Ocitinib, fully known as ocitinib mesylate tablets, is generally available for a long period of time without a withdrawal period; however, the resistance period of ocitinib mesylate tablets averages about 1 year, and after the emergence of resistance, it is necessary to discontinue the drug to choose other sensitive drugs. Ocitinib mesylate tablets are antitumor drugs used to treat locally advanced or metastatic non-small cell lung cancer. Although the drug can generally be taken for a long time, it will inevitably fall into the process of drug resistance in the course of use, which has been shown by research that the resistance period is about 1 year on average, and there are a few patients who have taken the drug for 8 years. As each patient’s physique is different, the condition is different, the time of taking the drug resistance can not be generalized. It is recommended that patients go to the hospital for checkups while taking the drug, and if drug resistance is confirmed, they need to choose other treatment options under the guidance of the doctor. If there is a need to use the drug, please use under the guidance of a doctor, do not blindly self-medication.