Tobramycin is an aminoglycoside antibiotic with pharmacokinetic characteristics similar to gentamicin. It is
bactericidal against some Gram-positive and many Gram-negative bacteria, including Pseudomonas aeruginosa1. See BNF and SPCs for information on contraindications, cautions and side effects of aminoglycosides.
A supply of tobramycin (80mg/2ml) 1 x 10 amps is available in the VHK Emergency Cupboard if required.
Indications
This guidance is intended for once daily intravenous dosing of tobramycin. It is not intended for cystic fibrosis patients who are prescribed individualised treatment regimens of intravenous or inhaled tobramycin.
Exclusions for once daily tobramycin1,2:
Endocarditis
Burns of >20% of total body surface area
Pregnancy
Significant ascites
Tobramycin should be prescribed only on the advice of a Consultant Microbiologist or Respiratory Physician.
Doses of tobramycin are equivalent to doses of gentamicin. Therefore, to calculate a tobramycin dose use the gentamicin 5mg / kg once daily dosing guideline (gentamicin calculator and guideline available via quicklinks on NHS Fife Intranet & NHS Fife antimicrobial guidelines on Right Decisions platform)3,4.
Doses should be prescribed on the drug kardex and NOT on the gentamicin prescribing chart.
For dosing advice in dialysis patients seek advice from Microbiology or Renal Consultant.
Intravenous infusion: Administer dose in 100mls 0.9% sodium chloride or glucose 5% over 30 minutes3,4,5.
To avoid potential venous irritation preferably administer via a central venous access device as the preparation has a low pH. If a central venous access device is unavailable a risk benefit analysis should be made on an individual patient basis. If given peripherally, the insertion site must be monitored closely for phlebitis5.
Therapeutic drug level monitoring is required and is done identically to gentamicin. Use the gentamicin
calculator and gentamicin 5mg / kg once daily monitoring guidance to check blood concentration levels at the appropriate time, and to interpret levels and adjust doses accordingly2,3.
Once a blood sample is taken it should be sent by pod to the Microbiology department at the North
Laboratory. (Please note this is different to the procedure for gentamicin and vancomycin samples, which are sent to Biochemistry).
The prescriber should contact the lab on 28820 during routine hours (8am – 8pm) prior to sending the sample. For an overnight sample please notify the lab before 5pm. They will send the tobramycin sample to the WGH lab, NHS Lothian to be analysed. Samples taken overnight which have not been notified to the lab should be notified after 8am.
WGH labs state that their turn-around time for samples is 24 hours. Results are sent to the Microbiology
department, who can advise the requesting team of results that may require dosages to be adjusted. The
result is also routinely available on Clinical Portal as soon as it has been processed, as WGH also use this
system.
Dosage adjustment can be made using the gentamicin prescribing chart (but as noted tobramycin
should not be prescribed on this chart).
Antimicrobial prescribing: NHS Fife