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Dr. Thomas J Williamson , MD

Internal Medicine • Houston, TX

Active NPI 1013003201 Individual Practitioner Male Practitioner Accepts Medicare assignment
Practice location in NPPES

560 Meyerland Plaza Mall
Houston, TX 770961615

Call 7134423222 Location details and other listings
Medical Disclaimer

This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.

Practice Location & Contact Primary Location

Practice Address

560 Meyerland Plaza Mall

Houston, TX 770961615

Telephone 7134423222
Organization at the Same NPPES Address or Phone
Laboratory Corporation Of America Facility NPI 1689017980

Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.

Other Listings in Public Data

CMS Doctors and Clinicians lists 1 group name: Kelsey-Seybold Medical Group, Pllc. See the list

Source: CMS Doctors and Clinicians National Downloadable File, release date unavailable.

Listings do not confirm current availability, employment or a shared ownership network.

Medicare Profile & Education

Source: CMS Doctors and Clinicians National Downloadable File

Medical School

Ohio State University College Of Medicine

Graduation Year

1997

30-day fills

20,421 standardized 30-day fills in 2024

CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.

What this does not show: 30-day fills

It is not a count of patients and not a measure of quality.

Part D drug cost

$694,251 in 2024

The total cost of these prescriptions in 2024, paid by Medicare drug plans, patients and other payers together.

What this does not show: Part D drug cost

A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.

Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024.

Industry payments (Open Payments)

Fewer than 11 payment records totaling $15.61 in 2024

Drug and medical device companies must report certain payments to doctors and some other clinicians to CMS, such as meals, travel, speaking fees or research funding.

These records are submitted by drug and medical device companies, and a reported payment does not necessarily mean the financial relationship is improper.

General: payments not tied to research, such as meals, travel, consulting or speaking fees.

A reported payment does not necessarily mean the financial relationship is improper. Research payments can go to a hospital or university for a study the clinician leads, not to the clinician personally. Clinicians can dispute records with the company that reported them.

Source: CMS Open Payments, program year 2024.

Guide: How to read an Open Payments record

Years since graduation

29 years (graduated 1997)

CMS Doctors and Clinicians data list 1997 as the year this clinician finished professional school.

What this does not show: Years since graduation

It is not the number of years in practice, and more years does not mean better care.

Source: CMS Doctors and Clinicians National Downloadable File.

NPI first issued

2006

The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.

What this does not show: NPI first issued

NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.

Source: CMS NPPES NPI Registry.

Accepts Medicare assignment

CMS data list this clinician as accepting Medicare assignment. This means agreeing to take the Medicare-approved amount as full payment for covered services.

Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.

Source: CMS Doctors and Clinicians; Medicare.gov, “Does your provider accept Medicare as full payment?”

Guide: What Medicare assignment means

No telehealth indicator

CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.

Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.

Guide: How Medicare covers telehealth

Enrolled in Medicare (PECOS)

Dr. Williamson has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.

It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.

Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.

Guide: What Medicare enrollment (PECOS) means

Can order Medicare-covered services

CMS lists Dr. Williamson as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.

What this does not show: Can order Medicare-covered services

It does not mean the clinician offers these services directly.

Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.

Guide: What ordering and referring status means

Compared with the same specialty in Houston and Texas

Billing and prescribing volume is not a quality rating.

Medicare Part D prescriptions

More Part D prescriptions than 90% of clinicians listed under Internal Medicine in Houston, TX (2024, 826 clinicians with data). Median for this group: 877. Middle half: 121 to 4,265.

More Part D prescriptions than 85% of clinicians listed under Internal Medicine in Texas (2024, 5,674 clinicians with data). Median for this group: 828. Middle half: 121 to 4,824.

Part D drug cost

A higher Part D drug cost than 85% of clinicians listed under Internal Medicine in Houston, TX (2024, 826 clinicians with data). Median for this group: $119,398. Middle half: $7,661 to $420,598.

A higher Part D drug cost than 85% of clinicians listed under Internal Medicine in Texas (2024, 5,674 clinicians with data). Median for this group: $64,859. Middle half: $4,211 to $436,775.

1,488 active clinicians are listed under Internal Medicine with a practice address in Houston, TX (9,191 in Texas).

Addresses are self-reported to NPPES and may be out of date.

Telehealth indicator in Houston

21.8% of these 1,488 clinicians have the CMS telehealth indicator.

61.6% of these 1,488 clinicians are listed by CMS as accepting Medicare assignment.

Sources: CMS Medicare Part D Prescribers (2024), CMS Open Payments (2024), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.

Text: T-MedInfo · Report an error.

Pharma & Medical Device Financial Disclosures

Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments

Open Payments · Program Year 2024

Program year 2024 (payments made January 1 – December 31, 2024): fewer than 11 records totaling $15.61.

Manufacturer Payment Nature Product Type Amount ($)
AstraZeneca Pharmaceuticals LP
Food and Beverage
In-kind items and services
ENHERTU General $15.61

Source: CMS Open Payments, program year 2024, released June 30, 2026.

Medicare Part D Prescribing Profile & Medications

Medicare Part D prescriptions filled, including refills, in 2024.

CMS Part D · Data Year 2024
Prescription Year:
Brand Name Generic Name Prescriptions Day Supply Total Cost Patients
Atorvastatin Calcium Atorvastatin Calcium 630 47,737 $18,860.89 174
Amlodipine Besylate Amlodipine Besylate 420 31,468 $3,595.83 117
Levothyroxine Sodium Levothyroxine Sodium 301 23,318 $774.36 81
Lisinopril Lisinopril 295 22,328 $3,113.90 72
Omeprazole Omeprazole 283 20,757 $7,243.32 73
Tamsulosin Hcl Tamsulosin Hcl 270 19,811 $11,937.58 75
Losartan Potassium Losartan Potassium 251 18,967 $5,444.94 73
Metformin Hcl Metformin Hcl 229 18,317 $3,897.13 60
Rosuvastatin Calcium Rosuvastatin Calcium 216 16,677 $9,535.47 57
Simvastatin Simvastatin 214 18,486 $2,798.09 61
Furosemide Furosemide 213 12,365 $955.75 52
Metformin Hcl Er Metformin Hcl 197 15,635 $2,543.51 54
Gabapentin Gabapentin 187 12,058 $1,638.85 59
Glimepiride Glimepiride 166 13,035 $3,444.72 43
Pantoprazole Sodium Pantoprazole Sodium 158 12,000 $3,128.40 48
Hydrochlorothiazide Hydrochlorothiazide 153 12,108 $788.12 44
Carvedilol Carvedilol 151 10,550 $1,985.55 43
Olmesartan Medoxomil Olmesartan Medoxomil 142 8,520 $12,997.19 33
Pravastatin Sodium Pravastatin Sodium 140 11,920 $5,592.68 36
Famotidine Famotidine 134 8,975 $2,130.70 41
Fluticasone Propionate Fluticasone Propionate 131 7,860 $2,244.64 51
Jardiance Empagliflozin 130 5,759 $109,863.47 21
Trazodone Hcl Trazodone Hcl 128 6,720 $1,179.75 33
Metoprolol Succinate Metoprolol Succinate 123 10,018 $3,158.63 37
Eliquis Apixaban 123 4,691 $88,734.00 24

(top 25 shown)

Source: CMS Part D by Provider and Drug, 2024; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits

Specialties & License Numbers Reported to NPPES

Self-certified to NPPES: 2021-06-23
Internal Medicine Primary Specialty

NUCC Taxonomy Code: 207R00000X

License # reported to NPPES TX L0701

A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.

Check License Status with the State Board License numbers are self-reported to NPPES; T-MedInfo does not confirm them against state records. Current status: Texas Medical Board.
Look Up on State Board Site

Additional State Medicaid & Healthcare Payer Identifiers

Medicaid ID
143528103 (TX)

Medicare (PECOS) Enrollment & Ordering Eligibility

Source: CMS PECOS
Medicare FFS Enrollment Status Medicare Enrollment on File
CMS Provider Specialty

PRACTITIONER - INTERNAL MEDICINE

Medicare Enrollment ID

I20031205000087

Enrollment State Jurisdiction

TX

PECOS Control ID

8527963230

Medicare Order & Referring Eligibility
Clinical Lab & Imaging (Part B) Eligible
Durable Medical Equipment (DME) Eligible
Home Health Agency (HHA) Eligible
Power Mobility Devices (PMD) Eligible

Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.

Medicare Group Practice Enrollments

Source: CMS Doctors and Clinicians National Downloadable File

Kelsey-Seybold Medical Group, Pllc

560 Meyerland Plaza Mall, Houston, TX 770961615

Phone: 7134423222

Clinicians Sharing This Practice Address or Phone

Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.

29 listed
Amaka Akinade , NP

Nurse Practitioner

NPI 1942781257

Nurse Practitioner

Dr. Jenny Bao , MD

Family Medicine

NPI 1295029882

Doctor of Medicine (M.D.)

Dr. Lee Bar-Eli , MD

Family Medicine

NPI 1609006543

Doctor of Medicine (M.D.)

Dr. Alvin Barrow , MD

Family Medicine

NPI 1255517231

Doctor of Medicine (M.D.)

Dr. Vinita Bhagia , MD

Internal Medicine - Endocrinology, Diabetes & Metabolism

NPI 1508060104

Doctor of Medicine (M.D.)

NPI 1659018844

Doctor of Medicine (M.D.)

Career & Practice History

NPI enumerated October 05, 2006.

No changes to the name, practice address, taxonomy or NPI status in this record have been observed in the monthly NPPES data files from January 2017 to August 2026.

No reviews have been published yet. Leave a review.

NPI Administrative Meta

NPI Number: 1013003201
Entity Type:
Individual Provider Physician, Nurse Practitioner, or Solo Healthcare Professional (Type 1 NPI)
Enumeration Date: October 05, 2006
Last Update: June 23, 2021
Sole Proprietor: No

Other Internal Medicine Providers in Houston

All Internal Medicine Providers in Houston

More public profiles in Texas

Directory navigation, in NPI number order.

Mailing Address

11511 Shadow Creek Parkway

Pearland, TX 775847298

Phone: 7134420000

About This Data NPPES fields (address, phone, specialty, license) are self-reported and may be outdated; Medicare fields follow the CMS dataset named in each section. Correct directly at NPPES.