Claire Katherine Horton, MD
Internal Medicine Physician · Oakland, CA
Claire Katherine Horton, MD is an internal medicine physician with a practice address in Oakland, California, and NPI 1649374109, issued on Sep 12, 2006. Check the license (California A71387, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Claire Katherine Horton
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A71387 CA
Self-reported in NPPES; status is on the state search - Practice location
- 3451 E 12TH Street, Oakland, CA 94601
- Phone
- (510) 535-3500
- Enumerated
- Sep 12, 2006
- Record last updated
- Dec 18, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (510) 535-4187
- Medicaid ID
- FHC71021F CA
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 3451 E 12TH Street
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Barbara Benzwi, MDFamily Medicine Physician1063512317
- Roxanna Buenrosto, RNRegistered Nurse1083737852
- Marcos Contreras, RPHPharmacist1184727679
- Caryn Gottcent, NPFFamily Nurse Practitioner1366545683
- Clyde Hinsz, RPHPharmacist1144314006
- Randall Jackson, PHARMD RPHPharmacist1487748323
Verify Claire Katherine Horton in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A71387Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
80% fewer Medicare Part D claims than the average internal medicine physician in 2024
637 Medicare Part D claims for 52 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 16% of claims. 30 claims were for opioids.
Most prescribed
- Atorvastatin Calcium45 claims
- Amlodipine Besylate44 claims
- Levothyroxine Sodium28 claims
- Finasteride26 claims
- Gabapentin24 claims
- Benazepril Hcl22 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.
Claire Katherine Horton among 17,696 internal medicine physician records in California
Claire Katherine 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 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 fileNo · 63% of these records are
- Record last updated2007 · 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).
432 internal medicine physician records list a practice address in Oakland
They are 432 of the 18,558 NPPES records with a practice address in Oakland, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Oakland → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Zaina El-Isa, MDOakland, CA 946011861623555
- Astha Kanani, M.D.Oakland, CA 946011770880163
- Bhrett Lash, MDOakland, CA 946011568489383
- Esteban Lovato, M.D.Oakland, CA 946011376610923
- Joseph Marquis, MDOakland, CA 946011598084329
- John Murphy, M.D.Oakland, CA 946011437119591
- Bruce O'Neil, M.D.Oakland, CA 946011255399580
- Mark Robb, MDOakland, CA 946011053499665
Common questions
What is Claire Katherine Horton, MD's NPI number?
Claire Katherine Horton, MD's National Provider Identifier (NPI) is 1649374109, issued on Sep 12, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Claire Katherine Horton, MD located?
The NPPES record lists a practice address at 3451 E 12TH Street, Oakland, CA, 94601. Phone: (510) 535-3500. Providers update this record themselves, so call before visiting.
How can I verify Claire Katherine Horton, MD's license?
NPPES lists California license number A71387, 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 Claire Katherine Horton, MD prescribe under Medicare Part D?
In 2024, Claire Katherine Horton, MD had 637 Medicare Part D claims for 52 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.