Mary M. Hammack, MD
NPI 1871501874ActiveIndividual· Internal Medicine· Plano, TX
Internal Medicine (MD) in Plano, Texas, trained at University of Texas Medical School at San Antonio (class of 1988). Their prescriptions cost Medicare Part D more than their services did: $800,132 for 8,463 claims, against $447,001 paid for services in 2024. Lilly USA, LLC was the largest of 17 companies reporting payments in 2025, $1,049 in all, mostly food and beverage.
Overview
| NPI | 1871501874 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Aug 4, 2006 |
| Last updated in NPPES | Dec 23, 2008 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | H6269 | TX |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Internal Medicine (TX) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 641 |
|---|---|
| Services billed | 13,001 across 83 procedure codes |
| Paid by Medicare | $447,001 |
Part D prescriptions in 2024
| Prescriptions (claims) | 8,463 · 19,642 30-day fills |
|---|---|
| Patients | 559 |
| Total drug cost | $800,132 |
| Generic share | 87% of claims |
Education and affiliations
| Medical school | University of Texas Medical School at San Antonio |
|---|---|
| Graduation year | 1988 |
| Medicare specialty | Internal Medicine |
| Telehealth | Offers telehealth |
Medical group
- Internal Medicine Associates of Plano PARichardson, TX · 25 clinicians
Hospital affiliations
- Baylor Scott & White Medical Center PlanoPlano, TX
- Dallas Regional Medical CenterMesquite, TX
- Medical City PlanoPlano, TX
- Texas Health Presbyterian Hospital AllenAllen, TX
- Texas Health Presbyterian Hospital PlanoPlano, TX
Other facilities
- Paradigm HomecareHome health agency · Plano, TX
- Baylor Scott & White Institute for RehabilitationInpatient rehabilitation facility · Dallas, TX
Industry payments (Open Payments)
- 2025$1,049 · 61 payments from 17 companies
- 2024$359.76 · 18 payments from 12 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Lilly USA, LLC | $215.60 | 7 |
| Amgen Inc. | $174.42 | 18 |
| Novo Nordisk Inc | $164.03 | 10 |
| Bayer Healthcare Pharmaceuticals Inc. | $78.87 | 4 |
| Abbott Laboratories | $58.16 | 3 |
What the 2025 payments were for
- Food and Beverage$1,049 · 61 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 314 internal medicine physicians in Plano · All internal medicine physicians in Texas