Nearly 30 Years of Medical Experience. Dr. John A. Demopulos is an internal medicine doctor with nearly 30 years of experience. Dr. Demopulos and his team offer primary care services and can treat routine problems such as a cold or the flu, or provide on-going management for illnesses such as high blood pressure, diabetes or heart disease. We treat patients aged 17 and up.Home‧Location‧Our Physician‧Patient Center‧Contact Us‧Pay My Bill.