Marylyn Virginia Grondin, M.D.
NPI 1841266327ActiveIndividual· Internal Medicine, Gastroenterology· Portsmouth, NH
Internal Medicine, Gastroenterology (M.D.) in Portsmouth, New Hampshire, licensed in NH, with an NPI issued in February 2006. Their prescriptions cost Medicare Part D more than their services did: $248,282 for 504 claims, against $164,985 paid for services in 2024. Phathom Pharmaceuticals, Inc. was the largest of 3 companies reporting payments in 2025, $191.20 in all, mostly food and beverage.
Overview
| NPI | 1841266327 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Feb 24, 2006 |
| Last updated in NPPES | Feb 13, 2012 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Gastroenterology Primary | 207RG0100X | 8703 | NH |
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 - Gastroenterology (NH) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 494 |
|---|---|
| Services billed | 5,303 across 35 procedure codes |
| Paid by Medicare | $164,985 |
Part D prescriptions in 2024
| Prescriptions (claims) | 504 · 1,124 30-day fills |
|---|---|
| Patients | 144 |
| Total drug cost | $248,282 |
| Generic share | 85% of claims |
Industry payments (Open Payments)
- 2025$191.20 · 3 payments from 3 companies
- 2024$413.49 · 8 payments from 6 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Phathom Pharmaceuticals, Inc. | $104.44 | 1 |
| Genzyme Corporation | $61.96 | 1 |
| Salix Pharmaceuticals, A Division of Bausch Health US, LLC | $24.80 | 1 |
What the 2025 payments were for
- Food and Beverage$191.20 · 3 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
Other gastroenterologists in Portsmouth
- 1487932885
- 1891101374