Lesson on the antibiotic Metronidazole (Flagyl). Metronidazole is a small sized antibiotic, which allows it to be easily absorbed and diffusely distributed throughout the body. This makes it particularly important in bone and brain infections. Metronidazole has important activity against obligate anaerobes and some protozoal species, but has limited effects on aerobes. Metronidazole’s mechanism of action (which is described in the video) allows it to be an effective bacteriocidal antibiotic. Metronidazole has a wide variety of adverse effects, including GI side effects and specific side effects when alcohol is consumed when taking it.
Hey ron this lesson is on the antibiotic metronidazole metronidazole is also known as flagyl flagyl is its trade name and here is a image of metronidazole it’s a small molecule with a low molecular weight and that will become important we talk about its mechanism of action and distribution because it is a low mutlar weight molecule it has a rapid and effective
Absorption and it can be absorbed equally well with oral and iv administrations and it penetrates all tissues well because of its small size it can penetrate bone well and also penetrate in the blood into the brain through the blood-brain barrier so what are some of the bacterial targets for metronidazole the key targets for metronidazole are the obligate anaerobes
These include clostridium difficile cluster difficile is one of the biggest targets for metronidazole use other targets include cost radium perfringens that is involved in gas gangrene it’s also involved in treating bacteroides infections you can also have some activity against facultative anaerobes such as helical bachelor pleura in gardnerella vaginalis and
Some other targets for metronidazole include protozoa which include entamoeba histolytica giardia lamblia and trichomonas vaginalis so these are important targets for metronidazole as well and the key thing i want you to take from this slide is that metronidazole is not effective against a robes it’s only used for anaerobes and some protozoa and particularly
The obligate anaerobes so again the biggest target i want a member is clostridium difficile for metronidazole but it’s also good for other obligate anaerobes and some protozoa so the infections that metronidazole can be used to treat include anaerobic infections pseudomembranous colitis which is caused by classroom difícil bacterial vaginosis some sti is like
Trichomoniasis so which is due to the protozoa trichomonas vaginalis and also intra-abdominal abscess –is but a big one is brain abscesses because of its ability to cross the blood-brain barrier so metronidazole is good for cost ribbing difícil it’s good for some st eyes and it’s also good for abscesses so how does metronidazole work what is its mechanism of
Action metronidazole is a bacteria seidel antibiotic it is bacterial sidle through its ability to damage microbial dna and its ability to inhibit nucleic acid synthesis and it does these things through its ability to induce the formation of reactive oxygen species or raus so when metronidazole comes into contact with a bacteria it can easily diffuse through the
Bacterial cell membrane due to its small size and it can actually diffuse into both a robes and anaerobes but it only has effects on killing anaerobes so in an anaerobic bacteria they use the pyruvate ferredoxin oxido reductase system to basically process pyruvate into atp so what happens is ferredoxin can become reduced through this reaction but when metronidazole
Is around metro 9 is all through its nitro group here can actually take a few of these electrons so becomes an electron sink so the nitro group on metronidazole is an electron sink it takes electrons from ferredoxin essentially oxidizing ferredoxin to become itself a nitro radical anion this nitro radical anion can then become a reactive oxygen species which can then
Lead to dna damage and fragmentation destroying the anaerobe so this is essentially a simplified mechanism of action of metronidazole and this is how it occurs again through its nitro group on the metronidazole acting as an electron sink it picks up electrons from ferredoxin becoming an anion leading to reactive oxygen species production and dna damage and eventual
Cell death so what are some of the adverse reactions of metronidazole use some of the big ones are gastrointestinal side effects these include nausea vomiting anorexia diarrhea abdominal pain and constipation and taking a pee oh a patient may complain of a metallic taste so it’s a unpleasant metallic taste some of the other adverse reactions include nervous system
Side effects which include seizures dizziness peripheral neuropathy vertigo a taxi and confusion there are some allergic reactions include including your dock area and rash can occur with its use there are genitourinary effects including a transient deep red brown color urine so this is this is just a temporary thing and it doesn’t really have a disconcerting or a
Particular irritating effect and the big one that i want you to take from this slide is ethanol consumption if you take metronidazole or you prescribe it to your patient make sure that they don’t consume ethanol when using metronidazole that’s the big one when someone takes metronidazole and consumes ethanol they can have a sulphur ‘m like reaction this means that
They can have symptoms of flushing tachycardia palpitations and severe nausea and vomiting so again when a patient’s taking night metronidazole make sure that they don’t drink alcohol with metronidazole that was a quick lesson on metronidazole hope you found this lesson how if you did please i can subscribe for more lessons like this one also please check out my
Other antibiotic lessons in my infectious disease playlist thank you so much for watching and i hope to see you next time
Transcribed from video
Metronidazole | Bacterial Targets, Mechanism of Action, Adverse Effects By JJ Medicine
