TABLE 3.

Relative cochlear and vestibular toxicity patterns of aminoglycosides.

Agent	Cochleotoxicity	Vestibulotoxicity	Onset speed	Primary pattern
Gentamicin	++	++++	Moderate	Preferential vestibular injury reported; cellular uptake and retention patterns differ by tissue
Streptomycin	+	++++	Slow	Preferential vestibular accumulation is described in experimental models
Amikacin	+++	+	Moderate	Higher cochlear injury potential in experimental models; outer hair cell uptake implicated
Kanamycin	++++	+	Rapid	Enhanced cochlear penetration is described; ROS and oxidative stress pathways are implicated
Neomycin	++++	++	Very rapid	Rapid ROS generation in experimental models; mitochondrial pathways implicated
Tobramycin	+++	++	Moderate	Relatively balanced cochlear and vestibular distribution reported

+ = minimal effect; ++ = mild; +++ = moderate; ++++ = severe. Plus symbols indicate relative patterns of cochleotoxicity and vestibulotoxicity synthesized from patterns consistently reported across experimental hair-cell studies and clinical observational literature, rather than representing quantitative comparative effect sizes. “Onset speed” reflects the relative time to detectable functional or histologic injury under typical experimental or clinical exposure conditions and does not represent a fixed temporal threshold. Patterns may vary depending on dose, cumulative exposure, route of administration (e.g., intravenous vs. inhaled), population, and monitoring methodology.

Exposure metrics: Comparative toxicity patterns across agents are derived from studies using heterogeneous exposure metrics (Cmax, trough concentration, AUC, cumulative dose, and/or treatment duration). Rankings should be interpreted in the context of this methodological variability.

Abbreviations: ROS, reactive oxygen species.