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NRS 270: Pharmacology > Abx targeting DNA & RNA synthesis/replication > Flashcards

Abx targeting DNA & RNA synthesis/replication Flashcards

1
Q

Rifamycins

A
  • bind to RNA polymerase = prevent mRNA elongation
  • rifampin (PO, IV, cyp 450 inducer!!!!!! will clear the drug faster) , rifaputin (less DDI), rifapentine(longer half life), rifaxamin (only for travelers diarrhea, poor absorption)
  • used in combination with other drugs due to bacterial rapidly gaining resistance
  • tx: (GRAM -, cocci and coccobacillus) My New Strange Friend
    • ​Mycobacterium
    • Neiserria meningitidis
    • Staph
    • H.flu
    • prophylaxis of Neisseria and H.flu
  • SEs:
    • N/V/D: MOSTLY GI
    • hepatitis
    • rashes
    • orange-red discoloration of tears, urine, and other body fluids
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2
Q

Aminoglycosides coverage, resistance, meds, and SEs

A
  • Excellent against Gram negative
    • enterobacter, pseudomonas, mycobacterium tuberculosis, or mycobacterium avium complex (MAC)
  • synergistic effects to affect gram positive
    • need to break down cell wall
  • Streptomycin: IV
  • Gentamycin: IV
  • Tobramycin : IV, no activity against enterococcus
  • Amikacin: IV, no activity against enterococcus
  • Neomycin: topical eye cream, ointment, eye drops– not for systemic use
    • only PO use: bowel prep or hepatic encephalopathy
  • SEs: ototoxicity –irreversible hearing loss
    • vestibular toxicity: balance problems
      • nephrotoxicity
        • penetrate the proximal renal tubules
    • test for toxicity with creatinine tests, check trough level of meds
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3
Q

Macrolides and Ketolides general function

A
  • bind reversibly to the 50S subunit→ inhibit peptidyltransferase
    • prevent formation of peptide bonds
  • bulky structure
    • sometimes prevents penetration
    • effflux
    • resistance is a class effect
  • Spectrum:
    • G+: strep, staph
    • G-: Neisseria, Hflu, Bordetella, pertussis
    • Atypicals: chlamydia, mycoplasma, legionella, rickettsia, mycobacterium, spirochetes
  • Meds: Erythromycin PO and IV
    • azithromycin PO and IV
    • Clarithromycin PO
    • Fidaxomicin PO
    • Telithromycin PO
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4
Q

Tetracyclines and Glycyclines Action and Resistant Modes

A
  • Bind to 30s subunit, prevent binding of tRNA
    • blocks tRNA
  • Resistant modes:
    • efflux pumps
    • mutation of the ribosome
      • prevents TCN from binding
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5
Q

Tetracyclines Spectrum, drugs, and SEs

A
  • Spectrum:
    • Strep pneumo, staph aureus (MRSA)
    • H.flu, and Neisseria
    • Atypical: Rickettsia, Chlamydia, Mycoplasma, Borrelia, Treponema
  • Meds: Doxycycline: PO IV
    • Minocycline PO IV
    • Omadacycline PO IV
    • Tetracycline PO
    • Sarecycline PO
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6
Q

Aminoglycoside MOA and Resistant Modes

A
  • MOA:
    • AG = positive and binds to negative membrane charge
    • they create holes for the AG to move into but require 0xygen by the bacterial transporter to get actively transported inside
      • leads to poor anaerobe coverage
    • binds to 30S⇒ causes mismatch of tRNA
  • Resistant modes:
    • efflux
    • enzymes get modified so that aminoglycosides cannot bind to ribosomes
    • random mutation of ribosomes → AGs can’t bind
    • Resistance is NOT classwide
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7
Q

Ketolides

A
  • tighter binding to 50S subunit (preventing peptidyltransferase from forming peptide bonds between amino acid)
    • more resistance to efflux
  • for respiratory infections:
    • Covers:
      • strep, staph, Hflu, pertussis, Atypical: chlamydia, mycoplasma, and legionella
  • SEs:
    • ​erythromycin: N/V/D, GI, phlebitis
    • QT prolongation
    • erythromycin and clarithromycin: = inhibit CYP3A4
    • blurred vision, diplopia, difficulty focusing
    • severe liver damage
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8
Q

Glycycline

A
  • binds to 30S prevents tRNA binding and thus prevents protein synthesis
  • Resistant modes:
    • efflux pumps
  • Tigecycline
    • glycyl amide group: prevents recognition of the efflux pumps
  • Improved sensitivity to TCN resistant bacteria
  • spectrum:
    • G+: Strep, Staph (MRSA), enterococci (including VRE)
    • G-: H.flu, Neisseria, Enterobacteriacea
    • anaerobes: B. fragilis, and many others
    • Mycoplasma
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9
Q

Chloramphenicol

A
  • bind to 50S to block formation of peptide bonds
  • Resistant modes:
    • prevent binding to target
    • efflux pumps
  • only IV in the US
  • Spectrum:
    • strep, H.flu, Neisseria, Salmonella, Shigella
    • Anaerobes: B fragillis, and others
    • Atypical: Mycoplasma, Chlamydia, Rickettsia
  • SEs:
    • Reversible bone marrow suppression
    • irreversible aplastic anemia
    • gray baby syndrome
      • accumulation of unmetabolized chloramphenicol
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10
Q

Clindamycin

A
  • Binds to 50S and inhibits protein synthesis
  • MOA similar to macrolides
  • **most gram negative are intrinscially resistant to clindamycin because the outermembrane resists penetration**
  • **bacteria resistant to macrolides are also resistant to clindamycin**
  • Spectrum:
    • G+: strep, staph (MSSA & CA-MRSA)
    • Anaerobes: B. fragillis, clostridium (NOT C. diff), and most others
  • Toxicity:
    • induces C.diff colitis
    • diarrhea
    • rashes
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11
Q

Streptogramin

A
  • 2 different macrocyclic compounds that work synergistically
    • bind to 50S subunit and prevent protein synthesis
      • binding site is same one as macrolides and clindamycin
      • bugs that are resistant to macrolides and clindamycin will also be resistant to streptogramin
  • COVERS G+ only
  • Resistances modes:
    • efflux pumps
    • mutation in 50s subunit
    • enzymatic inactivation
  • CYP450 inhibitor
  • Toxicity:
    • phlebitis (should only be given via central line)
    • arthralgias
    • hyperbilirubinemia
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12
Q

Linezolid

A
  • completely synthetic
  • binds to 50s and prevents 30s from associating
    • no ribosome formation
  • Resistant mode:
    • mutation of ribosomes
    • efflux pumps
  • Spectrum: G+ : strep, staph (MRSA and VRE)
  • SEs:
    • NVD
    • thrombocytopenia
    • anemia, leukopenia
    • not to be given with MAO inhibitors
    • can be given with SSRIs BUT→ can cause serotonin syndrome
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13
Q

Nitrofurantoin

A
  • MOA: inhibits translation
    • concreates in urine but poor levels in blood
    • tx: acute cystitis
  • spectrum: staph and enterococcus
  • SEs:
    • N/V
    • rash, interstitial pneumonitis, hepatitis, hemolytic anemia, and neuropathy
    • contraindicated in patients with poor renal function
      • Crcl < 60ml/min
    • ineffective in pts Crcl<40ml/min
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14
Q

Sulfa Drugs MOA and different meds

A
  • Abx that target DNA and Replication
  • target folic acid synthesis
  • sulfamethoxazole (SMX) mimics PABA and competitively inhibits DHT synthetase (Dapsone also works here)
  • Trimethoprim (TMP) revents formation of dihydrofolate reductase
  • risk of resistance is less
  • TMP/SMX = given both IV and PO
  • Dapsone: PO
  • Sulfisoxaole/erythromycin (Pediazole): PO
    • toxoplasmosis
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15
Q

Sulfa Drugs Spectrum and Toxicity

A
  • Spectrum: G+: staph strep, Listeria
    • not helpful for enterococcus
    • G-: H.flu enterobacteriaceae
  • anaerobes and atypicals tend to be resistant to Septra
  • Dapsone: txs mycobacterium leprae
  • SEs:
    • GI effects
    • fever
    • rash/Steven Johnson Syndrome
    • leukopenia
    • thrombocytopenia
    • hepatitis
    • hyperkalemia
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16
Q

Azithromycin Dosing

A

1gm for one dose

17
Q

Macrolide and Ketolide SEs

A
  • SEs:
    • ​erythromycin: N/V/D
    • QT prolongation
    • erythromycin and clarithromycin: = CYP3A4 inhibitor
    • blurred vision, diplopia, difficulty focusing
    • severe liver damage
18
Q

Doxycline IV dosing

A
  • 100mg q 12 hours for syphilis
  • IV dosing
19
Q

Quinolones MOA and drugs

A
  • Abx that target DNA and replication
  • G+ (staph aureus): primary activity @ topoisomerase IV
  • G-: (E.coli): primary activity at DNA gyrase
  • Drugs:
    • Ciprofloxacin IV and PO
    • Levofloxacin IV and PO
    • Moxiflocaxin IV and PO
    • Gemifloxacin: PO
    • Ofloxacin: PO
    • Delafloxacin: IV and PO
20
Q

Quinolones Resistant Modes

A
  • Mutation of DNA gyrase and topoisomerase IV
  • overexpression of efflux pumps
  • cross-resistance of carbapenems and quinolones in pseudomonas
21
Q

Quinolones Spectrium and SEs

A
  • Spectrum:
    • G+ = staph and strep
    • G- = H.flu, enterobacteriacea, neisseria
    • anaerobic =clostridium, bacteroids
    • atypical = mycoplasma, legionella, chlamydia
    • Mycobacteria = TB, MAC, leprae
  • SEs:
    • N/V/D
    • rashes
    • cartilage abnormalities:
      • avoid in children younger than 18yo
      • avoid in pregnant women
    • achilles tendon rupture in elderly
    • QT prolongation
    • higher risk for C.diff
22
Q

Abx that Target DNA and Replication

A
  • sulfa drugs
    • dapsone
  • quinolones
  • Metronidazole
23
Q

Abx that target Protein Production

A
  • rifamycin (RNA pol)
  • amingoglycosides (bind to 30S, mismatched tRNA)
  • Tetracyclines and glycyclines (binds to 30S)
  • Chloramphenicol (bind to 50S)
  • Macrolides and Ketolides ( bind to 50S, if resistance to this will also have resistance to clindamycin)
  • Clindamycin (bind to 50S)
  • Linezolid (bind to 50S prevent formation of ribosome)
  • Streptogramin (bind to 50S)
  • Nitrofurantoin (prevents protein synthesis, MOA unknown)
24
Q

Metronidazole

A
  • small molecule–can passively diffuse into bacteria
  • nitro group is present that needs to get broken down to become active = forms free radicals which causes DNA breakage
  • covers nearly all anaerobes because the anaerobes have electron transport proteins that break down the nitro group
    • aerobic bacteria do not have this so not effective for them
  • resistance is rare
  • SEs:
    • nausea, epigastric discomfort
    • metallic taste
    • furry tongue
    • headache, dizzines, neuropahty
    • disulfiram-like reaction
25
Q

Bacitracin

A
  • produced by Bacillus subtilis (gram + soil bacteria)
  • MOA: inhibits synthesis of bacterial cell wall
    • inhibits amino acids and nucleotides from building the wall
  • Spectrum:
    • G+ cocci and bacilli
    • Neisseria and Hflu
    • Treponema,
  • Resistance:
    • enterobacteriae, pseudomonas, candida, norcardia
  • ONLY TOPICAL
  • Tx: furunculosis (boils), pyoderma, carbuncle, impetigo, abscesses
26
Q

Mupirocin

A
  • topical only 2%
  • Spectrum:
    • G+ and G-
  • MOA:
    • reversible inhibits aminoacyl-tRNA synthetase → prevents AA from attaching to tRNA which stops protein synthesis
  • Low level of resistance
  • when absorbed systemically: quickly metabolized to inactive monic acid
  • tx: skin infections
    • eliminates MRSA nasal colonization
  • SEs:
    • irritation, tearing, burning if contact with eyes
27
Q

Ciprofloxacin

A
  • quinolone
  • Enhanced G- activity
  • Covers pseudomonas
  • Weak G+ acitivty →do not use to tx strep pneumo
  • covers many atypicals and some mycobacteria
28
Q

Levofloxacin

A
  • quinolone
  • 2x more potent than ofloxacin
  • less active against G- and more active against G+ than ciprofloxacin
    • ​okay to tx strep pneumo including pcn resistance
29
Q

Moxifloxacin and Gemifloxacin

A
  • quinolone
  • enhanced activity against strep pneumo including PCN resistant
  • atypicals
  • **less active against G- (pseudomonas)
  • good coverage for anaerobes
30
Q

Delafloxacin

A
  • staph, strep
  • E.coli, enterobacter, Klebsiella
  • pseudomonas

NRS 270: Pharmacology (14 decks)

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