Healthcare provider profile · identity verified

Thomas J Williamson, MD

Internal Medicine · HOUSTON, TX · NPI 1013003201

Profile state: partd only Open Payments: 2025 Medicare Part D: 2024 Last identity check: 2026-08-10 Page data build: 2026-08-12

Verified facts

What the public records show

We did not find matching Open Payments records for this doctor in 2025.

These records do not establish that a payment influenced prescribing or medical care.

Payment overview · 2025

General Payments

We did not find matching Open Payments records for this doctor in the selected program year.

Separate record types

Research & Ownership

Research Payments (direct recipient): not present in the loaded data

Associated Research Funding (for example, named PI): not present in the loaded data

Ownership / Investment: not present in the loaded data

These categories are never added into the General Payments headline. Associated research funding must not be described as money the doctor personally received unless the source record supports that conclusion.

Analysis 1 · Payment-linked products

Products named in Open Payments records

No payment-linked product analysis is available because no matching General Payment records were found for the selected year.

Public prescribing for products named in payments

There is no explicit payment-product set available for a Part D comparison.

The presence of the same drug in both datasets does not show that a payment caused or influenced a prescription.

Analysis 2 · Same-company prescribing overlap

Drugs reported in other payments from the same company that also appear in Medicare Part D

This analysis is independent from products named on this doctor’s individual payment records. A row appears only when the exact Open Payments reporting entity paid this doctor, that same reporting entity reported the drug or biological on at least 10 loaded General Payment records involving at least 2 distinct recipient NPIs, and this doctor has the same non-generic brand in public Part D data. This does not mean the company owns or manufactures the drug.

There is no payer-company set available for this comparison.

These facts do not show that a payment was for the drug, that the company owns or manufactures the drug, or that a payment caused or influenced prescribing.

Public Medicare Part D data

Provider-and-drug rows loaded for 2024

Brand	Generic	Claims	Beneficiaries
Atorvastatin Calcium	Atorvastatin Calcium	630	174
Amlodipine Besylate	Amlodipine Besylate	420	117
Levothyroxine Sodium	Levothyroxine Sodium	301	81
Lisinopril	Lisinopril	295	72
Omeprazole	Omeprazole	283	73
Tamsulosin Hcl	Tamsulosin Hcl	270	75
Losartan Potassium	Losartan Potassium	251	73
Metformin Hcl	Metformin Hcl	229	60
Rosuvastatin Calcium	Rosuvastatin Calcium	216	57
Simvastatin	Simvastatin	214	61
Furosemide	Furosemide	213	52
Metformin Hcl Er	Metformin Hcl	197	54
Gabapentin	Gabapentin	187	59
Glimepiride	Glimepiride	166	43
Pantoprazole Sodium	Pantoprazole Sodium	158	48
Hydrochlorothiazide	Hydrochlorothiazide	153	44
Carvedilol	Carvedilol	151	43
Olmesartan Medoxomil	Olmesartan Medoxomil	142	33
Pravastatin Sodium	Pravastatin Sodium	140	36
Famotidine	Famotidine	134	41
Fluticasone Propionate	Fluticasone Propionate	131	51
Jardiance	Empagliflozin	130	21
Trazodone Hcl	Trazodone Hcl	128	33
Eliquis	Apixaban	123	24
Metoprolol Succinate	Metoprolol Succinate	123	37
Ozempic	Semaglutide	104	18
Amlodipine Besylate-Benazepril	Amlodipine Besylate/Benazepril	102	27
Clopidogrel	Clopidogrel Bisulfate	102	34
Sertraline Hcl	Sertraline Hcl	98	30
Finasteride	Finasteride	97	22
Allopurinol	Allopurinol	93	28
Lisinopril-Hydrochlorothiazide	Lisinopril/Hydrochlorothiazide	89	29
Amlodipine-Olmesartan	Amlodipine Bes/Olmesartan Med	87	23
Potassium Chloride	Potassium Chloride	87	29
Metoprolol Tartrate	Metoprolol Tartrate	85	27
Ezetimibe	Ezetimibe	83	19
Hydrocodone-Acetaminophen	Hydrocodone/Acetaminophen	83	29
Citalopram Hbr	Citalopram Hydrobromide	77	14
Hydralazine Hcl	Hydralazine Hcl	75	16
Losartan-Hydrochlorothiazide	Losartan/Hydrochlorothiazide	74	20
Albuterol Sulfate Hfa	Albuterol Sulfate	67	29
Alendronate Sodium	Alendronate Sodium	67	16
Meloxicam	Meloxicam	67	21
Triamcinolone Acetonide	Triamcinolone Acetonide	67	27
Atenolol	Atenolol	65	22
Nifedipine Er	Nifedipine	63	14
Baclofen	Baclofen	61	17
Escitalopram Oxalate	Escitalopram Oxalate	55	14
Sildenafil Citrate	Sildenafil Citrate	53	suppressed
Montelukast Sodium	Montelukast Sodium	50	15
Basaglar Kwikpen U-100	Insulin Glargine,hum.Rec.Anlog	48	11
Ondansetron Odt	Ondansetron	47	15
Doxazosin Mesylate	Doxazosin Mesylate	46	suppressed
Warfarin Sodium	Warfarin Sodium	45	12
Valsartan	Valsartan	43	11
Olmesartan-Hydrochlorothiazide	Olmesartan/Hydrochlorothiazide	39	suppressed
Tizanidine Hcl	Tizanidine Hcl	39	19
Glipizide-Metformin	Glipizide/Metformin Hcl	37	suppressed
Donepezil Hcl	Donepezil Hcl	36	suppressed
Lorazepam	Lorazepam	36	12
Mounjaro	Tirzepatide	36	suppressed
Januvia	Sitagliptin Phosphate	34	suppressed
Pregabalin	Pregabalin	34	suppressed
Glipizide	Glipizide	33	suppressed
Tramadol Hcl	Tramadol Hcl	32	20
Amiodarone Hcl	Amiodarone Hcl	30	13
Valacyclovir	Valacyclovir Hcl	30	14
Alprazolam	Alprazolam	29	12
Oxybutynin Chloride	Oxybutynin Chloride	28	suppressed
Bumetanide	Bumetanide	27	suppressed
Bupropion Xl	Bupropion Hcl	27	suppressed
Pioglitazone Hcl	Pioglitazone Hcl	26	suppressed
Fenofibrate	Fenofibrate	25	suppressed
Ibuprofen	Ibuprofen	25	suppressed
Fenofibrate	Fenofibrate Nanocrystallized	24	suppressed
Irbesartan	Irbesartan	24	suppressed
Prednisone	Prednisone	24	15
Spironolactone	Spironolactone	24	suppressed
Triamterene-Hydrochlorothiazid	Triamterene/Hydrochlorothiazid	24	suppressed
Trulicity	Dulaglutide	24	suppressed
Olmesartan-Amlodipine-Hctz	Olmesartan/Amlodipin/Hcthiazid	23	suppressed
Duloxetine Hcl	Duloxetine Hcl	22	suppressed
Hydrocortisone	Hydrocortisone	22	suppressed
Memantine Hcl	Memantine Hcl	22	suppressed
Azelastine Hcl	Azelastine Hcl	21	suppressed
Clonazepam	Clonazepam	21	suppressed
Latanoprost	Latanoprost	21	suppressed
Ropinirole Hcl	Ropinirole Hcl	21	suppressed
Valsartan-Hydrochlorothiazide	Valsartan/Hydrochlorothiazide	21	suppressed
Wixela Inhub	Fluticasone Propion/Salmeterol	21	suppressed
Chlorhexidine Gluconate	Chlorhexidine Gluconate	20	suppressed
Methylprednisolone	Methylprednisolone	20	18
Topiramate	Topiramate	20	suppressed
Acyclovir	Acyclovir	19	suppressed
Ciprofloxacin Hcl	Ciprofloxacin Hcl	19	15
Clotrimazole	Clotrimazole	19	suppressed
Jantoven	Warfarin Sodium	19	suppressed
Mirtazapine	Mirtazapine	19	suppressed
Oxybutynin Chloride Er	Oxybutynin Chloride	19	suppressed
Azithromycin	Azithromycin	18	18
Celecoxib	Celecoxib	18	suppressed
Clonidine Hcl	Clonidine Hcl	18	suppressed
Ketoconazole	Ketoconazole	18	suppressed
Ibandronate Sodium	Ibandronate Sodium	17	suppressed
Mupirocin	Mupirocin	17	suppressed
Rybelsus	Semaglutide	17	suppressed
Ciclopirox	Ciclopirox Olamine	16	suppressed
Esomeprazole Magnesium	Esomeprazole Magnesium	15	suppressed
Fluticasone-Salmeterol	Fluticasone Propion/Salmeterol	15	suppressed
Terazosin Hcl	Terazosin Hcl	15	suppressed
Nitrofurantoin Mono-Macro	Nitrofurantoin Monohyd/M-Cryst	14	suppressed
Nystatin	Nystatin	14	suppressed
Ondansetron Hcl	Ondansetron Hcl	14	suppressed
Venlafaxine Hcl Er	Venlafaxine Hcl	14	suppressed
Breyna	Budesonide/Formoterol Fumarate	13	suppressed
Farxiga	Dapagliflozin Propanediol	13	suppressed
Naproxen	Naproxen	13	suppressed
Synthroid	Levothyroxine Sodium	13	suppressed
Diclofenac Sodium	Diclofenac Sodium	12	suppressed
Dorzolamide-Timolol	Dorzolamide Hcl/Timolol Maleat	12	suppressed
Indapamide	Indapamide	12	suppressed
Lantus Solostar	Insulin Glargine,hum.Rec.Anlog	12	suppressed
Metoclopramide Hcl	Metoclopramide Hcl	12	suppressed
Ultra-Fine Mini Pen Needle	Pen Needle, Diabetic	12	suppressed
Bupropion Hcl Sr	Bupropion Hcl	11	suppressed
Diltiazem 24hr Er	Diltiazem Hcl	11	suppressed
Klor-Con M20	Potassium Chloride	11	suppressed
Shingrix	Varicella-Zoster Ge/As01b/Pf	11	11
Ultra-Fine Short Pen Needle	Pen Needle, Diabetic	11	suppressed
Zafirlukast	Zafirlukast	11	suppressed

Timeline

Payment and prescribing data by year

Open Payments and Medicare Part D may refer to different years. They are shown separately rather than aligned as if they describe the same period.

Year	General Payments	Main payer	Explicit products	Company overlaps	Part D coverage
2025	—	—	—	—	—
2024	—	—	—	—	Complete

Questions to ask

Questions you could discuss with your doctor

Are there reasonable alternatives I should understand when we discuss treatment options?
How should I interpret the industry-payment records shown here in the context of my care?

These are general questions generated from reviewed templates. They are not personalized medical advice.

Sources and limitations

How to read this page

Payment and Medicare prescribing data can cover different years; every comparison shows both years explicitly.
Part D does not represent a doctor’s entire practice; it excludes many patients and is subject to CMS public-release thresholds.
Company–drug relationships must have an auditable source, a precise relationship type, and a valid evidence period. Unresolved mappings are not published.
Generic drug claims are not attributed to a specific manufacturer without manufacturer-level evidence.
When a source extract is incomplete, missing rows are never treated as proof of no payments or no prescriptions.

Loaded source releases

Dataset	Year	Publication	Source
CMS Open Payments — General Payments	2025	2026-06-30	Original source
Medicare Part D Prescribers by Provider and Drug	2024	2026-05-06	Original source
NPPES Data Dissemination V2	current / reference data	2026-08-10	Original source

Methodology version: 2.1

Editorial template version: 2.4

Product contract version: 2.0

Schema version: 0.7.0

Page data build: 2026-08-12T23:34:59.370714+00:00

Publication policy: eligible for indexing after public-launch controls are enabled

Full methodology · Questions & answers · Report a possible error