2026 NPPES data Internal Medicine Physician NPI 1366418667 M.D.
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TERRENCE BRENNAN, M.D.

Internal Medicine Physician in WARREN, Michigan. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
5K
Medicare Part D claims · 374 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
91%
generic claims · 9% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$120.19
6 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

TERRENCE BRENNAN, M.D. filed 5,301 Medicare Part D claims in 2023 as a Internal Medicine Physician in WARREN, Michigan, prescribing 91% generic.

5K
Part D claims, 2023
91%
generic prescribing
$120.19
industry payments (Sunshine Act)

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.

TERRENCE BRENNAN, M.D.'s Medicare Part D volume vs every U.S. prescriber

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

5,301 Top 6% higher than 94% 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%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2,000–2,200: 213,991 prescribers (16%). This entry sits in this band. 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)

TERRENCE BRENNAN, M.D. 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 TERRENCE BRENNAN, M.D.?

Quality data not reported

NPI registry status

Active

Issued 02/27/2006

NPI 1366418667

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

5,301 95% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Michigan

How Internal Medicine Physician compares to other specialties among Michigan providers

Michigan providers

Internal Medicine Physician share within Michigan

1. Internal Medicine Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Internal Medicine Physician share within Michigan

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).

TERRENCE BRENNAN, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 27472 SCHOENHERR RD STE 100, WARREN, MI, 48088, with a listed phone of (586) 751-8844. NPI 1366418667 was issued on 02/27/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what BRENNAN 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 5,301 prescription claims written by this provider, covering 374 Medicare beneficiaries and totaling roughly $357K in drug spend, split 9% brand-name and 91% generic by claim count, with an opioid prescribing rate of 0.8%. 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

27472 SCHOENHERR RD STE 100
WARREN, MI 48088

Provider Details

NPI 1366418667
Specialty Internal Medicine Physician
Credentials M.D.
Gender Male
NPI Issued 02/27/2006

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for TERRENCE BRENNAN, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$120

Largest payer

Grifols USA, LLC

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

License & disciplinary context — Michigan MI-BOM 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 ~41K Michigan medical licensees in 2023 — they are NOT specific to TERRENCE BRENNAN, M.D.. To verify TERRENCE BRENNAN, M.D.'s current license status, search the MI-BOM public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

123
Total board actions, Michigan 2023
Across 120 cases
3.00
Actions per 1,000 licensees
Michigan statewide rate
probation
Most common action type
44 cases

MI-BOM 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 Michigan disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Generic-heavy

TERRENCE BRENNAN, M.D. — brand share 9.0%
Specialty average (est.)

9% brand-name claims vs 91% generic, on 5,301 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.

5,301
Total Claims
$357K
Total Drug Cost
374
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
13,504
Total Day Supply
399,731
Brand vs Generic
9% brand / 91% generic
Brand Drug Cost
$243K
Generic Drug Cost
$113K
Opioid Claims
41 (0.8% rate)
Antibiotic Claims
115

Patient Demographics

Average Patient Age
79.6 years
Avg HCC Risk Score
1.30
Gender Split
45% female / 55% male

Top Prescribed Drugs (Medicare Part D)

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

What TERRENCE BRENNAN, M.D. 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
Atorvastatin Calcium
387
Simvastatin
362
Levothyroxine Sodium
356
Amlodipine Besylate
196
Lisinopril
182
Metformin Hcl
180
Omeprazole
176
Losartan Potassium
175
Allopurinol
168
Alprazolam
111

* 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 TERRENCE BRENNAN, M.D. 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

TERRENCE BRENNAN, M.D.'s 5,301 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Michigan

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

Compare Internal Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is TERRENCE BRENNAN, M.D.'s specialty?
TERRENCE BRENNAN, M.D. specializes in Internal Medicine Physician and practices in WARREN, Michigan. Credentials: M.D..
How much does TERRENCE BRENNAN, M.D. prescribe under Medicare Part D?
In 2023, TERRENCE BRENNAN, M.D. wrote 5,301 Medicare Part D claims totaling $357K in drug costs for 374 beneficiaries.
Where is TERRENCE BRENNAN, M.D. located?
TERRENCE BRENNAN, M.D. is located at 27472 SCHOENHERR RD STE 100, WARREN, MI, 48088. Phone: (586) 751-8844.
What is TERRENCE BRENNAN, M.D.'s NPI number?
TERRENCE BRENNAN, M.D.'s National Provider Identifier (NPI) is 1366418667, issued on 02/27/2006.
Does TERRENCE BRENNAN, M.D. prescribe more brand-name or generic drugs?
TERRENCE BRENNAN, M.D.'s prescribing is 9% brand-name and 91% generic drugs by claim count, with $243K in brand drug costs.
Does TERRENCE BRENNAN, M.D. prescribe opioids?
Yes, TERRENCE BRENNAN, M.D. had 41 opioid claims in 2023 with an opioid prescribing rate of 0.8%.
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 TERRENCE BRENNAN, M.D. prescribe most often?
Based on 2023 Medicare Part D data, TERRENCE BRENNAN, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Simvastatin, Levothyroxine Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does TERRENCE BRENNAN, M.D. accept Medicare?
TERRENCE BRENNAN, M.D. appears in CMS Medicare data with 5,301 Part D claims and 374 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify TERRENCE BRENNAN, M.D.'s credentials?
TERRENCE BRENNAN, M.D.'s NPI is 1366418667 with credentials M.D.. 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