Aetiopathology of the streptomycin ototoxicity.

Streptomycin causes toxicity due to direct action on the organs in labyrinth. The bioavailability of drug is dependent on its dosage, absorption, metabolism and excretion. Individual variables like age, sex, nutrition, haemoglobin levels. renal functions do not appear to lead to predispose the ototoxicity. The drug dosage and combinations of other drugs were considered in studying the ototoxicity. It is observed that serum levels of more than 2.5 microgram per milliliters predispose dispose to ototoxicity. So also the subjects having higher than 2.5 mgms/ml in serum at the 24th hour following single injection of drug are more vulnerable, (P<0.05) on the otherhand initial higher level at the end of 1st hour (mean 54.75 ugm/ml) do not have positive relationship with toxicity (P<0.05). Furthermore streptomycin appears to be more damaging to static than dynamic part of labyrinth and the later is more vulnerable than cochlear. [ABSTRACT FROM AUTHOR]