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Antimicrobials Flashcards

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1
Q

Block cell wall synthesis by in inhibition of peptidoglycan cross linking

A

Penicillin, methicillin, ampicillin, piperacillin, cephalosporins, aztreonam, imipenem

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2
Q

Block peptidoglycan synthesis

A

Bacitracin, vancomycin

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3
Q

Block nucleotide synthesis by inhibiting folic acid synthesis

A

Sulfonamides, trimethroprim

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4
Q

Block DNA topoisomerase

A

Fluoroquinolones

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5
Q

Block mRNA synthesis

A

Rifampin

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6
Q

Damage DNA

A

Metronidazole

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7
Q

Block protein synthesis at 50s ribosomal subunit

A

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

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8
Q

Block protein synthesis at 30s ribosomal subunit

A

Aminoglycosides, tetracyclines

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9
Q

Penicillin

A

G = IV and IM
V = oral
Bind to transpeptidases to prevent cross-linking of peptidoglycan. Use mostly for gram positive bacteria, N. meningitides, T. pallidum.
Resistance = beta lactamase cleaves beta lactam ring.

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10
Q

Penicillinase resistant penicillins

A

Oxacilin, nafcillin, dicloxacillin
Same MOA as penicillin. Resistant to beta lactamase b/c bulky R group blocks access of beta lactamase to beta lactam ring. USE: Staph aureus (except MRSA)

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11
Q

Aminopenicillins

A

Ampicillin, amoxicillin. Same MOA penicillin. Beta lactamase sensitive. Combine with clavulanic acid to protect against beta lactamase. Amoxicillin has greater oral bioavailability than ampicillin. Haemophilus influenzae, E. coli, Listeria monocytogenes, Proteus, Salmonella, Shigella, Enterococci. HELPSS kill enterococci.

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12
Q

Antipseuomonals

A

Same MOA as penicillin. Ticarcillin and piperacillin. Use for Pseudomonas and gram negative rods. susceptible to beta lactamase so use clavulanic acid.

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13
Q

beta lactamase inhibitors

A

CAST

Clavulanic Acid, Sulabactam, Tazobactam. Can add to penicillin antibiotics.

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14
Q

Cephalosporins and 1st gen

A 
B lactam drugs that inhibit cell wall synthesis but less susceptible to penicillinases.  
1st generation (Cefazolin, Cephalexin):  gram positive cocci and PEcK - proteus, E coli, Klebsiella.  Cefazolin before surgery to prevent S. Aureus wound infections.
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15
Q

2nd gen cephalosporins

A

Cefoxitin, cefaclor, Cefuroxime.
gram positive cocci + HEN PEcKS
H. influenzae, Enterobacter, Neisseria, Proteus, E coli, Klebsiella, Serratia

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16
Q

Aztreonam

A

Prevents peptidoglycan cross linking by binding to PBP3. Synergistic with aminoglycosides. Only for gram negative rods. For penicillin allergic pts and pts with renal insufficiency that cannot tolerate aminoglycosides.

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17
Q

Imipenem/cilastin, meropenem

A

Imipenem is a beta lactamase resistant carbapenem. Always with cilastatin (Inhibitor of renal dehydropeptidase I) to decrease inactivation of drug in renal tubules. Meropenem is stable to dehydropeptidase I and reduced risk of seizures.
SE - Can cause seizures.

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18
Q

Vancomycin

A

Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors. For gram positive only. For MRSA, enterococci, and C. Dif (pseudomembrane colitis - oral dose). SE: NOT many probs. Nephrotoxicity, Ototoxicity, Thrombophlebitis. Diffuse flushing - red man syndrome - prevent with antihistamines and slow infusion rate. Resistance = Dala D ala to D ala D lac.

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19
Q

Protein synthesis inhibitors

A

Target smaller bacterial ribosome (70s, made of 30s and 50s subunits), leaving 80s (human) unaffected. 30s inhibitors = Aminoglycosides and Tetracyclines. 50s = Choramphenicol, Clindamycin, Erythromycin, and Linezolid. So…buy AT 30, CCEL at 50.

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20
Q

Aminoglycosides

A

Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin. MOA: inhibit formation of initiation complex cause misreading of mRNA and block translocation. Require O2 for uptake…so ineffective against anaerobes. USE: gram negative rod infections. Synergistic with beta lactams. Neomycin for bowel surgery. SE: Nephrotoxicity, Neuromuscular blockade, Ototoxicity, Teratogen. SO….Mean (aminoglycoside) GNATS caNNOT kill anaerobes.

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21
Q

Tetracyclines

A

Tetracycline, doxycycline, demeclocycline, and minocycline. Demeclocycline is ADH antagonist that can be used as diuretic for SIADH. Binds to 30s and prevents attachment of aminoacyl - tRNA. Doxycycline is fecally eliminated so can be used in pts with renal failure. Divalent cations prevent absorption in gut so do not take with milk, antacids or iron preps. Use - borrelia, M pneumonia. Drug accumulates intracellular so can use against Rickettsia and Chlamydia. SE - Dicoloration of teeth and inhibit bone growth in children. CI in pregnancy. Resistance - efflux pumps or decrease uptake.

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22
Q

Macrolides

A

Azithromycin, Clarithromycin, Erythromycin
Block translocation to inhibit protein synthesis. Bind to 23S rRNA of 50S ribosome. USE: atypical pneumonia (mycoplasma, chlamydia, legionella), STDs(chlamydia) and gram positive cocci (step infections in pt allergic to penicillin). SE: MACRO: Motility issues, Arrhythmia by prolong QT, acute Cholestatic hepatitis, Rash, eosinophilia. Resistance - methylate 23s rRNA site.

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23
Q

Chloramphenicol

A

Block peptidyltransferase at 50S. USE: meningitis (H flue, N menigitidis, Strep pneumo) Toxicity: anemia, gray baby syndrome - premature baby has no liver UDP - glucuronyl transferase

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24
Q

Clindamycin

A

Block peptide transfer (transpeptidation) at 50s. for Anaerobic infections (Bacteroides, C perfringens) in aspiration pneumonia. oral infections with anaerobes. SE - pseudomembranous colitis (c dif overgrowth). tx anaerobes above the diaphragm vs metronidazole (anaerobic infections below the diaphragm).

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25
Sulfonamides
SMX (sulfamethoxazole), sulfisoxazole, sulfadiazine. MOA: PABA antimetabolites inhibit dihydropteroate synthase. For gram positive, gram negative, Nocardia, Chlamydia. SE: hemolysis if G6PD deficient, kernicterus in infants, displace other drugs from albumin (like warfarin)
26
Trimethoprim
Inhibit dihydrofolate reductase. Use with sulfonamides to cause blockage of folate synthesis. Combo for UTI, Shigella, Salmonella, pneumocystis jirovecii pneumonia. SE : TMP: treats marrow poorly....megaloblastic anemia, leukopenia, granulocytopenia.
27
Fluoroquinolones
End with floxacin. MOA: inhibit DNA gyrase (topoisomerase II) and topoisomerase IV. Do not take with antacids. USE: Gram negative rods of urinary and GI tract. SE: tendon rupture.
28
Metronidazole
Forms free radical toxic metabolites in bacteria that damage DNA. Tx: GET GAP on METRO. for Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobes (Bacteroides, C Dif). will take care of anaerobes below the diaphragm. Use with PPI and clarithromycin for triple therapy against H pylori. SE: Disulfiram like reaction with ETOH and metallic taste.
29
M. tuberculosis
Prophylaxis - isoniazid Tx - Rifampin, Isoniazid, Pyrazinamide, Ethambutol (RIPE)
30
M. avium
Azithromycin, rifampin, ethambutol, streptomycin
31
M. leprae
Long term tx with dapsone and rifampin for tuberculoid form. Add clofazimine for lepromatous form.
32
Isoniazid
Decrease synthesis of mycolic acid. Bacterial catalase peroxidase need to convert to active metabolite. For M tuberculosis. proph against TB. INH - injures neurons and hepatocytes
33
Rifampin
Inhibits DNA dependent RNA polymerase. USE - TB. Delays resistance to dapsone when used for leprosy. Prophylaxis for meningococcal and children in contact with H influenza type B. Increases P-450 activity. Orange body fluids. Rifampin 4 Rs: RNA polymerase inhibitor, Revs P450, red/orange body fluids, Rapid resistance if used alone.
34
Pyrazinamide
For TB. Effective in acidic pH of phagolysosomes. SE - hyperuricemia, hepatotoxicity.
35
Ethambutol
Decrease polymerizatiom of mycobacterium cell wall by blocking arabinosyltransferase. For TB. Can cause red-green color blindness.
36
N. meningitidis proph
Ciprofloxacin in adults | Rifampin in kids.
37
Gonorrhea proph
ceftriaxone.
38
Syphilis proph
Benzathine penicillin G
39
Hx of recurrent UTIs proph
TMP-SMX
40
proph for endocarditis with surgical or dental
Penicillin
41
Preg woman with group b strep
Ampicillin
42
Proph of strep in child with prior rheumatic fever
oral penicillin
43
Prevent postsurgical infection due to staph aureus
Cefazolin
44
Prevent gonococcal or chlamydia conjunctivitis in newborn
erythromycin ointment
45
HIV proph
CD4<50 Azithromycin for MAC
46
Amphotericin B
Binds ergosterol to form membrane pores. Ampho "tears" holes in membrane. Supplement with K and Mg b/c altered renal tubule permeability. SE - IV phlebitis
47
Nystatin
Same MOA as ampho B. Topical use only b/c too toxic for systemic use. use for thrush (candida)
48
Azoles
Inhibits ergosterol synthesis. SE: inhibits testosterone synthesis ...gynecomastia. Inhibits CYP450.
49
Flucytosine
Inhibits DNA and RNA synthesis by conversion to 5-fluorouracil by cytosine deaminase. SE - bone marrow suppression. Tx - used in combo with ampho B. esp for meningitis caused by Cryptococcus.
50
Caspofungin, micafungin
Inhibit cell wall synthesis by inhibiting synthesis of beta glucan. For aspergillosis and candida. SE - flushing b/c histamine release.
51
Terbinafine
Inhibits the fungal enzyme squalene epoxidase. used for dermatophytoses (especially onchomycosis - fungal infection of finger or toe nail). SE - abnormal LFTs, visual change.
52
Griseofulvin
Interferes with microtubules to disrupt mitosis. Deposits in keratin like nails. Txs superficial infections of fungi. SE - teratogenic
53
Antiprotozoan tx
Toxoplasma - pyrimethamine T brucei - suramin and melarsoprol T cruzi - nifurtimox Leishmaniasis - sodium stibogluconate
54
Chloroquine
Blocks detox of heme into hemozoin. Heme accumulates and is toxic. Tx for plasmodium other than falciparum (resistance). SE - retinopathy
55
Zanamivir, Oseltamivir
Inhibit influenza neuraminidase, decrease release of virus. Tx influenza A and B.
56
Ribavarin
Inhibit synthesis of guanine nucleotides . Tx: RSV and chronic hep C. SE: hemolytic anemia and teratogen.
57
Acyclovir
Monophosphorylated by HSV/VZV thymidine kinase. gaunosine analog. Inhibits viral DNA polymerase. Tx HSV and VZV.
58
Ganciclovir
5 monophosphate formed by CMV viral kinase. Guanosine analog. Inhibits viral DNA polymerase. Tx - CMV
59
Foscarnet
Viral DNA polymerase inhibitor. Does not require activation by viral kinase. It is a pyrophosphate analog. SE: nephrotoxicity.
60
Cidofovir
Inhibitis viral DNA polymerase. No phosphorylation by viral kinase. For CMV. SE: nephrotoxicity. Administer with probenecid and IV saline to reduce toxicity.
61
HAART Therapy?
Initiate when pt has less than 500 CD4 T cells. 3 drugs to prevent resistance. 2NRTIs + 1 NNRTI or 1 protease inhibitor or 1 integrase inhibitor.
62
Protease Inhibitors
End with -navir. Navir (never) tease a protease. HIV-1 protease (pol gene) cleaves the polypeptide products of HIV mRNA into their functional parts. SE: Ritonavir can increase the concentration of other drugs by inhibiting CYP 450. Hyperglycemia, lipodystrophy
63
NRTIs
Competitely inhibit nucleotide binding to reverse transcriptase and terminate the DNA chain (lack a 3'OH group). Zidovudine is for prophylaxis and during pregnancy to reduce the risk of fetal transmission. SE: Bone marrow suppression NNRTIS bind to reverse transcriptase at different site from NRTIS
64
Integrase Inhibitors
Raltegravir. Inhibit HIV integration into host chromosome. SE : high cholesterol
65
Interferons
Block replication of RNA and DNA viruses. IFNalpha: chronic hepB and C, Kaposi Sarcoma IFNbeta: MS IFNgamma: NADPH oxidase deficiency
66
Sulfonamides in preg
kernicterus
67
Aminoglycosides in preg
Ototoxicity
68
Fluoroquinolones in preg
cartilage damage
69
Tetracyclines in preg
Discolored teeth, inhibit bone growth
70
Griseofulvin and Ribavirin in Preg
teratogenic
71
Chloramphenicol in preg
gray baby

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