Lisinopril is a medication used to treat hypertension (high blood pressure). It can also improve conditions for individuals who have experienced a heart attack and to treat kidney problems caused by type 2 diabetes. Lisinopril requires a prescription and can be bought in both generic and branded forms. Belonging to the ACE class, this medication works to relax blood vessels and increase blood flow. There are two brands on the market today. Check with your doctor or the pharmacy label for the correct dosage as it may differ from brand to brand.