The dosage of phentolamine depends on what condition the patient is currently treating with the drug phentolamine and whether the patient is an adult or a child. There are some differences in the usage and dosage, for example, in adult patients, for the treatment of vasospastic disorders. It is recommended that 5-10 mg can be given per injection, either intramuscularly or intravenously, and the dose can also be repeated after 20-30 minutes. Currently it is used for pheochromocytoma surgery, the patient is recommended to give 5mg intravenously 1-2 hours before surgery and 5mg intravenously when doing surgery; if it is used for the treatment of heart failure, it is recommended to give 0.5-1mg intravenously and then drip intravenously at the rate of 2mg per hour and adjust the dosage until the heart failure is relieved; if it is for children, the dose is given 1-2 hours before doing pheochromocytoma surgery and The dose is the same for adults and can be repeated, and the dose can still be repeated when doing surgery.