NPI registry status
Active
2026 NPPES data Sleep Medicine (Internal Medicine) Physician NPI 1316954092 MD, PHD
Verify on CMS → Sonya Merrill, MD, PHD
Sleep Medicine (Internal Medicine) Physician in Dallas, Texas.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 859 in Sleep Medicine (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
321
Medicare Part D claims · 58 beneficiaries · Sleep Medicine (Internal Medicine) Physician avg: 1K
Generic prescribing
76%
generic claims · 24% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$99.99
1 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Sonya Merrill, MD, PHD filed 321 Medicare Part D claims in 2023 as a Sleep Medicine (Internal Medicine) Physician in Dallas, Texas, prescribing 76% generic.
- 321
- Part D claims, 2023
- 76%
- generic prescribing
- $99.99
- 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.
Sonya Merrill, MD, PHD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
321 Top 43% higher than 57% 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-eligible specialty (heuristic, not verified)
Sonya Merrill, MD, PHD 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 Sonya Merrill, MD, PHD?
Quality data not reportedPrimary specialty
Sleep Medicine (Internal Medicine) Physician
Medicare Part D claims
321 75% vs specialty avg
Specialty distribution in Texas
How Sleep Medicine (Internal Medicine) Physician compares to other specialties among Texas 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 Sleep Medicine (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).
Sonya Merrill, MD, PHD appears in the CMS NPPES registry as a Sleep Medicine (Internal Medicine) Physician provider holding MD, PHD credentials at 7777 FOREST LN, Dallas, TX, 75230, with a listed phone of (972) 566-7684. NPI 1316954092 was issued on 08/02/2006.
Medicare Part D records for calendar year 2023 show 321 prescription claims written by this provider, covering 58 Medicare beneficiaries and totaling roughly $36K in drug spend, split 24% brand-name and 76% generic by claim count.
Sleep Medicine (Internal Medicine) Physician is a narrow specialty nationwide, with 859 enrolled providers across 52 states and an average of 1,310 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 | 1316954092 |
|---|---|
| Specialty | Sleep Medicine (Internal Medicine) Physician |
| Credentials | MD, PHD |
| Gender | Female |
| NPI Issued | 08/02/2006 |
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 Sonya Merrill, MD, PHD. Source: openpaymentsdata.cms.gov.
Total received
$100
Largest payer
HARMONY BIOSCIENCES LLC
Most common payment type
Education
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 - Texas TMB 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 ~77K Texas medical licensees in 2023 - they are NOT specific to Sonya Merrill, MD, PHD. To verify Sonya Merrill, MD, PHD's current license status, search the TMB public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
344
Total board actions, Texas 2023
Across 334 cases
4.47
Actions per 1,000 licensees
Texas statewide rate
probation
Most common action type
94 cases
TMB 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 Texas disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Typical
Sonya Merrill, MD, PHD - brand share 24.0%
Sleep Medicine (Internal Medicine) Physician average
24% brand-name claims vs 76% generic, on 321 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.
321
Total Claims
$36K
Total Drug Cost
58
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 450
- Total Day Supply
- 13,440
- Brand vs Generic
- 24% brand / 76% generic
- Brand Drug Cost
- $22K
- Generic Drug Cost
- $14K
Patient Demographics
- Average Patient Age
- 73.0 years
- Avg HCC Risk Score
- 1.10
- Gender Split
- 50% female / 50% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Sonya Merrill, MD, PHD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Doxepin Hcl
Doxepin Hcl
77 claims
- Gabapentin
Gabapentin
63 claims
- Eszopiclone
Eszopiclone
56 claims
- Horizant 18
Horizant
18 claims
- Armodafinil 17
Armodafinil
17 claims
- Zaleplon 14
Zaleplon
14 claims
- Zolpidem Tartrate 14
Zolpidem Tartrate
14 claims
- Pramipexole Dihydr… 13
Pramipexole Dihydrochloride
13 claims
| Drug | Claims |
|---|---|
| Doxepin Hcl | 77 |
| Gabapentin | 63 |
| Eszopiclone | 56 |
| Horizant Gabapentin Enacarbil | 18 |
| Armodafinil | 17 |
| Zaleplon | 14 |
| Zolpidem Tartrate | 14 |
| Pramipexole Dihydrochloride Pramipexole Di-Hcl | 13 |
| Trazodone Hcl | 13 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Sleep Medicine (Internal Medicine) Physician in TX →
All providers in Texas →
Compare specialties →
Sleep Medicine (Internal Medicine) Physician Overview
How Sonya Merrill, MD, PHD fits within the Sleep Medicine (Internal Medicine) Physician landscape nationally.
859
Sleep Medicine (Internal Medicine) Physician Providers in US
52
States with Sleep Medicine (Internal Medicine) Physician
1,310
Avg Claims per Provider
Sonya Merrill, MD, PHD's 321 claims are below the specialty average of 1,310.
Nearby Sleep Medicine (Internal Medicine) Physician Providers in Texas
Other clinicians with the same primary specialty enrolled in Texas, drawn from the same CMS NPPES roster as Merrill.
Dr. Sanjay Aggarwal
MD
Lake Jackson, TX
Dr. Sergio Alvarez
M.D.
El Paso, TX
Dr. Sarah Andry
DO
San Antonio, TX
Dr. Strahil Atanasov
M.D.
Houston, TX
Dr. Joseph Austin
MD
Arlington, TX
Compare Sleep Medicine (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 Texas medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Sleep Medicine (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 Sonya Merrill, MD, PHD's specialty? ▼
Sonya Merrill, MD, PHD specializes in Sleep Medicine (Internal Medicine) Physician and practices in Dallas, Texas. Credentials: MD, PHD.
How much does Sonya Merrill, MD, PHD prescribe under Medicare Part D? ▼
In 2023, Sonya Merrill, MD, PHD wrote 321 Medicare Part D claims totaling $36K in drug costs for 58 beneficiaries.
Where is Sonya Merrill, MD, PHD located? ▼
Sonya Merrill, MD, PHD is located at 7777 FOREST LN, Dallas, TX, 75230. Phone: (972) 566-7684.
What is Sonya Merrill, MD, PHD's NPI number? ▼
Sonya Merrill, MD, PHD's National Provider Identifier (NPI) is 1316954092, issued on 08/02/2006.
Does Sonya Merrill, MD, PHD prescribe more brand-name or generic drugs? ▼
Sonya Merrill, MD, PHD's prescribing is 24% brand-name and 76% generic drugs by claim count, with $22K in brand drug costs.
How many Sleep Medicine (Internal Medicine) Physician providers are there in the US? ▼
There are 859 Sleep Medicine (Internal Medicine) Physician providers across 52 states in the US. The average Sleep Medicine (Internal Medicine) Physician provider writes 1,310 Medicare Part D claims per year.
What drugs does Sonya Merrill, MD, PHD prescribe most often? ▼
Based on 2023 Medicare Part D data, Sonya Merrill, MD, PHD's most frequently prescribed drugs include Doxepin Hcl, Gabapentin, Eszopiclone. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Sonya Merrill, MD, PHD accept Medicare? ▼
Sonya Merrill, MD, PHD appears in CMS Medicare data with 321 Part D claims and 58 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Sonya Merrill, MD, PHD's credentials? ▼
Sonya Merrill, MD, PHD's NPI is 1316954092 with credentials MD, PHD. 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
Compiled from official public sources by the PlainDoctor editorial team.
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.