Anit-Infectives Part I Flashcards
What two things must a provider know when prescribing antibiotics?
- What abx covers what bacteria
2. What bacteria typically lives in the infected area
What makes Gram neg bacteria non-staining and why is this clinically relevant?
Gram neg bacteria have an extra polysaccharide layer. This makes them more difficult to kill.
What is the most pathogenic Gram neg bacteria?
Pseudomonas
What is the most pathogenic Gram pos bacteria?
Enterococcus
What was the first abx and what bacteria does it cover?
PCN –> covers Gram pos bacteria
Differentiate between the two main types of PCN.
Penicillin G (IV) and Penicillin V (PO)
What abx treats syphilis and how is it administered?
Benzathine LA - Thick suspension given IM in gluteus maximus (painful injection)
What abx treats strep pneumonia and how is it administered?
Procaine - IM
PCN remains the drug of choice for what common infection?
Strep Throat (Group A Streprococcus)
What are the instructions given for taking PCN and what are the cautions?
Best taken around the clock and on an empty stomach. Cautions are diarrhea (may cause C-diff) and rash (antigenic - increased risk of allergic rxns)
How is PCN eliminated and what is the clinical significance?
Renally –> adjust dose if CrCl < 50
List the PCNs used to treat staphylococcus and state how they are administered.
IV: Methicillin, Oxacillin, Nafcillin
PO: Cloxacillin, Dicloxacillin
T/F: Methicillin is the only PCN that cannot be used to treat MRSA.
False: MRSA is resistant to all PCNs and almost all cephalosporins
What drugs can be used to treat MRSA and which is most common?
Most common: Vancomycin
Other: Ceftaroline (only cephalosporin that treats MRSA),
Dicloxacillin is the drug of choice for what type of infection and what are its cautions?
Cellulitis or any MSSA (Staph and Strep). Cautions: causes GI and taste issues
What are the two amino penicillins and what is the difference between the two?
Ampicillin: low Vd - must be taken on empty stomach
Amoxicillin: high Vd
What infections are covered by amoxicillin?
Everything PCN covers other than MSSA plus three Gram neg organisms - E. Coli, H. Flu, M. Cat.
What infections do E. Coli, H. Flu, and M. Cat most commonly cause?
E. Coli = UTIs
H. Flu = CAP pneumonia, otitis media, and sinusitis
M. Cat = sinusitis
What infections are covered by ampicillin? (2 zebras)
Enetrococcus and Listeria (Neonatal Meningitis)
What infection does listeria commonly cause?
Meningitis in newborns
What is the mechanism of action of a beta lactamase inhibitor?
Beta lactamase chews up beta lactam abx. Beta lactamase inhibitors keep the abx around longer.
What abx are beta lactams?
Amoxicillin, Ampicillin, all PCNs, Cephalosporins
List two combination drugs that have a beta lactamase inhibitor and state how they are administered.
Augmentin: Amoxicillin + Clavulanic Acid - PO
Unasyn: Ampicillin + Sulbactam - IV
In what patients would a combination of an abx + beta lactamase inhibitor be most useful?
Patients with > 1 infection that have shown resistance to the abx alone or patients with comorbidities in whom you don’t want to risk the abx failing.
What is the main difference between PCN and Extended Spectrum PCNs?
PCNs cover Gram pos while Extended Spectrum PCNs suck at Gram pos infections but cover Gram neg, including pseudomonas.
State two facts about the formulation of Extended Spectrum PCNs.
- Always combined with a beta lactamase inhibitor
2. Only available IV
List two combination Extended Spectrum PCN and state which is most commonly used.
Timentin: Ticarcillin + Clavulonate
Zosyn: Piperacillin + Tazobactam –> most used
Describe the interaction of PCNs with oral contraceptives.
Oral contraceptives are activated by bacteria in the gut. PCNs disrupt normal gut bacteria and make oral contraceptives less effective.
Describe the treatment for C. Diff brought on by PCN.
- Stop the antibiotic
- No anti-diarrheals - prolongs contact time with the toxin that is causing the C. Diff
- DOC = PO Vancomycin
How are cephalosporins related to PCNs and what is the clinical significance?
Cephalosporins, like PCNs, are beta lactams meaning there can be cross reactivity between the two.
List the drugs that are used to treat pseudomonas.
Extended Spectrum PCNs
Two cephalosporins - Ceftazidime and Cefepime
All Carbapenams EXCEPT Ertapenam
Ciprofloxacin (Only PO drug)
What PCN drugs are 1st generation cephalosporins most like and what do they cover?
Similar to amino-PCNs. They cover mostly gram pos. plus E. Coli and Klebsiella (Pneumonia)
List two 1st generation cephalosporins and state the use of each.
Cefazolin: IV admin to cover MSSA in PCN allergy
Cephalexin: PO cephalosporin
What do 2nd generation cephalosporins cover?
Hodge-podge of gram pos and neg.
What do third generation cephalosporins cover?
Gram negative
What type of drug is ceftriaxone and what are its uses?
3rd generation cephalosporin. Uses include:
- qd injection
- treatment of meningitis (double the dose)
- Lyme disease (late - when arthritic pain presents)
- treatment of gonorrhea (paired with chlamydia drug)
What are the two drugs administered to treat chlamydia and gonorrhea?
Azythromyocin and Ceftriaxone
What kind of drug is Ceftazidime and what is its primary use?
Third generation cephalosporin used to cover pseudomonas.
What type of drug is cefepime and what is its primary use?
Fourth generation cephalosporin used to cover pseudomonas.
What type of drug is ceftaroline and what is its primary use?
Fifth generation cephalosporin used to treat MRSA
T/F: Cephalosporins are made in combination with a beta lactamase inhibitor and are used frequently.
False: Cepahlosporins are coformulated with beta lactamase inhibitors but they are NOT used often.
