Allen J. Hamaker, MD
NPI 1326028663ActiveIndividual· Internal Medicine· Okc, OK
Internal Medicine (MD) in Okc, Oklahoma, trained at Wayne State University School of Medicine (class of 1990). Their prescriptions cost Medicare Part D more than their services did: $391,673 for 4,205 claims, against $82,915 paid for services in 2024. Amgen Inc. reported $24.58 in payments in 2025, mostly food and beverage.
Overview
| NPI | 1326028663 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | Yes |
| NPI issued | Jan 20, 2006 |
| Last updated in NPPES | Oct 14, 2014 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | 20735 | OK |
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 (OK) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 175 |
|---|---|
| Services billed | 9,275 across 41 procedure codes |
| Paid by Medicare | $82,915 |
Part D prescriptions in 2024
| Prescriptions (claims) | 4,205 · 8,457 30-day fills |
|---|---|
| Patients | 172 |
| Total drug cost | $391,673 |
| Generic share | 86% of claims |
Education and affiliations
| Medical school | Wayne State University School of Medicine |
|---|---|
| Graduation year | 1990 |
| Medicare specialty | Internal Medicine |
Hospital affiliations
- Integris Baptist Medical Center, IncOklahoma City, OK
- Integris Canadian Valley HospitalYukon, OK
- Mercy Hospital Oklahoma City, IncOklahoma City, OK
- O U Medical CenterOklahoma City, OK
- Onecore HealthOklahoma City, OK
Other facilities
- Providence Home CareHome health agency · Oklahoma City, OK
Industry payments (Open Payments)
- 2025$24.58 · 1 payment from 1 company
- 2024$137.38 · 2 payments from 2 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Amgen Inc. | $24.58 | 1 |
What the 2025 payments were for
- Food and Beverage$24.58 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
Other Internal Medicine providers in Okc
- 1720158397