chapter 87, aminoglycosides: exam 5
what are other, less severe adverse effects?
-blood dyscrasias this can be fatal.
what are the most common aminoglycosides in order?
-gentamicin -tobramycin -amikacin
what are the adverse effects of gentamicin (garamycin)
-nephrotoxicity -ototoxicity
what are the adverse effects of aminoglycosides?
-nephrotoxicity -ototoxicity -hypersensitivity reactions -neuromuscular blockade
what are examples of aerobic gram-negative bacilli?
-pseudomonas aeruginosa -escherichia coli -klebsiella -serratia -proteus mirabilis
what are other aminoglycosides?
-tobramycin -amikacin -neomycin -kanamycin -streptomycin -paromomycin
when do you monitor for trough levels with aminoglycosides?
30 minutes before the next dosage. no earlier than an hour,
what organisms are aminoglycosides used to treat?
Aerobic gram-negative bacilli (this is usually seen in pneumonia)
The patient is ordered daily divided doses of gentamycin. The patient received an intravenous dose of gentamycin at 4:00 PM. When should the nurse obtain the peak level? A. 4:30 PM B. 5:00 PM C. 5:30 PM D. 6:00 PM
Answer: A Rationale: When using divided daily doses, draw blood samples for measuring peak levels 1 hour after IM injection and 30 minutes after completing an IV infusion. When a single daily dose is used, measuring peak levels is unnecessary. Draw samples for trough levels just before the next dose (when using divided daily doses) or 1 hour before the next dose (when using a single daily dose).
Before administering gentamycin, it is most important for the nurse to assess the patient for a history of what? A. Hypertension B. Myasthenia gravis C. Diabetes mellitus D. Asthma
Answer: B Rationale: Aminoglycosides must be used with caution in patients with renal impairment, pre-existing hearing impairment, and myasthenia gravis, and in patients receiving ototoxic drugs (especially ethacrynic acid), nephrotoxic drugs (for example, amphotericin B, cephalosporins, vancomycin, cyclosporine, nonsteroidal anti-inflammatory drugs [NSAIDs]), and neuromuscular blocking agents.
The nurse is reviewing laboratory values from a patient who has been prescribed gentamicin. To prevent ototoxicity, it is most important for the nurse to monitor which value(s)? A. Serum creatinine and blood urea nitrogen levels B. Trough drug levels of gentamicin C. Peak drugs levels of gentamicin D. Serum alanine aminotransferase and aspartate aminotransferase levels
Answer: B Rationale: To minimize ototoxicity, trough levels must be sufficiently low to reduce exposure of sensitive sensory hearing cells. The risk of ototoxicity is related primarily to persistently elevated trough drug levels rather than to excessive peak levels.
The nurse is caring for a patient receiving intravenous gentamicin for a severe bacterial infection. Which assessment finding by the nurse indicates the patient is experiencing an adverse effect of gentamycin therapy? A. Blurred vision B. Hand tremors C. Urinary frequency D. Tinnitus
Answer: D Rationale: Ototoxicity can result from accumulation of the drug in the inner ear. Early signs that should be reported include tinnitus or headache. Other major adverse effects include nephrotoxicity and neuromuscular blockade.
what is the minimum inhibitory concentration?
antibacterial agent in a given culture medium below which bacterial growth is not inhibited
are aminoglycosides bactericidal or static?
cidal, they don't stop growing
why are aminoglycosides narrow spectrum?
only effects the gram negatives
what is important in regards to peak and trough levels of aminoglycosides?
peak levels need to be high enough to kill bacteria trough levels need to be low enough to minimize toxicity
How do you dose aminoglycosides?
single large dose once a day or small dose 2-3 times per day
where are these drugs NOT absorbed?
the GI tract
why do you monitor plasma levels in patients taking aminoglycosides?
they dose can produce different effects depending on the patient
What is gentamicin (Garamycin) used for?
treat serious infections caused by aerobic gram-negative bacilli
Why are aminoglycosides used with penicillins?
you get a higher kill rate - synergy
