Gentamicin Dosing, Administration, and Pharmacokinetics Case Study
Assignment Instructions:
A patient is prescribed gentamicin 5 mg/kg IV once daily for a 60 kg patient. The
pharmacy stocks gentamicin in 80 mg/2 mL vials.
How much gentamicin (mg) should be administered per dose?
How many milliliters of gentamicin solution should be drawn up for each dose?
If the infusion rate is 10 mg/min, how long will it take to administer one dose?
A trough level is drawn 30 minutes before the next dose, and the result is 3 mcg/mL. Is
the current dosing regimen appropriate based on the trough level? Would you increase,
decrease, or leave the dose the same? Please include a complete medication order. What
are risks associated with aminoglycoside therapy?
Why is gentamicin typically administered intravenously rather than orally? How does this
relate to bioavailability?
, Introduction
Gentamicin is an aminoglycoside antibiotic commonly used to treat serious Gram-
negative bacterial infections, including sepsis, pneumonia, and urinary tract infections. It
acts by binding to the 30S ribosomal subunit of bacteria, inhibiting protein synthesis and
leading to bacterial cell death. Accurate dosing and monitoring are essential to ensure
efficacy and minimize the risk of toxicity, particularly nephrotoxicity and ototoxicity.
Dose Calculation (mg and mL)
The prescribed dose is 5 mg/kg for a 60 kg patient.
Dose (mg) = 5 mg/kg × 60 kg = 300 mg.
Each vial of gentamicin contains 80 mg in 2 mL, or 40 mg/mL.
To determine the volume to be drawn:
Volume (mL) = Dose (mg) ÷ Concentration (mg/mL) = 300 mg ÷ 40 mg/mL = 7.5 mL.
Therefore, 7.5 mL of gentamicin solution should be drawn up for each dose, which
corresponds to a total dose of 300 mg IV once daily.
Infusion Rate Calculation
The infusion rate is 10 mg/min.
To determine the infusion time:
Infusion Time (min) = Total Dose (mg) ÷ Rate (mg/min) = 300 mg ÷ 10 mg/min = 30
minutes.
Thus, the total infusion time should be 30 minutes to deliver the 300 mg dose safely.
Trough Level Interpretation and Dosing Adjustment
Assignment Instructions:
A patient is prescribed gentamicin 5 mg/kg IV once daily for a 60 kg patient. The
pharmacy stocks gentamicin in 80 mg/2 mL vials.
How much gentamicin (mg) should be administered per dose?
How many milliliters of gentamicin solution should be drawn up for each dose?
If the infusion rate is 10 mg/min, how long will it take to administer one dose?
A trough level is drawn 30 minutes before the next dose, and the result is 3 mcg/mL. Is
the current dosing regimen appropriate based on the trough level? Would you increase,
decrease, or leave the dose the same? Please include a complete medication order. What
are risks associated with aminoglycoside therapy?
Why is gentamicin typically administered intravenously rather than orally? How does this
relate to bioavailability?
, Introduction
Gentamicin is an aminoglycoside antibiotic commonly used to treat serious Gram-
negative bacterial infections, including sepsis, pneumonia, and urinary tract infections. It
acts by binding to the 30S ribosomal subunit of bacteria, inhibiting protein synthesis and
leading to bacterial cell death. Accurate dosing and monitoring are essential to ensure
efficacy and minimize the risk of toxicity, particularly nephrotoxicity and ototoxicity.
Dose Calculation (mg and mL)
The prescribed dose is 5 mg/kg for a 60 kg patient.
Dose (mg) = 5 mg/kg × 60 kg = 300 mg.
Each vial of gentamicin contains 80 mg in 2 mL, or 40 mg/mL.
To determine the volume to be drawn:
Volume (mL) = Dose (mg) ÷ Concentration (mg/mL) = 300 mg ÷ 40 mg/mL = 7.5 mL.
Therefore, 7.5 mL of gentamicin solution should be drawn up for each dose, which
corresponds to a total dose of 300 mg IV once daily.
Infusion Rate Calculation
The infusion rate is 10 mg/min.
To determine the infusion time:
Infusion Time (min) = Total Dose (mg) ÷ Rate (mg/min) = 300 mg ÷ 10 mg/min = 30
minutes.
Thus, the total infusion time should be 30 minutes to deliver the 300 mg dose safely.
Trough Level Interpretation and Dosing Adjustment
