Antibiotics - Aminoglycosides: Nursing pharmacology

Definitions & Key takeaways

Aminoglycosides refer to a class of antibiotics that work by binding to the 30S subunit of the bacterial ribosome, thus inhibiting bacterial protein synthesis, and then death. Aminoglycosides are used to treat a variety of infections, including respiratory, urinary tract, gastrointestinal infections, meningitis, and sepsis. However, they can cause serious side effects, including ototoxicity (damage to the inner ear) and nephrotoxicity (damage to the kidneys).

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Introduction0:00–1:13

Aminoglycosides are a class of antibiotics used to treat severe systemic infections caused by aerobic gram-negative bacteria, such as Escherichia coli, Klebsiela pneumonia, Pseudomonas aeruginosa, and the Enterobacter species.
Additionally, aminoglycosides can be effective against certain Gram-positive bacteria when used in combination with cell wall inhibitors like penicillins or cephalosporins.
Now, aminoglycoside antibiotics used to treat bacterial infections include streptomycin, amicain, gentamicin, Tobramycin, and neomycin.
These medications are poorly absorbed in the gastrointestinal tract, so they are primarily administered intramuscularly or intravenously.
Streptomycin and amicain can be used in the treatment of mycobacterial infections. Gentamicin can also be applied topically to treat eye or ear infections, while Tobramycin can be given topically to treat eye infections, or in a nebulized form to treat pseudomonas infections in clients with cystic fibrosis.
Neomycin can be given orally to treat hepatic encephalopathy, and before colorectal surgeries to act directly in the intestinal bacterial flora and reduce the risk of infection after surgery.

Mechanism of action1:13–1:45

Aminoglycosides are powerful bactericidal antibiotics that work by binding to the 30S subunit of the bacterial ribosome.
As a result, these medications disrupt bacterial protein synthesis and ultimately kill the bacteria. Since aminoglycosides need to enter the bacteria in order to be effective, they may be given alongside an antibiotic that inhibits bacterial cell wall synthesis, such as beta lactams, to facilitate access of the aminoglycoside across the cell wall.

Side effects1:45–3:00

Regarding side effects, one thing to keep in mind is that aminoglycosides have a significant post-antibiotic effect, meaning that their bactericidal activity persists for a period of time even after the antibiotic is stopped.
In addition, although aminoglycosides are very effective antibiotics, they also have a high risk of toxicity, which limits their usefulness.
Amino glycosides come with a boxed warning for a serious risk of neurotoxicity, possibly leading to hearing loss, vertigo, ataxia, and loss of balance, as well as nephrotoxicity, which may progress to kidney failure.
Clients may also present with a skin rash, urticaria, photosensitivity, and alopecia. Often, clients can also experience gastrointestinal side effects, such as anorexia, nausea, vomiting, and diarrhea.
Aminoglycosides can also result in bone marrow suppression, which can put clients at higher risk for infections. Finally, amino glycosides inhibit the release of acetylcholine from the motor neurons at the neuromuscular junction, so they may cause weakness and paralysis.
This effect is more common if aminoglycosides are given to clients who are also receiving anesthetics, or neuromuscular blocking agents such as succinylcholine.

Contraindications3:00–3:45

As far as contraindications go, aminoglycosides shouldn't be used in clients with renal or hepatic disease, pre-existing hearing loss, and active infections that could be worsened by the effect of these antibiotics on normal defense mechanisms.
Some aminoglycosides also have a boxed warning against their use in clients with myasthenia gravis or Parkinsonism, which could be exacerbated by a prolonged neuromuscular blockade.
Additionally, they have a box warning against their use during pregnancy, and they should be used with caution during breastfeeding and in neonates.
Finally, these medications should be used cautiously in elderly clients, as well as in those receiving loop diuretics or other neurotoxic or nephrotoxic medications, because the combination increases the risk of toxicity.

Nursing Considerations & Client Education3:45–6:20

Alright, when caring for a client with an infection, before administering an aminoglycoside like gentamicin, be sure to review their history for hearing difficulties or problems with balance.
Next, perform a baseline assessment, including weight, vital signs, and hydration status. And review their medication list in order to ensure that they are not receiving any medications that could increase the risk of neurotoxicity and nephrotoxicity.
Then review their laboratory test results, especially CBC, renal and liver function tests, as well as culture and sensitivity results and urinalysis.
If your female client is of childbearing age, remember to obtain a negative pregnancy test. Lastly, ensure the prescribed dosing is correct by calculating the dose in milligrams or kilograms per day.
Next, explain to your client how the medication will help resolve their infection, and that you'll be administering the medication intravenously once each day.
Let them know about the important side effects, such as damage to their hearing and kidney function, and reassure them you will be checking the medication levels closely to decrease the risk of these effects.
OK, before administering gentamicin to your client, ensure they are adequately hydrated by administering fluids orally or intravenously as ordered.
Then, infuse the gentamicin over 30 minutes to 1 hour. While your client is receiving the medication, monitor their vital signs and assess for neurotoxicity by instructing them to let you know if they experience ringing or buzzing in their ears, as well as dizziness, vertigo, or headache.
Also, monitor them for nephrotoxicity by keeping a close eye on their fluid intake and output, as well as their renal function tests, and evaluating their urinalysis for the presence of protein, casts, or red blood cells, as well as specific gravity.
Be sure to draw a trough level 1 hour before the next daily dose. Hold the dose if the trough level is more than 2 mcg per milliliter per protocol.
Lastly, be sure to perform regular assessments to look for signs of opportunistic infections, such as fever or stomatitis.
And if your client develops bloody diarrhea during therapy, send a specimen to the lab for clostridioides and notify the healthcare provider.
Finally, while caring for a client receiving an aminoglycoside like gentamicin, be sure to monitor their medication trough levels closely, per protocol.
In addition, watch for the development of side effects and evaluate your client for the therapeutic response to the medication, such as absence of fever and resolution of their infection.

Review6:20–7:01

All right, as a quick recap, aminoglycosides are a class of antibiotics used to treat severe infections. These medications work by binding to the 30S subunit of the bacterial ribosome, disrupting bacterial protein synthesis, and ultimately resulting in the bacterial cell death.
These medications have a high risk of neurotoxicity, nephrotoxicity, and neuromuscular blockade. When caring for a client taking an aminoglycoside, nursing considerations include performing a baseline assessment, monitoring for signs of toxicity, and evaluating for the therapeutic response.
Client teaching is focused on what to expect during treatment and learning to recognize signs and symptoms that should be reported.
Antibiotics - Aminoglycosides: Nursing Pharmacology: Video | Osmosis