ANTIMICROBIALS Flashcards
1
Q
The AE of which drug can be largely prevented by administration of histamines and a slow infusion rate?
A
Vancomycin (red man syndrome)
1
Q
Which tetracycline is rarely used as an antibiotic but instead to act as a diuretic in SIADH?
A
Demeclocycline
1
Q
What is the mechanism of resistance to tetracyclines?
A
Decreased uptake by cells or increased efflux by PLASMID ENCODED GENES
1
Q
What autoantibodies may be found in the serum of a person on isoniazid?
A
Antihistone; it causes a lupus like syndrome
1
Q
Which enzyme activates isoniazid to the active form?
A
Mycobacterial Catalase Peroxidase (KatG)
1
Q
Which antifungal binds ergosterol but is only available topically? Which is used systemically?
A
Nystatin; Ergosterol
2
Q
What is the mechanism of resistance to acyclovir?
A
mutation of viral thymidine kinase
3
Q
The uptake of which type of antibiotics is inhibited by divalent cations?
A
Tetracyclines
3
Q
Which drugs inhibit 50 S and prevent translocation?
A
Macrolides
4
Q
Which type of antibiotics is aztreonam synergistic with?
A
aminoglycosides
5
Q
What is nifurtimox used to Tx?
A
Trypanosoma cruzi
6
Q
Which aminopenicillin has the greatest oral bioavailability?
A
amOxicillin (greater Oral) than ampicillin
6
Q
Which carbapenem does not require coadministration of cilastatin? What does this mean?
A
Meropenem, it is not degraded in kidneys by dehydropeptidase I
6
Q
MOA of oseltamivir
A
neuraminidase inhibitor that decreases release of influenza A and B viral progeny
7
Q
What 2 types of HSV infections can you use acyclovir for? What is the benefit of valacyclovir?
A
mucocutaneous (i.e. genitals and cold sores) and encephalitis; better oral bioavailability
8
Q
What do you use to treat NADPH oxidase deficiency?
A
IFN gamma
9
Q
MOA of trimethoprim
A
Inhibits dihydrofolate reductase
10
Q
How do you prevent postsurgical infection due to S. aureus?
A
Cefazolin
10
Q
What can be treated with IFN alpha? (3)
A
HBV, HCV, and Kaposi
11
Q
What cephalosporin is used prior to surgery to prevent S. aureus skin infections?
A
cefazolin
12
Q
Why do you avoid chloramphenicol in pregnancy?
A
Gray Baby syndrome, baby has low levels of UDP glucuronyl transferase
12
Q
MOA of foscarnet
A
Pyrophosphate analog that inhibits CMV viral DNA polymerase
13
Q
Which drugs inhibit fungal cell wall synthesis by inhibiting B-glucan?
A
Caspofungin and Anidulfungin
13
Q
What is the mechanism of resistance to ganciclovir?
A
mutated CMV DNA polymerase or viral kinase
13
In which circumstance could you use foscarnet in a ganciclovir resistant strain of CMV?
If the resistance is from lack of viral kinase. Foscarnet does not require viral kinase, however, if the resistance is from viral DNA pol then neither will work
14
What highly virulent bug is covered by ceftaroline?
MRSA
14
This antibiotic blocks peptidyltransferase at the 50S subunit
Chloramphenicol
15
What is pyrimethamine used to treat?
Toxoplasmosis
15
What is sodium stibogluconate used to Tx?
Leishmaniasis
17
What is the mechanism of resistance to penicillins?
Beta Lactamase
17
Why do you avoid fluoroquinolones in pregnancy?
Cartilage damage
18
Why do you avoid ribavirin in pregnancy?
Teratogenic
19
Which TB drug may cause optic neuropathy?
Ethambutol
19
MOA of zanamavir
neuraminidase inhibitor that decreases release of influenza A and B viral progeny
20
Which drugs are given as prophylaxis for A) Mycobacterium tuberculosis B) MAC and C) M. leprae?
A) Isoniazid B) Azithromycin (when CD4
20
What is Terbinafine? Terbutaline?
Terbinafine is an antifungal that inhibits squalene epoxidase and is used to Tx dermatophytes; Terbutaline is a B2 agonist used to relax the uterus
21
Which generation of cephalosporins covers gram positive bacteria and Proteus, E. coli, Klebsiella, Haemophilus, Enterobacter, and Neisseria?
Second Generation (HEN PEcK)
22
What inhibits the uptake of tetracyclines?
Divalent cations: milk, antacids, or iron
22
What is triple therapy for H pylori?
Metronidazole, Clarithromycin and PPI's
22
Which 2 antifungals affect cell wall synthesis?
Caspofungin and Anidulfungin
22
Which antiviral inhibits IMP dehydrogenase?
Ribavirin
22
How can you reverse the bone marrow suppression caused by NRTI's?
G-CSF and EPO
22
What kind of drugs are nevirapine, delavirdine, and efavirenz?
NNRTI's
23
How do you prophylax against gonorrhea?
Ceftriaxone
24
What 7 bugs are covered by aminopenicillins that are not by penicillins?
Haemophilus influenzae b, E. coli, Listeria, Proteus, Salmonella, Shigella, and Enterococci (HELPSS kill enterococci)
24
How do you treat tuberculous leprosy?
Dapsone and Rifampin
25
What are 3 AE of ampicillin?
Hypersensitivity, Ampicillin rash if underlying mono, and pseudomembranous colitis
25
How do you prophylax against meningitis?
Ciprofloxacin = adults; Rifampin = kids
25
What is the MOA of raltegravir?
inhibits HIV integrase
26
What makes nafcillin, oxacillin, and dicloxacillin resistant to beta lactamases?
They have a bulky R group which sterically hinders them
27
MOA of metronidazole?
disulfiram like reaction, headache, and metallic taste
28
This TB drug blocks arabinosyltransferase and decreases carbohydrate polymerization of the cell wall
Ethambutol
28
Major AE of rifampin
orange body fluids and hepatoxicity (induce CYP450)
29
Which drug is used against cryptococcus and is converted to 5-FU by cytosine deaminase?
Flucytosine
30
What are the AE of penicillins (2)?
Hypersensitivity reactions and Hemolytic anemia
30
Aminoglycosides and tetracyclines both act on _____ S
30 S
30
What drug is used to treat Giardia in A) Non pregnant and B) Pregnant
A) metronidazole B) Paramomycin
31
Which antibiotic inhibits dihydrofolate reductase? Which drug also does this as an antineoplastic?
Trimethoprim; Methotrexate
33
Which antifungals inhibit nucleic acid synthesis?
5-Flucytosine
34
This tetracycline is excreted fecally rather than renally
Doxycycline
34
What is the antiviral that inhibits IMP dehydrogenase indicated for (2)?
This is ribavirin (Chronic Hepatitis C and RSV)
35
What molecule is truly a "quinolone"?
nalidixic acid --all others are FLUOROquinolones
36
Which 30S inhibitors are bacteriostatic and bactericidal?
Bactericidal = aminoglycoside; Bacteriostatic = tetracyclines
38
Which electrolytes need to be supplemented when on amphotericin B?
K and Mg
40
What is the difference between acyclovir and ganciclovir?
Not much really, both are guanosine analogs that are monophosphorylated by a viral kinase HOWEVER, ganciclovir is more effective against CMV and acyclovir is more effective against HSV
40
Name the 3 NNRTI's
Nevirapine, Efavirenz, and Delavirdine
41
Which cephalosporin covers MRSA?
Ceftaroline
43
What other disorders can hydroxychloroquine be used for aside from malaria?
Rheumatologic disorders
43
What is special about tenofovir when compared to other NRTI's?
Does not have to be activated
44
What may relieve the bone marrow issues of trimethoprim?
Leucovorin = same as rescue for methotrexate (folinic acid)
44
MOA of nystatin
Binds ergosterol to form membrane pores in fungi; unlike amphotericin B, only available topically because too toxic
45
How do you prophylax against syphilis?
Benzathine penicillin G
46
What determines the half life of isoniazid?
whether the person is a fast or slow acetylator
48
Which generation of cephalosporins covers gram positive bacteria and Proteus, E. coli, and Klebsiella?
First Generation (PEcK)
49
What is the MOA of aztreonam?
Monobactam that prevents peptidoglycan crosslinking by binding to PBP3
49
What must you co-administer with cidofovir?
It is nephrotoxic so it should be given probenicid and IV saline to decrease toxicity
50
What bugs are covered by first generation cephalosporins?
Gram positives and Proteus, E. coli, and Klebsiella (PeCK)
51
Which 3rd generation cephalosporin is used against Pseudomonas?
Ceftazidime
53
How do you prophylax against strep pharyngitis in a kid with Hx of rheumatic fever?
oral penicillin
54
What is the MOA of griseofulvin?
Interferes with fungal microtubules and disrupts mitosis
56
How do you prophylax against gonococcal and chlamydial conjunctivitis in a newborn?
Erythromycin ointment
56
What are the 2 most serious side effects of amphotericin
Nephrotoxicity and Arryhthmias (and the arrhythmias are ultimately due to the nephrotoxicity)
57
What is the mechanism of resistance to macrolides
methylation of the 23S rRNA binding site
58
Which type of bugs can vancomycin be used against?
GRAM POSITIVE ONLY
59
This TB drug blocks the synthesis of mycolic acid
Isoniazid
59
This TB drug blocks DNA dependent RNA polymerase
Rifampin
60
What drug inhibits HIV integrase
Raltegravir
61
Which antifungal drug interferes with microtubule function and may be carcinogenic?
Griseofulvin
62
MOA of ergosterol
Binds ergosterol to form membrane pores in fungi
64
Describe the full MOA of acyclovir
Gets into cells and is monophosporylated by viral thymidine kinase to the active form. This then functions as a guanosine analog and causes CHAIN TERMINATION (no 3' OH)
65
Which type of beta-lactam have seizures as an AE?
Carbapenems
66
What bugs are covered by second generation cephalosporins?
Gram positives, Haemophilus, Enterobacter, Neisseria, Proteus, E. coli, Klebsiella (HEN PEcK)
68
What are the AE (6) of sulfonamides?
Hypersensitivity, hemolysis in G6PD, nephrotoxicity (tubulointerstitial nephritis), photosensitivity, KERNICTERUS, and displace drugs from albumin such as warfarin
69
How do you prevent red man syndrome?
Antihistamines and a slow infusion rate of vancomycin
70
What is the MOA of cilastatin, always given with?
Inhibits renal dehydropeptidase I to prevent the breakdown of imipenem
72
Which beta-lactams may cause vitamin K deficiency? How would this manifest?
Cephalosporins, bleeding (loss of II, VII, IX, X, and proteins C and S)
73
This TB drug has an unknown MOA but may acidify the intracellular environment by forming \_\_\_\_\_\_\_\_\_\_\_\_\_
Pyrazinamide; pyrazinoic aci
74
Which bactericidal antibiotics inhibit formation of the initiation complex and cause misreading of mRNA?
aminoglycosides
75
Ototoxicity with aminoglycosides is potentiated with __________ while nephrotoxicity is potentiated with \_\_\_\_\_\_\_\_\_\_\_\_\_\_
Loop diuretics; Cephalosporins
75
Which type of anemia is formed by trimethoprim? What could you give to rescue?
Megaloblastic anemia (lack of folate); rescue with folinic acid (leucovorin) same as for methotrexate
76
Which antibiotics function by blocking DNA topoisomerase II and IV?
Fluoroquinolones
77
Which ribosomal inhibitor has a dose dependent risk of aplastic anemia?
chloramphenicol
79
What is the MOA of aminoglycosides
Bind 30 S ribosome to inhibit formation of initiation complex
81
What is the MOA of ribavirin?
inhibits synthesis of guanine nucleotides by inhibiting IMP dehydrogenase
82
Which drug that treats anaerobes blocks peptide transfer at 50S?
clindamycin
82
What is used to Tx flukes such as Schistosomes?
Praziquantel
83
Which drugs all end in -navir?
Protease inhibitors
85
Which 2 antifungals inhibit lanosterol synthesis?
Naftifine and Terbinafine
87
Which protease inhibitor can cause hematuria?
Indinavir
88
Which bacteria are not affected by aztreonam?
Gram positive and Anaerobes (Dr. Randolf: Aztreonam is the atom bomb of gram negatives)
89
Which antibiotic is best for anaerobes above the diaphragm?
Clindamycin
90
Which antibiotic is best for anaerobes below the diaphragm?
Metronidazole
92
With which drugs are aminoglycosides synergistic? What problems arise?
Cephalosporins potentiate them but they also increase the risk for nephrotoxicity
93
What is the major AE of chloroquine?
Retinopathy
94
Methylation of the 23S rRNA binding site confers resistance to \_\_\_\_\_\_\_\_\_\_
Macrolides but not telithromycin (a ketolide)
94
Which drug is indicated to treat Hep C and RSV?
Ribavirin
95
DOC for Trypanosoma brucei
Suramin and melarsoprol
96
What is the MOA of caspofungin and micafungin
inhibit cell wall synthesis by inhibiting synthesis of B-glucan
96
What CMV drug must be coadministered with probenecid?
Cidofovir due to nephrotoxicity
97
Which drugs are indicated for both influenza A and B?
Neuraminidase inhibitors = oseltamavir and zanamavir
98
What is the mechanism of resistance to the aminopenicillins?
Beta-lactamases (same as regular penicillins)
99
Why is cefazolin used prior to surgery?
To prevent staphylococcal wound infections
101
Which gene encodes HIV-1 protease?
pol gene
102
Which azole is best for chronic suppression of cryptococcal meningitis?
Fluconazole
104
Why do you avoid tetracyclines in pregnancy?
Discolored teeth and inhibition of bone growth
106
How do you prophylax against group B strep in a carrier pregnant female?
Ampicillin (intrapartum)
108
Which types of bugs can carbapenems be used against?
Gram positive, Gram negative, and anaerobe = very wide spectrum but serious AE = seizures
110
What are the AE of ganciclovir?
BONE MARROW AND KIDNEY (renal toxicity, leuko, neutro, thrombocytopenia)
111
What is praziquantel used to Tx?
Flukes such as Schistosoma
113
Which 2 types of antibiotics cannot be taken with antacids?
Tetracyclines and Fluoroquinolones
114
Which medication would increase the likelihood of tendon rupture in a patient taking fluoroquinolones?
Corticosteroids (prednisone)
115
What is the DOC for Leishmaniasis?
Sodium Stibogluconate
116
AE of macrolides (5)
Motility issues, Arrhythmia (QT prolonged), Cholestatic hepatitis, Rash, eOsinophilia (MACRO)
117
Why do you avoid sulfonamides in pregnancy?
Potential for kernicterus
118
Name 2 antipseudomonals
Ticarcillin and Piperacillin
120
What 5 types of drugs block protein synthesis at the 50 S ribosomal subunit?
Chloramphenicol, Macrolides, Clindamycin, Streptogramins, and Linezolid
121
What are the penicillinase resistant penicillins?
Nafcillin, Oxacillin, and Dicloxacillin
123
What are the main 3 AE of protease inhibitors?
Hyperglycemia, GI intolerance, and Lipodystrophy
125
Which aminoglycoside is commonly used for bowel surgery?
Neomycin
126
What kind of bugs are covered by 3rd generation cephalosporins?
Serious gram negative infections
127
What kind of drugs are ampicillin and amoxicillin?
AMINOpenicillins
128
Which azole is best for candidal infections of all kinds?
Fluconazole
129
What is the mechanism of resistance to aminoglycosides?
transferase enzymes that inactivate the drug via acetylation, adenylation, or phosphorylation
130
What drug is impenem always adminstered with and why?
Cilastatin to decrease renal dehydropeptidase I? This would inactivate imipenem
131
Which monobactam prevents peptidoglycan crosslinking by binding to PBP3
Aztreonam
133
What are the AE of cephalosporins?
Hypersensitivity, Vitamin K deficiency (bleeding), and increased nephrotoxicity of aminoglycosides
134
What do you use to treat onychomycosis?
Terbinafine
136
What are the 4 AE of vancomycin?
Nephrotoxicity, Ototoxicity, and Thrombophlebitis as well as Red Man Syndrome
136
Which CMV drug is a pyrophosphate analog?
Foscarnet
137
What 2 bugs can TMP-SMX prophylax against in an AIDS patient? Azithromycin?
TMP-SMX = Pneumocystis when CD4
138
What are ticarcillin and piperacillin used for?
Antipseudomonal penicillins
139
Name 2 aminopenicillins
Ampicillin and Amoxicillin
140
What is the MOA of ethambutol? AE?
Blocks arabinosyltransferase which decreases carbohydrate polymerization of the cell wall; optic neuropathy
142
How can bacteria become resistant to fluoroquinolones?
mutation in DNA gyrase, plasmid mediated resistance, efflux pumps
143
What is the common toxicity of all CMV drugs?
Nephrotoxicity
144
Which antiviral should you use against HSV? VZV?
HSV = Acyclovir; VZV = Famciclovir
144
What is IFN B used to TX?
Multiple Sclerosis
145
Which form of malaria is resistant to chloroquine?
P. falciparum--Tx with artemether/lumifantrine or atovaquone/proguanil
146
What is the AE of flucytosine?
Bone Marrow Suppression
147
What kind of bugs are covered by 4th generation cephalosporins?
Pseudomonas and gram positives
149
Which drugs block the conversion of lanosterol to ergosterol?
azoles
151
Compare the AE of penicillins to the penicillinase-resistant penicillins
Regular penicillins = hypersensitivity and hemolytic anemia whereas Penicillinase resistant ones are allergic rxns and interstitial nephritis
152
Name 3 CMV drugs
Ganciclovir, Foscarnet, and Cidofovir
154
What is the AE of zidovudine?
anemia (NRTI)
155
Which azole is most likely to cause gynecomastia?
Ketoconazole by inhibiting testosterone synthesis
156
Which drugs block mRNA synthesis?
Rifampin
158
Why do you avoid clarithromycin in pregnancy?
Embryotoxic
160
What drug is often co-administered with ticarcillin and piperacillin? Why?
Clavulanic acid, inhibits beta lactamase
161
How do you treat life-threatening malaria?
Quinidine (quinine in places outside US)
162
Which drug, related to ganciclovir, is a prodrug with better bioavailability?
Valganciclovir
164
What is the mechanism of resistance to chloramphenicol?
Plasmid-encoded acetyltransferase that inactivates it
165
Which bacteria is penicillin most effective for?
Gram positives but also some gram negatives and spirochetes (Syphilis)
166
Why do you avoid griseofulvin in pregnancy?
Teratogenic
168
What is the advantage of a cephalosporin over a penicillin regarding beta-lactamase?
Cephalosporins are overall less sensitive to beta lactamase
168
What is the general rule for clindamycin and metronidazole?
Clindamycin = anaerobes above the diaphragm; Metronidazole = anaerobes below the diaphragm
169
What is the AE of terbinafine? What is it used to treat?
abnormal LFTs; used to treat onychomycosis
170
Why do you avoid aminoglycosides in pregnancy?
They are ototoxic
171
What is famciclovir used for?
VZV; this drug is related to acylclovir
173
Which drug is used to Tx the hypnozoites of Plasmodium vivax malaria?
Primaquine
175
This drug inhibits renal dehydropeptidase I to prevent breakdown of imipenem
cilastatin
177
Which 2 antifungals affect membrane function?
Amphotericin B, Nystatin
178
What is used to treat VRE?
Streptogramins (quinupristin and dalfopristin)
179
Which antifungals inhibit ergosterol SYNTHESIS?
the conazoles
180
What kind of bacteria are aminoglycosides most effective against?
gram negative
181
What are the 2 neuraminidase inhibitors?
Zanamavir and Oseltamivir
183
What is the MOA of the azoles for antifungal therapy? How is it different from terbenafine?
Inhibition of the CYP450 that converts lanosterol to ergosterol; Terbenafine inhibits squalene epoxidase which converts squalene to lanosterol
184
2 antibiotic classes inhibiting 30 S
Aminoglycosides and tetracyclines
185
Which protease inhibitor is used to "boost" others by inhibiting cytochrome P450?
Ritonavir
187
How do you treat lepromatous leprosy?
Dapson, Rifampin, and Clofazimine
189
What are 3 beta-lactamase inhibitors?
Clavulanic acid, sulbactam, and tazobactam
190
What is valganciclovir?
Prodrug of ganciclovir with better oral bioavailability
191
What are 3 mechanisms of resistance to sulfa drugs?
Increased PABA production to outcompete, alteration of dihydropteroate synthase, or decreased uptake
192
In which generation of cephalosporins do you lose gram positive coverage?
3rd (ceftriaxone, cefotaxime, and ceftazidime)
193
What drug can be used to treat HBV, HCV, and Kaposi's?
IFN alpha
194
What are suramin and melarsoprol used to treat?
Trypanosoma brucei
194
What is the MOA of chloroquine?
Blocks detoxification of heme to HEMOZOIN so heme accumulates and is toxic to plasmodia
195
Which tetracycline is best for a renally impaired patient?
Doxycycline because it is fecally excreted
196
How do you prophylax against endocarditis from surgery and dental procedures?
Penicillins
197
What are the AE of the penicillinase-resistant penicillins?
Hypersensitivity reactions and Interstitial nephritis
199
Why are tetracyclines so effective against Chlamydia and Rickettsia?
They can accumulate intracellularly
200
What is the AE of raltegravir?
hypercholesterolemia
201
Is it safe to give cephalosporins in a penicillin allergic patient?
yes there is low cross-reactivity between the two
202
Which ribosomal inhibitors can cause QT prolongation?
macrolides
203
DOC for 1) T. brucei 2) T. cruzi
1) Suramin and Melarsoprol 2) Nifurtimox
204
What are the 3 anti-staphylococcal penicillins?
Nafcillin, Oxacillin, and Dicloxacillin
205
Which bacteria can you NOT use the penicillinase resistant penicillins on?
MRSA
206
What is the MOA of flucytosine? Used for?
blocks DNA and RNA synthesis by using cytosine deaminase to convert to 5 FU
207
How do you prevent neurotoxicity in a patient on isoniazid?
Pyridoxine (B6)
208
Which azole is best for Blastomyces, Coccidiodes, and Histoplasma?
Itraconazle
210
Which antifungal deposits in keratin-containing tissues?
Griseofulvin
211
What is the DOC for toxoplasmosis? Prophylaxis in AIDS?
Pyrimethamine; TMP-SMX when CD4 less than 100
212
What are the AE of ribavirin (2)?
Hemolytic anemia and SEVERE TERATOGEN
213
What is the most important AE of carbapenems?
Seizures! Use is therefore limited to serious drug rxns
214
DOC for Trypanosoma cruzi
Nifurtimox
215
What is the MOA of macrolides?
Bind to 23S rRNA at the 50S ribosome and prevent translocation
216
What are sulbactam, tazobactam, and clavulanic acid used for?
Beta lactamase inhibitors
217
How are NNRTI's different from NRTI's?
They bind to reverse transcriptase at a different site than the NRTI's
218
In which setting would you choose aztreonam over aminoglycosides? Can you give both?
In renal failure because aminoglycosides are nephrotoxic. However, the two are synergistic so can be given together under other circumstances.
219
What is the MOA of sulfa drugs?
They are PABA antimetabolites that inhibit dihydropteroate synthase
220
Which drugs inhibit squalene epoxidase and therefore prevent formation of lanosterol?
Terbinafine and Naftifine
221
In which tissue is griseofulvin most likely to deposit?
Keratin containing tissues
222
How do you prophylax against recurrent UTI's?
TMP-SMX
223
What are the 4 AE of aminoglycosides?
Nephrotoxicity, Neuromuscular blockade, Ototoxicity, and Teratogenic
224
What is the MOA of tetracyclines?
Inhibit 30 S to prevent attachment of aminoacyl tRNA
225
Why do infants on chloramphenicol get "Gray baby syndrome"
They lack liver UDP-glucuronyl transferase to glucuronidate it
226
Which NRTI does NOT have to be activated?
Tenofovir
227
Which drugs potentiate the nephrotoxicity of aminoglycosides?
Cephalosporins
228
Which ribosomal inhibitors can cause cholestatic hepatitis?
Macrolides
229
How can you reduce the nephrotoxicity of amphotericin B?
HYDRATE
230
What is the utility of ritonavir vs. other protease inhibitors?
Ritonavir is used to boost the concentrations of others by inhibiting cytochrome P450
