DCInternists - Your Personal Private Physician

our concierge model

Our concierge practice enrolls a limited number of patients, many of whom we’ve known for decades. By keeping our panels relatively small, we can provide longer visits, offer same or next day appointments and guarantee access to a physician on a 24/7 basis, through phone and email. We offer in-house lab and other diagnostic testing, with referrals to outside facilities when needed.

We are committed to providing you personalized attention and seamless experience with our team. When you call our office, you will always reach one of our team members, and not be put through a phone tree. Your requests will be handled quickly and efficiently. We will assist you with referrals both within and outside the DC area.

meet our providers

Mitchell Dunn, MD
General Internist

Beth Horowitz, MD
General Internist

Gregory Prokopowicz, MD, MPH
General Internist

Catherine Okuliar, MD
General Internist

Mitchell Dunn, MD

Board Certified General Internist

“I value the long-term relationships with patients that are a special part of practicing internal medicine. I am eager to learn more about new research and technology and incorporate the best into the care I provide.”

I have been active in the Washington DC medical community for 40 years. My extensive network of professional colleagues allows me to guide my patients to the right specialists in the metro area and beyond if necessary. I am dedicated to my patients and am interested in all that is happening in your lives and your families. I often see multiple family members and have patients who travel from outside the United States to meet with me for regular examinations.

I attended the Duke University School of Medicine and completed my residency at George Washington University. I served as Chief Medical Resident and spent several years as a member of the full time faculty before starting in private practice. I am a Diplomat of the American Board of Internal Medicine and have been listed as a Washingtonian Top Doctor in every medical issue over the past 20 years. My hobbies include personal fitness and working with computers and information technology. I am married to Susan Lacks, MD and we have three wonderful sons and are proud grandparents.

Beth Horowitz, MD

Board Certified General Internist

I received my BA from Stanford University. I am a graduate of the University of California San Francisco medical school and completed my internal medicine residency at the Mount Zion/UCSF program. I also have a masters in health and medical education from UC Berkeley. After moving back to the East Coast in 1987, I joined the faculty of George Washington University Medical Center, eventually becoming director of the medical residency program. While at GW, I developed courses and gave numerous presentations on issues related to women’s health.

I opened a private practice in 1996, but have maintained an academic appointment and have taught first and second year medical students over the years. I have worked with Peace Corps volunteers, am a Fellow of the American College of Physicians and an active member of Physicians for Human Rights. I enjoy treating patients at all stages of adulthood. I have a special interest in adolescents and often begin working with them when they first leave their pediatrician. To better understand the health problems facing people at the other end of life, I became board certified in geriatrics in the early 1990s.

I have been named a Washington magazine Top Doctor and listed in Best Doctors in America.

I live in Washington DC with my husband, Michael Kazin, who is a professor of US history at Georgetown University. We have 2 grown children and an unruly dog.

Gregory Prokopowicz, MD, MPH

Board Certified General Internist

“As a physician, my role is not just to diagnose and treat, but to help the patient understand medical concepts and to successfully navigate the medical system and coordinate their care with multiple specialists. It has never been more important to have a trustworthy interpreter of medical knowledge, and I strive to play that role through teaching and conversation with my patients.”

I received my BS in philosophy and psychology, MPH in epidemiology, and MD from the University of Michigan. I completed my residency in internal medicine at Johns Hopkins and joined the faculty, where I maintained a busy primary care practice for 25 years, taught generations of medical students and residents, and directed the Johns Hopkins Hypertension Center.

I am board certified in Internal Medicine and am a fellow of the American College of Physicians and the American Society of Hypertension. I was selected as a Top Doctor by Baltimore Magazine in 2020 and 2021.

I have particular expertise in the management of cardiovascular disease, diabetes, and obesity.

My wife, Kimberley, is also a physician, and I have two sons, Michael and Matthew. My interests include fitness, classical music, and current affairs.

Catherine Okuliar, MD

Board Certified General Internist

My philosophy of patient care centers on educating patients and working with them to develop a personalized healthcare plan that meets their needs and incorporates best practice standards. I consider it a privilege to get to know my patients well, and I value the long-term relationships that are at the heart of high quality primary care. I also enjoy coordinating with colleagues in other fields and helping patients navigate our complex health care system.

I graduated magna cum laude from Rice University with a BA in Biology and received my MD from the University of Texas Southwestern. I completed my Internal Medicine internship at the University of California San Francisco and my residency training at Georgetown University. I then joined the faculty at Georgetown where I had an active primary care practice for 17 years. As an associate professor, I was also engaged in teaching and research, and I held multiple leadership roles in medical student and resident education.

I am board certified in Internal Medicine and am a Fellow of the American College of Physicians. I am also a member of the Phi Beta Kappa and Alpha Omega Alpha honor societies. Over the past decade, I have been frequently acknowledged as a Top Doctor by Washingtonian Magazine.

My husband, Alex, is an attorney and we have two teenage sons and a labradoodle. My hobbies include travel, hiking, and tennis.

contact us

If you would like to become a patient in our concierge practice, schedule a meet and greet or request more details regarding our concierge services, please let us know and a concierge coordinator will reach out by phone.

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202.293.3636

our concierge model

meet our providers

Mitchell Dunn, MD General Internist

Beth Horowitz, MD General Internist

Gregory Prokopowicz, MD, MPH General Internist

Catherine Okuliar, MD General Internist

Mitchell Dunn, MD

Board Certified General Internist

Beth Horowitz, MD

Board Certified General Internist

Gregory Prokopowicz, MD, MPH

Board Certified General Internist

Catherine Okuliar, MD

Board Certified General Internist

contact us

payment portal

Mitchell Dunn, MD
General Internist

Beth Horowitz, MD
General Internist

Gregory Prokopowicz, MD, MPH
General Internist

Catherine Okuliar, MD
General Internist