Drugs: Basics Flashcards
What is the best drug to use for hospital-acquired MRSA?
-Vancomycin
What is MRSA resistant to?
- Penicillin
- Cephalosporin
What is natural penicillin (Penicillin VK and aqueous Penicillin G) good at treating?
- Gram positive (streptococci)
- Anaerobes (oral only)
What is natural penicillin the drug of choice for?
- N. meningitidis
- Syphilis
What are aminopenicillins good at treating?
- Gram positive (streptococci, enterococci)
- Some gram negatives
- Anaerobes (oral only)
- Often resistance w respiratory infections
What are the penicillinase-resistant penicillins?
- Dicloxacillin
- Nafcillin
What are the penicillinase-resistant penicillins good at treating?
- Drug of choice for MSSA!
- Gram positive: streptococcus, MSSA
- Anaerobes (oral only)
What are the aminopenicillins?
- Ampicillin
- Amoxicillin
What are the extended-spectrum penicillins?
- Piperacillin
- Ticarcillin
What are the extended-spectrum penicllins good at treating?
- Broad spectrum, severe infections
- Gram positive: streptococcus, staphylococcus
- Gram negative: excellent! include coverage against pseudomonas
- Anaerobes (oral); but there are better ones out there
Are the extended spectrum penicillins available orally or IV?
-IV only. You reserve these for pretty severe issues, like pseudomonas and bad gram-negative pathogens.
What does adding a beta-lactamase inhibitor to your penicillins do?
-It takes away the major resistance mechanism. Now, you have a drug that is 1) great against MSSA, 2) increases coverage against all enterobacteriacea, 3) great against anaerobes.
What penicillins are best for treating MSSA?
Dicloxacillin and nafcillin (the penicillase-resistant penicillins)
What penicillins are best for treating MRSA?
None!
What penicillins are best for treating psuedomonas?
Piperacillin and tazocillin (the extended-spectrum penicillins)
What penicillins are best for treating anaerobes?
- Penicillin for oral anaerobes
- Am/sulbactam and pip/tazo for B.fragilis
What are common adverse reactions to penicillins?
- Allergic reactions
- Diarrhea
What are the first generation cephalosporins?
- Cefazolin
- Cephalexin
What are the second generation cephalosporins?
- Cefuroxime
- Cefoxitin
What are the third generation cephalosporins?
- Ceftriaxone
- Ceftazidime
What is the fourth generation cephalosporin?
-Cefepime
Which of the cephalosporins is only available orally?
-Cephalexin
Which of the cephalosporins is available both IV and orally?
-Cefuroxime
What are first generation cephalosporins good at covering?
- Great gram + coverage: streptococcus, MSSA
- Not good gram - coverage; some e.coli, klebsiella
- Anaerobes: oral only
Bottom line: good for skin infections, some respiratory. Main activity is against strep and staph
What are the second generation cephalosporins good at covering?
- Moderate gram + and gram - coverage
- Some respiratory (oral)
- Anaerobes: can cover b.fragilis!!
Bottom line: they are moderately good for covering a lot of things, which is why they are not used a lot - don’t have a niche.
What are the third generation cephalosporins good at covering?
- Great gram - coverage (includes pseudomonas wtih ceftazidime coverage)
- Not good gram + coverage
Bottom line: good for respiratory infections, serious infections
What is the fourth generation cephalosporin good at covering?
-Both gram - (inc. pseudomonas) and gram + (strept, MSSA)!
-Anaerobes (oral only)
But is $$$
Bottom line: used for serious hospital infections. Not so good for MRSA (use vanco instead).
What do none of the cephalosporins cover?
Enterococcus
What kind of infections might present with enterococcus?
Intraabdominal infections
Diabetic foot ulcers with mixed flora
What is the new cephalosporin on the market and what is it good for?
- Ceftaroline!
- Covers MRSA (the only ceph to do so!)
- Covers strep pneumo
- Covers gram negative rods (doesn’t cover pseudomonas)
When do we really use ceftaroline?
For MRSA. We don’t use it widely, we are reserving this puppy for something really resistant.
What is the only cephalosporin that covers b.fragilis?
-Cefoxitin (a 2nd gen ceph)
What are the only cephalosporins that cover pseudomonas?
-Ceftazidime (a 3rd gen) and cefepime (4th gen)
What do ALL of the cephalosporins cover?
-MSSA, e.coli, klebsiella, h.flu, oral anaerobes
What are adverse reactions of the cephalosporins?
- Allergic reactions (3-7% cross resistance with PCN allergy)
- Diarrhea
What are the carbapenems?
- Imipenem
- Meropenem
- Ertapenem
- Doripenem
What can the carbapenems cover?
- Very broad spectrum! Only really used in severe infections
- Excellent anaerobic coverage
- Key forte: gram negatives; most can cover pseudomonas!
- No MRSA coverage, not terrible MSSA drugs.
Bottom line: use these for when you want to “throw the kitchen sink” at someone in a severe case where you need good broad spectrum coverage.
What is the one carbapenem that doesn’t cover pseudomonas?
-Ertapenem
What are the adverse reactions of carbapenems?
-Gastrointestinal
Are the carbapenems available orally or IV?
IV only
What kind of patients should you NOT use carbapenems with?
Those with severe PCN allergies
What are the aminoglycosides?
- Gentamicin
- Tobramycin
- Amikacin
What is the coverage like for aminoglycosides?
- Good gram negative, includes pseudomonas coverage
- Only synergistic gram + activity, so would not use this to cover gram +’s by themselves
- Do not cover ANY anaerobes!!
What are the adverse reactions of aminoglycosides?
- Nephrotoxicity 10-15%! (usually reversible)
- Ototoxicity 1-5% (often irreversible)
Yikes. So dose very carefully due to toxicity potential. Dosage according to weight, renal function, and severity/site of infection.
What are the fluoroquinolones?
- Ciprofloxacin
- Levofloxacin
- Moxifloxacin
- Gemifloxacin
What are the fluoroquinolones good at covering?
- Potent agents
- Most gram - (including psuedomonas)
- Some gram + (strept, MSSA)
- Anaerobes: minimal
Bottom line: good at covering atypical respiratory pathogens! Legionella, chlamydia pneumoniae, mycoplasma pneumoniae
Which fluoroquinolone is NOT good at covering MSSA or a respiratory infection caused by strep?
Ciprofloxacin - don’t use it!
What are the adverse effects of the fluoroquinolones?
- Nausea
- HA, dizziness, insomnia
Which of the classes of drugs have faced major resistance issues recently (starting in 1994)?
Fluoroquinlones!! Use with caution!
What are the macrolides?
- Erythromycin
- Clarithromycin
- Azithromycin
What are the macrolides good at covering?
- Respiratory infections
- Gram positive: strept
- Anaerobes (oral only)
- Atypical respiratory pathogens! Legionella, chlamydia pneumoniae, mycoplasma pneumoniae
What is the only gram negative that we cover with the macrolides?
H. influenzae
What are the adverse reactions of the macrolides?
- GI
- Phlebitis w IV erythro
Which macrolide is more commonly associated with the adverse reactions?
-Erythromycin
Which macrolide usually has less severe adverse reactions?
Azithromycin
What are the anti-anaerobe drugs?
- Metronidazole
- Clindamycin
For which anti-anaerobe drug does resistance more commonly occur?
-Clindamycin
What does metronidazole cover?
ONLY anaerobes!!! Great b.fragilis coverage, pretty good oral anaerobe coverage
-No gram + or gram - coverage
What does clindamycin cover?
- Gram positives: strept, MSSA
- Gram negative: none!
- Anaerobes: great oral anaerobe coverage, ok w b.fragilis
What is the hallmark agent responsible for c.diff?
-Clindamycin
What are some common adverse reactions of clindamycin?
- Diarrhea
- C.diff
What are some adverse reactions to metronidazole?
- Nausea
- Metallic taste
- Drug interaction with alcohol - flushing, sweating, nausea
Are the anti-anaerobes available orally or IV?
Both are available in both formulations
What is the coverage of vancomycin?
- Gram +: covers strept, all staph, moderate enterococcus coverage
- NO gram - coverage
- Anaerobes: gram + oral only
BOTTOM LINE: drug of choice for hospital-acquired MRSA
What is the coverage of linezolid?
- Gram +: strept, all staph, enterococcus
- Gram -: none (eh, h.flu)
- Anaerobes: none
BOTTOM LINE: gram positives only, used for serious infections, resistance is rare for this. Drug of choice for VRE (vancomycin resistant enterococcus)!
What is the coverage of daptomycin?
- Gram +: strept, all staph, all entero
- Gram -: none
- Anaerobes: none
BOTTOM LINE: gram +s only, for serious infections
A second line agent used for resistant pathogens when vanco has failed.
What are the adverse reactions of vancomycin?
- “red man” syndrome: infusion related flushing
- Nephrotoxicity with other agents and ototoxicity with high concentrations (but not as big a problem as with fluoroquinolones)
What are the adverse reactions of linezolid?
- Thrombocytopenia
- Anemia
- Neutropenia
What are some precautions that you should take when administering vancomycin?
- Weight and renal function based dosing (so do carefully!)
- Monitor renal function when using other nephrotoxins
What is the coverage of trimethoprim-sulfamethoxazole (bactrim)?
- Variable wide activity
- Gram +: strept, MSSA
- Gram -: most enterobacteriaceae
- Anaerobes: oral only
BOTTOM LINE: small pockets of use: UTIs, some skin infections, etc
What is the coverage of tetracyclines?
- Gram +: strept, MSSA
- Gram -: h.flu
- Anaerobes: mostly oral
- Atypical respiratory pathogens: legionella, c.pneumoniae, m.pneumoniae
BOTTOM LINE: used for respiratory and intracellular infections, includes coverage for atypical respiratory pathogens
What are the adverse reactions of TMP/SMX?
- Allergic reactions
- GI effects
- Neutropenia, thrombocytopenia
What are the adverse reactions of tetracyclines?
- Photosensitivity
- Nausea and diarrhea
- Tooth discoloration in kiddos
What do you need to be careful for with TMP/SMX?
Increases the effects of warfarin
What do you need to be careful about with tetracyclines?
-Don’t take with dairy products/calcium/cations because they will chelate w these products
What drugs cover pseudomonas?
- Aminoglycosides (gentamicin, tobramycin, amikacin)
- Cipro, levo (the only oral drugs) (fluoroquinolones)
- Ceftazidime, cefepime (2nd and 4th gen cephs respectively)
- Piperacillin, ticarcillin (the extended-spectrum penicillins)
- Impenem, meropenem, doripenem (most of the carbapenems)
What drugs cover hospital-acquired MRSA?
- Vancomycin
- Linezolid
- Daptomycin
What are the best drugs for covering anaerobes?
- Metronidazole
- Imipenem, meropenem, ertapenem
- Beta lactam/beta lactamase inhibitors
