Adult outpatient parenteral antimicrobial therapy (OPAT) good practice prescribing guide

Amikacin - management of Gram-negative infections

Amikacin is an aminoglycoside antibacterial with activity against a range of Gram-negative organisms including Pseudomonas, some Gram-positive organisms and also mycobacteria.  It is licensed for the treatment of serious infections where amikacin susceptible organisms have been identified.

This guide shares practical experience of the use of amikacin in an OPAT setting. We took an evidence based approach to create the guidance. We also used expert consensus and practical experience from across NHS Scotland.

This drug summary does not provide specific treatment guidance. Individual patient treatment should take into account the core principles of antimicrobial stewardship. This includes selection of the appropriate antimicrobial for the shortest duration with oral therapy being preferred, whenever possible.

For information on Route and method of administration, Contraindications, Cautions and adverse effects and Drug interactions please refer to the following approved resources:

These resources also have more information on licensed indication, use in pregnancy and use in breast feeding. When using unlicensed medicines, and/or off-label doses or indications, follow local health board governance processes.    

It is strongly recommended that OPAT services in Scotland adhere to the Key performance indicators for the management of patients in an outpatient parenteral antimicrobial therapy (OPAT) setting.

1. Indication and dose

Off-label indications

It is recommended that off-label use is agreed with local OPAT infection specialist.
Scottish experience of use in practice for off-label indications are below.

Off-label indications in the OPAT setting Dose
Multi-drug resistant Gram negative urinary tract infections Calculate the amikacin dose using the dosing table below


Route and method of administration

Refer to Summary of Product Characteristics (SPC) or NHS Injectable Medicines Guide (Medusa) for further information. Intravenous infusion is the preferred route of administration:

  • Further dilute the required dose to 100ml with sodium chloride (NaCl) 0.9% or glucose 5% and give over 30 minutes.

2. Dose adjustments and monitoring

Dosage adjustments may be required under the following circumstances

Patient characteristic Dosage advice
Renal impairment See dosage table below
Hepatic impairment No dose adjustment necessary
Obesity See dosage table below
  • DO NOT use eGFR. Calculate creatinine clearance (CrCl) using Cockcroft Gault equation (see below)
  • *Use the patient’s total body weight (TBW) unless BMI over 30 kg/m2 where adjusted body weight (AdjBW) is recommended.
Creatinine Clearance (CrCl) CrCl = (((140 – age in years) x weight* (kg)) / serum creatinine in micromol/L) x 1.04 (female) or 1.23 (male)
Body mass index (BMI) Weight (kg) / height (m)2
Ideal body weight (IBW) IBW = (((Height in cm – 152.4 cm) / 2.54) x 2.3) + 45 kg (female) or 50 kg (male)
Adjusted body weight (AdjBW) AdjBW = (0.4 x (total body weight – IBW)) + IBW


Amikacin dosing table for the Management of Gram negative bacteria: 

Creatinine Clearance
(CrCl ml/min)*

 Amikacin dose
(use total body weight or if BMI over 30 kg/m2 use adjusted body weight)		 Dose frequency Administration
Less than 20 2.5 mg/kg (max 200 mg) Re-dose once trough concentration is less than 5mg/L IV infusion  over 30 mins
20 – 29 5.5 mg/kg (max 550mg) 24 hourly IV infusion  over 30 mins
30 – 49 6 mg/kg (max 600mg) 24 hourly IV infusion  over 30 mins
50 – 70 12 mg/kg (max 1200mg) 24 hourly IV infusion  over 30 mins
Over 70 15 mg/kg (max 1500mg) 24 hourly IV infusion  over 30 mins

*If creatinine is not known give 7.5 mg/kg amikacin (maximum 600 mg) and seek advice from pharmacy.

Monitoring requirements

Frequency Recommended monitoring
Baseline Urea and electrolytes (U&Es), liver function tests (LFTs), C-reactive protein (CRP) and full blood count (FBC).

The mitochondrial DNA mutation m.1555A>G predisposes to severe hearing loss following aminoglycoside exposure.  Consider genetic testing, especially in patients requiring recurrent or long-term treatment with aminoglycosides (e.g. complex drug resistant infections including tuberculosis, cystic fibrosis or recurrent neutropenic sepsis) but DO NOT delay urgent treatment in order to test.
Routine monitoring WEEKLY U&Es, LFTs, CRP and FBC
(Note this may be more frequent if clinically necessary)
Therapeutic drug monitoring Ensure amikacin is administered as a 30 minute intravenous infusion.

Week 1; peak and trough concentration (see ‘Therapeutic drug monitoring’ section below), 
Week 2 onwards; if peak satisfactory repeat trough concentration weekly 
Perform both peak and trough monitoring more frequently if clinically indicated (e.g. if renal function deteriorates or improves significantly or there is a change in creatinine of over 15–20% during amikacin therapy).
Audiology Audiometry is required if duration of amikacin is likely to be over 7 days.  Baseline then monthly audiometry is recommended
Follow up Ensure follow up is arranged with referring specialty and/or an infection specialist


Therapeutic drug monitoring

Amikacin concentrations measurements are essential to guide ongoing therapy, clinical efficacy and possible toxicity.  See table below for target amikacin concentrations or seek advice from pharmacy if you are unsure how to interpret the results or if the concentrations are not within the target ranges below.

  • Take a peak amikacin concentration 1 hour after the end of the first amikacin infusion. Ensure 1 hour has elapsed, from the end of the infusion, as early concentrations will be invalid.
  • Take a trough amikacin concentration at the end of dosage interval (prior to the next dose).  Do not delay giving the second amikacin dose while waiting for the trough concentration to be reported, unless there are concerns over deteriorating renal function or CrCl is less than 30 ml/min. 
  • If the amikacin trough concentration is higher than the target concentration (see table below) and a further dose has already been administered, repeat the trough concentration measurement and await the result before re-dosing. DO NOT give a further dose until the amikacin concentration is within target range.

 Target amikacin peak and trough concentrations

Creatinine Clearance
(CrCl ml/min)		 Target peak concentration
(1 hour post end of infusion)		 Target trough concentration
(end of dosage interval)
50 or more over 35 mg/L Less than 2 mg/L
Over 50 15 – 30 mg/L Less than 5 mg/L


For the use of other antibiotics in an OPAT setting please refer to the SAPG website

 

 Scottish Antimicrobial Prescribing Group (SAPG) | January 2024 for review January 2027

Content updated: May 2024