| Question | Answer |
| Aminoglycosides
CANNOT READILY CROSS MEMBRANE | Most commonly used agents,
•Gentamicin, tobramycin, amikacin
Narrow-spectrum antibiotics
Bactericidal
Use: Aerobic gram-negative bacilliCan cause serious injury to inner ear and kidney
Not absorbed from GI tract
Microbial resistance |
| Adverse effects
general anesthetics, and in myasthenia gravis | Nephrotoxicity•Ototoxicity (total cumulative and trough levels)•Hypersensitivity reactions•Neuromuscular blockade: Concurrent use with neuromuscular blocking agents,.Treatment of choice: Reversal with IV infusion of a calcium salt (eg, calcium gluconate) |
| Other adverse effects | Hypersensitivity reactions •Blood dyscrasias
•Others |
| Drug interactions | CAUTION W/ RENAL IMPAIRMENT
SAFE FOR INFANTS, BREST-FEEDINGNOT IN PREGNANY |
| Serum Levels
trough levels must be low enough to minimize toxicity | dosing •Single large dose each day or 2 or 3 smaller dosesMonitoring of serum levels is common; the same aminoglycoside dose can produce very different plasma levels in different patientsPeak levels must be high enough to kill bacteria; |
| Peak Levels? | should be taken 30 minutes after giving an IM injection or after completing a 30-minute IV infusion |
| TROUGH LEVELS? for trough levels depends on the dosing schedule | for trough levels depends on the dosing schedule |
| DOSES? | Divided doses: Take sample just before the next dose •Once-daily doses: Draw a single sample 1 hour before the next dose; value should be very low—preferably close to zero |
| Gentamicin [Garamycin] | Used to treat serious infections caused by aerobic gram-negative bacilli
•Pseudomonas aeruginosa•Escherichia coli•Klebsiella•Serratia•Proteus mirabilis |
| Adverse effects | Nephrotoxicity•Ototoxicity |
| Other Aminoglycosides | Tobramycin Amikacin Neomycin
Kanamycin Streptomycin
Paromomycin |
| he 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? | Tinnitus
Ototoxicity can result from accumulation of the drug in the inner ear. Early signs that should be reported include tinnitus or headache. |
| 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)? | Trough drug levels of gentamicin
The risk of ototoxicity is related primarily to persistently elevated trough drug levels rather than to excessive peak levels. |
| Before administering gentamycin, it is most important for the nurse to assess the patient for a history of what? | B. Myasthenia gravis |
| 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? | 4:30 PM |
