Displaying 4 results of Phentolamine Impurities Phentolamine is a medication used to treat high blood pressure and other conditions. However, during the manufacturing process, impurities can be introduced which may have harmful effects on the body. These impurities include related substances, residual solvents, and heavy metals. It is important to monitor and control the levels of these impurities to ensure the safety and efficacy of the medication.