i had the hearing/ear issues, fullness and slight ringing the last few times i did tobra. i ended up with ototoxicity(not sure if it was due to one series of tobra or the fact that i had been taking it for 10 years when i would get sick). it is serious, my vestibular system, basically my ability to balance, was destroyed by tobra i.v.'s. being off balance most of the time sucks and if i had paid attention to the signs it may have been preventable. it basically affects everything i do in my waking life and makes it much more difficult, tiresome, or just plain impossible. i had just picked up my new custom surfboard about a week before all of this hit...it now sits in my closet and will probably never be used by me.
from <a target=_blank class=ftalternatingbarlinklarge href="http://www.vestibular.org/vestibular-disorders/specific-disorders/ototoxicity.php">vestibular.org</a>
Ototoxicity
Ototoxicity ("ear poisoning") is due to drugs or chemicals that damage the inner ear or the vestibulo-cochlear nerve, which sends balance and hearing information from the inner ear to the brain. Ototoxicity can result in temporary or permanent disturbances of hearing, balance, or both.
Many chemicals have ototoxic potential, including over-the-counter drugs, prescription medications, and environmental chemicals. If you are taking any drugs on the advice of your physician, do not stop taking them just because you see them listed below. Speak with your doctor or other health care advisor about your concerns.
Substances that may cause ototoxicity include:
Aminoglycoside antibiotics, including gentamicin, streptomycin, kanamycin, tobramycin, neomycin, amikacin, netilmicin, dihydrostreptomycin, and ribostamycin. All members of this family are well known for their potential to cause permanent ototoxicity. They can enter the inner ear through the blood system, through inhalation, or via diffusion from the middle ear into the inner ear. They enter the blood stream in largest amounts when given intravenously (by IV).