A pt has a sinus infx susceptible to both amoxicillin and ampicillin. Which agt would you choose and why?
Amoxicillin because it has better bioavailability, can be given with or without food, and has less frequent dosing (bid or tid vs. qid)
An MD wants to presribe Augmentin 500 mg TID for a pt with recurrent sinusitis. The pt can't swallow Augmentin 500 mg tablets. He writes for Augmentin 250 mg 2 tabs TID. Is this a good idea? Why?
No. The pt would receive more clavulanic acid than with the 500 mg tabs which could lead to diarrhea.
A pt has a severe PCN allergy. Can the patient receive aztreonam? A carbapenem?
Which FQs inhibit DNA gyrase? Topoisomerase IV? What is the advantage of inhibiting Topoisomerase IV?
3rd and 4th Generation
Less resistance to G- and enhanced G+ activity
Why shouldn't pediatric pts generally receive FQs? Which pediatric pts sometimes receive FQs?
cartilage malformations (note: this is not the same as the tendon problems in adults)
A pt develops a sternal wound infx following bypass surgery after an acute MI. He is placed on vancomycin. the pt is now complaining of severe itching on his face and neck. the nurse just hung the vanco bag on this pt about 10 min ago. He has been receiving vanco for about 7 days. What is the most plausible explanation for this event? How can you treat/prevent this reaction?
Red Man Syndrome
slow the rate of infusion, give diphenhydramine, give fluids, dilute, change antibiotics
What is the difference in indications for vanco PO and IV?
PO is for C. diff and IV is for G+ resistant infx (MRSA, MRSE)
Describe the ototoxicity and nephrotoxicity that can occur with AGs
Oto - cochlear and vestibular
may or may not be reversible
related to prolonged duration of therapy, concurrent ototoxic drugs
Nephro - acute tubular necrosis
prolonged trough, concurrent nephrotoxic agents
Which macrolide would you not use for bacteremia because of its extensive tissue penetration?
Why should you drink a full glass of water with tetracyclines and not take any doses at bedtime?
to prevent esophogeal ulcerations
Which of the following antibiotics can be used to treat CAP in a pt on antiarrhythmics? Moxifloxacin? Azithromycin? Doxycycline?
You have a pt on clindamycin that developed severe diarrhea and is C. difficile (+) by toxin assay. How would you manage the diarrhea? List antibiotics that can be used to treat AAD.
Stop the clindamycin. Give flagyl 1st line. Vanco is 2nd line.
List 3 unique side effects of metronidazole. what drug intx would you caution a pt about?
What are some general counseling points for pts being started on an antibiotic?
can cause diarrhea
if rash or diarrhea, call Dr
take until gone
how to take in regard to meals and other meds
when to expect sx improvement
What 4 categories of antibiotics are beta-lactams?
What is the MOA for all beta-lactams?
Inhibit bacterial cell wall synthesis - bind to PBPs (catalyze cell wall synth) and interfere with production of mucopeptide layer resulting in weak cell wall which becomes leaky then the bacterial cell expands and bursts
Which type of hypersensitivity to antibiotics is IgE mediated? Which is not?
Immediate is IgE mediated (type I)
Late is not (type II, III, IV)
What pregnancy category are beta-lactams?
What is the main cephalosporin used?
Ceftriaxone (Rocephin) - 3rd Generation
Which generations of cephalosporins penetrate CSF? What is the purpose of this?
2nd and 3rd
to treat meningitis
Side Effects of cephalosporins
Hematologic effects (incr INR)
Bilirubin encephalopathy (ceftriaxone - can displace bilirubin - avoid in neonates)
Increased mortality with cefepine vs. other beta-lactam antibiotics
Which ceph should not be administered with calcium-containing IV fluids in neonates? Why?
ceftriaxone because of increased risk of precipitation
Which antibiotic is a monobactam?
What route of administration are all carbapenems?
What is the role of cilastatin in Primaxin (imipenem/cilastatin)?
It has no antibacterial activity. It inhibits the DHP-I enzyme in renal tubular cells that inactivates imipenem by hydrolyzing the beta-lactam ring. Cilastatin's role is to prevent renal tubular damage from imipenem and to increase its urinary recovery.
SEs of carbapenems
HA, confusion, seizures (highest risk with imipenem)
Nephrotoxicity (imipenem >/= meropenem)
All preg Cat B except imipenem which is Cat C
DIs with carbapenems
Valproic acid - its levels are reduced by meropenem