The invention discloses a new application of ligustrazine in the field of
analgesic drugs, and particularly discloses an application of the ligustrazine in preparation of medicines for enhancing the
analgesic effect of
opioid agents, and delaying or relieving the
opioid tolerance. The ligustrazine is matched with the
opioid agents for use, or is prepared into a compound preparation together with the opioid agents for use; the
analgesic time can be prolonged; the
analgesic effect can be enhanced; the phenomenon of
opioid tolerance caused in the treatment process of the chronic opioid agents can also be delayed or relieved; and the ligustrazine has the specific effects of inhibiting excessive activation of spinal
microglia induced by the opioid agents through the ligustrazine and inhibiting realization of excessive increase p-P38 induced by opioid.