Sensorineural deafness accompanied by tinnitus; permanent deafness in patients w/ compromised auditory or renal function; hypotension, palpitations, substernal pressure, phlebitis, tachycardia; pruritus at inj site, generalised flushing, erythematous macular rash w/ intense pruritus over face, neck & upper body; tissue irritation & necrosis occurs after IM inj or extravasation from IV site.; bullous eruption disorders, rashes including exfoliative dermatitis, SJS, TEN, & linear IgA bullous dermatosis; overgrowth of non-susceptible organisms resulting in new bacterial or fungal infections; transient elevations of urea & granular casts in the urine; reversible neutropenia (usually starting ≥1 wk after onset of IV therapy or after a total dose of >25 g); neutropenia; histamine release w/ chills, nausea, urticaria, macular rash, fever, rigors; anaphylactoid/hypersensitivity reactions, anaphylaxis; subconjunctival inj; pain & muscle spasm of the chest & back.