A nurse is administering gentamicin, an aminoglycoside antibiotic, to a client with a severe gram-negative infection. The nurse should monitor the client for signs of nephrotoxicity and ototoxicity, which are potential adverse effects of this antibiotic.
The nurse should also be aware that these adverse effects are:

This means that the higher the dose and the longer the duration of aminoglycoside therapy, the greater the risk of nephrotoxicity and ototoxicity, which are damage to the kidneys and ears respectively.These adverse effects are irreversible because they cause permanent damage to the cells of these organs.

Choice A is wrong because dose-dependent and reversible implies that the adverse effects can be reversed by lowering the dose or stopping the therapy, which is not true for aminoglycosides.

Choice C is wrong because time-dependent and reversible implies that the adverse effects are related to the length of exposure and can be reversed by shortening the therapy, which is also not true for aminoglycosides.

Choice D is wrong because time-dependent and irreversible implies that the adverse effects are related to the length of exposure and cannot be reversed by shortening the therapy, which is partly true but not as accurate as choice B.

Normal ranges for BUN are 7 to 20 mg/dL and for creatinine are 0.6 to 1.2 mg/dL for men and 0.5 to 1.1 mg/dL for women.Signs of nephrotoxicity include increased BUN and creatinine levels, decreased urine output, proteinuria, hematuria, and casts in urine.Signs of ototoxicity include tinnitus, hearing loss, dizziness, vertigo, and headache

The bacteria have an altered target site that methicillin cannot bind to.This means that the bacteria have changed their structure so that the antibiotic cannot attach to them and kill them.

Choice A is wrong because methicillin does not work by being broken down by an enzyme.Some other antibiotics, such as penicillin, can be inactivated by bacterial enzymes, but not methicillin.

Choice C is wrong because methicillin does not work by entering the bacterial cell.Some other antibiotics, such as tetracycline, can be expelled by bacterial membrane pumps, but not methicillin.

Choice D is wrong because methicillin does not work by blocking an alternative pathway.Some other antibiotics, such as sulfonamides, can be bypassed by bacterial alternative pathways, but not methicillin.