Castro

Getting Here

Public Transportation

Muni

  • F, K, L, M, S trains to Castro/Market
  • 24, 33, 35 run nearby

Bart

All lines to 16th St/Mission Walk to 33-Stanyan at 16th/Mission.

San Francisco Metro Transit Home

Parking

Metered street parking is available near our Castro office.

Additional Information

Our Castro doctors' office at 595 Castro is at street level, near the corner of 19th Street.

Hours

Mon - Fri: 8am - 6pm

Lab Tests

Mon - Fri: 8am - 11am, 12pm - 3pm

Services

Primary Care

Meet the Doctors

  • Michelle Rhee, MD, PhD

    Michelle Rhee, MD, PhD

    Specialty

    Family Medicine

    Years practicing

    8

      Interests

    • Birth Control Counseling
    • Diabetes, Hypertension, Lipid Disorders
    • Exercise, Nutrition, Weight Management
    • LGBT Care
    • Pregnancy and Fertility
    • Preventive Health and Education
    • Women's Health

    Michelle enjoys getting to know her patients on an individual level and within the context of their communities, seeking to understand how environmental factors may be contributing to their health issues. She gives her patients space in which to voice their concerns, and fully engages patients in the medical decision-making process. After graduating with honors from Stanford University, Michelle went on to earn her PhD in biological sciences from the University of Edinburgh in Scotland and her MD from Stanford Medical School. She completed her residency through the San Jose-O'Connor Family Medicine Residency Program and gained extensive knowledge of travel medicine through her over 10 years of postdoctoral research of HIV, tuberculosis and malaria in Africa. Before joining One Medical, she practiced family medicine at Palo Alto Medical Foundation, focusing on pediatrics, women's health, lifestyle modification, travel medicine and chronic disease management. She is board-certified in both Family Medicine and Integrative Holistic Medicine.

  • John Nienow, MD

    John Nienow, MD

    Specialty

    Internal Medicine

    Years practicing

    26

      Interests

    • Complex Medical Conditions
    • HIV Management
    • LGBT Care
    • Men's Health
    • Travel Medicine

    John brings extensive knowledge and expertise in the management of chronic viral diseases, including HIV and Hepatitis C, to One Medical Group. He puts the doctor-patient relationship at the forefront of his practice, spending time getting to know his patients in order to better understand how to treat their health issues. After completing his undergraduate studies at Stanford, John went on to earn his MD from Yale University School of Medicine and completed his residency in Internal Medicine at the University of Washington where he was chief resident. He is a credentialed HIV Specialist and is certified through the American Board of Internal Medicine and the American Board of Addiction Medicine.

    Note: sees patients age 18 and older.

  • Sarah Vensel, PA-C

    Sarah Vensel, PA-C

    Years practicing

    4

      Interests

    • Birth Control Counseling
    • Diabetes, Hypertension, Lipid Disorders
    • Digestive Disorders
    • Integrative Medicine
    • LGBT Care
    • Lifestyle Modification
    • Preventive Health and Education

    East coast native Sarah K. Vensel entered the primary care field in order to get to know her patients, build lasting relationships, and partner with each individual in his or her care. One Medical Group appealed to Sarah because of the longer appointment times, easy accessibility for patients, and the level of collaboration between various types of providers within the practice. Sarah listens intently to each patient and believes every person has a unique history and lifestyle that contributes to his or her health concerns. She also believes there are multiple, valid ways to approach healthcare management. She prefers to work collaboratively with her patients in order to discover what is best suited for each person. She values a well-rounded approach and welcome discussions about medications, lifestyle changes, integrative medicine, as well as combinations of all three. She particularly enjoys working with patients to manage diabetes, hypertension, lipid disorders, and digestive disorders, as well as working with patients in areas of integrative medicine, LGBT care, lifestyle modification, and preventive health and education. To stay fit, Sarah enjoys hiking, biking, and strength training, and in her spare time she loves traveling, camping, taking road trips, or just kicking back in her hammock, reading a book. Sarah attended Albany Medical College and is NCCPA-certified.

  • Yoon Kim-Butterfield, MD

    Yoon Kim-Butterfield, MD

    Specialty

    Internal Medicine

    Years practicing

    8

      Interests

    • Coming soon.

    Yoon Ju Kim-Butterfield was drawn to primary care out of a desire to provide holistic and longitudinal care with an emphasis on prevention. She chose One Medical Group because of the shared commitment to providing quality care in a setting that allows for a patient-centered focus. Yoon listens carefully to each patient’s concerns and collaborates with each individual to create a health care plan that fits into their lifestyle. Yoon particularly enjoys treating endocrine diseases like diabetes, thyroid disorders, and metabolic dysfunction. To stay healthy, she loves hiking and hopping on a bike. In her spare time, she loves to spend time with her son, playing the ukelele, and reading. Yoon grew up in the Chicago area and has been in the Bay Area since completing a yearlong clinical endocrinology fellowship at Stanford University. She attended the University of Illinois Medical School and completed the primary care track of Beth Israel Deaconess Medical Center’s internal residency program. She is ABIM-certified.

  • Martin Kramer, PA-C

    Martin Kramer, PA-C

    Years practicing

    26

      Interests

    • Anxiety, Depression, Insomnia
    • Diabetes, Hypertension, Lipid Disorders
    • Exercise, Nutrition, Weight Management
    • HIV Management
    • Integrative Medicine
    • LGBT Care
    • Men's Health

    Martin takes a proactive approach to patient care, developing personalized treatment plans to head off disease and improve their quality of life. He enjoys getting to know his patients on a personal level, and is especially interested in men’s health and HIV care. Martin completed his physician assistant training at St. Louis University and has honed his skills at several clinics and private practices in the last 20 years, including the Haight-Ashbury Free Clinic and the Conant Medical Group. He is certified through the NCCPA and the AAHIVM as an HIV specialist.

  • Alberto Vajrabukka, NP

    Alberto Vajrabukka, NP

    Years practicing

    5

      Interests

    • Allergies and Asthma
    • Digestive Disorders
    • LGBT Care
    • Musculoskeletal Conditions
    • Preventive Health and Education
    • Travel Medicine

    Alberto shares One Medical's commitment to making health care more accessible to patients through the use of technology. He sees his role as a guide and advocate, listening attentively to his patients' health concerns and conveying information in a clear, approachable manner. Alberto earned his master's of nursing from San Francisco State University and a post-master's certificate as an Adult and Occupational Health Nurse Practitioner from UCSF. He gained extensive travel medicine experience working for the San Francisco Department of Public Health and also practiced several years at CPMC. Most recently he was an occupational health nurse practitioner at the San Francisco VA Medical Center, providing urgent care for work-related injuries and illnesses. He is certified in Adult Medicine through the ANCC.

  • Renaldo Barrios, NP

    Renaldo Barrios, NP

    Years practicing

    18

      Interests

    • Adolescent Medicine
    • Cardiovascular Disease
    • Diabetes, Hypertension, Lipid Disorders
    • HIV Management
    • LGBT Care
    • Men's Health
    • Thyroid Disorders

    Nicaragua native Renaldo Barrios lived in Los Angeles, Miami, New York, and San Diego before settling in San Francisco. Primary care appeals to Renaldo because of the ongoing opportunities he has to treat a wide range of adult health problems. He believes One Medical Group’s model removes barriers and time constraints to allow him to provide the best care possible and establish a professional relationship with his patients. Renaldo enjoys treating diverse patient populations and addressing concerns related to HIV, STDs, diabetes, hypertension, and LGBT issues. Renaldo is a certified diabetes educator and is certified by the Academy of HIV Medicine as an HIV specialist. He is also a current member and former volunteer with the California Association for Nurse Practitioners and has served as a clinical preceptor for NP students. To stay healthy, Renaldo enjoys hiking local trails and exploring the city.

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