Healthcare provider profile · identity verified

Daniel R Zenk, MD

Internal Medicine · GREELEY, CO · NPI 1326026956

Profile state: partd only Open Payments: 2025 Medicare Part D: 2024 Last identity check: 2026-08-10 Page data build: 2026-08-12

Verified facts

What the public records show

We did not find matching Open Payments records for this doctor in 2025.

These records do not establish that a payment influenced prescribing or medical care.

Payment overview · 2025

General Payments

We did not find matching Open Payments records for this doctor in the selected program year.

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.

Analysis 1 · Payment-linked products

Products named in Open Payments records

No payment-linked product analysis is available because no matching General Payment records were found for the selected year.

Public prescribing for products named in payments

There is no explicit payment-product set available for a Part D comparison.

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.

There is no payer-company set available for this comparison.

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
Levothyroxine Sodium	Levothyroxine Sodium	977	257
Atorvastatin Calcium	Atorvastatin Calcium	942	269
Lisinopril	Lisinopril	817	224
Losartan Potassium	Losartan Potassium	735	219
Omeprazole	Omeprazole	615	174
Amlodipine Besylate	Amlodipine Besylate	603	184
Metoprolol Succinate	Metoprolol Succinate	596	163
Tamsulosin Hcl	Tamsulosin Hcl	405	119
Simvastatin	Simvastatin	391	106
Hydrochlorothiazide	Hydrochlorothiazide	334	102
Pantoprazole Sodium	Pantoprazole Sodium	320	94
Duloxetine Hcl	Duloxetine Hcl	275	75
Gabapentin	Gabapentin	274	75
Metformin Hcl	Metformin Hcl	264	72
Furosemide	Furosemide	263	82
Meloxicam	Meloxicam	245	73
Citalopram Hbr	Citalopram Hydrobromide	218	58
Rosuvastatin Calcium	Rosuvastatin Calcium	209	64
Metoprolol Tartrate	Metoprolol Tartrate	205	53
Eliquis	Apixaban	195	53
Trazodone Hcl	Trazodone Hcl	191	57
Escitalopram Oxalate	Escitalopram Oxalate	184	50
Tramadol Hcl	Tramadol Hcl	181	58
Pravastatin Sodium	Pravastatin Sodium	168	53
Metformin Hcl Er	Metformin Hcl	148	40
Carvedilol	Carvedilol	147	45
Potassium Chloride	Potassium Chloride	147	52
Bupropion Xl	Bupropion Hcl	138	40
Clopidogrel	Clopidogrel Bisulfate	137	41
Finasteride	Finasteride	137	36
Spironolactone	Spironolactone	135	43
Allopurinol	Allopurinol	117	37
Donepezil Hcl	Donepezil Hcl	117	30
Sertraline Hcl	Sertraline Hcl	85	26
Atenolol	Atenolol	84	23
Warfarin Sodium	Warfarin Sodium	82	22
Albuterol Sulfate Hfa	Albuterol Sulfate	79	47
Trulicity	Dulaglutide	79	18
Xarelto	Rivaroxaban	79	18
Fluoxetine Hcl	Fluoxetine Hcl	73	23
Jardiance	Empagliflozin	70	20
Buspirone Hcl	Buspirone Hcl	69	21
Lisinopril-Hydrochlorothiazide	Lisinopril/Hydrochlorothiazide	69	19
Tizanidine Hcl	Tizanidine Hcl	68	34
Synthroid	Levothyroxine Sodium	66	20
Ropinirole Hcl	Ropinirole Hcl	65	18
Hydroxyzine Hcl	Hydroxyzine Hcl	64	18
Venlafaxine Hcl Er	Venlafaxine Hcl	64	19
Montelukast Sodium	Montelukast Sodium	63	20
Prednisone	Prednisone	63	42
Triamterene-Hydrochlorothiazid	Triamterene/Hydrochlorothiazid	63	20
Mirtazapine	Mirtazapine	62	17
Nitrofurantoin Mono-Macro	Nitrofurantoin Monohyd/M-Cryst	59	53
Doxazosin Mesylate	Doxazosin Mesylate	58	18
Glimepiride	Glimepiride	56	17
Losartan-Hydrochlorothiazide	Losartan/Hydrochlorothiazide	55	15
Cefuroxime	Cefuroxime Axetil	53	45
Benazepril Hcl	Benazepril Hcl	48	12
Mounjaro	Tirzepatide	47	suppressed
Oxybutynin Chloride Er	Oxybutynin Chloride	47	13
Valacyclovir	Valacyclovir Hcl	47	19
Estradiol	Estradiol	44	23
Pramipexole Dihydrochloride	Pramipexole Di-Hcl	42	suppressed
Triamcinolone Acetonide	Triamcinolone Acetonide	42	28
Ozempic	Semaglutide	40	13
Symbicort	Budesonide/Formoterol Fumarate	40	11
Ezetimibe	Ezetimibe	39	12
Lorazepam	Lorazepam	39	21
Lantus Solostar	Insulin Glargine,hum.Rec.Anlog	38	17
Celecoxib	Celecoxib	37	16
Fluticasone Propionate	Fluticasone Propionate	37	17
Ondansetron Odt	Ondansetron	35	19
Amitriptyline Hcl	Amitriptyline Hcl	34	suppressed
Lansoprazole	Lansoprazole	34	suppressed
Memantine Hcl	Memantine Hcl	34	suppressed
Propranolol Hcl Er	Propranolol Hcl	34	suppressed
Diltiazem 24hr Er (Cd)	Diltiazem Hcl	33	11
Irbesartan	Irbesartan	33	12
Methenamine Hippurate	Methenamine Hippurate	33	suppressed
Alendronate Sodium	Alendronate Sodium	32	suppressed
Zolpidem Tartrate	Zolpidem Tartrate	32	14
Doxycycline Hyclate	Doxycycline Hyclate	30	29
Pregabalin	Pregabalin	30	suppressed
Alprazolam	Alprazolam	28	15
Isosorbide Mononitrate Er	Isosorbide Mononitrate	28	suppressed
Glipizide	Glipizide	27	suppressed
Chlorthalidone	Chlorthalidone	26	suppressed
Etodolac	Etodolac	26	13
Famotidine	Famotidine	26	suppressed
Farxiga	Dapagliflozin Propanediol	26	suppressed
Labetalol Hcl	Labetalol Hcl	26	suppressed
Quetiapine Fumarate	Quetiapine Fumarate	26	suppressed
Ramipril	Ramipril	26	suppressed
Lamotrigine	Lamotrigine	25	suppressed
Nabumetone	Nabumetone	25	suppressed
Ventolin Hfa	Albuterol Sulfate	25	suppressed
Clonazepam	Clonazepam	24	suppressed
Fluticasone-Salmeterol	Fluticasone Propion/Salmeterol	24	11
Trelegy Ellipta	Fluticasone/Umeclidin/Vilanter	24	suppressed
Cyclobenzaprine Hcl	Cyclobenzaprine Hcl	23	12
Lovastatin	Lovastatin	22	suppressed
Diclofenac Sodium	Diclofenac Sodium	21	suppressed
Bumetanide	Bumetanide	20	suppressed
Felodipine Er	Felodipine	20	suppressed
Nano 2nd Gen Pen Needle	Pen Needle, Diabetic	20	suppressed
Amlodipine Besylate-Benazepril	Amlodipine Besylate/Benazepril	19	suppressed
Sumatriptan Succinate	Sumatriptan Succinate	19	suppressed
Breo Ellipta	Fluticasone/Vilanterol	18	suppressed
Gemfibrozil	Gemfibrozil	18	suppressed
Hydrocodone-Acetaminophen	Hydrocodone/Acetaminophen	18	16
Aripiprazole	Aripiprazole	17	suppressed
Basaglar Kwikpen U-100	Insulin Glargine,hum.Rec.Anlog	17	suppressed
Dicyclomine Hcl	Dicyclomine Hcl	17	suppressed
Januvia	Sitagliptin Phosphate	17	suppressed
Primidone	Primidone	17	suppressed
Valsartan	Valsartan	17	suppressed
Doxepin Hcl	Doxepin Hcl	16	suppressed
Fenofibrate	Fenofibrate Nanocrystallized	16	suppressed
Glipizide Er	Glipizide	16	suppressed
Humulin 70/30 Kwikpen	Insulin Nph Hum/Reg Insulin Hm	16	suppressed
Carbamazepine	Carbamazepine	15	suppressed
Clonidine Hcl	Clonidine Hcl	15	suppressed
Clotrimazole-Betamethasone	Clotrimazole/Betamethasone Dip	15	suppressed
Olmesartan Medoxomil	Olmesartan Medoxomil	15	suppressed
Oxybutynin Chloride	Oxybutynin Chloride	15	suppressed
Oxycodone Hcl	Oxycodone Hcl	15	suppressed
Cephalexin	Cephalexin	14	11
Amoxicillin	Amoxicillin	13	suppressed
Levemir Flexpen	Insulin Detemir	13	suppressed
Levetiracetam	Levetiracetam	13	suppressed
Linzess	Linaclotide	13	suppressed
Methimazole	Methimazole	13	suppressed
Ciprofloxacin Hcl	Ciprofloxacin Hcl	12	12
Colchicine	Colchicine	12	suppressed
Fosinopril Sodium	Fosinopril Sodium	12	suppressed
Lantus	Insulin Glargine,hum.Rec.Anlog	12	suppressed
Torsemide	Torsemide	12	suppressed
Baclofen	Baclofen	11	suppressed
Fenofibrate	Fenofibrate	11	suppressed
Ipratropium Bromide	Ipratropium Bromide	11	suppressed
Loperamide	Loperamide Hcl	11	suppressed
Raloxifene Hcl	Raloxifene Hcl	11	suppressed
Ultra-Fine Nano Pen Needle	Pen Needle, Diabetic	11	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	—	—	—	—	—
2024	—	—	—	—	Complete

Questions to ask

Questions you could discuss with your doctor

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

Methodology version: 2.1

Editorial template version: 2.4

Product contract version: 2.0

Schema version: 0.7.0

Page data build: 2026-08-12T23:34:59.370714+00:00

Publication policy: eligible for indexing after public-launch controls are enabled

Full methodology · Questions & answers · Report a possible error