Anti-infective Agents (Ch 34) Flashcards
What is the general spectrum of aminoglycosides? (2)
- Gram (-)
2. Select aerobic gram (+)
What is the mechanism for aminoglycosides? (2)
- Inhibit protein synthesis through binding to the 30S ribosomal subunit “3 (common aminoglycosides) 30S”
- This irreversibly inhibits bacterial RNA
Are aminoglycosides bactericidal or bacteriostatic?
Bactericidal
Which aminoglycosides are minimally absorbed and are used to decrease bacterial content in the bowel? (2)
- Kanamycin
2. Neomycin
What are important ADRs of aminoglycosides? (3)
- Nephrotoxicity
- Ototoxicity
- Neuromuscular blockade
What are risk factors for neuromuscular blockade caused by aminoglycosidses? (3)
- Myasthenia gravis
- Hypocalcemia
- Elevated peak concentrations
What nerve is damaged in aminoglycoside induced ototoxicity?
Eighth cranial nerve
How are aminoglycosides dosed?
- Actual body weight
2. Unless patient is obese 20% over ideal use adjusted
What is the equation for ideal body weight (only needed for aminoglycosides to calculate adjusted if obese)?
Males: IBW = 50 kg + 2.3 kg for each inch over 5 feet.
Females: IBW = 45.5 kg + 2.3 kg for each inch over 5 feet.
1. My ideal 6ft = 77.6 kg
What is the equation for adjusted body weight?
- IBW + 0.4 (actual - ideal)
2. Ideal is on the outsides
What are the target serum concentrations for amikacin?
- Peak = 20-30 mcg/ml
2. Trough = <10 mcg/ml
What are the target serum concentrations for gentamicin and tobramycin?
- Peak = 4-10 mcg/ml
2. Trough = <2mcg/ml
Which aminoglycoside can be inhaled via nebulization?
Tobramycin
What is the rationale for extended interval dosing with aminoglycosides? What trait is helpful in this dosing?
- Designed to drive the peak very high to max the concentration dependent killing and allow troughs to fall to reduce toxicity
- They have a significant postantibiotic effect
What is the mechanism of penicillins?
- Bind to penicillin binding protein in cell wall
2. Cell wall synthesis is inhibited
Are penicillins bactericidal or bacteriostatic?
Bactericidal
What does the chemical structure of penicillins consist of?
- Beta-lactam
2. Thiazolidine Ring
How are penicillins eliminated? Name two exceptions.
- Renal
2. Nafcillin and oxacillin are hepatic
What are examples of “natural penicillins?” (2)
Penicillin G
Penicillin V
What are examples of “penicillinase-resistant penicillins?” (4)
Oxacillin
Nafcillin
Cloxacillin
Dicloxacillin
What are examples of penicillin + beta lactamase inhibitors? (4)
- Amoxicillin Clavulanic acid (Augmentin)
- Ticarcillin Clavulanic acid (Timentin)
- Ampicillin Sulbactacm (Unasyn)
- Piperacillin Tazobactam (Zosyn)
What bacteria are natural penicillins ineffective against?
Staphylococcus aureus (penicillinase) Natural = Pen G and V
What do aminopenicillins have greater penetration for and higher affinity for?
- The outer membrane of gram (-) rods
2. Penicillin binding proteins
Are cephalosporins bactericidal or bacteriostatic?
Bactericidal
What is the mechanism of cephalosporins?
- Inhibit mucopeptide synthesis in the bacterial cell wall
2. Formation of defective cell walls
What is a common dose for penicillin G benzathine (Bicillin LA)? For syphilis treatment?
- 2 million units IM single dose
2. 4 million units IM single dose
What are the first generation cephalosporins? (3)
- Cephalexin (Keflex) po
- Cefadroxil (Duricef) po
- Cefazolin (Ancef) IV
“ALEX tried to keep up with the FADs but they FAZzled out”
What is the general spectrum for first generation cephalosporins?
More gram (+) than gram negative coverage
What are the second generation cephalosporins? (5)
- Cefaclor (Ceclor) po
- Cefuroxime (Ceftin, Zinacef) IV IM po
- Cefoxitin (Mefoxin) IV
- Cefotetan (Cefotan) IV IM
- Cefprozil (Cefzil) po
“The FACt is the FURry FOX crossed the TETANs like a PRO”
What is the general spectrum for second generation cephalosporins?
Enhanced gram (-) over 1st gen
What are the third generation cephalosporins? (7)
- Cefpodoxime (Vantin) po
- Ceftazidime (Fortaz, Tazicef) IV IM
- Cefixime (Suprax) po
- Cefdinir (Omnicef) po
- Ceftriaxone (Rocephin) IV IM
- Cefibuten (Cedax) po
- Cefotaxime (Claforan) IV
“Listening to his iPOD, TAZ was so FIXed on DINIR he fell off his TRIke onto his BUT and had to pay TAXes”
What is the general spectrum for third generation cephalosporins?
- More gram (-) than positive coverage
2. Cerebrospinal fluid penetration
What is the fourth generation cephalosporin?
Cefepime (Maxipime) IV IM
What is the fifth generation cephalosporin?
Ceftaroline (Teflaro) IV
What cephalosporins have antipseudomonal activity?
- Ceftazidime
2. Cefepime
Which cephalosporin has no gram (+) activity?
Ceftazidime