Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

USMLE > Pharm_Antibiotics > Flashcards

Pharm_Antibiotics Flashcards

You may prefer our related Brainscape-certified flashcards:
USMLE® Step 1 flashcards
1
Q

Aminoglycosides: Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin

A

Mechanism: Bactericidal; inhibit formation of initiation complex and cause misreading of mRNA. Requite O2 for uptakel therefore ineffective against anaerobes. Clinical use: Severe gram-negative rod infections. Synergistic with β-lactam antibiotics. Neomycin for bowel surgery. Toxicity: Nephrotoxicity (+ cephalosporins), Ototoxicity (+ loop diuretics). Teratogen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ampicillin, amoxicillin (aminopenicillins)

A

Mechanism: Same as penicillin. Wider spectrum; penicillinase sensitive. Also combine with clavulanic acid to enhance spectrum. Amoxicillin has greater oral bioavailability than ampicillin. Clinical use: Extended-spectrum penicillin - certain gram-positive bacteria (Listeria monocytogenes, Enterococci) and gram-negative rods (Haemophilus influenza, E.coli, Proteus mirabilis, Salmonella) Toxicity: Hypersensitivity reactions; ampicillin rash; pseudomembranous colitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Anti-TB drugs (5)

A

1st line - Streptomycin, Pyrazinamide, Isoniazid (INH), Rifampin, Ethambutol 2nd line - Cycloserine Important side effect of ethambutol is optic neuropathy (red-green color blindness). For other drugs, hepatotoxicity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Antimycobacterial drugs

A

M.tuberculosis Prophylaxis: Isoniazid; Treatment: Rifampin, Isoniazid, Pyrazinamide, Ethambutol M.avium-intracellulare Prophylaxis: Azithromycin; Treatment: Azithromycin, rifampin, ethambutol, streptomycin M.leprae Prophylaxis: N/A; Treatment: Dapsone, rifampin, clofazimine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Aztreonam

A

Mechanism: A monobactam resistant to β-lactamases. Inhibits cell wall synthesis (binds to PBP3). Synergistic with aminoglycosides. No cross-allergenicity with penicillins. Clinical use: Gram-negative rods only - No activity against gram-positive anaerobes. For penicillin-allergic patients and those with renal insufficiency who cannot tolerate aminoglycosides. Toxicity: Usually nontoxic; occasional GI upset. No cross-sensitivity with penicillin or cephalosporins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Bactericidal antibiotics (6)

A

Vancomycin, Fluoroquinolones, Penicillin, Aminoglycosides, Cephalosporins, Metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Bacteriostatic antibiotics (6)

A

Erythromycin, Clindamycin, Sulfamethoxazole, Trimethoprim, Tetracyclines, Chloramphenicol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cephalosporins: 1st generation (cefazolin, cephalexin)

A

Mechanism: β-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases. Bactericidal. Clinical use: gram-positive cocci, Proteus mirabilis, E.coli, Klebsiella pneumoniae Toxicity: Hypersensitivity reactions, vitamin K deficiency. Cross-hypersensitivity with penicillins occurs in 5-10% of patients. ↑nephrotoxicity of aminoglycosides; disulfiram-like reaction with ethanol (in cephalosporins with a methylthiotetrazole group, e.g., cefamandole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cephalosporins: 2nd generation (cefoxitin, cefaclor, cefuroxime)

A

Mechanism: β-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases. Bactericidal. Clinical use: gram-positive cocci, Haemophilus influenzae, Enterobacter aerogenes, Neisseria spp., Proteus mirabilis, E.coli, Klebsiella pneumoniae, Serratia marcescens Toxicity: Hypersensitivity reactions, vitamin K deficiency. Cross-hypersensitivity with penicillins occurs in 5-10% of patients. ↑nephrotoxicity of aminoglycosides; disulfiram-like reaction with ethanol (in cephalosporins with a methylthiotetrazole group, e.g., cefamandole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cephalosporins: 3rd generation (ceftriaxone, cefotaxime, ceftazidime)

A

Mechanism: β-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases. Bactericidal. Clinical use: serious gram-negative infections resistant to other β-lactams Toxicity: Hypersensitivity reactions, vitamin K deficiency. Cross-hypersensitivity with penicillins occurs in 5-10% of patients. ↑nephrotoxicity of aminoglycosides; disulfiram-like reaction with ethanol (in cephalosporins with a methylthiotetrazole group, e.g., cefamandole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cephalosporins: 4th generation (cefepime)

A

Mechanism: β-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases. Bactericidal. Clinical use: ↑ activity against Pseudomonas and gram-positive organisms Toxicity: Hypersensitivity reactions, vitamin K deficiency. Cross-hypersensitivity with penicillins occurs in 5-10% of patients. ↑nephrotoxicity of aminoglycosides; disulfiram-like reaction with ethanol (in cephalosporins with a methylthiotetrazole group, e.g., cefamandole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Chloramphenicol

A

Mechanism: Inhibits 50S peptidyltransferase activity. Bacteriostatic. Clinical use: Meningitis (Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae). Conservative use owing to toxicities but often still used in developing countries due to low cost. Toxicity: Anemia (dose dependent), aplastic anemia (dose dependent), gray baby syndrome (in premature infants because they lack liver UDP-glucuronyl transferase)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Clavulanic acid

A

β-lactamase inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Clindamycin

A

Mechanism: Blocks peptide bond formation at 50S ribosomal subunit. Bacteriostatic. Clinical use: Anaerobic infections (e.g., Bacterioides fragilis, Clostridium perfrigens) in aspiration pneumonia or lung abscesses. Toxicity: Pseudomembranous colitis (C. difficile overgrowth), fever, diarrhea PS: Treats anaerobes above the diaphragm vs. metronidazole (anaerobic infections below the diaphragm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Contraindication: Tetracyclines

A

in pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Contraindications: Fluoroquinolones

A

in pregnant women and in children because animal studies show damage to cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Demeclocycline

A

ADH antagonist; acts as a diuretic in SIADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

DOC: Candida albicans

A

Nystatin for superficial infection; amphotericin B for serious systemic infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

DOC: Chlamydiae

A

azithromycin or doxycycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

DOC: Gardnerella vaginalis

A

metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

DOC: Haemophilus influenzae

A

Treat meningitis with ceftriaxone. Rifampin prophylaxis in close contacts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

DOC: Helicobacter pylori (3)

A

Triple therapy: (1) metronidazole, bismuth, tetracycline / amoxicillin; (2) metronidazole, omeprazole, clarithromycin (3) PPI, clarithromycin, amoxicillin / metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

DOC: Legionella pneumophila

A

erythromycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

DOC: Leprosy (Hansen’s disease)

A

Long-term oral dapsone; toxicity is hemolysis and methomoglobinemia. Alternate treatments include rifampin and combination of clofazimine and dapsone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

DOC: Lyme disease - Borrelia burgdorferi

A

doxycycline, ceftriaxone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

DOC: Mycoplasma pneumoniae

A

tetracycline or erythromycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

DOC: Neonatal Chlamydia trachomatis

A

azithromycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

DOC: Pneumocystis jiroveci (formerly carinii)

A

TMP-SMX, pentamidine, dapsone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

DOC: Pseudomembranous colitis - Clostridia difficile

A

Metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

DOC: Pseudomonas aeruginosa

A

Aminoglycoside + extended-spectrum penicillin (e.g., piperacillin, ticarcillin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

DOC: Rickettsiae

A

Doxycycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

DOC: Sporothrix schenckii

A

Itraconazole or potassium iodide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

DOC: Syphilis

A

penicillin G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

DOC: Systemic mycoses (Histoplasmosis, Blastomycosis, Coccidioidomycosis, Paracoccidioidomycosis)

A

fluconazole or ketoconazole for local infection; amphotericin B for systemic infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

DOC: Tinea pedis (foot), Tinea cruris (groin), Tinea corporis (ringworm on body), Tinea capitis (head, scalp) - Microsporum, Trichophyton, and Epidermophyton

A

treated with topical azoles

36
Q

DOC: Tinea versicolor - Malassezia furfur

A

topical miconazole, selenium sulfide (Selsun)

37
Q

Ethambutol

A

↓ carbohydrate polymerization of mycobacterium cell wall by blocking arabinosyltransferase

38
Q

Fluoroquinolones: Ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin, moxifloxacin, gatifloxacin, enoxacin (fluoroquinolones), nalidixic acid (a quinolone)

A

Mechanism: Inhibit DNA gyrase (topoisomerase II). Bactericidal. Must not be taken with anticids. Clinical use: Gram-negative rods of urinary and GI tracts (including Pseudomonas), Neisseria, some gram-positive organisms. Toxicity: GI upset, superinfections, skin rashes, headache, dizziness. Tendonitis and tendon rupture in adults; leg cramps and myalgias in kids

39
Q

Imipenem / cilastatin, meropenem

A

Mechanism: Imipenem is a broad-spectrum, β-lactamase-resistant carbapenem. Always administered with cilastatin (inhibitor of renal dehydropeptidase I) to ↓ inactivation of drug in renal tubules. Clinical use: Gram-positive cocci, gram-negative rods, and anaerobes. Wide spectrum, but the significant side effects limit use of life threatening infections, or after other drugs have failed. Meropenem, however, has a reduced risk of seizures and is stable to dihydropeptidase I. Toxicity: GI distress, skin rash, and CNS toxicity (seizures) at high plasma levels

40
Q

Isoniazid (INH)

A

Mechanism: ↓ synthesis of mycolic acids. Bacteria catalase-peroxidase needed to convert INH to active metabolite Clinical use: Mycobacterium tuberculosis. The only agent used as solo prophylaxis against TB. (Different INH half-lives in fast vs. slow acetylators) Toxicity: Neurotoxicity, hepatotoxicity, lupus. Pyridoxine (vitamin B6) can prevent neurotoxicity, lupus

41
Q

Macrolides: Erythromycin, azithromycin, clarithromycin

A

Mechanism: Inhibit protein synthesis by blocking translocation; bind to the 23S rRNA of the 50S ribosomal subunit. Bacteriostatic. Clinical use: Atypical pneumonias (Mycoplasma, Chlamydia, Legionella), URIs, STDs, gram-positive cocci (streptococcal infections in patients allergic to penicillin), and Neisseria Toxicity: Prolonged QT interval (especially erythromycin), GI discomfort (most common cause of noncompliance), acute cholestatic hepatitis, eosinophilia, skin rashes. Increases serum concentration of theophyllines, oral anticoagulants.

42
Q

Mechanism in resistance: Fluoroquinolones

A

Chromosome-encoded mutation in DNA gyrase

43
Q

Mechanism of action: Block cell wall synthesis by inhibition of peptidoclycan cross-linking

A

Drugs: Penicillin, ampicillin, ticarcillin, piperacillin, imipenem, aztreonam, cephalosporins

44
Q

Mechanism of action: Block DNA topoisomerases

A

Drugs: Fluoroquinolones

45
Q

Mechanism of action: Block mRNA synthesis

A

Drugs: Rifampin

46
Q

Mechanism of action: Block nucleotide synthesis

A

Drugs: Sulfonamides, trimethoprim

47
Q

Mechanism of action: Block peptidoglycan synthesis

A

Drugs: Bactitracin, vancomycin

48
Q

Mechanism of action: Block protein synthesis at 50S ribosomal subunit

A

Drugs: Chloramphenicol, macrolides, clindamycin, streptogramins (quinupristin, dalfopristin), linezolid

49
Q

Mechanism of action: Blocks protein synthesis at 30S ribosomal subunit

A

Drugs: Aminoglycosides, tetracyclines

50
Q

Mechanism of action: Disrupt bacterial cell membranes

A

Drugs: Polymyxins

51
Q

Mechanism of resistance: Aminoglycosides

A

Transferase enzymes that inactivate the drug by acetylation, phosphorylation, or adenylation

52
Q

Mechanism of resistance: Chloramphenicol

A

Plasmid-encoded acetyltransferase that inactivates drug

53
Q

Mechanism of resistance: Macrolides

A

Methylation of 23S rRNA binding site

54
Q

Mechanism of resistance: Sulfonamides

A

Altered enzyme (bacterial dihydropteroate synthetase), ↓ uptake, or ↑PABA synthesis

55
Q

Mechanism of resistance: Tetracyclines

A

↓ uptake into cells or ↑ efflux out of cell by plasmid-encoded transport pumps

56
Q

Mechanism of resistance: Vancomycin

A

Occurs with amino acid change of D-ala D-ala to D-ala D-lac

57
Q

Methicillin, nafcillin, dicloxacillin (penicillinase-resistant penicillins)

A

Mechanism: Same as penicillin. Narrow spectrum; penicillinase resistant because of bulkier R group. Clinical use: S. aureus (except MRSA; resistant because of altered penicillin-binding protein target site) Toxicity: Hypersensitivity reactions; methicillin - interstitial nephritis

58
Q

Metronidazole

A

Mechanism: Froms free radical toxic metabolites in the bacterial cell that damage DNA. Bactericidal, antiprotozoal. Clinical use: Treats Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobes (Bacteroides, Clostridium). Used with bismuth and amoxicillin (or tetracycline) for “triple therapy” against H.Pylori Toxicity: Disulfiram-like reaction with alcohol; headache, metallic taste

59
Q

Nonsurgical antimicrobial prophylaxis: Endocarditis with surgical or dental procedures

A

Penicillins

60
Q

Nonsurgical antimicrobial prophylaxis: Gonorrhea

A

Ceftriaxone

61
Q

Nonsurgical antimicrobial prophylaxis: History of recurrent UTIs

A

TMP-SMX

62
Q

Nonsurgical antimicrobial prophylaxis: Meningococcal infection

A

Rifampine (drug of choice), minocycline

63
Q

Nonsurgical antimicrobial prophylaxis: Mycobacterium avium-intracellulare

A

Azithromycin

64
Q

Nonsurgical antimicrobial prophylaxis: Pneumocystis jiroveci pneumonia

A

TMP-SMX (drug of choice), aerosolized pentamidine

65
Q

Nonsurgical antimicrobial prophylaxis: Syphilis

A

Benzathine penicillin G

66
Q

Penicillin: Penicillin G (IV form), Penicillin V (oral). Prototype β-lactam antibiotics.

A

Mechanism: 1. Bind penicillin-binding proteins 2. Block transpeptidase cross-linking of cell wall 3. Activate autolytic enzymes Clinical use: Mostly used for gram-positive organisms (S.pneumoniae, S.pyogenes, Actinomyces) and syphilis. Not penicillinase resistant. Toxicity: Hypersensitivity reactions, hemolytic anemia.

67
Q

Polymyxins: Polymyxin B, colistimethate (polymyxin E)

A

Mechanism: Bind to cell membrane of bacteria and disrupt their osmotic properties. Polymyxins are cationic, basic proteins that act like detergents Clinical use: Resistant gram-negative infections. Toxicity: Neurotoxicity, acute renal tubular necrosis

68
Q

Prophylaxis: Mycobacteria avium-intracellulare

A

azithromycin

69
Q

Prophylaxis: Neisseria Meningococci

A

Rifampin prophylaxis in close contacts

70
Q

Protein synthesis 30S inhibitors

A

Aminoglycosides [bactericidal] Tetracyclines [bacteriostatic]

71
Q

Protein synthesis 50S inhibitors

A

Chloramphenicol, Clindamycin [bacteruistatic] Erythromycin [bacteriostatic] Lincomycin [bacteriostatic] Linezolid [variable]

72
Q

Pyrazinamide

A

Effective in acidic pH of phagolysosomes, where TB engulfed by macrophages is found

73
Q

Rifampin

A

Mechanism: Inhibits DNA-dependent RNA polymerase Clinical use: Mycobacterium tuberculosis; delays resistance to dapsone when used for leprosy. Used for meningococcal prophylaxis and chemoprophylaxis in contacts of children with Haemophilus influenzae type B. Toxicity: Minor hepatotoxicity and drug interaction (↑P-450); orange body fluids (nonhazardous side effect)

74
Q

Rifampin’s 4 R’s

A

RNA polymerase inhibitor Revs up microsomal P-450 Red/orange body fluids Rapid resistance if used alone

75
Q

Sulbactam

A

β-lactamase inhibitors

76
Q

Sulfa drug allergies

A

Patients who do not tolerate sulfa drugs should not be given sulfonamides or other sulfa drugs, such as sulfasalazine, sulfonylureas, thiazide diuretics, acetazolamide, furosemide, celecoxib, or probenecid

77
Q

Sulfonamides: Sulfamethoxazole (SMX), sulfisoxazole, sulfadiazine

A

Mechanism: PABA antimetabolites inhibit dihydropteroate synthetase. Bacteriostatic. Clinical use: Gram-positive, gram-negative, Nocardia, Chlamydia. Triple sulfas or SMX for simple UTI. Toxicity: Hypersensitivity reactions, hemolysis if G6PD deficient, nephrotoxicity (tubulointerstitial nephritis), photosensitivity, kernicterus in infants, displace other drugs from albumin (e.g., warfarin)

78
Q

Tazobactam

A

β-lactamase inhibitors

79
Q

Tetracyclines: Tetracycline, doxycycline, demeclocycline, minocycline

A

Mechanism: 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 take with milk, antacids, or iron-containing preparations because divalent cations inhibit its absorption in the gut. Clinical use: Borrelia burgdorferi, H.pylori, M.pneumoniae. Drug’s ability to accumulate intracellularly makes it very effective against Rickettsia and Chlamydia Toxicity: GI distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity.

80
Q

Ticarcillin, carbenicillin, piperacillin (antipseudomonals)

A

Mechanism: Same as penicillin. Extended spectrum Clinical use: Pseudomonas spp. and gram-negative rods; susceptible to penicillinase; use with clavulanic acid Toxicity: Hypersensitivity reactions

81
Q

Treatment of MRSA

A

Vancomycin

82
Q

Treatment of VRE

A

Linezolid and streptogramins (quinupristin / dalfopristin)

83
Q

Trimethoprim

A

Mechanism: Inhibits bacterial dihydrofolate reductase. Bacteriostatic. Clinical use: Used in combination with sulfonamides (trimethroprim-sulfamethoxazole [TMP-SMX]), causing sequential block of folate synthesis. Combination used for recurrent UTIs, Shigella, Salmonella, Pneumocystis jiroveci pneumonia. Toxicity: Megaloblastic anemia, leukopenia, granulocytopenia (May alleviate with supplemental folinic acid [leucovorin rescue])

84
Q

Vancomycin

A

Mechanism: Inhibits cell wall mucopeptide formation by binding D-ala D-ala portion of cell wall precursors. Bactericidal. Clinical use: Gram positive only - serious, multidrug-resistant organisms, including S.aureus, enterococci and Clostridium difficile (pseudomembranous colitis) Toxicity: Nephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing - “red man syndrome”. Well tolerated in general.

85
Q

β-lactamase inhibitors

A

Include clavulanic acid, sulbactam, tazobactam. Often added to penicillin antibiotics to protect the antibiotic from destruction by β-lactamase (penicillinase)

USMLE (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions