Hi,,welcome to HCM Tobramycin is an aminoglycoside antibiotics which is used to combat infection....though textural change is not a well known side effect of the drug,,more likely the hairfall and textural changes you are experiencing is due to your health problem... Take a protein rich diet and eat fruits and vegs rich in all the vitamin and minerals... Exercise daily... Do frequent hair massage with tips of your fingers with lukewarm olive and coconut oil in equal proportion,,this will increase the circulation of scalp and improve the textyre of hairs too... Conditioning of hair is a must thing after wash... You can opt for hair spas or use fenugreek hair mask to combat hairloss... Hope this will help you.