Shannon Marek, MD
Gastroenterology · San Marcos, TXNPI 1528282050
Payments from drug & device makers
What this record shows
Almost everything reported here is food and beverage — 100.0% of the total across 435 separate payments, which is the pattern of a clinician who attends manufacturer presentations rather than one with a consulting arrangement. 35 manufacturers reported payments, led by AbbVie at 29.2% of the total.
Across 435 payments — averaging $16.45 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- AbbVie$2K
- Salix Pharmaceuticals, A Division Of Bausch Health US, LLC$909
- Bristol Myers Squibb$542
- Johnson & Johnson$538
- QOL Medical, LLC$418
- Takeda Pharmaceuticals U.S.A., Inc.$305
- plus $2K from 29 others
Across 162 payments — averaging $3758.15 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- Gilead$494K
- Pfizer$77K
- E.r. Squibb & Sons, L.L.C.$37K
What the payments were for
- Food & beverage$7,155100%
Most of this is food and beverage — typically meals provided during product presentations at a clinic or hospital. Nationally that is the single largest category of reported payments by count.
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| AbbVie(2 entities) | 141 | $2,093 |
| Salix Pharmaceuticals, A Division Of Bausch Health US, LLC | 69 | $909 |
| Bristol Myers Squibb | 39 | $542 |
| Johnson & Johnson(2 entities) | 34 | $538 |
| QOL Medical, LLC | 18 | $418 |
| Takeda Pharmaceuticals U.S.A., Inc. | 18 | $305 |
| Janssen Scientific Affairs, LLC | 2 | $235 |
| Gilead | 11 | $193 |
| Sanofi | 7 | $176 |
| Regeneron Healthcare Solutions, Inc. | 5 | $162 |
| Lilly USA, LLC | 6 | $146 |
| Phathom Pharmaceuticals, Inc. | 8 | $140 |
| Pfizer | 10 | $137 |
| Intercept Pharmaceuticals, Inc. | 9 | $133 |
| Ferring Pharmaceuticals Inc. | 9 | $122 |
| Merck | 5 | $104 |
| Madrigal Pharmaceuticals | 5 | $94 |
| AMAG Pharmaceuticals, Inc. | 4 | $70 |
| Ipsen Biopharmaceuticals, Inc | 3 | $67 |
| Celltrion USA Inc. | 3 | $65 |
| Shield Therapeutics Inc | 3 | $57 |
| Ardelyx, Inc. | 3 | $46 |
| Pharmacosmos Therapeutics Inc. | 2 | $45 |
| Ironwood Pharmaceuticals, Inc | 3 | $44 |
| Nestle Healthcare Nutrition Inc. | 2 | $40 |
| Evoke Pharma, Inc. | 2 | $37 |
| Amgen | 2 | $36 |
| Aimmune Therapeutics, Inc. | 2 | $36 |
| Daiichi Sankyo Inc. | 2 | $34 |
| Romark Laboratories, LC | 3 | $31 |
| Lucid Diagnostics Inc. | 1 | $24 |
| Vivus LLC | 1 | $23 |
| Braintree Laboratories, Inc. | 1 | $20 |
| Azurity Pharmaceuticals, Inc. | 1 | $17 |
| UCB, Inc. | 1 | $17 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
How this compares
$7,155 in reported general payments places this provider in the 70th percentile of 1,350 gastroenterology providers in Texas.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| CreonLipase/Protease/Amylase | 38 | $105,347 |
| Humira(Cf)Adalimumab | 12 | $81,740 |
| ZenpepLipase/Protease/Amylase | 16 | $64,114 |
| XifaxanRifaximin | 14 | $40,960 |
| LinzessLinaclotide | 31 | $40,313 |
| TrulancePlecanatide | 26 | $25,560 |
| ClenpiqSod Picosulf/Mag Ox/Citric Ac | 136 | $21,218 |
| Mesalamine | 28 | $17,313 |
| Pantoprazole Sodium | 671 | $10,622 |
| Dexlansoprazole DrDexlansoprazole | 31 | $8,804 |
| Budesonide DrBudesonide | 23 | $3,668 |
| Omeprazole | 173 | $3,078 |
| Peg 3350-ElectrolyteSodium Chloride/Nahco3/Kcl/Peg | 123 | $3,017 |
| Sucralfate | 77 | $2,772 |
| Esomeprazole Magnesium | 42 | $1,990 |
Paid to pharmacies, not to this prescriber.
Companies that both paid and supply prescribed drugs
These companies both reported payments to this provider and make drugs the provider prescribed under Medicare Part D in 2024. For most specialties this overlap is expected — a cardiologist who is paid by a cardiology drugmaker also treats heart disease. It is shown so the reader can see it, not because it implies anything on its own.
| Company | Paid to this provider | Part D cost of their drugs |
|---|---|---|
| AbbVieCreon, Humira(Cf), Linzess | $2,093 | $227,40081 claims |
| Salix Pharmaceuticals, A Division Of Bausch Health US, LLCXifaxan, Trulance | $909 | $66,52040 claims |
| Aimmune Therapeutics, Inc.Zenpep | $36 | $64,11416 claims |
| Ferring Pharmaceuticals Inc.Clenpiq | $122 | $21,218136 claims |
Reading this fairly. The Part D column is what drug plans and patients paid pharmacies — this provider received none of it, and it reflects how many patients they treat and what those drugs cost. Against peers, this provider's reported payments sit in the 70th percentile of 1,350 gastroenterology providers in Texas.
Other gastroenterology in San Marcos
- John FordtranDallas$9.9M
- Michael BrownDallas$5.5M
- Bincy AbrahamHouston$1.6M
- Mazen NoureddinHouston$1.5M
- Stephen PappasHouston$1.4M
- Anish PatelFort Sam Houston$1.3M
- Timothy RitterSouthlake$961K
- Parvez MantryDallas$958K
- Nadege GunnWaco$933K
- Brooks CashHouston$867K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.