Eye drops and ointments (tobramycin only, Tobrex, or combined with dexamethasone, sold as Tobradex) and nebulised formulations both have low systemic absorption.

The nebulised formulation (brand name Tobi) is indicated in the treatment of exacerbations of chronic infection with Pseudomonas aeruginosa in people diagnosed with cystic fibrosis.

[8] Like other aminoglycosides, a major side effect for tobramycin is ototoxicity or a loss of equilibrioception, or both in genetically susceptible individuals.

[24] Nephrotoxicity can be particularly worrisome when multiple doses accumulate over the course of a treatment[25] or when the kidney concentrates urine by increasing tubular reabsorption during sleep.

[26] For these reasons parenteral tobramycin needs to be carefully dosed by body weight, and its serum concentration monitored.

Likewise, combining injected tobramycin with other nephrotoxic or ototoxic drugs can lead to more adverse effects; examples include amphotericin B, ciclosporin, cisplatin, vancomycin, and the diuretic furosemide.

However, when they are given through the same drip, as well as in people with reduced kidney function, they can react with each other to form antibiotically inactive amides.

People with reduced kidney function also have a longer half-life for tobramycin, while in those with severe burns it can be shorter.

[12] Tobrex eye drops are a 0.3% tobramycin sterile ophthalmic solution produced by Alcon Pharmaceuticals.

[citation needed] In Egypt, tobramycin (in the form of eye drops) is sold under the brand Tobrin, produced by EIPICo.