Phentolamine mesylate can be hard for how long, mainly related to the patient’s individual physical condition and the dose of medication, should be a specific analysis of the problem, not a generalization. Phentolamine Mesylate Tablets is a drug for erectile dysfunction, which can make the penis continuously erect without sexual stimulation, and has a better effect. If the patient’s impotence and premature ejaculation symptoms are mild, taking phentolamine mesylate before sex can enable the patient to complete a satisfactory sex life, which can generally last for more than 10 minutes. If the patient’s impotence and premature ejaculation symptoms are more severe, the dose should be adjusted according to their own needs or tolerance level as prescribed by the doctor, and the specific duration varies from person to person and cannot be clarified clinically. Patients are recommended to do sexual nerve sensitivity test and other related sexual function tests to clarify the cause for better targeted treatment. Patients taking phentolamine mesylate should also be aware that common adverse reactions to this drug include nasal congestion, palpitations, flushing, dizziness, chest tightness, and in a few patients, mild changes in heart rate and blood pressure. It should also be used with caution in patients with coronary artery supply deficiency and diabetes mellitus.