2026 NPPES data Endocrinology, Diabetes & Metabolism Physician NPI 1093840811 M.D.
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MARK MCCLANAHAN, M.D.

Endocrinology, Diabetes & Metabolism Physician in FREDERICKSBURG, Virginia. 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
6K
Medicare Part D claims · 754 beneficiaries · Endocrinology, Diabetes & Metabolism Physician avg: 3K
Generic prescribing
57%
generic claims · 43% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$469
23 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

MARK MCCLANAHAN, M.D. filed 5,964 Medicare Part D claims in 2023 as a Endocrinology, Diabetes & Metabolism Physician in FREDERICKSBURG, Virginia, prescribing 57% generic.

6K
Part D claims, 2023
57%
generic prescribing
$469
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.

MARK MCCLANAHAN, M.D.'s Medicare Part D volume vs every U.S. prescriber

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

5,964 Top 5% higher than 95% 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)

MARK MCCLANAHAN, 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 MARK MCCLANAHAN, M.D.?

Quality data not reported

NPI registry status

Active

Issued 02/22/2007

NPI 1093840811

Primary specialty

Endocrinology, Diabetes & Metabolism Physician

Mid-sized

7,852 US NPIs in this specialty

Medicare Part D claims

5,964 126% vs specialty avg

2023 prescription claims

Specialty avg: 2,639

Specialty distribution in Virginia

How Endocrinology, Diabetes & Metabolism Physician compares to other specialties among Virginia providers

Virginia providers

Endocrinology, Diabetes & Metabolism Physician share within Virginia

1. Endocrinology, Diabetes & Metabolism Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Endocrinology, Diabetes & Metabolism Physician share within Virginia

Specialty board-certification context

Estimated specialty board-certified rate — Endocrinology, Diabetes & Metabolism Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Endocrinology, Diabetes & Metabolism Physician ABMS/AOA estimate

Est. board-certified rate (Endocrinology, Diabetes & Metabolism Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Endocrinology, Diabetes & Metabolism 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).

MARK MCCLANAHAN, M.D. appears in the CMS NPPES registry as a Endocrinology, Diabetes & Metabolism Physician provider holding M.D. credentials at 10711 SPOTSYLVANIA AVE, FREDERICKSBURG, VA, 22408, with a listed phone of (540) 891-8499. NPI 1093840811 was issued on 02/22/2007. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what MCCLANAHAN 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 5,964 prescription claims written by this provider, covering 754 Medicare beneficiaries and totaling roughly $3.3 million in drug spend, split 43% brand-name and 57% generic by claim count, with an opioid prescribing rate of 0.5%. 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.

Endocrinology, Diabetes & Metabolism Physician is a mid-sized specialty nationwide, with 7,852 enrolled providers across 54 states and an average of 2,639 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

10711 SPOTSYLVANIA AVE
FREDERICKSBURG, VA 22408

Provider Details

NPI 1093840811
Specialty Endocrinology, Diabetes & Metabolism Physician
Credentials M.D.
Gender Male
NPI Issued 02/22/2007

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 MARK MCCLANAHAN, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$469

Largest payer

SANOFI-AVENTIS U.S. 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.

Brand vs generic prescribing mix · Above average

MARK MCCLANAHAN, M.D. — brand share 43.0%
Specialty average (est.)

43% brand-name claims vs 57% generic, on 5,964 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.

5,964
Total Claims
$3.3M
Total Drug Cost
754
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
15,003
Total Day Supply
446,233
Brand vs Generic
43% brand / 57% generic
Brand Drug Cost
$3.1M
Generic Drug Cost
$76K
Opioid Claims
28 (0.5% rate)

Patient Demographics

Average Patient Age
74.5 years
Avg HCC Risk Score
1.38
Gender Split
63% female / 37% male
Age Distribution
<65: 30, 65-74: 356, 75-84: 300, 85+: 68

Top Prescribed Drugs (Medicare Part D)

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

What MARK MCCLANAHAN, 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
Levothyroxine Sodium
607
Glimepiride
361
Metformin Hcl Er
Metformin Hcl
335
Metformin Hcl
273
Trulicity
Dulaglutide
246
Synthroid
Levothyroxine Sodium
230
Ozempic
Semaglutide
215
Atorvastatin Calcium
191
Jardiance
Empagliflozin
176
Rosuvastatin Calcium
96

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Endocrinology, Diabetes & Metabolism Physician Overview

How MARK MCCLANAHAN, M.D. fits within the Endocrinology, Diabetes & Metabolism Physician landscape nationally.

7,852
Endocrinology, Diabetes & Metabolism Physician Providers in US
54
States with Endocrinology, Diabetes & Metabolism Physician
2,639
Avg Claims per Provider

MARK MCCLANAHAN, M.D.'s 5,964 claims are above the specialty average of 2,639.

Nearby Endocrinology, Diabetes & Metabolism Physician Providers in Virginia

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

Compare Endocrinology, Diabetes & Metabolism Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is MARK MCCLANAHAN, M.D.'s specialty?
MARK MCCLANAHAN, M.D. specializes in Endocrinology, Diabetes & Metabolism Physician and practices in FREDERICKSBURG, Virginia. Credentials: M.D..
How much does MARK MCCLANAHAN, M.D. prescribe under Medicare Part D?
In 2023, MARK MCCLANAHAN, M.D. wrote 5,964 Medicare Part D claims totaling $3.3M in drug costs for 754 beneficiaries.
Where is MARK MCCLANAHAN, M.D. located?
MARK MCCLANAHAN, M.D. is located at 10711 SPOTSYLVANIA AVE, FREDERICKSBURG, VA, 22408. Phone: (540) 891-8499.
What is MARK MCCLANAHAN, M.D.'s NPI number?
MARK MCCLANAHAN, M.D.'s National Provider Identifier (NPI) is 1093840811, issued on 02/22/2007.
Does MARK MCCLANAHAN, M.D. prescribe more brand-name or generic drugs?
MARK MCCLANAHAN, M.D.'s prescribing is 43% brand-name and 57% generic drugs by claim count, with $3.1M in brand drug costs.
Does MARK MCCLANAHAN, M.D. prescribe opioids?
Yes, MARK MCCLANAHAN, M.D. had 28 opioid claims in 2023 with an opioid prescribing rate of 0.5%.
How many Endocrinology, Diabetes & Metabolism Physician providers are there in the US?
There are 7,852 Endocrinology, Diabetes & Metabolism Physician providers across 54 states in the US. The average Endocrinology, Diabetes & Metabolism Physician provider writes 2,639 Medicare Part D claims per year.
What drugs does MARK MCCLANAHAN, M.D. prescribe most often?
Based on 2023 Medicare Part D data, MARK MCCLANAHAN, M.D.'s most frequently prescribed drugs include Levothyroxine Sodium, Glimepiride, Metformin Hcl Er. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does MARK MCCLANAHAN, M.D. accept Medicare?
MARK MCCLANAHAN, M.D. appears in CMS Medicare data with 5,964 Part D claims and 754 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify MARK MCCLANAHAN, M.D.'s credentials?
MARK MCCLANAHAN, M.D.'s NPI is 1093840811 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