Exam 4-2 Antibiotics Part 2 Flashcards
Antibiotic Therapy: Concepts
- Multidrug resistance
- Therapeutic drug monitoring
- Minimum inhibitory concentration (MIC)
- Time-dependent killing
Antibiotic Therapy: concepts-Concentration-dependent killing
- Once-daily vs. multi-daily dosing
- Peak and nadir (trough) blood levels
- Synergistic effects
- Post-antibiotic effect (PAE)
Antibiotic Therapy: Toxicities- Ototoxicity
*Temporary or permanent hearing loss, balance problems
Nephrotoxicity
- Varying degrees of reduced renal function
* Rising serum creatinine clearance
Antibiotic Therapy: Monitor for:
- nadir levels every 5 to 7 days while on therapy as ordered
* serum creatinine levels at least every 3 days as an index of renal function
Aminoglycosides:
- gentamicin (Garamycin)
- neomycin (Neo-fradin)
- tobramycin (Nebcin)
- amikacin (Amikin)
- kanamycin
- stretomycin
Aminoglycosides: Characteristics
- Natural and semisynthetic
- Produced from Streptomyces
- Poor oral absorption; no PO forms
- Very potent antibiotics with serious toxicities
- Bactericidal; prevent protein synthesis
- Kill mostly gram-negative; some gram-positive
Aminoglycosides: Indications
- Used to kill gram-negative bacteria such as Pseudomonas spp., E. coli, Proteus spp., Klebsiella spp., Serratia spp.
- Often used in combination with other antibiotics for synergistic effects
- Certain gram-positive infections that are resistant to other antibiotics
Aminoglycosides are poorly-
absorbed through the GI tract and administered parenterally
- Exception: neomycin
- Given orally to decontaminate the GI tract before surgical procedures
- Also used as an enema for this purpose
Aminoglycosides cause serious
toxicities
- nephrotoxicity (renal damage)
- ototoxicity (auditory impairment and bestibular eighth cranial nerve)
- Must monitor drug levels to prevent toxicities
Fluoroquinolones
- ciprofloxacin (Cipro)
- norfloxacin (Noroxin)
- levofloxacin (Levaquin)
- moxifloxacin (Avelox)
Fluoroquinolones: Characteristics
- Excellent oral absorption
- Absorption reduced by antacids
- Effective against gram-negative organisms and some gram-positive organisms
Fluoroquinolones: Mechanism of Action
- Bactericidal
- Alter DNA of bacteria, causing death
- Do not affect human DNA
Fluoroquinolones: Indications
- Gram negative bacteria such as pseudomonas
- Respiratory infections
- Bone and joint infections
- GI infections
- Skin infections
- Sexually transmitted diseases
- Anthrax
Other Antibiotics
- clindamycin (Cleocin)
- linezolid (Zyvox)
- metronidazole (Flagyl)
- nitrofurantoin (Macrodantin)
- quinupristin and dalfoprisitin (Synercid)
- daptomycin (Cubicin)
- vancomycin (Vancocin)
clindamycin (Cleocin)
- Used for chronic bone infections, GU infections, intraabdominal infections
- May cause pseudomembranous colitis
linezolid (Zyvox)
- New class; oxazolidinones
- Used to treat vancomycin resistant Enterococcus faecium (VREF, VRE), hospital-acquired skin and skin structure infections, including those with MRSA
metronidazole (Flagyl)
- Used for anaerobic organisms
- Intraabdominal and gynecologic infections
- Protozoal infections
- EtOH intolerance
nitrofurantoin (Macrodantin)
- Primarily used for UTI’s (E. coli, S. aureus, Klebsiella spp., Enterobacter spp.)
- Use carefully if renal function is impaired
- Drug concentrates in the urine
- Keep patient well hydrated
- May cause fatal hepatotoxicity
quinupristin and dalfopristin (Synercid)
- 30:70 combination, work synergistically
- Used for bacteremia and infections caused by vancomycin-resistant Enterococcus (VRE) and other complicated skin infections
daptomycin (Cubicin)
- New class: lipopeptide
- Used to treat complicated skin and soft-tissue infections
vancomycin
- Natural, bactericidal antibiotic
- Interferes with cell wall synthesis
- Treatment of choice for MRSA and other gram-positive infections
- Must monitor blood levels to ensure therapeutic levels and prevent toxicity
- May cause ototoxicity and nephrotoxicity
- Should be infused over 60 minutes
- Rapid infusions may cause hypotension
vancomycin may cause
Red man syndrome
-flushing/itching of the head, neck, face, upper trunk
-Antihistamine may be ordered to reduce these effects
Ensure adequate hydration (2 L fluids/24 hr) if not contraindicated to prevent nephrotoxicity
