NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1962848663 MD
Verify on CMS → Eugene Tan, MD
Internal Medicine Physician in Wheat Ridge, Colorado.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 172,737 in Internal Medicine Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
3K
Medicare Part D claims · 823 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
90%
generic claims · 10% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
What the federal data shows
Eugene Tan, MD filed 2,872 Medicare Part D claims in 2023 as an Internal Medicine Physician in Wheat Ridge, Colorado, prescribing 90% generic.
- 3K
- Part D claims, 2023
- 90%
- generic prescribing
- Likely
- board-certified (heuristic)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Eugene Tan, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
2,872 Top 12% higher than 88% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
✓
Board certification likely (heuristic, not verified)
Eugene Tan, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Eugene Tan, MD?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
2,872 6% vs specialty avg
Specialty distribution in Colorado
How Internal Medicine Physician compares to other specialties among Colorado providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Internal Medicine Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Eugene Tan, MD appears in the CMS NPPES registry as an Internal Medicine Physician provider holding MD credentials at 4803 WARD RD, Wheat Ridge, CO, 80033, with a listed phone of (303) 338-4545. NPI 1962848663 was issued on 05/21/2013.
Medicare Part D records for calendar year 2023 show 2,872 prescription claims written by this provider, covering 823 Medicare beneficiaries and totaling roughly $148K in drug spend, split 10% brand-name and 90% generic by claim count, with an opioid prescribing rate of 1.7%.
Internal Medicine Physician is a high-volume specialty nationwide, with 172,737 enrolled providers across 56 states and an average of 2,716 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1962848663 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 05/21/2013 |
Hospital and facility affiliations
Facilities where Eugene Tan, MD bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Colorado Permanente Medical Group PC
Denver, CO
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Brand vs generic prescribing mix · Typical
Eugene Tan, MD - brand share 10.0%
Internal Medicine Physician average
10% brand-name claims vs 90% generic, on 2,872 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
2,872
Total Claims
$148K
Total Drug Cost
823
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 6,516
- Total Day Supply
- 185,099
- Brand vs Generic
- 10% brand / 90% generic
- Brand Drug Cost
- $97K
- Generic Drug Cost
- $51K
- Opioid Claims
- 49 (1.7% rate)
- Antibiotic Claims
- 135
Patient Demographics
- Average Patient Age
- 76.1 years
- Avg HCC Risk Score
- 1.33
- Gender Split
- 55% female / 45% male
- Age Distribution
- <65: 22, 65-74: 343, 75-84: 330, 85+: 128
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Eugene Tan, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
202 claims
- Tizanidine Hcl
Tizanidine Hcl
118 claims
- Amlodipine Besylate
Amlodipine Besylate
97 claims
- Levothyroxine Sodium
Levothyroxine Sodium
86 claims
- Simvastatin
Simvastatin
83 claims
- Duloxetine Hcl
Duloxetine Hcl
81 claims
- Omeprazole 79
Omeprazole
79 claims
- Losartan Potassium 72
Losartan Potassium
72 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 202 |
| Tizanidine Hcl | 118 |
| Amlodipine Besylate | 97 |
| Levothyroxine Sodium | 86 |
| Simvastatin | 83 |
| Duloxetine Hcl | 81 |
| Omeprazole | 79 |
| Losartan Potassium | 72 |
| Lisinopril | 69 |
| Rosuvastatin Calcium | 62 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Internal Medicine Physician Overview
How Eugene Tan, MD fits within the Internal Medicine Physician landscape nationally.
172,737
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider
Eugene Tan, MD's 2,872 claims are above the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in Colorado
Other clinicians with the same primary specialty enrolled in Colorado, drawn from the same CMS NPPES roster as Tan.
Dr. Emily Aaron
MD
Denver, CO
Dr. Cynthia Abacan
MD
Pueblo, CO
Dr. David Abbey
MS MD
Fort Collins, CO
Dr. Ahmed Abdulrahman
MD
Pueblo, CO
Dr. Victor Abela
D.O.
Denver, CO
Compare Internal Medicine Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Colorado medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Internal Medicine Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Eugene Tan, MD's specialty? ▼
Eugene Tan, MD specializes in Internal Medicine Physician and practices in Wheat Ridge, Colorado. Credentials: MD.
How much does Eugene Tan, MD prescribe under Medicare Part D? ▼
In 2023, Eugene Tan, MD wrote 2,872 Medicare Part D claims totaling $148K in drug costs for 823 beneficiaries.
Where is Eugene Tan, MD located? ▼
Eugene Tan, MD is located at 4803 WARD RD, Wheat Ridge, CO, 80033. Phone: (303) 338-4545.
What is Eugene Tan, MD's NPI number? ▼
Eugene Tan, MD's National Provider Identifier (NPI) is 1962848663, issued on 05/21/2013.
Does Eugene Tan, MD prescribe more brand-name or generic drugs? ▼
Eugene Tan, MD's prescribing is 10% brand-name and 90% generic drugs by claim count, with $97K in brand drug costs.
Does Eugene Tan, MD prescribe opioids? ▼
Yes, Eugene Tan, MD had 49 opioid claims in 2023 with an opioid prescribing rate of 1.7%.
How many Internal Medicine Physician providers are there in the US? ▼
There are 172,737 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does Eugene Tan, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Eugene Tan, MD's most frequently prescribed drugs include Atorvastatin Calcium, Tizanidine Hcl, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Eugene Tan, MD accept Medicare? ▼
Eugene Tan, MD appears in CMS Medicare data with 2,872 Part D claims and 823 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Eugene Tan, MD's credentials? ▼
Eugene Tan, MD's NPI is 1962848663 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.