Fluroquinoloness FQ (Anti-Biotics) Flashcards
Name the 4 drugs of this class and their generations.
Ciprofloxacin (2nd gen), Norfloxacin (2nd gen), Levofloxacin (3rd gen), Moxifloxacin (4th gen).
Are they bacteriocidal or static? Are the dose/time dependent or concentration dependent?
They are bacteriocidal and dose/time dependent.
What’s special about Norfloxacin in terms of absorption as opposed to the other FQ’s?
Other FQ’s have good absorption, Norfloxacin does not.
What can decrease the absorption of FQ’s?
It is impaired or decreased by food or drugs with divalent cations.
How are FQ’s excreted? What is the exception?
They are renally excreted and thus require dose adjustments for the renally impaired. However, Moxifloxacin has partial hepatic metabolism and excretion.
What’s special about the elimination of Moxifloxacin?
There doesn’t need to be dose adjustments for renally impaired but dose adjustments needed for hepatically impaired.
What’s interesting about the 1st gen of FQ’s?
It only has one drug, Nalidixic acid, which would work for Gram neg bacteria only for the Tx of UTI’s. This isn’t used much.
When would you use the 2nd gen FQ’s?
It’s good vs gram neg, esp cipro. Also good against MRSA, aerobic, enterobactericeae, pseudomonas, atypicals, and also TB. Not good vs strep or enterococci.
When would you use 3rd gen FQ’s?
What you would use for 2nd gen, but in addition Strep (including pneumo, MSSA), E. Faecalis. Although it has activity against gram neg including pseudomonas, its less than Cipro. Also hits atypicals (like cipro) and mycobacterium spp (cipro only hits TB)
When would you use 4th gen FQ’s?
It has good activity vs strep, including pneumo and MSSA like the 3rd gen, and for gram neg it has good activity against respiratory pathogens and enterobactericeae, POOR ACTIVITY vs pseudomonas. Also atypicals.
Which FQ should we go to if we are treating gram neg?
Cipro, 2nd gen.
What are the “Respirators FQ”?
This is the name given to the 3rd and 4th gen FQ’s, meaning very good vs strep pneumo, Haemophilis and Morsella, all of which causes respiratory infections.
What is the MOA of FQ’s?
It inhibits DNA Gyrase and Topoisomerase IV during bacterial cell growth and reproduction, makes a FQ-enzyme-DNA tertiary complex that blocks the resealing step, promotes DNA breaking and cell death.
What is the function of topoisomerase?
Releive torsonal strain during DNA replication.
What is the function of DNA gyrase?
Relaxing the positive supercoiling of the DNA.
What does blocking topoisomerase IV specifically induce?
Prevention of seperation of replicated chromosomal DNA into daughter cells.
What organisms are FQ’s losing effictivity against due to increased resistance?
Pseudomonas (Cipro used to be great against it), Staph, C. Jejuni, Salmonella, Gonorrhea, S. pneumo and enterococci.
If you have a resp infection, use…?
Levo, Moxi or Gemifloxacin, this treats strep pneumo and other resp pathogens.
If you have a UTI, use…?
Cipro, norflox, or Levo/
What causes Prostatis and what FQ’s treat it?
P. Aeruginosa, Enterobactericeae, and Enterocicc. Tx with Cipro or Levo.
What causes Traveller’s diarrhea and what to use to Tx it?
Salmonella, Shigella, Campylobacter, enterotoxigenic E. Coli, and treat with Cipro or Levo, just like prostattis.
What FQ’s to use for E. Coli 0157:H7 strand and what’s special about this strand?
This strand can cause HUS (Hemolytic-Uremic Syndrome by a shiga like toxin), and you CANNOT use FQ’s for this.
What FQ’s to use for STDs?
None, FQ’s are generally ineffective against STD’s (like Gonorrhea to T. Pallidum) or we have other drugs that tx STDs better (C. trachomatus tx with doxy or azithro, etc).
For Bone/Joint infections we can use…?
Cipro.
What is one of the few times that FQ’s can be use as prophylaxis in kids?
Px for anthrax.
Multidrug resistant TB we can use?
FQ’s seem to have activity against multidrug-resistant TB.
GI AE”s of FQ?
Nausea, vomitting, diarrhea.
HS rxns of FQ?
Almost as bad as sulfas, can also cause photosensitivity.
CV problems with FQ’s?
QT prolongation like the macrolides
CNS AE’s of FQ’s?
Minor stuff like headaches or dizziness, major stuff like seizures esp if taking other meds that make seizure more prone.
What AE do we specially have to look out for in old patients, patients getting organ transplants or corticosteroids?
Tendon ruptures.
What metabolic AE’s to look out for in FQ’s?
Glucose maintenance issues like hyper or hypo glycemia, potentially fatal.
Myasthenia gravis and FQ’s? Secondary infections?
FQ’s can exacerbate MG and can cause resp failure as a result, can cause secondary infections of C. Diff and Candida.
CYP interactions of FQ’s?
Cipro and Norflox are strong inhibitors of 1A2, Norflox in addition also inhibits 3A4.
Theophyline + Cipro?
Seizures. Cipro on its own can cause seizures, and in addition theophyline is metabolized by 1A2, which Cipro inhibits; seizure is a major tox of theophyline.
What CV DDI are we concerned with for FQ’s?
Anything that prolongs QT intervals like macrolides, TCAs, anti arrythmics and anti psychotics, among others.
Patients taking glucocorticoids should not take FQ’s because of increased risk of?
Tendon ruptures. Also, older patients are more prone to this AE, as well as those receiving organ transplants (who are probably taking GC’s anyway).
Divalent cations and ant-acids shouldnt be taken with FQ’s because?
It would decrease FQ absorption.
