Ythanh Duy Nguyen, MD
Internal Medicine Physician · Rancho Cucamonga, CA
Ythanh Duy Nguyen, MD is an internal medicine physician with a practice address in Rancho Cucamonga, California, and NPI 1255391181, issued on Mar 24, 2006. Check the license (California A84989, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Ythanh Duy Nguyen
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A84989 CA
Self-reported in NPPES; status is on the state search - Practice location
- 8235 Rochester Ave, Rancho Cucamonga, CA 91730
- Phone
- (909) 484-4900
- Enumerated
- Mar 24, 2006
- Record last updated
- Dec 14, 2025
- Fax
- (909) 781-2949
- Medicare enrollment
- Enrolled (PECOS I20050804000570); 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 8235 Rochester Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Rene Lee, D.O.Pediatrics Physician1467694000
- Tiffany Quan, M.D.Pediatrics Physician1750397261
- Viet Ta, MDFamily Medicine Physician1861415390
Verify Ythanh Duy Nguyen in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A84989Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
26% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,357 Medicare Part D claims for 508 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 19% of claims. 126 claims were for opioids.
Most prescribed
- Furosemide154 claims
- Carvedilol87 claims
- Levofloxacin71 claims
- Atorvastatin Calcium68 claims
- Eliquis64 claims
- Pantoprazole Sodium63 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.
Industry payments in 2024: $121.41
5 payments; by number, the most common kind was food and beverage; the largest payer was Pfizer Inc. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through 2 group practices
- Premier Hospitalist Group IncUpland, CA
- Premier Medical Group OF CaliforniaUpland, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Ythanh Duy Nguyen among 17,696 internal medicine physician records in California
Ythanh Duy Nguyen, 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
- Graduated2002 · 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).
Internal Medicine Physician providers in California
There are 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Rancho Cucamonga → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Mohamed Ali, M.D.Rancho Cucamonga, CA 917301548395239
- Nena ArciagaRancho Cucamonga, CA 917301497594097
- Catherine Joy CabugaoRancho Cucamonga, CA 917301063091098
- Tarek Ezzeddine, MDRancho Cucamonga, CA 917301740471879
- Hetalben Makwana, MDRancho Cucamonga, CA 917301093028078
- Cong Phan, M.D.Rancho Cucamonga, CA 917301386778033
- Teri Rhetta, M.D.Rancho Cucamonga, CA 917301669685293
- Rishi Talwar, MDRancho Cucamonga, CA 917301699184184
Common questions
What is Ythanh Duy Nguyen, MD's NPI number?
Ythanh Duy Nguyen, MD's National Provider Identifier (NPI) is 1255391181, issued on Mar 24, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Ythanh Duy Nguyen, MD located?
The NPPES record lists a practice address at 8235 Rochester Ave, Rancho Cucamonga, CA, 91730. Phone: (909) 484-4900. Providers update this record themselves, so call before visiting.
How can I verify Ythanh Duy Nguyen, MD's license?
NPPES lists California license number A84989, 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 Ythanh Duy Nguyen, MD prescribe under Medicare Part D?
In 2024, Ythanh Duy Nguyen, MD had 2,357 Medicare Part D claims for 508 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.