Antibacterials Flashcards
1
Q
Beta lactamase inhibitors
A
Clavulanic Acid, Sulbactam, Tazobactam, Avibactam
2
Q
DOC for syphilis and Rheumatic fever prophylaxis
A
benzathine penicillin G
- lasts for 3-4 weeks
- given IM
3
Q
Drug less active against Gram neg and given orally
A
Penicillin V
4
Q
Drug of choice for:
• Strep throat
A
Penicillin V
Employed mostly orally for mild-moderate infections eg,
pharyngitis, tonsilitis, skin infections (caused by
Strep)
5
Q
Restricted to treatment of b-lactamase-producing
staphylococci
A
Nafcillin, Oxacillin, Dicloxacillin
- b-lactamase resistant
6
Q
Used for treatment of a number of infections: acute otitis media, streptococcal pharyngitis, pneumonia, skin infections, UTIs etc.
• Widely used to treat upper respiratory infections
Safe in pregnancy and children
A
Amoxicillin
7
Q
prophylactic treatment for dog, cat, and human bites - immediate
A
Amoxicillin + clavulanic acid
8
Q
prophylactic treatment for dog, cat, and human bites - a week or more
A
Ampicillin + sulbactam
Ampicillin used for same things as amoxicillin
9
Q
Commonly used to treat Pseudomonas aeruginosa
Main clinical use = as an injectable treatment of Gram
negatives
A
Ticarcillin, Piperacillin
10
Q
Which penicillin is safe to give to a patient with kidney failure
A
Nafcillin
- bc excreted in bile
11
Q
Which penicillin causes maculopapular rash
A
Ampicillin and amoxicillin
12
Q
Which penicillin causes pseudomembranous colitis
A
Ampicillin
13
Q
Which penicillin causes interstitial nephritis
A
Methicillin
14
Q
Which penicillin causes neutropenia
A
Nafcillin
15
Q
Which penicillin causes hepatitis
A
Oxacillin
16
Q
Which penicillin causes positive combs test
A
Penicillin G and V
17
Q
less susceptible to beta-lactamases. Rarely need to combine with a beta-lactamase inhibitor
A
Cephalosporins
18
Q
All cephalosporins are inactive against ?
A
LAME
listeria, legionella, acinetobacter, mycoplasma, enterocci
19
Q
Which cephalosporin generation is active against MRSA
A
5th
20
Q
DOC for surgical prophylaxis
A
1st gen cephalosporins —> cephazolin
*from gen 1-3 gram pos activity decreases
* first gens are Cefazolin, Cephalexin
21
Q
prophylaxis & therapy of abdominal and pelvic cavity infections
A
Cefotetan & cefoxitin
* second gen cephalosporins are Cefaclor, Cefoxitin, Cefotetan, Cefamandole
22
Q
DOC for gonorrhea
A
Ceftriaxone
* 3rd gen cephalosporins—> Ceftriaxone, Cefoperazone, Cefotaxime, Ceftazidime,
Cefixime
23
Q
Prophylaxis of meningitis in exposed individuals
A
Ceftriaxone and vancomycin
24
Q
Treatment of disseminated Lyme disease (CNS or
joint infection)
A
Ceftriaxone
25
Cephalosporins that have action against P.aeruginosa
Cefoperazone, Ceftazidime
26
Treatment of complicated UTI’s, complicated intra-abdominal infections, febrile neutropenia
Wide antibacterial spectrum eg, enterobacter,
Haemophilis, Neisseria, E.coli, pneumococci, P.mirabilis & P.aeruginosa
Cefipime
*4th gen cephalosporins (broad spectrum)
27
Treatment for Skin and soft tissue infection due to MRSA, particularly if Gram-negative pathogens are coinfecting
Ceftaroline
*5th gen
28
Cephalosporins are eliminated via kidney except
ceftriaxone & cefoperazone excreted in bile
29
Which drug AE is kernicterus
Ceftriaxone
30
Cefamandole, cefoperazone & cefotetan contain
methyl-thiotetrazole group, all can cause
hypoprothrombinemia and disulfiram- like reactions
Prevent by k1 admin and avoiding alcohol
31
Which carbapenem is less broad and not active against P.aeruginosa
Ertapenem
* DIME: Doripenem, Imipenem, meropenem, Ertapenem
- generally broad spectrum
32
Imipenem forms potentially nephrotoxic metabolite. Combine with what to prevent toxicity ?
Cilastatin
33
Active against Aerobic Gram-negative rods ONLY (including pseudomonas)
Aztreonam - monobactam
- resistant to beta lactamases
34
Useful for treatment of Gram-negative infections in
patients allergic to penicillin
Aztreonam
35
Bacterial glycoprotein
Active against Gram-positive bacteria only
Effective against multi-drug resistant organisms (eg,
MRSA, enterococci, PRSP)
Vancomycin
- can give if patient allergic to penicillin
36
Binds to the D-Ala-D-Ala terminus of nascent
peptidoglycan pentapeptide
Vancomycin
37
Given orally (and Drug of Choice) for the treatment of
staphylococcal enterocolitis or antibiotic-associated
pseudomembranous colitis (C.difficile)
Vancomycin
38
Which drug causes red man or red neck syndrome ?
Vancomycin
- infusion-related flushing over face and upper torso
39
AE of vancomycin
Ototoxicity (drug accumulation)
• Nephrotoxicity (drug accumulation)
• DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms) syndrome
40
Effective against resistant Gram-positive organisms
(eg, MRSA, enterococci, VRE & VRSA)
Treatment of complicated skin/structure infections
caused by susceptible S.aureus
Daptomycin
41
This drug AE is Elevated creatine phosphokinases (recommended to discontinue coadmin. of statins)
Daptomycin
42
Marked nephrotoxicity → mainly topical use
Bacitracin
43
Bind reversibly to 30S subunit of ribosome, preventing attachment of aminoacyl tRNA
Tetracyclines
44
Drugs of choice for:
• Chlamydia
• Mycoplasma pneumoniae
• Lyme disease
• Cholera
• Anthrax prophylaxis
• Rickettsia (Rocky Mountain Spotted Fever,
typhus)
Tetracyclines
45
Tetracyclines are excrete in urine except
doxycycline
- through bile
46
Discoloration & hypoplasia of teeth, stunting of
growth (generally avoided in pregnancy & not given in
children under 8y)
TERATOGENIC – all cross placenta & are excreted into
breast milk (FDA category D)
Photosensitization
Tetracyclines
47
Generally used to treat complicated skin, soft tissue and intraabdominal infections. Increased risk of mortality has been observed compared with other antibiotics when used to treat serious infections
Tigecycline- glycylcyclines
48
Glycylcycline Contraindications
Pregnancy & children <8y
49
This drug only requires once daily dosing
Aminoglycosides
** Amikacin, Gentamicin, Tobramycin, Streptomycin,
Neomycin
50
Concentration-dependent killing
aminoglycosides
51
Time-dependent killing
penicillins, cephalosporins
52
Covalently bind to 30S ribosomal subunit prior to
ribosome formation leading to irreversible inhibition of initiation complex :
• misreading of mRNA, &
• blockade of translocation
Aminoglycosides
53
Aminoglycosides resistance
Inactivated by acetylation, phosphorylation and adenylation
54
Drugs of choice for:
• Empiric therapy of infective endocarditis
Gentomycin and vancomycin
55
AE OF AMINOGLYCOSIDES
Ototoxicity
• Nephrotoxicity
• Neuromuscular blockade (myasthenia gravis =
contraindicated)
• Pregnancy (contraindicated unless benefits outweigh risks – FDA Category D)
56
Used as adjunct in treatment for hepatic
encephalopathy
Oral neomycin
- reduces gut flora to reduce the nitrogen containing compounds that can cross the BBB
Other alternatives
• Lactulose
• Oral vancomycin
• Oral metronidazole
• Rifaximin
57
Who traps NH4 in colon effectively reducing
plasma ammonia concentrations
Lactulose
58
Reversibly bind to the 23S rRNA of the 50S subunit
blocking translocation
Macrolides
- Erythromycin, Clarithromycin, Azithromycin
- mainly treats gram pos infections
- bacteriostatic
59
DOC for whooping cough (B.pertussis)
Erythromycin
60
These macrolides inhibit CYP450
Erythromycin & clarithromycin
61
inhibit protein synthesis in mitochondrial ribosomes
→ bone marrow toxicity
Very broad spectrum
Chloramphenicol
62
Inhibits hepatic oxidases (3A4 & 2C9)
Chloramphenicol
63
Drug causes bone marrow depression and Gray baby syndrome (cyanosis)
Chloramphenicol
64
Number 1 drug for Potentially fatal pseudomembranous colitis (superinfection of C.difficile)
Clindamycin
- ampicillin also causes this problem
65
treatment of infections caused by drugresistant Staphylococci or VRE
Streptogramins
Quinupristin, Dalfopristin
66
Inhibitors of CYP 3A4
Streptogramin
67
Oral bioavailability 100%
Linezolid
68
Cannot combine linezolid with
antidepressants
- non selective inhibitor of MAO
- like SSRIs bc it is a weak reversible inhibitor of MAO
- can lead to serotonin syndrome
69
Only treats C. difficile
Fidaxomicin
70
Antibiotic belonging to monoxycarbolic acid class
• Activity against most Gram-positive cocci, including
MRSA and most streptococci (but not enterococci)
Mupirocin
71
How is mupirocin given
Intranasal:
• Eradication of nasal colonization with MRSA in
adult patients and healthcare workers
• Topically:
• Treatment of impetigo or secondary infected
traumatic skin lesions
72
Fluoroquinolones
Second generation
Ciprofloxacin
Third generation
Levofloxacin
Fourth generation
Gemifloxacin, Moxifloxacin
73
Inhibit bacterial DNA replication via interference with
topoisomerase II (DNA gyrase) & IV
Fluoroquinolones
74
Gram -ve activity with some activity against Gram +ve and atypical organisms.
Synergistic with b-lactams
Ciprofloxacin
75
Expanded Gram -ve activity
Improved activity against Gram +ve and atypical organisms. Excellent activity against S.pneumoniae
Levofloxacin
76
Improved Gram +ve activity and anaerobic activity
Moxifloxacin and Gemifloxacin
77
Travelers diarrhea
P.aeruginosa (CF patients)
Prophylaxis against meningitis
(alternative to ceftriaxone & rifampin)
Ciprofloxacin
2nd gen
78
Prostatitis
STD’s (not syphilis)
Skin infections
Acute sinusitis, bronchitis, TB
Community acquired pneumonia
Levofloxacin
3rd gen
79
Community acquired pneumonia
Moxifloxacin and gemifloxacin
80
Fluoroquinolones AE
Connective tissue problems (avoid in pregnancy,
nursing mother, under 18’s) – Black Box Warning!
• Peripheral neuropathy (FDA warning)
• QT prolongation (moxifloxacin, gemifloxacin,
levofloxacin)
• High risk of causing superinfections (C.difficile, C
albicans, streptococci)
81
Inhibit bacterial folic acid synthesis
• Synthetic analogs of PABA (p-amino-benzoic acid)
• Competitive inhibitors (& substrate) of dihydropteroate synthase
Sulfonamides
Sulfamethoxazole, Sulfadiazine, Sulfisoxazole
82
Sulfonamides AE
Crystalluria (nephrotoxicity)
• Hypersensitivity reactions
• Hematopoietic disturbances (esp. patients with G6PD deficiency)
• Kernicterus (in newborns and infants <2 months)
** Ceftriaxone (2nd gen cephalosporins also causes kernicterus)
83
inhibitor of bacterial dihydrofolate reductase
Trimethoprim
84
Drug used for
- UTI’s
- Bacterial prostatitis
- Bacterial vaginitis
Antifolate effects (contraindicated in pregnancy)
Trimethoprim
85
Combination of trimethoprim & sulfamethoxazole
Cotrimoxazole
Synergistic: inhibition of sequential steps in
tetrahydrofolic acid synthesis
86
Uncomplicated UTI’s (drug of choice)
Cotrimoxazole
87
PCP (drug of choice)
Nocardiosis (drug of choice)
Toxoplasmosis (alternative drug)
Cotrimoxazole
88
Contraindicated in pregnancy (esp. 1st trimester)
Cotrimoxazole
89
Anaerobic conditions are vital for optimal activity
• Undergoes reductive bioactivation of its nitro group by ferredoxin
• Forms cytotoxic products that interfere with nucleic acid synthesis → damage DNA
Metronidazole
90
Metronidazole AE
Disulfiram-like effect (avoid alcohol)
Headache, dark coloration of urine, metallic taste
Not advised in 1st trimester
91
Blocks transcription by binding to b subunit of bacterial DNA-dependent RNA polymerase
→ leading to inhibition of RNA synthesis
Rifampin
92
Patient not responding to vancomycin to treat mycobacteri. What to use ?
Rifampin
93
Rifampin resistance
Point mutations in rpoB, the gene for the b subunit of RNA polymerase
→ decreased affinity of bacterial DNA-dependent RNA polymerase for drug
• Decreased permeability
94
Treatment for
- TB
• Prophylaxis for individuals exposed to meningitis
• Prophylaxis in contacts of children with H.influenzae
type B
• MRSA (with vancomycin)
Rifampin
95
Imparts harmless orange/red color to bodily fluids
• Strongly induces most CYP P450 isoforms
• SAFE IN PREGNANCY
Rifampin AE
96
Attach to and disrupt bacterial cell membranes
Also, bind to and inactivate endotoxin
Gram-positive bacteria are resistant
Extremely nephrotoxic
Polymyxin B
97
This drug is contraindicated in patients with
- Significant renal insufficiency
• Pregnancy at term (38-42 weeks)
• Infants <1 month (risk of hemolytic anemia)
Nitrofurantoin
- may cause hemolytic anemia (G6PD deficient patients)
98
What is the empiric antibacterial treatment for infective endocarditis?
Vancomycin and gentamicin (due to emergence of
MRSA and penicillin-resistant streptococci)
99
When can Rifampin be added to empiric antibacterial treatment for infective endocarditis?
In the presence of a prosthetic heart valve.
Linezolid or daptomycin are options for patients with
intolerance to vancomycin of resistant organisms.
100
What is the antibacterial treatment for infective
endocarditis caused by a-hemolytic streptococci?
Penicillins (penicillin G and ampicillin) often in
combination with gentamicin.
