Which antibiotic has a therapeutic serum range of 3-5 mg/L?

Which antibiotic has a therapeutic serum range of 3-5 mg/L?

• A. Gentamicin
• B. Amikacin
• C. Vancomycin
• D. Tobramycin

Answer: (A)

Therapeutic drug monitoring looks at keeping an antibiotic’s levels just right: high enough to kill bacteria effectively, but low enough to avoid toxicity. For aminoglycosides, this is done with a high peak to maximize bactericidal activity and a very low trough to reduce risk of kidney damage or ear toxicity. Among the options, vancomycin is known for needing relatively high trough levels (often in the tens of mg/L), reflecting its different pharmacodynamics. Amikacin and tobramycin are usually dosed to achieve higher peak concentrations with strict, very low troughs as well. Gentamicin, on the other hand, is commonly managed so that trough levels fall within the low single-digit range, and in some dosing guidelines a trough of approximately 3–5 mg/L is considered acceptable. That makes the 3–5 mg/L range a plausible therapeutic target for gentamicin, which is why it’s identified as the best match for this question. Always refer to your local dosing guidelines, as exact targets can vary by protocol.

Therapeutic drug monitoring looks at keeping an antibiotic’s levels just right: high enough to kill bacteria effectively, but low enough to avoid toxicity. For aminoglycosides, this is done with a high peak to maximize bactericidal activity and a very low trough to reduce risk of kidney damage or ear toxicity. Among the options, vancomycin is known for needing relatively high trough levels (often in the tens of mg/L), reflecting its different pharmacodynamics. Amikacin and tobramycin are usually dosed to achieve higher peak concentrations with strict, very low troughs as well. Gentamicin, on the other hand, is commonly managed so that trough levels fall within the low single-digit range, and in some dosing guidelines a trough of approximately 3–5 mg/L is considered acceptable. That makes the 3–5 mg/L range a plausible therapeutic target for gentamicin, which is why it’s identified as the best match for this question. Always refer to your local dosing guidelines, as exact targets can vary by protocol.