Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
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Dr. Nicholas Gaston Callihan, MD

Individual provider Emergency Medicine Physician · NPI 1821482357

Dr. Nicholas Gaston Callihan, MD is an Emergency Medicine in Houston, Texas. Graduated from Medical College of Georgia School of Medicine in 2015, 11 years ago. Practices with Memorial Hermann Hospital Based Physician Group, a 269-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Texas.

Years since qualifying
11
Trained at
Medical College of Georgia School of Medicine
Licensed in
TX
In the registry since
2015
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

1635 N Loop W
Houston, TX 77008
Phone: (713) 867-2000
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 6431 Fannin St, Houston, TX 77030-1501 — (713) 500-7882

Specialties & licences

Emergency Medicine Physician (primary) Taxonomy 207P00000X · Licence R6532 (TX)

Record details

NPI number1821482357
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedMarch 23, 2015
Last updated in NPPESSeptember 13, 2024
Certification dateSeptember 13, 2024

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyEMERGENCY MEDICINE
Medical schoolMEDICAL COLLEGE OF GEORGIA SCHOOL OF MEDICINE
Graduated 2015 (11 years in practice)
Group practice Memorial Hermann Hospital Based Physician Group — 269 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

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