- the treatment of suspected or documented bacterial infections, normally caused by Gram-negative organisms.
- tobramycin is an aminoglycoside antibiotic
- aminoglycosides, which are generally bactericidal, are believed to act by irreversibly binding to 30S ribosomal subunits, thereby inhibiting protein synthesis
- aminoglycosides are active against many aerobic Gram-negative bacteria and some Gram-positive bacteria; their clinical application is usually reserved for Gram-negative organisms
- aminoglycosides are inactive against fungi, viruses and most anaerobic bacteria
- the average serum half life of tobramycin in neonates (< 1 week) varies between 3 and 12 hours; the half life is inversely correlated to birth weight and gestational age
- tobramycin may have better antibacterial activity than gentamicin against Pseudomonas sp.
- 8th nerve damage, deafness, ataxia, vestibulitis and renal failure
- these effects are somewhat dose related, ie. the higher the dose, the greater potential for toxicity
- never inject into a closed space (eg. pleural space or peritoneal cavity) in the neonate because there have been some reported incidences of sudden respiratory arrest in association with the injection
- tobramycin may cause renal damage; therefore, accurate in and outs should be done; monitor serum creatinine
- take peak values 30 minutes after the end of the 30 minute infusion (should be 13 - 22.0 micromol/L)
- take trough values immediately before the next dose (should be less than 1.0 - 3.0 micromol/L)
- levels should initially be monitored before and after the third dose
- 0.25 mL of blood is required for the assay
- furosemide and ethacrynic acid - increase ototoxicity
- ticarcillin inactivates tobramycin if mixed together in vitro
- carbenicillin - same as ticarcillin
- cephalosporins - increased nephrotoxicity
- skeletal muscle relaxants - (eg. pancuronium) tobramycin may potentiate muscle relaxation
- vancomycin - concurrent use may increases the risk of ototoxicity. Although it is generally not recommended, if this combination is used, then monitor serum levels of both drugs, and renal function, closely.
- The following guidelines are for the FIRST WEEK OF LIFE.
GESTATIONAL AGE DOSE AND FREQUENCY > 35 weeks 3.5 mg/kg q24h
< 35 weeks
3 mg/kg q24h
- pre and post levels with 3rd dose
- given IV by slow infusion
- in overwhelming infection a loading dose of 4 mg/kg may be given, followed by the maintenance dosage regimen. If a loading dose is given, it is especially important to closely follow serum tobramycin levels
- AFTER THE FIRST WEEK OF LIFE, a larger dose (3.5 mg/kg) with the frequency based on postconceptional age, may be appropriate.
POST CONCEPTIONAL AGE FREQUENCY < 26 weeks q24h 27-32 weeks q18h
> 32 weeks
- 10 mg/mL, 2mL vial
- 10 mg/mL syringe, prepared by Pharmacy
- McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
- Roberts, RJ: Drug Therapy in Infants, W.B. Saunders, Toronto, 1984.
- Watterberg KL, Kelly HW, Angelus P and Backstrom C: The need for a loading dose of gentamicin in neonates, Ther Drug Monitor 1989; 11:16-20.
- Bloome MR, Warren AJ, Ringer L and Walker PC: Evaluation of an empirical dosing schedule for gentamicin in neonates, Drug Intelligence and Clinical Pharmacy 1988; 22: 618-622.
- Taketomo CK, Hodding JH and Kraus DM: Pediatric Dosage Handbook, Lexi-Comp Inc., Cleveland, 1992.
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