Payment overview · 2025
General Payments
$427.83
17 reported records · 11 companies
Healthcare provider profile · identity verified
Nathan E. Riddell, M.D.
Allopathic & Osteopathic Physicians|Internal Medicine|Cardiovascular Disease · WORCESTER, MA · NPI 1245670983
Verified facts
What the public records show
CMS Open Payments records show Nathan E. Riddell, M.D. received $427.83 in general payments during 2025 across 17 reported records.
Amgen Inc. accounted for 16.2% of that reported general-payment amount.
The Open Payments records used for this analysis explicitly named 11 associated products.
A separate comparison found the same explicitly named product in public Medicare Part D data: Farxiga.
AstraZeneca Pharmaceuticals LP reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported BRILINTA as an associated drug or biological on 993 records involving 512 distinct recipient NPIs. Public Medicare Part D data also shows 12 claims for Brilinta by this doctor in 2024.
AstraZeneca Pharmaceuticals LP reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported FARXIGA as an associated drug or biological on 106133 records involving 42906 distinct recipient NPIs. Public Medicare Part D data also shows 28 claims for Farxiga by this doctor in 2024.
PFIZER INC. reported payments to this doctor in 2025. Across the 2025 Open Payments General Payment records loaded for this analysis, that same reporting entity reported ELIQUIS as an associated drug or biological on 87112 records involving 36032 distinct recipient NPIs. Public Medicare Part D data also shows 64 claims for Eliquis by this doctor in 2024.
These records do not establish that a payment influenced prescribing or medical care.
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.
Who paid this doctor?
Companies in 2025 General Payments
| Reported company | Canonical company | Amount | Share | Records | Year |
|---|---|---|---|---|---|
| Amgen Inc. | Unresolved — no canonical attribution shown | $69.24 | 16.2% | 3 | 2025 |
| Alnylam Pharmaceuticals Inc. | Unresolved — no canonical attribution shown | $67.77 | 15.8% | 3 | 2025 |
| Bard Peripheral Vascular, Inc. | Unresolved — no canonical attribution shown | $62.77 | 14.7% | 2 | 2025 |
| Boston Scientific Corporation | Unresolved — no canonical attribution shown | $55.29 | 12.9% | 1 | 2025 |
| Novartis Pharmaceuticals Corporation | Unresolved — no canonical attribution shown | $45.39 | 10.6% | 2 | 2025 |
| CARDIVA MEDICAL, INC. | Unresolved — no canonical attribution shown | $28.38 | 6.6% | 1 | 2025 |
| BridgeBio Pharma, Inc. | Unresolved — no canonical attribution shown | $22.81 | 5.3% | 1 | 2025 |
| Veryan Medical Incorporated | Unresolved — no canonical attribution shown | $21.00 | 4.9% | 1 | 2025 |
| Merck Sharp & Dohme LLC | Unresolved — no canonical attribution shown | $19.83 | 4.6% | 1 | 2025 |
| AstraZeneca Pharmaceuticals LP | Unresolved — no canonical attribution shown | $17.70 | 4.1% | 1 | 2025 |
| PFIZER INC. | Unresolved — no canonical attribution shown | $17.65 | 4.1% | 1 | 2025 |
What were the payments for?
Payment categories
| Category | Amount | Records |
|---|---|---|
| Food and Beverage | $427.83 | 17 |
A meal, consulting fee, royalty, and travel payment describe different kinds of reported relationships and should not be interpreted as equivalent.
Analysis 1 · Payment-linked products
Products named in Open Payments records
| Reported product | Type | Reported company | Related amount* | Records | Year |
|---|---|---|---|---|---|
| REPATHA Normalized: repatha |
Biological | Amgen Inc. | $69.24 | 3 | 2025 |
Source payment records
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| AMVUTTRA Normalized: amvuttra |
Drug | Alnylam Pharmaceuticals Inc. | $67.77 | 3 | 2025 |
Source payment records
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| RotarexS 6 F x 135 cm Normalized: rotarexs 6 f x 135 cm |
Device | Bard Peripheral Vascular, Inc. | $62.77 | 2 | 2025 |
Source payment records
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| OptiCross 6 Normalized: opticross 6 |
Device | Boston Scientific Corporation | $55.29 | 1 | 2025 |
Source payment records
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| LEQVIO Normalized: leqvio |
Drug | Novartis Pharmaceuticals Corporation | $45.39 | 2 | 2025 |
Source payment records
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| CARDIVA VASCADE MVP XL VVCS 10-12F Normalized: cardiva vascade mvp xl vvcs 10 12f |
Device | CARDIVA MEDICAL, INC. | $28.38 | 1 | 2025 |
Source payment records
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| Attruby Normalized: attruby |
Drug | BridgeBio Pharma, Inc. | $22.81 | 1 | 2025 |
Source payment records
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| BioMimics 3D Vascular Stent System Normalized: biomimics 3d vascular stent system |
Device | Veryan Medical Incorporated | $21.00 | 1 | 2025 |
Source payment records
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| VERQUVO Normalized: verquvo |
Drug | Merck Sharp & Dohme LLC | $19.83 | 1 | 2025 |
Source payment records
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| FARXIGA Normalized: farxiga |
Drug | AstraZeneca Pharmaceuticals LP | $17.70 | 1 | 2025 |
Source payment records
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| VYNDAQEL Normalized: vyndaqel |
Drug | PFIZER INC. | $17.65 | 1 | 2025 |
Source payment records
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* Product-associated amounts are non-additive because one payment record may name more than one product.
These products were named on specific Open Payments records. A named product does not show that the payment influenced treatment or prescribing.
Public prescribing for products named in payments
| Open Payments product | Payment year | Part D brand | Part D year | Claims | Match method | Source |
|---|---|---|---|---|---|---|
| FARXIGA farxiga |
2025 | Farxiga | 2024 | 28 Beneficiary count suppressed |
exact normalized | Medicare Part D |
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.
| Paying company | Payment year | Drug reported by same entity | Open Payments evidence | Part D | Claims | Beneficiaries |
|---|---|---|---|---|---|---|
| AstraZeneca Pharmaceuticals LP Exact reporting entity; no affiliate inference |
2025 | BRILINTA open payments reported associated product |
CMS Open Payments — General Payments 993 supporting records · 512 recipient NPIs · example record 1206131430 |
Brilinta · 2024 Exact normalized brand match · 1 Part D row |
12 | suppressed by CMS |
| AstraZeneca Pharmaceuticals LP Exact reporting entity; no affiliate inference |
2025 | FARXIGA open payments reported associated product |
CMS Open Payments — General Payments 106133 supporting records · 42906 recipient NPIs · example record 1206131362 |
Farxiga · 2024 Exact normalized brand match · 1 Part D row |
28 | suppressed by CMS |
| PFIZER INC. Exact reporting entity; no affiliate inference |
2025 | ELIQUIS open payments reported associated product |
CMS Open Payments — General Payments 87112 supporting records · 36032 recipient NPIs · example record 1228794063 |
Eliquis · 2024 Exact normalized brand match · 1 Part D row |
64 | 22 |
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 |
|---|---|---|---|
| Metoprolol Succinate | Metoprolol Succinate | 181 | 55 |
| Atorvastatin Calcium | Atorvastatin Calcium | 171 | 55 |
| Clopidogrel | Clopidogrel Bisulfate | 113 | 33 |
| Spironolactone | Spironolactone | 100 | 33 |
| Furosemide | Furosemide | 75 | 29 |
| Lisinopril | Lisinopril | 74 | 29 |
| Eliquis | Apixaban | 64 | 22 |
| Amlodipine Besylate | Amlodipine Besylate | 54 | 18 |
| Isosorbide Mononitrate Er | Isosorbide Mononitrate | 47 | 13 |
| Losartan Potassium | Losartan Potassium | 47 | 15 |
| Metoprolol Tartrate | Metoprolol Tartrate | 41 | 12 |
| Warfarin Sodium | Warfarin Sodium | 30 | suppressed |
| Farxiga | Dapagliflozin Propanediol | 28 | suppressed |
| Carvedilol | Carvedilol | 27 | 11 |
| Torsemide | Torsemide | 24 | 13 |
| Xarelto | Rivaroxaban | 20 | suppressed |
| Diltiazem 24hr Er (Cd) | Diltiazem Hcl | 16 | suppressed |
| Simvastatin | Simvastatin | 16 | suppressed |
| Prasugrel Hcl | Prasugrel Hcl | 15 | suppressed |
| Hydrochlorothiazide | Hydrochlorothiazide | 14 | suppressed |
| Amiodarone Hcl | Amiodarone Hcl | 13 | suppressed |
| Rosuvastatin Calcium | Rosuvastatin Calcium | 13 | suppressed |
| Brilinta | Ticagrelor | 12 | suppressed |
| Omeprazole | Omeprazole | 12 | suppressed |
| Valsartan | Valsartan | 12 | 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 | $427.83 · 17 records | Amgen Inc. | AMVUTTRA, Attruby, BioMimics 3D Vascular Stent System, CARDIVA VASCADE MVP XL VVCS 10-12F, FARXIGA, LEQVIO, OptiCross 6, REPATHA, RotarexS 6 F x 135 cm, VERQUVO, VYNDAQEL | 3 | — |
| 2024 | — | — | — | — | Complete |
Questions to ask
Questions you could discuss with your doctor
- What role, if any, does Farxiga play in your treatment recommendations for me?
- How do you evaluate evidence when you have a financial relationship with AstraZeneca Pharmaceuticals LP?
- 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 |
Full methodology · Questions & answers · Report a possible error