Gentamicin trough

To avoid dangerous side effects from this medication, gentamicin must be closely monitored.

Gentamicin trough Overview

Reviewed: April 23, 2014

Gentamicin is an aminoglycoside antibiotic, and is used primarily to treat infections caused by aerobic gram-negative bacilli. Trough level is monitored mainly to avoid toxicity. Trough level is taken 30 minutes prior to the next dose after steady state has been reached (after 3rd dose).

Gentamicin trough is measured in to micrograms/milliliters (mcg/ml) .

The recommended gentamicin trough is less than or equal to 2 mcg/ml.


Blood draw


No preparation needed, but timing of the sample for testing is important.

Follow your doctor's directions.

What the results mean

Aminoglycosides may accumulate in the kidneys, increasing the risk of nephrotoxicity (kidney damage). This may relate to the amount of time gentamicin trough levels are >2 mcg/mL. Higher than normal trough values indicate an increased risk for ototoxicity.