Brompystin does not fail after taking it for a long time, but it may develop resistance, which means that the same dose produces progressively less effect. Brompheniramine is mainly used for the treatment of myasthenia gravis and post-surgical functional bowel distension and urinary retention. Prolonged use of the drug may cause the body to develop resistance to the drug as the effect of the drug gradually decreases. The patient’s condition may recur. Prolonged use of brompheniramine is not recommended for the treatment of myasthenia gravis, as long-term use of the drug may produce adverse reactions, such as diarrhea, nausea, vomiting, stomach cramps and other gastrointestinal adverse reactions, and prolonged use of the drug may also lead to mental abnormalities. It is contraindicated in patients with angina pectoris, bronchial asthma, urinary tract obstruction and mechanical intestinal obstruction. Clinical treatment should be selected according to the patient’s condition, in addition to the use of brompheniramine medication, can also be taken to thymectomy treatment, thymus radiation therapy and so on. Patients are advised to use the drug under the guidance of the interviewing doctor.