2026 NPPES data Internal Medicine Physician NPI 1013981349 MD
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Richard Warren, MD

Internal Medicine Physician in Chicago, Illinois. This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers — including 172,858 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
519
Medicare Part D claims · 118 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
89%
generic claims · 11% brand-name · higher generic rates reduce patient out-of-pocket costs
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Richard Warren, MD filed 519 Medicare Part D claims in 2023 as a Internal Medicine Physician in Chicago, Illinois, prescribing 89% generic.

519
Part D claims, 2023
89%
generic prescribing

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.

Richard Warren, MD's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

519 Top 34% higher than 66% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). This entry sits in this band. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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-eligible specialty (heuristic — not verified)

Richard Warren, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about Richard Warren, MD?

Quality data not reported

NPI registry status

Active

Issued 02/14/2006

NPI 1013981349

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

519 81% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Illinois

How Internal Medicine Physician compares to other specialties among Illinois providers

Illinois providers

Largest specialties in Illinois (% of in-state providers)

Clinical Social Worker — 5.2%Clinical Social Worker5.2%Physical Therapist — 5%Physical Therapist5%Mental Health Counselor — 4.5%Mental Health Counselor4.5%Speech-Language Pathologist — 4.2%Speech-Language Pathologist4.2%Student in an Organized Health Care Education/Training Program — 4.2%Student in an Organized Health Care Education/Training Program4.2%Pharmacist — 4.1%Pharmacist4.1%Internal Medicine Physician — 3.6%Internal Medicine Physician3.6%
Largest specialties in Illinois (% of in-state providers)

Specialty board-certification context

Estimated specialty board-certified rate — Internal Medicine Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Internal Medicine Physician ABMS/AOA estimate

Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate

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).

Richard Warren, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 2301 E 93RD ST, Chicago, IL, 60617, with a listed phone of (773) 731-2982. NPI 1013981349 was issued on 02/14/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Warren most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 519 prescription claims written by this provider, covering 118 Medicare beneficiaries and totaling roughly $780K in drug spend, split 11% brand-name and 89% generic by claim count, with an opioid prescribing rate of 16.2%. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 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

2301 E 93RD ST
Chicago, IL 60617

Provider Details

NPI 1013981349
Specialty Internal Medicine Physician
Credentials MD
Gender Male
NPI Issued 02/14/2006

License & disciplinary context — Illinois IDFPR 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~42K Illinois medical licensees in 2023 — they are NOT specific to Richard Warren, MD. To verify Richard Warren, MD's current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases

IDFPR publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Illinois disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Typical

Richard Warren, MD — brand share 11.0%
Internal Medicine Physician average

11% brand-name claims vs 89% generic, on 519 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.

519
Total Claims
$780K
Total Drug Cost
118
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
719
Total Day Supply
17,582
Brand vs Generic
11% brand / 89% generic
Brand Drug Cost
$648K
Generic Drug Cost
$133K
Opioid Claims
84 (16.2% rate)
Antibiotic Claims
17

Patient Demographics

Average Patient Age
75.0 years
Avg HCC Risk Score
2.08
Gender Split
58% female / 42% male

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What Richard Warren, MD prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Anastrozole
90
Ondansetron Hcl
35
Prochlorperazine Maleate
33
Potassium Chloride
29
Hydrocodone-Acetaminophen
Hydrocodone/Acetaminophen
27
Dexamethasone
25
Oxycodone Hcl
25
Hydroxyurea
20
Valacyclovir
Valacyclovir Hcl
13
Klor-Con M20
Potassium Chloride
11

* 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 Richard Warren, MD fits within the Internal Medicine Physician landscape nationally.

172,858
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider

Richard Warren, MD's 519 claims are below the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Illinois

Other clinicians with the same primary specialty enrolled in Illinois, drawn from the same CMS NPPES roster as Warren.

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 Illinois 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.

Frequently Asked Questions

What is Richard Warren, MD's specialty?
Richard Warren, MD specializes in Internal Medicine Physician and practices in Chicago, Illinois. Credentials: MD.
How much does Richard Warren, MD prescribe under Medicare Part D?
In 2023, Richard Warren, MD wrote 519 Medicare Part D claims totaling $780K in drug costs for 118 beneficiaries.
Where is Richard Warren, MD located?
Richard Warren, MD is located at 2301 E 93RD ST, Chicago, IL, 60617. Phone: (773) 731-2982.
What is Richard Warren, MD's NPI number?
Richard Warren, MD's National Provider Identifier (NPI) is 1013981349, issued on 02/14/2006.
Does Richard Warren, MD prescribe more brand-name or generic drugs?
Richard Warren, MD's prescribing is 11% brand-name and 89% generic drugs by claim count, with $648K in brand drug costs.
Does Richard Warren, MD prescribe opioids?
Yes, Richard Warren, MD had 84 opioid claims in 2023 with an opioid prescribing rate of 16.2%.
How many Internal Medicine Physician providers are there in the US?
There are 172,858 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 Richard Warren, MD prescribe most often?
Based on 2023 Medicare Part D data, Richard Warren, MD's most frequently prescribed drugs include Anastrozole, Ondansetron Hcl, Prochlorperazine Maleate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Richard Warren, MD accept Medicare?
Richard Warren, MD appears in CMS Medicare data with 519 Part D claims and 118 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Richard Warren, MD's credentials?
Richard Warren, MD's NPI is 1013981349 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

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

Compiled from official public sources by the PlainDoctor editorial team.