Tobramycin
Mechanism :
Aminoglycoside antibiotic. It is available as injectable, ointments and ophthalmic solutions.
Indication :
- Gram negative infection: E.coli, Klebsiella, Enterobacter, Serratia, Proteus and Pseudomonas infections
- Cystic fibrosis
Contraindications :
Hypersensitivity to tobramycin and myasthenia gravis is a contraindication to its use. During therapy renal function should be monitored. Dose adjustment is required in impaired renal function. Hearing tests are recommended in cystic fibrosis patients receiving repeated doses of aminoglycosides.
Dosing :
In neonates:
<30 weeks gestation:
<28 days: 2.5 mg/kg/day IV/IM.
>28 days: 3 mg/kg/day IV/IM.
30-36 weeks gestation:
<14 days: 3 mg/kg/day IV/IM.
>14 days: 5 mg/kg/day IV/IM in 2 divided doses.
>37 week gestation:
<7 days: 5 mg/kg/day IV/IM in 2 divided doses.
>7 days: 7.5 mg/kg/day IV/IM in 3 divided doses.
Children:
<5 years: 2.5 mg/kg/dose every 8 hours, IM/IV.
>5 years: 2-2.5 mg/kg/dose every 8 hours, IM/IV.
Pseudomonas aeruginosa in cystic fibrosis:
In children >6 years: 300 mg via nebuliser inhaled twice daily.
Adverse Effect :
Ototoxicity, nephrotoxicity. Bronchospasm, voice alteration, myalgia, laryngitis, epistaxis can occur if nebulised.
Interaction :
Seen mostly with parenteral administration of drug.
Vancomycin, Cephalosporin, Cyclosporine, Furosemide, Cisplatin, Amphotericin: Increases chances of ototoxicity and nephrotoxicity.
Non-Depolarising Muscle Relaxants: Enhances effect.
Neostigmine, Pyridostigmine: Antagonises effect.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Give 1–2 mg/kg then dose according to serum levels |
| 10-20 | Give 1 mg/kg then dose according to serum levels |
| <10 | Give 1 mg/kg then dose according to serum levels |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Dialysed. Dose as in GFR<10 mL/min |
| HD | Dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Dialysed. Dose as in GFR<10 mL/min |
| CAV/VVHD | Dialysed. 1.5–2 mg/kg every 24 hours and monitor levels |
Hepatic Dose :
No dose adjustment recommended.