James D. O'Brien, MD
Internal Medicine Physician · Irvine, CA
James D. O'Brien, MD is an internal medicine physician with a practice address in Irvine, California, and NPI 1922188168, issued on Oct 16, 2006. Check the license (California 000000G78458, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- James D. O'Brien
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 000000G78458 CA
Self-reported in NPPES; status is on the state search - Practice location
- 4870 Barranca Pkwy, Irvine, CA 92604
- Phone
- (949) 272-3800
- Enumerated
- Oct 16, 2006
- Record last updated
- Apr 23, 2013 (not updated in 13 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20071110000190); may accept Medicare assignment
- Medical or professional school
- New York Medical College, 1992
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 4870 Barranca Pkwy
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify James D. O'Brien in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 000000G78458Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
5% fewer Medicare Part D claims than the average internal medicine physician in 2024
3,015 Medicare Part D claims for 207 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 35 claims were for opioids.
Most prescribed
- Atorvastatin Calcium264 claims
- Rosuvastatin Calcium144 claims
- Amlodipine Besylate139 claims
- Levothyroxine Sodium129 claims
- Metformin Hcl Er104 claims
- Lisinopril92 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Spectrum Internal Medicine Associates, Inc. A Professional CorporationIrvine, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
James D. O'Brien among 17,696 internal medicine physician records in California
James D. O'Brien, MD is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated1992 · median 2004 among the 11,065 with a school on file
- Record last updated2013 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
155 internal medicine physician records list a practice address in Irvine
They are 155 of the 7,778 NPPES records with a practice address in Irvine, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Irvine → Internal Medicine Physician nationwide →
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Common questions
What is James D. O'Brien, MD's NPI number?
James D. O'Brien, MD's National Provider Identifier (NPI) is 1922188168, issued on Oct 16, 2006. An NPI identifies a provider in billing; it is not a license.
Where is James D. O'Brien, MD located?
The NPPES record lists a practice address at 4870 Barranca Pkwy, Irvine, CA, 92604. Phone: (949) 272-3800. Providers update this record themselves, so call before visiting.
How can I verify James D. O'Brien, MD's license?
NPPES lists California license number 000000G78458, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does James D. O'Brien, MD prescribe under Medicare Part D?
In 2024, James D. O'Brien, MD had 3,015 Medicare Part D claims for 207 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.