Condition analysis: Central nervous system stimulants are drugs that can increase the functional activity of the central nervous system. According to the different sites of action of central stimulants, they are divided into cerebral cortex stimulants, medullary respiratory center stimulants, and drugs that promote brain function recovery. Methylphenidate, a drug that mainly excites the cerebral cortex, is an amphetamine drug. It is easily absorbed after oral administration and reaches Cmax in 2 hours. The drug concentration in the brain is higher than the blood concentration. 80% of the ester is decomposed into rital acid, which is excreted in the urine at t1/2 of about 2 hours. The effect of one dose lasts for 4 hours. This requires going to the hospital to buy medicine with a prescription.