Antimicrobial Tx Flashcards
Bacterial meningitis empiric tx (unknown organism/pre-culture results)
Vancomycin + ceftriaxone/cefotaxime (IV)
Vancomycin adverse rxns
“The “red man” life is NOT trouble free”
Nephrotoxicity
Ototoxicity
Thrombophlebitis
“red man syndrome” - hypotension, diffuse flushing, erythematous rash on head and neck -
Tx for “red man syndrome” assoc. with Vanc
slow infusion rate + antihistamines
Vanc MOA
Inhibits cell wall peptidoglycan formation by binding D-ala D-ala precursors (G+ organisms only)
Vanc MOR
VanA gene - encodes for amino acid modification of D-ala D-ala to D-ala D-lac
S. pneumoniae tx (pneumonia/systemic infection)
Penicillin/cephalosporin
S. pneumoniae meningitis tx - organism susceptible to PCN
Ampicilin or ceftriaxone/cefotaxime
S. pnumoniae meningitis tx - organism resistant to PCN, susceptible to cephalosporins
ceftriaxone/cefotaxime
S. pneumoniae meningitis tx - organism resistant to PCN AND cephalosporins
IV vancomycin x 10-14 days
M. leprae - lepromatous leprae
- Dapsone
- Rifampin
- Clofazimine
M. leprae - tuberculoid type
- Dapsone
2. Rifampin
Proteus mirabilis
Fluoroquinolones - e.g. Ciprofloxacin
Fluoroquinolone MOA
Inhibit DNA topoisomerase II (DNA gyrase) and IV
Do NOT take with antacids!
Fluoroquinolones (floxacins/enoxacins) - clinical use
G- rods of GI/Urinary Tract:
Psuedomonas
Neisseria
Proteus mirabilis
Some G+ organisms
Fluoroquinolone CI’s
- pregnancy
- nursing mothers
- children
Fluoroquinolone adverse rxns
“FluoroquinolONES hurt attachments to your bONES”
(e. g. levaquin)
- Cartilage damage in children 60 years or pts taking prednisone.
- leg cramps
- myalgias
- SUPERINFECTIONS (C.diff)
- skin rash
- HA/dizziness
- GI upset
Fluoroquinolones
floxacins: e.g. ciproflocacin, levofloxacin
+ enoxacin
Cryptococcal meningitis (AIDS pts - serious infection)
Amphotericin B w/ or w/o flucytosine
Amphotericin B MOA
“TEaRs” holes in fungal membrane by forming pores = leakage of electrolytes.
- binds ergosterol (unique to fungi)
Sporothrix shenkii (Sporotrichosis) Tx
Itraconazole
Sporothrix shenkii (Sporotrichosis) "rose garden disease"
Dimorphic cigar-shaped budding yeast
Grows in branching hyphae with rosettes of conidia
Lives on vegetation
Introduced traumatically e.g. by a thorn
Drugs associated with disulfiram reaction
Metronidazole (some) cephalosporins griseofulvin procarbazine 1st gen sulfonylureas
Giardia tx
Metro
Quinacrine (if can’t tolerate metro) - but not available in US?
Chlamydia histo findings
**non-staining (intracellular) - Gram - bacteria, elementary and reticulate bodies
Chlamydia (no co-infection) tx
Doxycycline (unless pregnant = azithromycin)
Schistosomiasis (e.g. S.hematobium) tx
Praziquantel
E.Coli UTI tx
Amoxicillin
Isoniazid AE’s
“INH “I”njures “N”eurons and “H”epatocytes”
- Hepatotoxicity = spotty necrosis (“balooning degeneration with numerous eosinophils”) or fulminant liver failure. (d/t covalent boding to hepatocytes=actin/mitochondrial disruption)
- P-450 inhibition
- Drug-induced SLE
- Vitamin B6 deficiency(**peripheral neuropathy, sideroblastic anemia)
**Administer with pyridoxine (B6)
Isoniazid MOA
Decreased synthesis of mycolic acids
Bacterial catalase-peroxidase (encoded by KatG) needed to convert INH to active metabolite.
TB prophylaxis
Isoniazid (supplement B6)
Latent TB tx
Isoniazid (supplement B6)
Active TB tx
RIPE = Rifampin + Isoniazid + Pyrazinamide + Ethambutol x 2 weeks, then:
RI x 4 weeks
M.avium - intracellulare prophylaxis
Azithromycin + rifabutin
M.avium tx
More drug resistant than M tuberculosis.
Azithromycin or clarithromycin + ethambutol.
Can add rifabutin or ciprofloxacin.
M.leprae prophylaxis
NONE!
M.leprae tx
Tuberculoid form: Long-term with Dapsone + Rifampin
Lepromatous form: Dapsone + Rifampin + Clofazimine
Rifampin MOA
Inhibits DNA-dependent RNA polymerase
= stops mRNA synthesis
H. influenzae type B meningitis prophylaxis (contacts of infected children)
Rifampin
Rifamycin AE’s
“Rifampin “ramps up” CP450, “but” Rifabutin does not”
Rifampin’s 4 R’s:
- RNA polymerase inhibitor
- Ramps up microsomal cytochrome P-450 (minor hepatotoxicity and drug interactions)
- Red/orange body fluids (non-hazardous)
- Rapid resistance if used alone (d/t mutations that reduced drug binding to RNA polymerase)
**monitor liver fn for hepatotoxicity
Rifabutin favored over rifampin in patients with HIV infection due to less cytochrome P-450 stimulation.
Rifampin purpose in M.leprae tx
Delays resistance to Dapsone
Isoniazid MOR
Mutations leading to underexpression of KatG
Pyrazinamide AE’s
- **Hyperuricemia
- Hepatotoxicity
Ethambutol AE’s
""EYE"thambutol" Optic neuropathy (red-green color blindness)
Ethambutol MOA
Decreases carbohydrate polymerization of mycobacterium cell wall by blocking arabinosyltransferase
Streptomycin Clinical Use
M.tuberculosis (2nd line)
Streptomycin (aminoglycoside) AE’s
Ototoxicity (Tinnitus,Vertigo,Ataxia)
Nephrotoxicity
Pyrazinamide MOA
Prodrug that is converted to the active compound **pyrazinoic acid.
Works best at acidic pH (eg, in host phagolysosomes)
Streptomycin MOA
Interferes with 30S component of ribosome (aminoglycoside)
-azole
Ergosterol synthesis inhibitor
-bendazole
Antiparasitic/antihelmithic
-cillin
Peptidoglycan cross-linking inhibitor
Chlamydia/Gonorrhea Co-Infection tx
Doxy + Ceftriaxone
C. diff tx
Oral metronidazole
C.diff (refractory) tx
ORAL vancomycin
C.botulinum, C.tetani tx
Antitoxin
CMV tx
Ganciclovir, foscarnet, cidofovir
Initial empiric tx for Sickle Cell + osteomyelitis
Need to cover G+ and G- organisms (S.aureus and Salmonella)
= Ciprofloxacin (fluoroquinolone for Salmonella) + Vancomycin (S.aureus and MRSA)
MCC osteomyelitis (overall)
S.aureus
MCC osteomyelitis IVDU
Pseudomonas, candida, S. aureus
C.tetani exotoxin
Tetanospasmin - protease
C.tetani toxin MOA
Cleaves SNARE proteins = decreased release of GABA and glycine (inhibitory NT’s)
S. pyogenes exotoxin MOA
Binds IgM and C3b = blocks phagocytosis
S. aureus TSST-1 MOA
Binds MHC-II and T-cell receptor outside of peptide groove, leads to NONSPECIFIC, LARGE number of activated T-cells releasing cytokines
C.botulinum exotoxin MOA
Cleaves SNARE proteins = decreased release of ACh (excitatory NT’s)
C. botulinum paralysis
Descending paralysis
Bendazole MOA
inhibits microtubule formation
Hookworm (N. americanus, A.duodenale) tx
Bendazoles or Pyrantel Pamoate