Host: The Japanese Society of Toxicology
Name : The 49th Annual Meeting of the Japanese Society of Toxicology
Date : June 30, 2022 - July 02, 2022
[Background] Benzodiazepines are known to induce side effects like muscle relaxant action which can cause falls and lightheadedness. Their combined administration may increase the frequency of these side effects. Therefore, we evaluated the effects of benzodiazepines and nonbenzodiazepines on lightheadedness using motor-coordination as an index the action at their alone and combined administration. [Method] Male SD rats were made to walk for 2 min on a 90-mm-diameter rotating rod with 10 revolutions per minute, and the time for the rats to fall off the rod was used as an index of motor incoordination. Etizolam, brotizolam, and zolpidem were used at their clinical doses as the low dose and the twice as the high dose. The effects of each alone and of the combination of etizolam and zolpidem and of brotizolam and zolpidem, on it were evaluated. [Results] Etizolam or zolpidem alone did not affect motor-coordination. Brotizolam alone tended to suppress it at the high dose. On the other hand, the combination of low doses of etizolam and zolpidem inhibited motor-coordination time-dependently and showed the suppression at even 32 hours after the combined administration. The combined administration of brotizolam and zolpidem did not show a cooperative effect on it. [Discussion] Hypnotic-sedative drugs alone may not show their inhibitory effects on motor coordination, but they could induce the suppressive action even at clinical doses in combined administration. The results also suggest that the onset of action may be different at the combination of concomitant medications.
