Isaiah Mark Horton, MD
Internal Medicine Physician · Redlands, CA
Isaiah Mark Horton, MD is an internal medicine physician with a practice address in Redlands, California, and NPI 1053803940, issued on Jun 5, 2018. Check the license (California A200368, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Isaiah Mark Horton
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License numbers
- A200368 CA
0101268175 VA
Self-reported in NPPES; status is on the state search - Practice location
- 245 Terracina Blvd Ste 105, Redlands, CA 92373
- Phone
- (909) 335-4102
- Enumerated
- Jun 5, 2018
- Record last updated
- Dec 17, 2025
- Medicare enrollment
- Enrolled (PECOS I20250619001054); accepts Medicare assignment
- Medical or professional school
- Loma Linda University School Of Medicine, 2018
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 245 Terracina Blvd Ste 105
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Jimfry LinPhysical Therapist1295697274
- Justin WoodPhysical Therapist1073039798
Verify Isaiah Mark Horton in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A200368Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
99% fewer Medicare Part D claims than the average internal medicine physician in 2024
18 Medicare Part D claims, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
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.
The practice group's MIPS final score for 2023 (Medicare payment program): 76.2 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Bills Medicare through one group practice
- Southern California Permanente Medical GroupOntario, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Isaiah Mark Horton among 17,696 internal medicine physician records in California
Isaiah Mark Horton, 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 2018, is newer than 84% of them.
- NPI issued2018 · 84% of these records are older, 14% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2018 · median 2004 among the 11,065 with a school on file
- Record last updated2025 · 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).
56 internal medicine physician records list a practice address in Redlands
They are 56 of the 2,498 NPPES records with a practice address in Redlands, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Redlands → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Charles Chen, M.D.Redlands, CA 923731124050463
- Jun Chiong, M.D., M.P.H.Redlands, CA 923731598730590
- Regan Douty, D.O.Redlands, CA 923731295766442
- Mamdooh Gayid, MDRedlands, CA 923731477554988
- Junku Kang, MDRedlands, CA 923731265474225
- Casey Kennedy, MDRedlands, CA 923731801839246
- Mohammad Osmani, MDRedlands, CA 923731568479483
- Moses Park, M.D.Redlands, CA 923731528079639
Common questions
What is Isaiah Mark Horton, MD's NPI number?
Isaiah Mark Horton, MD's National Provider Identifier (NPI) is 1053803940, issued on Jun 5, 2018. An NPI identifies a provider in billing; it is not a license.
Where is Isaiah Mark Horton, MD located?
The NPPES record lists a practice address at 245 Terracina Blvd Ste 105, Redlands, CA, 92373. Phone: (909) 335-4102. Providers update this record themselves, so call before visiting.
How can I verify Isaiah Mark Horton, MD's license?
NPPES lists California license number A200368, 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 Isaiah Mark Horton, MD prescribe under Medicare Part D?
In 2024, Isaiah Mark Horton, MD had 18 Medicare Part D claims; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is Isaiah Mark Horton, MD's MIPS final score?
The 2023 MIPS final score is 76.2 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.