Antimicrobials IV Flashcards
mechanism of chloramphenicol
blocks peptidyltransferase at 50S ribosomal subunit (bacteriostatic) –> protein synthesis inhibition
what changes causes resistance to chloramphenicol
- production of chloramphenicol acetyltransferase which inactivates drug
- changes in membrane permeability
clinical application of chloramphenicol
topical treatment of ear and eye infections (no systemic adverse effects)
drug interaction of chloramphenicol
it is a CYP450 inhibitor
adverse effects of chloramphenicol
Aplastic Anemia
Gray Baby Syndrome (cyanosis): newborns do not have effective glucuronic acid conjugation mechanism needed for breakdown of chloramphenicol –> vomiting, flaccidity, hyperthermia, gray color, shock and collapse
mechanism of clindamycin
blocks peptide transfer (translocation) at 50S ribosomal subunit (bacteriostatic) -> inhibition of protein synthesis
clinical applications of clindamycin
- Pneumocystis Jiroveci pneumonia in AIDs pts
- Toxoplasmosis in AIDS pts
- Prophylaxis for endocarditis for those who are undergoing a dental procedure
adverse effects of clindamycin
Fatal Pseudomembrane Colitis
diarrhea, nausea, skin disease
Impaired liver function and neutropenia
what is the streptogramins
Dalfopristin-Quinupristin
mechanism of dalfopristin-quinupristin
cause protein synthesis inhibition by binding to separate sites on 50S ribosome (mainly bacteriocidal)
clinical application of streptogramins
dalfopristin-quinupristin
infections caused by staph or vancomycin resistant strain of e. faecium (not e. faecalis)
mechanism of linezolid
binds to 23S ribosomal RNA of 50S subunit -> inhibition of protein synthesis
weak, reversible inhibitor of monoamine oxidase
main use of linezolid
treat multi drug resistant infections
what drug is 100% bioavailable after oral administration
linezolid
adverse effect of linezolid
- inhibitor of MOA –> increased serotonin in brain
- Lactic acidosis
- Optic and Peripheral Neuropathy
- Myelosuppression
mechanism of Fidaxomicin
binds to sigma subunit of RNA polymerase hence inhibiting it –> protein synthesis inhibition
main clinical application for Fidaxomicin
C. difficile colitis
mechanism of Mupirocin
binds to bacterial isoleucyl transfer-RNA synthetase –> inhibition of protein synthesis
clinical use of mupirocin
MSSA or MRSA
adverse effects of mupirocin
not used systemically so well tolerated
burning edema tenderness dry skin pruritis
drugs that affect nucleic acid synthesis
Fluoroquinolones
Sulfonamides
Trimethoprim
what are the fluoroquinolones
1st gen: Nalidixic acid
2nd gen: Ciprofloxacin
3rd gen: Levofloxacin
4th gen: Moxifloxacin and Gemifloxacin
mechanism of fluoroquinolones
direct inhibitor of bacterial DNA synthesis
inhibits bacterial enzymes, DNA gyrase (topoisomerase II) and topoisomerase IV –> damage to bacterial DNA –> bacterial cell death
mechanism of resistance in fluoroquinolones
mutation in genes that
- encode DNA gyrase (II) and topoisomerase IV
- regulate expression of efflux pumps
name and use of first generation fluroquinolones
Nalidixic acid
uncomplicated urinary tract infection
name and use of second generation fluoroquinolones
Ciprofloxacin
traveler’s diarrhea (e. coli)
pseudomonas aeruginosa (in CF patients)
prophylaxis for meningococcal infection
name and use of third generation fluororquinolones
Levofloxacin
CA pneumonia (most common) prostatitis caused by e. coli STDs (not syphilis) skin infections acute sinusitis chronic bronchitis tuberculosis
name and use of fourth generation fluoroquinolones
Moxifloxacin and Gemifloxacin
together with levofloxacin are referred to as respiratory fluoroquinolones
-used for pneumonia
adverse effect of fluroquinolones
Connective tissue problems
QT prolongation
GI disturbances (most common)
Superinfections
what drugs can enhance the toxicity of fluroquinolones
theophyllines, corticosteroids, NSAIDs,
Levofloxacin, Gemifloxacin, and Moxifloxacin can increase the serum levels of what drugs
warfarin, caffeine, and cyclosporine
contraindications of fluroquinolones
- pregnancy and nursing mothers
- children under 18 - due to erosion of cartilage in weigh bearing joints
