Medical School – Antibiotics: Fluoroquinolones

Medical School – Antibiotics: Fluoroquinolones


Hey this is Dr K from imedicalschool here
to talk about a class of antibiotics called fluoroquinolones. The fluoroquinolones that
are commenly used within the outpatient and inpatient setting include ofloxacin, ciprofloxacin,
levofloxacin, moxifloxacin and norfloxacin. The flurorquinolone groups of antibiotics
have an interesting property compared to other antibiotics as these are the only antibiotics
that directly inhibit bacterial DNA synthesis. How do the fluoruquinolones inhibit bacterial
DNA synthesis? Well these antibiotics work on the enzymes
DNA gyrase and topoisomerase four. These enzymes are involved in the winding and unwinding
of DNA. DNA gyrase and topoisomerase four aid the unwinding of DNA so it can be read
and replicated. With the inhibition of these enzymes, bacteria are unable to replicate
and more importantly are unable to produce proteins that they need for survival. As a
result the fluorquinolone class of antibiotics are bacteriacidal meaning they actually lead
to bacteria cell death. Now what organisms are targeted by fluoruquinolone
antibiotics? All the fluoruquinolones generally affect aerobic gram negative bacilli and gram
negative cocci. Examples of gram negative bacilli include enterobacteriaceia and haemophilus.
Examples of gram negative cocci include Neisseria and Moraxella. In addition fluoruquinolones
can also work against pseudomonas and staph aureus. Now the strength of each of the fluoruquinolones
on bacteria vary from each medication. For example norfloxacin, ciprofloxacin, and ofloxacin
have poor activity against streptococci and many anaerobes. Moxifloxacin has greater activity
against anaerobes. Both levofloxacin and moxifloxacn have good activity against gram positive cocci. In terms of treating Pseudomonas, ciprofloxacin
tends to have the best activity against pseudomonas . Moxifloxacin and levofloxacin tend to have
less anti-pseudomonal activity. Now ciprofloxacin is so frequently used that many areas of the
country have seen a significant surge of pseudomonas resistance to ciprofloxacin so it is important
to know what are the bacterial resistances that are present in your community. In terms fo respiratory infections all the
fluoruuquinolones are generally efffecive, however, both levofloxain and moxifloxacin
have better strep pneumoniae coverage than the other fluoruoquinolones. Now that we talked about the bacterial coverage
of the fluoroquinolones it is important to talk about how these drugs are absorbed and
cleared from the body. Fluorquinolones are absorbed well in the upper
gastrointestinal tract. One of their advantages is that they have a bioavailability that exceeds
50 percent and actually reaches 100 percent in some. Meaning for some fluoroquinolones
administering iV provides no greater bioavailability than administering it orally. Specifically
bioavalabiltiy for ciprofloxain is 70%,>95 percent for ofloxacin and levofloxacin with
greater than 85 percent bioavailability for moxifloxacin Though the fluoroquinolones are absorbed through
the GI tract they have different routes of elimination. Ofloxacin and levofloxacin are
renally eliminated. Moxifloxacin is eliminated predominately by the liver and ciprofloxacin
is excreted by both pathways It is important when administering any medication
that one understands the risks and adverse effects of the medication. In pregnant women
Fluoroquinolones have not been established as safe and more research needs to be done.
That being said quinolones should be avoided in children less than 18 ears old because
there have been reports of joint cartilage erosions in animal studies . The concerns
are these antibiotics can lead to detrimental outcomes on a child’s growth. What are the side effects associated with
fluoruoquibnolone use? Fluoruquinolones are associated with an increase
risk of developing c. diff colitis as these antibiotics clear the normal bowel flora. More recently Fluoroquinolones have been found
to cause a peripheral neuropathy. If this occurs they should be stopped and switched
to a different class of antibiotics. The neuropathy can last for months to years and occasionally
can be permanent. Fluoruquinolones have been associated with tendinopathy and tendon rupture.
Those highest at risk were greater than 60 years old, nonobese, female, and we’re using
glucocorticoids In addition to tendinopathy, Fluoroquinolones
cause QT interval prolongation due to inhibition of potassium channels. Moxifloxacin and ciprofolaxin
were associated with increase rates of cardiac arrythmias though ciprofloxacn was not associated
with an increase in cardiovascular mortality Patients who are elderly, female or have QT
prolongation at baseline are at the greatest risk. Rarely hepatotoxicity can occur due
to fluourquinolones and in some cases even lead to retinal detachment. Well that was a brief review of the fluoroquinlones,
I hope you enjoyed this video and if you did give this video a like. Make sure to put any
questions and comments down below, Share this video with your friends on twitter, google
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at imedicalschool. And most importantly subscribe. This is Dr K and I will see you next time.

17 Replies to “Medical School – Antibiotics: Fluoroquinolones”

  1. Fellow Med Students, 

    This video is phenomenal for a quick comprehensive review of fluoroquinolones. Unfortunately, the video does not generalize or emphasize any concepts or points and thus is practically useless for long term retention, and furthermore, for board studying. 

    also FYI (from wikipedia) Enterobacteraciae =  Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella, Proteus, Enterobacter, Serratia, and Citrobacter 

    http://en.wikipedia.org/wiki/Enterobacteriaceae

  2. I am a 3.5 year survivor of Fluoroquinolone toxicity. I was given Cipro, which cause me to go to the ER with heart palpitations, radiating pain in my legs, and now, I have lumps all over my legs. Then I was given Levaquin for 30 of 84 days prescribed. I was not able to walk for almost a year. I now have leukemia, hypothyroid, bursitis in hips, tendonitis in my rotator cuff, my super spinner and in several tendons in my legs, feet and hands. Was it worth the risk, to take a FQ? Absolutely NOT!! I believe the medical profession is minimizing the events of Adverse Drug Reactions, due to FQ's. And, I believe that a FQ should only be used in a life or death situation, when no other antibiotic will be effective. I hope many medical students will read this, and keep it in mind when considering a FQ for their patients. Do the benefits really out weigh the risk? I say unequivocally, NO 

  3. I am also a Fluoroquinolone victim of almost 2 years from on 9 of 10 Cipro pills.  I had 2 businesses, and haven't been able to run them in full capacity since Sept. 2013!  Thanks Bayer and J&J you did a wonderful job on damaging and even killing millions and millions … Countless of healthy of people of all ages all over the world with your worse than chemotheraputic so called antibiotics. Now you are allowing infants and children to be treated by their doctors with your FQ ear and eye drops that cause the same devestatiin to their little bodies as U.S. flixies live with and have to live with in their shorten life caused by your dangerous antibiotics! Thank you NOT!!!

  4. Dear future doctors, this class of AB's should be your very last line of defense for your patients, they are absolute poison!  My father received Levaquin as prophalactic before a prostate biopsy and now has had major tendonopathy all over his body; both rotator cuffs, ruptured achilles, knee tendons.  The same thing happened to his neighbor.  The FDA needs to re-evaluate the cost / benefit of this class of drugs.  Save yourself some legal headaches and do not prescribe, no matter how many golf vacations the drug rep promises you!

  5. FDA ALERT! Now there is yet another label change…black box to all FQs since May 12/16.

    Please be sure to let all medical doctors and pharmacies know. Thx

  6. I appreciate you talking about the ADRs of the fluoroquinolones–many videos don't. However, this is a little outdated as the FDA determined in 2016 that the risks of FQ's were not worth the benefits for simple infections and should only be used when other medical treatments have failed.

    This is due to these drugs causing systematic issues in patients who have an adverse reaction to them. There are now FIVE black box warnings related to these drugs, including permanent damage to the peripheral and central nervous systems.

  7. These drugs are toxic and should only be used as a last resort. Is what your video fails to emphasize is the lives that have been destroyed by these drugs.

  8. Gyrase inhbiting effect is based on chelating divalent magnesium cations. Just stupid that topoisomerase II of human mitochondrias work after same principle. So fluoroquinolones kill your mDNA what leads to devasting effects and chronical deseases, especially if you are short on cellular magnesium levels.

  9. Just dont take these types of "antibiotics" they were actually developed as cancer treatments and are chemotherapy drugs! They will ruin your life!!

  10. Yes that would be awesome if all these FQs did was destroy bacteria , but the problem is our own human DNA is attacked and some are destroyed or some are severely damaged which replicates thus the permanent disabling damage! How much DNA does one human body have yes sky is the limit for damage! The more FQs taken the worse it gets! Millions are suffering horrifically and many have died even after just one pill! This shit is poison! Research to find the truth because this video does not tell the whole story about FQs!

  11. i am victim of fluorochinolone me too, my doctor give me very easy and not told me nothing . now i use PQQ and help me a little

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