Flunarizine hydrochloride is a piperazine calcium antagonist, which is mainly used clinically for the treatment of migraine, vestibular migraine and dizziness and vertigo caused by vestibular dysfunction, and has the following side effects: 1. The most common is drowsiness and fatigue, leading to sleep regardless of the occasion and time, so it should be taken orally before bedtime, and driving work, overhead work, etc. should be avoided the next day. 2. Long-term use It can induce the aggravation of depressive symptoms, and it is easy to occur in female patients. 3. It affects the muscle activities of the elderly, with the appearance of extrapyramidal symptoms such as bradykinesia, tremor, tonicity, inability to sit still, involuntary jaw movements, etc. Most of them appear three weeks after taking the drug. 4. Appetite and weight gain appear. 5. Skin rash, milk spill, muscle pain and other symptoms may appear.