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112 Cards in this Set
- Front
- Back
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What is the MOA of Cephalosporins?
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• inhibitors of cell wall synthesis
* same MOA as PCN |
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Generally, first generation cephalosporin activity is effective against which organisms?
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• great for gram-positive (majority of action to gram +)
• some activity against some gram-negative |
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Second generation cephalosporin activity is effective against which organisms?
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• stronger gram-negative coverage
• weaker gram-positive |
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Generally, third generation cephalosporins have activity against which organisms?
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• even stronger gram-negative bacilli (rods) coverage
• much weaker gram-positive cooci |
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First generation cephalosporins are good to treat which organisms?
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Pneumonic: PEK
• Proteus mirabilis • E. Coli • Klebsiella (1st gen. are DOC) |
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1st generation cephalosporins are good agents to use for what patients?
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• UTI
• Surgical prophylaxis (Cefazolin/Ancef: 1 gm, ½ hr befor surgery) * if PCN allergic, give Vancomycin |
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What antibiotic would use for abdominal surgery prophylaxis?
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• Cefoxitin (covers more gram-negative & anaerobes)
* if allergic to PCN, use Levaquin + Metronidazole (Flagyl) |
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List examples of 1st generation cephalosporins
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Oral: Cephalexin (Keflex), Cefadroxil (Duricef)
IV: Cefazolin (Ancef) |
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2nd generation cephalosporins are good for what organisms?
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Pneumonic: HEN PEK
• H. Flu • Enterbacter • Neisseria + • Proteus mirabilis • E. Coli • Klebsiella |
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True/False: Cephalosporins are good agents against enterococcus
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• Cephalosporins are not good agents against enterococcus
• The correct answer is: False |
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List examples of oral 2nd generation cephalosporins
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• Cefaclor
• Loracarbef • Cefpodoxime |
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Cefuroxime is a 2nd generation cephalosporin that come in IV and PO formulations. What is the name of Cefuroxime IV and PO?
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• IV: Zinacef
• PO: Ceftin |
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Name 2nd generation cephalosporins that have mixed anaerobe/aerobe coverage?
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Hint: Metal tan fox
• Cefmetazole (hardly ever used) • Cefotetan * • Cefoxitin * * both come in IV formulation |
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Give examples of 3rd generation cephalosporins
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• Cefotaxime
• Ceftriaxone (Rocephin) • Cefixime • Ceftazadime |
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What is DOC for gonorrhea?
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Ceftriaxone (Rocephin)
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What is the DOC for meningitis? What is the dosage?
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Ceftriaxone (Rocephin) 2 gm IV Q 12
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3rd generation cephalosporins are good against which bacteria?
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Pneumonic: PEEK
• Proteus • E. Coli • Enterobacter • Klebsiella • very effective against gram-negative rods (not that good for gram-positive) • used for serious infection |
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What are the 3 cephalosporins that are effective against pseudomonas?
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• Cefoperazone
• Ceftriaxone/Ceftazidime (cross BBB) • Cefipime (only 4th gen.) |
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Which cephalosporins cross the blood-brain barrier?
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• Cefuroxime
• Cefotaxime • Ceftazidime • Ceftriaxone • Cefepime (4th gen) |
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What cephalosporins can you use empirically on infants (less than 3 months) for meningitis?
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• Cefuroxime
• Cefotaxime |
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Which cephalosporins do not need to be dose adjusted for renal failure patients?
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• Cefoperazone
• Cefaclor • Ceftriaxone |
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Which cephalosporin has the longest half-life?
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Ceftriaxone (half-life 14-24 hrs)
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What is the chance of being allergic to cephalosporins with a prior allergy to PCN? without allergy to PCN?
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• if allergic to PCN, 15% chance of being allergic
• without allergy to PCN, have 3% chance of allergy |
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Which cephalosporin could you use for resistant organisms, like extended-spectrum beta-lactamase organisms (ESBL)?
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Cefipime (4th gen)
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Which drugs are the "last resort" beta-lactams?
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Carbapenems
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List 2 Carbapenems
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• Imipenem-Cilastatin (Primaxin)
• Aztreonam (a Monbactam) |
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What are available formulations of Imipenem-Cilastatin (Primaxin)?
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IV only
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What is MOA of Cilastatin?
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inhibits dipeptidase enzyme of the bacteria (metabolizes a side chain)
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What are indications for using Imipenem-Cilastatin (Primaxin)?
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• indicated to use for multi-bacterial infections that are resistance to other antimicrobials
• broadest spectrum of all beta lactams (gram+/-, anaerobes, B. frag, pseudomonas) • not effective against enterococcus |
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What can be complications of Imipenem-Cilastatin (Primaxin)?
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• high sodium content (may not be good for elderly, CHF, HTN patients)
• lowers seizure threshold (more prone to seizures) • nephrotoxicity (may have to dose adjust for renal patients) |
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Aztreonam covers what type of organisms?
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only gram-negative
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What is indication for using Aztreonam?
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• used for gram-negative organisms and the patient is truely penicillin allergic
• Aztreonam has no cross sensitivty with PCN-allergic patients |
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What are available formulations of Aztreonam?
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IV only
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How is Aztreonam eliminated?
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renally eliminated (has to be dose adjusted for renal disease)
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What is the MOA of Vancomycin?
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inhibits synthesis of bacterial cell wall, phospholipids, and peptidglycan
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Is Vancomycin bacteriostatic or bacteriocidal?
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bacteriocidal
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What causes resistance to Vancomycin?
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plasmids
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What is Vancomycin used to treat?
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• MRSA
• used as prophylaxis in PCN allergic patients undergoing surgery (1 gm one time dose) |
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What is the dosing for Vancomycin?
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• 15 mg/kg
* if CrCl > 50, dose Q12; if CrCl < 50, dose Q24 * always use actual body weight |
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How do you monitor Vancomycin?
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• order peaks and troughs
• get trough level ½ hr before the 3rd dose • get peak level 1 hr after infusion |
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What should the trough level be in a patient receiving Vancomycin?
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10-15
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What are the situations where the trough level should be 15 - 20?
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• area of high penetration (such as a lung infection)
• bacterial endocarditis • very septic ICU patient w/ multi-organ failure |
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In older patients, a clinician can monitor only troughs for Vancomycin. What are 3 scearios when peaks & troughs should be monitored?
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• pts w/ ever changing volume of distribution (ex. dialysis patient)
• burn patient • very septic ICU patient w/ mult-organ failure |
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What are available formulations of Vancomycin?
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• only IV
• can make oral Vancomycin from IV solution to treat C. Difficile |
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What are adverse effects of Vancomycin?
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• allergy
• nephrotoxicity (need to dose adjust with rapid changing serum creatinine) • ototoxicity (need to stop drug) |
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How do you dose adjust Vancomycin if the trough is high?
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• increase to the next dosing interval
• Q12»Q24; Q24»Q36; Q36»Q48 |
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How do you dose adjust Vancomycin if the trough is low?
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• decrease to the next dosing level
• Q24»Q12; Q12»Q8 |
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What is Red-mans Syndrome?
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• an infusion-related toxicity to Vancomycin
• not an allergic reaction |
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How do you treat Redman's Syndrome?
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• stop Vancomycin for ½hr and infuse at a slower rate
• can give Benadryl for itching |
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What is the MOA of Tetracyclines?
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protein synthesis inhibitor
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Tetracyclines are broad spectrum antibiotics used first line to treat what?
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• Bacteria that causes acne
• Cholera • Chlamydia • Lyme Disease • Mycoplasma Pneumoniae • Rocky mountain spotted fever |
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Why should a patient taking Tetracyclines avoid dairy products?
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the drug will bind to calcium, causing the body to eliminate both the drug and calcium
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Where does Tetracycline concentrate in the body?
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• bones
• kidney • liver • spleen • teeth |
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True/False: Tetracycline does not cross the blood-brain barrier enough to treat meningeal disease.
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The correct answer is: True
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What are adverse effects of Tetracyclines?
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• Avoid in pregnant females
• Discoloration of teeth • Dizziness • Hepatotoxicity • Irritation to gastric mucosa • Phototoxicity • Superinfections (can get C. Diff from long-term use) • Stunt growth in children |
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Name 2 examples of Tetracyclines
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• Doxycycline (PO, IV)
• Tetracycline |
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List examples of aminoglycosides
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• Amikacin
• Gentamycin • Neomycin • Streptomycin • Tobramycin |
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What is the MOA of Aminoglycosides?
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• transported across bacterial membrane by a transport system that requires oxygen
• binds to the bacterial 30S and 50S ribosomal subunit • inhibits protein synthesis |
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How does resistance to Aminoglycosides develop?
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resistance develops by eliminating the energy needed to transport the drug across the bacterial membrane
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How are aminoglycosides eliminated from the body?
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• renally excreted
• would get peaks & troughs for Gentomycin and Tobramycin • troughs should be < 2 |
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What is the spectrum of activity for aminoglycosides?
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• good gram-negative, no anaerobic, fewer gram-positive
• effective against staph and enterococci when used in combination w/ PCN for endocarditis treatment • pseudomonas (with a beta-lactam; Tobramycin has more specificity for pseudomonas) |
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What are side-effects of aminoglycosides?
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• nephrotoxicity
• neuromuscular blocking activity • ototoxicity |
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What is the dosing for Gentamycin or Tobramycin?
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5 mg/kg per dose
* use actual body (except for obese patient) |
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Which side effects of the aminoglycosides are reversible? which are irreversible?
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• nephrotoxicity is reversible
• ototoxicity is irreversible |
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Which aminoglycoside is the most nephrotoxic? least nephrotoxic?
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• Neomycin is the most nephrotoxic (when taken PO to sterilize the gut)
• Streptomycin is the least nephrotoxic |
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Which aminoglycoside is used to sterilize the gut?
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Neomycin
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Which aminoglycoside can be used to treat pseudmonas?
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• Tobramycin (more specific for pseudomonas)
• Gentamycin |
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What is the MOA for Quinolones?
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inhibit DNA gyrase
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List some examples of Fluroquinolones
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• Ciprofloxin*
• Gatifloxin • Levofloxaxin* • Moxifloxin • Norfloxacin • Ofloxacin * most common (Cipro & Levaquin) |
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How do bacteria build resistance to fluoroquinolones?
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resistance is due to aleration of the biding affinity of the enzyme DNA-Gyrase
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What is the spectrum of activity of the fluoroquinolones?
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• Spectrum of activity: gram-positive & gram-negative
• Cipro and Levaquin have pseudomonal coverage |
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What are clinical uses for the fluoroquinolones?
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• Lower respirory infections
• Osteomyelitis • Prostate infection • Upper respiratory infections • UTI |
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List drugs that decreases the GI absorption of fluoroquinolones
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• antacids
• Didanosine (DDI) • Iron salts • Sucralfate • Zinc oxide |
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What is the effect of Theophylline on the fluoroquinolones?
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theophylline decreases clearance of the fluoroquinolones and can cause toxicity
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What are side effects of fluoroquinolones?
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• cartilage damage (can stunt growth in children)
• CNS disturbances • nausea/vomiting/diarrhea • phototoxicity • prolonging of QT interval • skin rashes |
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What is the MOA of the macrolides?
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binds irreversibly to 50S ribosomal subunit and inhibits protein synthesis
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List examples of macrolides
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• Azithromycin
• Clarithromycin • Erythromycin |
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Are macrolides bacteriocidal or bacteriostatic?
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bacteriocidal
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What is the spectrum of activity of marcrolides?
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• gram-positive and gram-negative cocci
• gram-positive bacilli • spirochetes |
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Macrolides are the DOC for what infections?
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• Atypicals
• Chlamydia infections during pregnancy • Legionairres • Syphillis (in PCN allergic patients) |
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What causes resistance to macrolides?
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decreased binding to the 50S subunit
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True/False: Macrolides cross the blood brain barrier
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• Macrolides distributes to all tissues except the brain
• The correct answer is: False |
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What are adverse effects of macrolides?
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• Cholestatic jaundice
• GI effects • Metallic taste (w/ Clarithromycin) • Ototoxicity (in very high doses) * high doses can increase incidence of adverse effects |
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What is the effects of macrolides on drugs like theophylline and cyclosporine?
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macrolides inhibits the metabolism of theophylline and cyclosporine
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What is the MOA of Chloramphenicol?
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binds to 50S subunit of the bacterial ribosome and inhibits protein synthesis
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What is the spectrum of activity of Chloramphenicol? Is it bacteriocidal or bacteriostatic?
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• very broad spectrum antimicrobial
• usually bacteiostatic, but is bacteriocidal in some cases |
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What are adverse effects of Chloramphenicol?
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• Anemias (Hemolytic and Aplastic anemia)
• Gray-baby syndrome |
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What is the MOA of Clindamycin?
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protein synthesis inhibitor
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What is the spectrum of activity of Clindamycin?
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• gram-positive cocci and bacilli
• spirochetes • anaerobes * does not cover gram-negative organisms * drug can be an alternative to PCN for gram-positive infections |
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What are adverse effects of Clindamycin?
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• rashes
• superinfections (C. Difficle/Pseudomembranous Colitis) |
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If the urinalysis (UA) shows positive nitrates, what is the most likely type of organism present?
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gram-negative
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If the UA is positive for leukocyte esterase, what is the most likely type of organism present?
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gram-positive
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What is the MOA, spectrum of activity, and available formulations of Nitrofurantoin (Macrodantin)?
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• MOA: inhibits bacterial enzymes and damages bacterial DNA
• Spectrum of Activity: gram-negative & gram-positive (bacteriostatic antimicrobial) • PO only |
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What are adverse effects of Nitrofurantoin (Macrodantin)?
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• Acute pneumonitis
• GI effects • Interstitial fibrosis • Nystagmus |
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What is the MOA of Isoniazid?
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inhibits synthesis of mycoli acid (part of the myobacterial cell wall)
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What is the spectrum of activity of Isoniazid?
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specificty for myobacterium tuberculosis
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What are adverse effects of Isoniazid?
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• hypersensitivity
• peripheral neuritis |
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Is Isoniazid an inhibitor or inducer?
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both (can be an inhibtor or inducer)
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What are the effects of Isoniazid on Phenytoin?
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Isoniazid inhibts the metabolism of Phenytoin
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What can be given to patient on Isoniazid to help prevent peripheral neuritis?
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Vit B6 (Pyridoxine)
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What is the MOA of Rifampin?
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inhibits RNA synthesis by inhibiting DNA-dependant RNA polymerase
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Is Rifampin bacteriocidal or bacteriostatic?
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bacteriocidal to both intracellular and extracellular M. Tuberculosis
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Is Rifampin an inducer or inhibitor?
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very powerful inducer
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What is the MOA of Fluconazole (Diflucan)?
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• blocks fungal CYP450 mediated synthesis of ergosterol
• sterols are not available to make fungal membranes |
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Fluconazole (Diflucan) is the DOC for what patients?
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most immunocompromised patients (HIV, chemotherapy pts)
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What does an absolute neutrophil count less than 1500 indicate?
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indicates high susceptibility to oppurtunistic infection
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What is the MOA of Ketoconazole?
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• blocks fungal CYP450 mediated synthesis of ergosterol
• sterols are not available to make fungal membranes • also blocks gonadal and adrenal steroid synthesis in humans |
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Is Ketoconazole an inhibitor or inducer?
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inhibitor
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Why should you take Coke with Ketoconazole?
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• Ketoconazole needs an acidic environment to be effective
• Coke will increase acidity |
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What are adverse effects of Ketoconazole?
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• GI
• Gynecomastia • Reduces androgen synthesis |
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What is the MOA, spectrum of activity, and available formulations of Metronidazole (Flagyl)?
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• metabolite binds to proteins and DNA causing cell death
• kills anaerobic bacteria • oral or IV |
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What are side effects of Metronidazole (Flagyl)?
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• metallic taste in mouth (w/ PO)
• nausea/vomiting |
