By C1, I assume that you mean "clonazepam" or some other street benzo. I am going to assume that you are calling it c1 because you purchased it from a "friend" and it was not prescribed to you. Your doctor has no idea what a c1 is because that is not what we call it. Your doctor also doesn't know what a zbar or a blue football is. The only reason I know is because I run a methadone clinic. I absolutely would NEVER take medication that was purchased from the internet or a friend. NEVER. The reason is the People's Republic of China. They are great counterfeiters. However, they don't care about you. They will put God knows what and press it into a pill and sell it. You could die. It could be laced with a synthetic fentanyl product. People have dropped from counterfeit pills. You have no idea what is in that pill. Your doctor can tell you if the medication that he/she prescribed has an interaction with your blood pressure pills. If the doctor who prescribed the medications are different doctors, you should inform the primary care doctor of your new medication, and ask your pharmacist to check for any drug interactions. It is great that you are being proactive and checking prior to starting a new drug, that is very smart!