

87
Q

What is the clinical use of Fluroquinolones?

A

Gram-negative rods of urinary and GI tracts (including Pseudomonas, salmonella typhi), Neisseria, some gram-positive oranisms.

88
Q

What is the toxicity of Fluoroquinolones?

A

Gi upset, superinfections, skin rashes, headache, dizziness. Less commonly, can cause tendonitis, tendon rupture, leg cramps, and myalgias. Some may cause prolonged QT interval. May cause tendon rupture in people >60 yo and people taking prednisone

89
Q

Fluoroquinolones are contraindicated in whom?

A

Pregnant bitches, nursing mothers, and children

90
Q

Pregnant woman should not take what antibiotics?

A

Tetracycline and Fluoroquinolones

91
Q

Which two antimicrobials can cause a prolonged QT interval?

A

Macrolides and Fluoroquinolones

92
Q

What is the mech of resistance to Fluoroquinolones?

A

Chromosome-encoded mutation in DNA gyrase, plasmid-mediated resistance, efflux pumps.

93
Q

What is the mech of Metrondiazole?

A

Binds DNA and unwinds helical structure then causes stand breaks to ultimately decrease protein synthesis

94
Q

M. TB Prophylaxis? Treatment?

A

Isoniazid. Rifampin, Isoniazid, Pyrazinamide, Ethambutol

95
Q

M. avium-intracellulare Prophylaxis? Treatment?

A

P: Azithromycin, rifabutin. Treatment: More drug resistant than M. TB. Azithromycin or clarithromycin + ethambutol. Can add rifabutin or ciprofloxacin

96
Q

M. Leprae Treatment?

A

Long term treatment with dapsone and rifampin for FB form. Add clofazimine for lepromatous form.

97
Q

Isoniazid mech?

A

decreases synthesis of mycolic acids. bacterial catalse-peroxidase (encoded by KatG) needed to convert INH to active metabolite

98
Q

Clinical use of Isoniazid?

A

M. TB. The only agent used as solo prophylaxis against TB.

99
Q

What determines the half life of Isoniazid?

A

Fast vs. Slow acetylators

100
Q

Isoniazid Toxicity?

A

Neurotoxicity, hepatotoxicity. Pyridoxine (Vit b6) can prevent neurotoxicity, lupus.

101
Q

mneumonic for Isoniazic?

A

INH Injures Neurons Hepatocytes

102
Q

Rifamycins

A

Rifampin, Rifabutin

103
Q

Rifamycins mech:

A

Inhibits DNA-dependent RNA polymerase

104
Q

What is the clinical use of Rifamycins?

A

M. TB; delays resistance to dapsone when used for leprosy. Used for meningococcal prophylaxis (neisseria) and chemoprophylaxis in contacts of children with Haemophilus influenzae type B

105
Q

menumonic for Rifampin’s 5 R’s

A

1) RNA polymerase inhibitor 2) Ramps up microsomal cytochrome P-450 3) Red/orange bodily fluids 4) Rapid resistance if used alone 5) Rifampin ramps up cytochrome P-450, but rifabutin does not

106
Q

What are the toxicities of Rifamycins?

A

Minor hepatotoxicity and drug interaction (Increased P-450); orange body fluids (nonhazardous SE).

107
Q

What drug is favored in HIV patients: Rifampin or Rifabutin?

A

Rifabutin due to less CYP indution

108
Q

Pyrazinamide Mech

A

Mech uncertain. Through to acidify intracellular environment via conversion to pyrazinoic acid. Effective in acidic pH of phagolysosomes, where TB engulfed by macrophages is found

109
Q

Clinical use of pyrazinamide

A

M. TB

110
Q

Toxicity/SE of Pyrazinamide

A

Hyperuricemia, hepatotoxicity

111
Q

Ethambutol mech

A

decrease carbohydrate polymerization of mycobacterium cell wall by blocking arabinosyltransferase.

112
Q

Clinical use of Ethambutol

A

M. TB

113
Q

Ethambutol Toxicity/SE

A

Optic Neuropathy (red-green color blindness)

114
Q

Prophylaxis for Endocarditis with surgical or dental procedures?

A

Penicillins

115
Q

Prophylaxis for Gonorrhea?

A

Ceftriaxone

116
Q

Prophylaxis for Hs of recurrent UTIs?

A

TMP-SMX

117
Q

Prophylaxis for meningococcal infection?

A

Ciprofloxacin, rifampin for children ***

118
Q

Prophylaxis for pregnant woman carrying group B strep?

A

Ampicillin

119
Q

Prophylaxis for preventino of gonococcal or chlamydial conjunctivitis in newborn?

A

Erhthromycin ointment

120
Q

Prophylaxis of strep pharyngitis in child with prior rheumatic fever?

A

oral penicillin

121
Q

Prophylaxis for Syphilis?

A

Benzathine Pen G

122
Q

Treatment of MRSA?

A

Vancomycin, daptomycin, linezolid, tigecycline, ceftaroline

123
Q

SE of linezolid?

A

serotonin syndrome

124
Q

Treatment of Vancomycin Resistant Enterococci?

A

Linezolid and streptogranins (quinupristin/dalfopristin)

125
Q

Which antibiotics are bactericidal?

A

Penicillin, Vancomycin, Aminoglycosides, Fluoroquinolones, Metrondiazole

125
Q

What treatment do you give for N. Gohnorrhea?

A

Ceftriaxone for the gonhorreah and must give a macrolide (azithromycin) for Claudia because of co infection

126
Q

What is the treatment of listeria monocytogenes?

A

Ampicillin

127
Q

What is the treatment for yersini?

A

Tetracycline and Aminoglycosides (streptomycin)

128
Q

What is the treatment of pseudomonas?

A

Piperacillin + tazobactam, Aminoglycosides (in combo with beta lactams), or fluoroquinolones (pseudomonas uti). Coproflixacin in CF patients

129
Q

Treatment for proteus?

A

Sulfonamides

130
Q

What is the indication of piperacillin-tazobactam?

A

Pseudomonas infection, resistant staph aureus infection, gram negative rods

131
Q

What is the mech of linezolid

A

Inhibits protein synthesis. Binds to 50s ribosomal subunit, interfering with formation of 70s initiation complex. Bacteriostatic for staph and enterococcus