Terrence Charles Tan, D.O.
Internal Medicine Physician · Colton, CA
Terrence Charles Tan, D.O. is an internal medicine physician with a practice address in Colton, California, and NPI 1851622435, issued on Jan 21, 2010. Check the license (California 20A11111, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Terrence Charles Tan
- Credential
- D.O.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A11111 CA
Self-reported in NPPES; status is on the state search - Practice location
- 400 N Pepper Ave, Colton, CA 92324
- Phone
- (909) 580-6275
- Enumerated
- Jan 21, 2010
- Record last updated
- Nov 18, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20100525000433); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 400 N Pepper Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Shangrila AbaricoRegistered Nurse1609659325
- Susana AbaroRegistered Nurse1114425162
- Patricia AbbaRegistered Nurse1013188838
- Mohammad Hossein Abbasi, MD, MPHStudent in an Organized Health Care Education/Training Program1609622166
- Ala AbedrabboCertified Registered Nurse Anesthetist1972333144
- Mary AboagyeLicensed Vocational Nurse1982875605
Verify Terrence Charles Tan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A11111Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
34% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,082 Medicare Part D claims for 512 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 24% of claims. 37 claims were for opioids.
Most prescribed
- Hydroxychloroquine Sulfate339 claims
- Prednisone312 claims
- Methotrexate189 claims
- Leflunomide117 claims
- Enbrel Sureclick112 claims
- Amjevita(Cf) Autoinjector106 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
- Southern California Permanente Medical GroupRiverside, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Terrence Charles Tan among 17,696 internal medicine physician records in California
Terrence Charles Tan, D.O. 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 2010, is newer than 63% of them.
- NPI issued2010 · 63% of these records are older, 34% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2008 · median 2004 among the 11,065 with a school on file
- Record last updated2021 · 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).
67 internal medicine physician records list a practice address in Colton
They are 67 of the 2,459 NPPES records with a practice address in Colton, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Colton → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Sarkis Arabian, DOColton, CA 923241336202266
- Yanfei Chen, MDColton, CA 923241437103322
- Calvin Duong, M.D.Colton, CA 923241184646119
- Anthony Enenmoh, MDColton, CA 923241811931603
- James Ericson, MDColton, CA 923241881731032
- Douglas Hay, MDColton, CA 923241386690980
- Ireny Ibrahim, MDColton, CA 923241811944598
- Cecilia Katz, MDColton, CA 923241376585349
Common questions
What is Terrence Charles Tan, D.O.'s NPI number?
Terrence Charles Tan, D.O.'s National Provider Identifier (NPI) is 1851622435, issued on Jan 21, 2010. An NPI identifies a provider in billing; it is not a license.
Where is Terrence Charles Tan, D.O. located?
The NPPES record lists a practice address at 400 N Pepper Ave, Colton, CA, 92324. Phone: (909) 580-6275. Providers update this record themselves, so call before visiting.
How can I verify Terrence Charles Tan, D.O.'s license?
NPPES lists California license number 20A11111, 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 Terrence Charles Tan, D.O. prescribe under Medicare Part D?
In 2024, Terrence Charles Tan, D.O. had 2,082 Medicare Part D claims for 512 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.