Internal Medicine - Infectious Diseases - Antibiotics Flashcards
Penicillins cover Strep viridans, Strep pyogenes, oral anaerobes, syphilis, and Leptospira. On top of these, what other organisms are covered by ampicillin and amoxocillin?
E. coli
Lyme disease
Some gram-negative bacteria
What are the five main organisms covered by amoxicillin?
HELPS: H. influenza E. coli Listeria Proteus Salmonella
What 2 important, common infections are NOT covered by penicillins?
MRSA and Enterococcus
Methicillin is never the right answer for any infection. Why?
It causes renal failure due to allergic interstitial nephritis.
What are the best initial therapy-agents for hospital-acquired/ventilator-associated pneumonia?
Pipercillin, ticarcillin, azlocillin, and mezlocillin
+ beta-lactamase inhibitors (ex: tazobactam or clavulanic acid)
What major bacteria/bacterial groups are covered by agents such as pipercillin, ticarcillin, azlocillin, and mezlocillin?
Gram-negative bacilli (ex: E. coli and Proteus)
Pseudomonas
When a patient tells you they are allergic to penicillin, you should ask them if they have ever taken/reacted to what other class of antibiotics?
Cephalosporins
If a question describes anaphylaxis, what antibiotic group should you NOT use?
Beta-lactam antibiotics
What major bacteria is NOT covered by first generation cephalosporins (ex: cefazolin, cephalexin, cephradrine, cefadroxyl)?
Brand names: Ancef, Keflex, Velosef, Duricef
Pseudomonas
What two agents are typically used to treat healthcare-associated pneumonia?
Vanc and Zosyn
vancomycin and pipercillin+tazobactam
What are two important side effects of cefotetan and cefoxitin (second generation cephalosporins)?
Increased risk of bleeding (deplete prothrombin)
Disulfiram-like reaction with alcohol
What two antibiotics are commonly used to treat community-acquired pneumonia?
What is the “best therapy” for community-acquired pneumonia?
Ceftriaxone and macrolide (azithromycin)
Fluoroquinolones (cipro, levo, etc.)
What population should ceftriaxone be avoided in? Why?
Neonates
Impairs biliary metabolism: displaces bilirubin from albumin leading to increased risk of bilirubin encephalopathy, especially in hyperbilirubinemic neonates.
What groups of bacteria do carbapenems cover?
Almost everything: gram-negative bacilli (including resistant organisms), anaerobes, streptococci, and staphylococci. They’re broad-spectrum big-guns.
How does ertapenem differ from other carbapenems?
Does NOT cover Pseudomonas.
What single drug belongs to the class of monobactams?
Aztreonam
What bacteria/groups of bacteria does aztreonam cover?
Exclusively gram-negative bacilli, including Pseudomonas.
What fluoroquinolone is commonly used to treat cystitis and pyelonephritis?
Ciprofloxacin
Fluoroquinolones are commonly used to treat diverticulitis and GI infections. However, they must be administered with one other medication. What is the medication and why?
What fluoroquinolone is an exception to this rule?
Metronidazole to cover anaerobes; fluorequinolones do not cover anaerobes…
EXCEPT moxifloxacin: can be used as a single agent (without metronidazole) for diverticulitis.
What are three major/most severe side effects of fluoroquinolones?
- Bone growth abnormalities in children and pregnant women.
- Tendonitis and Achilles tendon rupture
- QT prolongation
Aminoglycosides cannot be administered by themselves. What medication(s) must they be administered with and why?
Given with beta-lactam antibiotics; cannot penetrate cell wall on their own.
What group of bacteria do aminoglycosides NOT cover?
Anaerobes; aminoglycosides need oxygen to work.
What are the two main toxicities associated with aminoglycosides?
Nephrotoxicity
Ototoxicity
What are the major adverse effects (4) of doxycycline/tetracyclines?
Tooth discoloration (children)
Fanconi syndrome (type II renal tubular acidosis)
Photosensitivity
Esophagitis/ulcer
Trimethoprim/Sulfamethoxazole (Bactrim) is used in the setting of which type of pneumonia?
Treatment and prophylaxis of pneumocystis pneumonia (in HIV patients)
What are the two major/most dangerous side effects of TMP/SMX?
Hemolysis in patients with G6PD deficiency
Bone marrow suppression due to folate antagonism
What five antibiotics can be used to treat moderate to severe MRSA infections?
In order of escalation: Vancomycin Linezolid Daptomycin Tigecycline Ceftaroline
What is the major side effect with use of linezolid?
Reversible bone marrow toxicity
What is the major side effect with use of daptomycin?
Elevated CPK
What four antibiotics can be used to treat minor MRSA infections?
TMP/SMX
Clindamycin
Doxycycline
Linezolid
What major group(s) of antibiotics are used to treat infections with anaerobes above the diaphragm?
Clindamycin (preferred)
Penicillin (G, VK, amipicillin, or amoxicillin)
What major group(s) of antibiotics are used to treat infections with anaerobes below the diaphragm?
Metronidazole + beta-lactam/lactamase combinations
What is the one major indication for use of nitrofurantoin (Macrobid)?
Cystitis, especially in pregnant women.
