Aminoglycosides Pharmacology Nursing Antibiotics: Mechanism of Action, Mnemonic, Anti-Infectives
Summary
TLDRThis video covers aminoglycosides, a group of antibiotics primarily targeting gram-negative bacteria. They have a bactericidal effect, making them effective for infections like septicemia, UTIs, and pneumonia. Aminoglycosides inhibit protein synthesis by binding to the 30S ribosomal subunit. They're often used with other antibiotics, like penicillin, for a synergistic effect. The video discusses key drugs in this class, how they're administered, and the importance of monitoring for nephrotoxicity, ototoxicity, and neuromuscular issues, emphasizing the need for careful patient monitoring to avoid adverse effects.
Takeaways
- 💊 Aminoglycosides are antibiotics primarily targeting gram-negative bacteria, with bactericidal effects that kill the bacteria rather than just inhibiting its growth.
- 🦠 These antibiotics are effective against bacteria like E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens, but have limited effectiveness against gram-positive bacteria.
- 🧬 Aminoglycosides work by inhibiting protein synthesis in bacterial cells by targeting the 30S ribosomal subunit, leading to faulty protein production and bacterial death.
- 💉 Aminoglycosides are usually administered via the IM or IV route, as they are poorly absorbed through the gut, though certain exceptions exist (e.g., neomycin for gut infections).
- 🧪 Peak and trough levels should be closely monitored due to the narrow therapeutic index, ensuring the drug is effective while avoiding toxicity.
- 🚨 Nephrotoxicity (kidney damage) and ototoxicity (hearing damage) are major risks of aminoglycosides, requiring careful monitoring of renal function and hearing.
- 🔬 In some cases, aminoglycosides are combined with other antibiotics like penicillin for a synergistic effect, improving their ability to penetrate bacterial cells.
- 👂 Ototoxicity, or damage to the ears, is usually irreversible and may present as tinnitus, hearing loss, or dizziness, particularly in patients also taking loop diuretics.
- 🫁 Neuromuscular blockade, leading to muscle weakness or respiratory failure, is another rare but serious side effect, especially in patients with neuromuscular conditions.
- 🧴 The mnemonic 'GNATS' helps remember the main aminoglycosides: Gentamicin, Neomycin, Amikacin, Tobramycin, and Streptomycin.
Q & A
What types of bacteria do aminoglycosides primarily target?
-Aminoglycosides primarily target gram-negative microorganisms such as E. coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Serratia marcescens, and Enterobacter. They are less effective against gram-positive bacteria but can target some, like Staphylococcus aureus.
How do aminoglycosides kill bacteria?
-Aminoglycosides work by inhibiting protein synthesis in bacteria. They bind to the 30S subunit of the bacterial ribosome, disrupting the genetic code's reading, leading to the production of faulty proteins, which ultimately causes bacterial death.
Why are aminoglycosides often used in combination with other antibiotics?
-Aminoglycosides are used with other antibiotics, like Penicillin, for a synergistic effect. Penicillin helps aminoglycosides penetrate bacterial cell walls more effectively, enhancing their ability to kill bacteria.
What is the mnemonic to remember common aminoglycoside medications?
-The mnemonic to remember aminoglycosides is 'GNATS': G for Gentamicin, N for Neomycin, A for Amikacin, T for Tobramycin, and S for Streptomycin.
How are aminoglycosides typically administered?
-Aminoglycosides are usually administered via intramuscular (IM) or intravenous (IV) routes because they are not well-absorbed through the gut. Exceptions include Tobramycin for inhalation in cystic fibrosis patients and Neomycin for oral use in specific conditions like hepatic encephalopathy.
What conditions can aminoglycosides effectively treat?
-Aminoglycosides are used to treat septicemia, severe urinary tract infections, infections of the eyes, ears, bones, abdomen, pelvis, endocarditis, and hospital-acquired pneumonia. They can also target mycobacterial infections such as tuberculosis.
Why is monitoring peak and trough levels important when administering aminoglycosides?
-Monitoring peak and trough levels ensures the medication is at a therapeutic level to effectively treat the infection while avoiding toxicity. Peak levels are monitored for effectiveness, and trough levels are monitored to prevent toxic accumulation in the body.
What are the major toxic effects of aminoglycosides?
-Aminoglycosides can cause nephrotoxicity (kidney damage) and ototoxicity (hearing damage). Nephrotoxicity is often reversible, but ototoxicity, affecting hearing and balance, is usually permanent.
How can aminoglycosides lead to neuromuscular blockade?
-Aminoglycosides can cause neuromuscular blockade, leading to muscle weakness and respiratory failure, especially in patients with neuromuscular disorders or those who have received neuromuscular blocking medications during anesthesia.
What signs should nurses monitor to ensure aminoglycosides are effectively treating an infection?
-Nurses should monitor for signs like the resolution of fever, normal blood pressure and heart rate, and normal white blood cell count (5,000-10,000 cells/mcL). These indicators suggest that the infection is being effectively treated.
Outlines
💉 Overview of Aminoglycosides and Their Bactericidal Effect
Aminoglycosides are a class of antibiotics that target gram-negative bacteria by killing them rather than merely inhibiting growth (bactericidal effect). They are highly effective against organisms like E. coli, Klebsiella, Pseudomonas, and more. Though mainly effective on gram-negative bacteria, they can also target some gram-positive bacteria and mycobacteria. Aminoglycosides are often used in combination with other antibiotics like penicillin to enhance their effect (synergistic effect). A mnemonic 'GNATS' (Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin) helps remember the common drugs in this group.
🔬 Mechanism of Action: Targeting the Ribosome
Aminoglycosides kill bacteria by inhibiting protein synthesis, a vital process for bacterial survival. They specifically bind to the 30S subunit of the ribosome, disrupting the reading of genetic code, leading to the production of faulty proteins. This interference with protein production results in the death of the bacteria. The ribosome consists of two subunits, 50S and 30S, and aminoglycosides particularly affect the 'A' site of the 30S subunit, preventing proper protein assembly.
🏥 Nursing Role: Monitoring and Toxicity Management
When administering aminoglycosides, nurses should ensure that patients are not allergic, check cultures, and monitor peak and trough levels to avoid toxicity. Peak levels should be measured 1 hour after IM administration or 30 minutes after IV infusion. Trough levels are measured just before the next dose. Nurses should assess whether the treatment is effective (e.g., reduced fever, normal blood pressure, and white blood cell count). It's crucial to monitor for nephrotoxicity (kidney damage) by checking urine output and renal function labs and for ototoxicity (ear damage), especially when patients take other ototoxic drugs like loop diuretics.
👂 Ototoxicity, Nephrotoxicity, and Neuromuscular Risks
Aminoglycosides can cause two primary toxic effects: nephrotoxicity (kidney damage) and ototoxicity (hearing loss or balance issues). Nephrotoxicity may be reversible, so nurses should monitor urine output and renal function tests like BUN and creatinine. Ototoxicity, affecting the cochlear and vestibular systems, is often irreversible, with symptoms like ringing in the ears or dizziness. Patients at higher risk include those taking ototoxic drugs. Additionally, aminoglycosides may cause neuromuscular blockade, especially in patients with preexisting neuromuscular conditions, leading to muscle weakness and respiratory failure.
Mindmap
Keywords
💡Aminoglycosides
💡Gram-negative bacteria
💡Synergistic effect
💡Bactericidal
💡Ribosome
💡Nephrotoxicity
💡Ototoxicity
💡Peak and trough levels
💡Protein synthesis
💡Mycobacterium tuberculosis
Highlights
Aminoglycosides are a group of antibiotics primarily targeting gram-negative bacteria.
These antibiotics are bactericidal, meaning they kill bacteria rather than just inhibiting their growth.
Aminoglycosides target bacteria like E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, and Enterobacter.
They are used to treat severe infections like septicemia, urinary tract infections, and hospital-acquired pneumonia.
Aminoglycosides are often combined with other antibiotics like Penicillin for a synergistic effect.
The mnemonic 'GNATS' helps to remember aminoglycosides: Gentamicin, Neomycin, Amikacin, Tobramycin, and Streptomycin.
These antibiotics work by inhibiting protein synthesis within bacterial cells, specifically targeting the 30S ribosomal subunit.
They bind to the A-site of the 30S subunit, causing the bacteria to produce faulty proteins, leading to bacterial death.
Aminoglycosides are typically administered via injection (IM or IV) as they are poorly absorbed through the gut.
Special cases like cystic fibrosis can involve inhalation administration of Tobramycin or oral use of Neomycin for gut bacteria.
The peak and trough levels of aminoglycosides must be closely monitored to avoid toxicity, given their narrow therapeutic index.
Nephrotoxicity (kidney damage) and ototoxicity (hearing damage) are two major risks associated with aminoglycosides.
Nephrotoxicity can potentially be reversed, but ototoxicity is often irreversible.
Patients at higher risk of ototoxicity may be taking other medications like Loop Diuretics or have pre-existing conditions.
In rare cases, aminoglycosides can cause neuromuscular blockade, leading to muscle weakness and respiratory failure.
Transcripts
hey everyone it's Sarah with registered
nurse rn.com and in this video I'm going
to be covering Amino glycosides so let's
get started aminoglycosides are a
particular group of antibiotics that
Target mainly gram-negative
microorganisms therefore they're really
gram-negative Killers because they have
this bacterial subtle effect on the
bacteria where they go in and just kill
it rather than just inhibiting its
growth which would be known as having a
bacteriostatic effect now as I cover the
different types of antibiotics in this
series you're going to see that some
antibiotics are really good at killing
bacteria whereas other types just really
inhibit their growth so what
gram-negative bacteria do
aminoglycosides Target well they target
E coli klebsiella pneumonia a
pseudomonas ergonosa serratia marcessins
and interobacter now they're not really
helpful with targeting grandpas and
microorganisms but they can kill a few
such as staphylococcus aureus and then
enterococcus furthermore aminoglycosides
can Target mycobacteria infections such
as mycobacterium tuberculosis so because
of all these microorganisms that
aminoglycosides can Target they're
really good at treating certain cases of
septicemia where we have infection in
the blood severe cases of urinary tract
infection and then infections that
affect certain parts of the body such as
the eyes the ears the bone the abdomen
the pelvic areas and they can treat
cases of endocarditis where you have
infection in the heart specifically on
those heart valves and then severe cases
of pneumonia that are usually acquired
from the hospital setting because those
strains tend to be very severe now in
practice you may see that
aminoglycosides are used in combination
with other types of antibiotics and the
reason for this is because whenever you
throw an aminoglycoside on let's say
with Penicillin it all of a sudden has a
synergistic effect which means it allows
that aminoglycoside to work in ways
where it normally wouldn't be able to
work if it wasn't on board with this
other type of medication so let's say we
have Penicillin and aminoglycoside on
well aminoglycoside without penicillin
normally wouldn't be able to get inside
that cell wall and kill it but because
we have Penicillin on board we have the
synergistic effect and aminoglycoside is
able to get in and Target that bacteria
so how do we remember the medications
that are included with the
aminoglycosides well let's remember the
word Nats g-n-a-t-s so the GN part is
going to help you remember that
aminoglycosides mainly Target
gram-negative
microorganisms so the G is for
Gentamicin n is for neomycin
A is for Emma Cason T is for Tobramycin
and then the last one s is for
streptomycin now as you can see these
medications in in mycin whether
m-i-c-i-n or m-y-c-i-n but don't let
that tip you off that it's an
aminoglycoside because some other groups
of antibiotics such as the microlides
they end in nycin some of them do like
erythromycin so that might throw you off
and get you a little confused so just
try to remember the names with this
mnemonic and just know that
unfortunately it doesn't follow that
rule that sometimes we can use with
those names now how are aminoglycosides
administered well this particular group
of medications doesn't like to be
absorbed through the gut so we don't
like to give them orally but rather we
like to give them via the parental route
so the im or IV route now there are some
exceptions to this depending on what's
going on with the patient for instance
to cobramycin can be given via
inhalation to patients who have cystic
fibrosis and they have a lung infection
or we can give neomycin via the oral
route if we're trying to Target certain
bacteria in the gut for instance if the
patient has hepatic encephalopathy we
can give them neomycin to help bring
down that ammonia level or let's say the
patient's having bowel surgery we can
give them this to help prep that bowel
before they actually have surgery so now
let's talk about how aminoglycosides
work and how they actually kill that
bacteria well depending on the
antibiotic group you're talking about
they will Target certain parts of that
bacterial cell some will inhibit the
cell wall synthesis of that bacteria
While others will inhibit nucleic acid
synthesis and then some will inhibit
protein synthesis within that bacterial
cell and that is what aminoglycosides do
they inhibit protein synthesis inside
that bacterial cell so we don't get the
creation of proteins now now proteins
are really important for that bacterial
survival it's really the backbone of its
ability to thrive and survive so if we
can stop that process of that bacteria
that's inhabited our body we can kill it
and get rid of it and that's what
aminoglycosides do so what makes the
proteins in that bacteria cell it is the
ribosome so remember ribosome it's it's
what we're targeting so the ribosome is
a really cool structure it is made up of
two subunits you have a large subunit
known as 50s and then you have a smaller
one known as 30s and these two subunits
work together to their whole goal is to
stack amino acids together and make a
beautiful polypeptide chain hence our
protein
so aminoglycosides say I need to stop
this process so I'm going to affect one
of these subunits so we can't have this
happen making these polypeptide chains
so what it does is aminoglycosides binds
to the 30s on the ribosome so it binds
to the subunit particularly it's a site
so remember aminoglycoside starts with a
it targets the a site of 30s and
whenever it does this it causes its
genetic code to not be read properly so
we don't have good instructions
happening here so we're not going to
really make great healthy proteins
instead we're going to make junky
proteins and junkie proteins lead to the
death of that bacteria can't function if
it doesn't have healthy ones so there we
get that bacterial subtle effect and
that is how in the end they kill the
bacteria now let's talk about our role
as the nurse whenever we're
administering aminoglycosides so before
administer during these medications you
want to confirm that your patient is not
allergic to them and that you've
obtained any necessary cultures that
have been ordered by The Physician and
that you are monitoring the peak and
trough levels why your patient is taking
this group of antibiotics and the reason
for this is because these medications
are very powerful so we want to make
sure our patient's not becoming too
toxic on them because it has a very
narrow therapeutic index but we want to
make sure that the medications being
effective and that they have enough of
the medication in their system to really
Target that bacteria and kill it so
first let's talk about Peak so the peak
is the highest concentration of the
medication in the blood so remember this
medication can be given I am or IV so if
your patient's getting an IM you would
want to do a blood draw for the peak one
hour after the injection but let's say
your patient is getting it IV it's
typically a 30 minute infusion so you
would want to do a blood draw about 30
minutes after the infusion has been
completed and then the trough is the
lowest concentration of the medication
in the patient's system and we're really
interested in this level because it
helps us monitor for toxicity so if your
patient's getting an IM or IV you would
just collect it you do a blood draw
right before the next dose and then
another thing you want to be monitoring
for is that this medication is working
like it should so is the medication
treating this infection what are some
signs that tells you it's doing that
well the patient doesn't have a fever
anymore those fevers are dropping or
they just don't have one anymore they're
normal
they don't show signs and symptoms of
sepsis so their blood pressure is within
normal range it's not hypotensive and
their heart rates within normal range is
not tachycardic and their white blood
count is in normal range like five
thousand to ten thousand anything
greater than that tells us oh the white
blood cells are on board we've got a
massive infection because that's what
white blood cells do they target
bacteria so if they're elevated that's
not a good thing now let's talk about
the toxic effects that aminoglycosides
can have in your patient that you want
to monitor for so two terms I want you
to remember nephrotoxic and ototoxic so
in an O So in aminoglycosides remember
the n and the O for nephrotoxic and
ototoxic so nephro toxic in medical
terminology remember nephro meant
kidneys so we're talking about the
kidneys the kidneys can really be
affected and if they're affected it
could be reversed so we can reverse the
nephrotoxicity and what happens what
increases the patient's risk of having
this is that they've been using
aminoglycosides for too long or they're
on a really high dose so as a nurse when
you want to be looking out for is you
want to be looking at the patient's
urinary output make sure that they're
putting out a normal amount of urine so
typically that's 30 ml per hour for an
adult and you want to be looking at
those labs that tells you about the
renal function these will be ordered so
you want to look those over like for
instance the bun you want to make sure
that's within normal limits like 5 to
20. and they're creating level anywhere
between 0.6 to 1.2 milligrams per
deciliter it varies depending on male
and female and then you want to look at
their GFR that is a glomerular
filtration rate and this is the rate
that our glomerulus filters waste ions
and water so anything less than 90 ml
per minute is concerning so we want to
make sure that it doesn't get there now
the next type of toxic your patient can
experience is ototoxicity and Odo
remember means ears and we're
specifically talking about those hearing
structures in the ear now if your
patient experiences this unfortunately
it's not likely going to be reversed
like over here with the kidneys and what
increases your patient's risk of
developing this is if they're taking
other medications that can really cause
this to happen for instance if they're
taking Loop Diuretics like furosemide it
increases the risk of them developing
hearing problems so because this
medication can damage the vestibular and
cochlear parts of the ears you want to
tell your patient to Monitor and to
report any type of ringing in the ear
hearing loss or feeling dizzy because
this could be a sign that this
medication is messing with the ears and
then lastly this medication can cause a
neuromuscular blockade so this can be
experienced through muscle weakness and
respiratory failure and it tends to
happen in patients who've received
neuromuscular blocking medications like
during anesthesia or who have
neuromuscular disorders like myasthenia
gravis so in these patients you want to
make sure that you're on high alert for
these potential problems like muscle
weakness and respiratory failure that
could develop while taking this
medication okay so that wraps up this
review over aminoglycosides and if you'd
like to watch more review lectures over
antibiotics in this series you can
access the link in the YouTube
description below
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