Simultaneous administration of amikacin and mannitol prolongs the latencies in waves iii-v in the rat's brainstem auditory response [Amikasin ve manitol si{dotless}çan beyinsapi{dotless} i̇şitsel yani{dotless}tlari{dotless}nda iii-v dalgalari{dotless}ni{dotless}n latanslari{dotless}ni{dotless} uzati{dotless}r]

After severe head injury,the use of osmotic agents for decreasing intracranial pressure (icp) includes administration of mannitol and also amikacin,an ototoxic agent that prevents the development of infections. objective: the aim of this report was to describe the effects of amikacin and mannitol on the brainstem auditory-evoked potentials (baep's),as an index of drug toxicity. methods: after a basal record was taken,twenty four male wistar rats (210-230g) were allocated into three groups,where the substances were administered daily in one dose for 7 days. the first group received mannitol (m; 0.75 ml i.p. n=8); the second one received amikacin + mannitol (a+m; 0.75 ml+40 mg/kg i.p.; n=8); and,the third group was treated with amikacin (a; 40 mg/kg i.p.,n=8). in order to obtain baep's,clicks of equal intensity (70 db) were applied in pentobarbital sodium anaesthetized rats (50 mg/kg ip.). results: showed that both,a and a+m treatment increased latency in waves iii,iv and v. however,latencies in waves iii and v were significantly longer in a+m treated rats,as compared with a treated rats. on the other hand,central nervous conduction velocity was slower in a+m treated rats,mainly in i-iii,i-v and iii-v intervals. conclusions: these findings indicate that synergistic effect of a+m implies a high dysfunction in the auditory central pathway,specifically in the superior olivary complex.