Canterbury DHB


Gentamicin/Tobramycin Dosing in Patients with Spinal Injuries (Adults)

Prescribe in MedChart with frequency set as ‘variable dose’.

In This Section

Paraplegic Patients

Tetraplegic Patients (including those with T1 involvement)

Paraplegic Patients

Dose and monitor as for non-spinal injury patients BUT ensure at least 8 hours have passed since an aminoglycoside has been given.

Tetraplegic Patients (including those with T1 involvement)

Gentamicin and tobramycin are usually given in daily divided doses to minimise possible risks of respiratory compromise. High aminoglycoside concentrations have been associated with neuromuscular blockade so target peak plasma concentrations are low.

  1. Target plasma concentrations: peak 6 to 10 mg/L, trough < 1 mg/L.
  2. For all indications except endocarditis, give a loading dose of 3 mg/kg (ideal body weight). Omit this loading dose if patient has received any aminoglycoside within 12 hours (e.g. for prophylaxis of urological procedure).

    Ideal body weight (kg) males = 50 kg + 0.9 kg for each cm > 150 cm (4 foot 11 inches) height.
    Ideal body weight (kg) females = 45 kg + 0.9 kg for each cm > 150 cm (4 foot 11 inches) height.

  3. For endocarditis, use the endocarditis guidelines under Gentamicin/Tobramycin Dosing Guidelines (Adults).
  4. Eight hours after the loading dose, start the maintenance dose of 1.5 – 2 mg/kg (ideal body weight). Adjust for severity and give every 8 hours.
  5. Give all doses by IV infusion over 30 minutes in 100 mL of sodium chloride 0.9%.
  6. Take 2 blood samples for gentamicin/tobramycin concentrations around the third dose:
    1. a trough sample just before (within 30 minutes of) the third dose, and
    2. approximately 30 minutes after the end of the infusion (i.e. 1 hour post infusion start).
  7. Contact the Ward Pharmacist or Drug Information (Phone 80900) during normal working hours with the drug concentration results to get a prediction for the next dose. Alternatively, contact the pharmacist on call after hours (call before 10.30 pm unless the dose must be given before 8 am).

Information about this Canterbury DHB document (90760):

Document Owner:

Not assigned (see Who's Who)

Last Updated:

May 2019 (Antimicrobial Dosing Guidelines (Adults) - Gentamicin/Tobramycin and Vancomycin)

Next Review Due:

May 2022


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Topic Code: 90760