The pharmacodynamics and pharmacokinetics of the drug are characterized by “slow onset of action, enhanced efficacy and slow elimination”, as the water content in the body of elderly patients decreases, liver and kidney function decreases, and renal excretion function decreases. Therefore, when the elderly repeatedly use drugs, the drugs may accumulate in the body and increase the blood concentration. At the same time, the drug toxicity is enhanced due to the interaction between drugs in the body. Therefore, elderly patients should pay attention to individualized dose adjustment. To fully grasp the systemic status and vital organ functions, accurately design the applied analgesic dose, repeatedly assess the effect of drugs and timely adjust the drug dose in time, and change the drug type when necessary.