Healthcare provider profile · identity verified

Mark T. O'Brien, D.O.

Family Practice · SAINT CLAIR, MI · NPI 1255322509

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

BrandGenericClaimsBeneficiaries
Atorvastatin CalciumAtorvastatin Calcium20960
Hydrocodone-AcetaminophenHydrocodone/Acetaminophen19035
Levothyroxine SodiumLevothyroxine Sodium18854
AlprazolamAlprazolam10932
Amlodipine BesylateAmlodipine Besylate10334
GabapentinGabapentin10224
Losartan PotassiumLosartan Potassium10226
Metformin HclMetformin Hcl10126
LisinoprilLisinopril8530
SimvastatinSimvastatin8523
Metoprolol TartrateMetoprolol Tartrate8322
Metoprolol SuccinateMetoprolol Succinate8126
OmeprazoleOmeprazole7723
Tamsulosin HclTamsulosin Hcl7623
FurosemideFurosemide6018
HydrochlorothiazideHydrochlorothiazide6019
Albuterol Sulfate HfaAlbuterol Sulfate5519
MeloxicamMeloxicam5513
IbuprofenIbuprofen5313
Montelukast SodiumMontelukast Sodium5216
Pantoprazole SodiumPantoprazole Sodium5217
Tramadol HclTramadol Hcl4812
Sertraline HclSertraline Hcl46suppressed
Citalopram HbrCitalopram Hydrobromide4513
Fluticasone PropionateFluticasone Propionate4418
SpironolactoneSpironolactone4414
AtenololAtenolol41suppressed
ClopidogrelClopidogrel Bisulfate4012
AllopurinolAllopurinol39suppressed
Oxycodone-AcetaminophenOxycodone Hcl/Acetaminophen35suppressed
Enalapril MaleateEnalapril Maleate3411
PrednisonePrednisone3322
Ventolin HfaAlbuterol Sulfate33suppressed
AzithromycinAzithromycin3130
EliquisApixaban28suppressed
Potassium ChloridePotassium Chloride2811
Pravastatin SodiumPravastatin Sodium28suppressed
Rosuvastatin CalciumRosuvastatin Calcium2811
Duloxetine HclDuloxetine Hcl26suppressed
Hydroxyzine HclHydroxyzine Hcl26suppressed
JardianceEmpagliflozin25suppressed
GemfibrozilGemfibrozil24suppressed
LorazepamLorazepam24suppressed
Ultra-Fine Short Pen NeedlePen Needle, Diabetic24suppressed
ClonazepamClonazepam22suppressed
Cyclobenzaprine HclCyclobenzaprine Hcl22suppressed
Diclofenac SodiumDiclofenac Sodium22suppressed
Pioglitazone HclPioglitazone Hcl22suppressed
TemazepamTemazepam22suppressed
Lantus SolostarInsulin Glargine,hum.Rec.Anlog21suppressed
Zolpidem TartrateZolpidem Tartrate2111
Lisinopril-HydrochlorothiazideLisinopril/Hydrochlorothiazide20suppressed
EzetimibeEzetimibe19suppressed
Metformin Hcl ErMetformin Hcl19suppressed
SynthroidLevothyroxine Sodium19suppressed
Doxepin HclDoxepin Hcl18suppressed
Fluticasone-SalmeterolFluticasone Propion/Salmeterol18suppressed
Isosorbide Mononitrate ErIsosorbide Mononitrate18suppressed
MethocarbamolMethocarbamol18suppressed
Bupropion XlBupropion Hcl17suppressed
CarvedilolCarvedilol17suppressed
CholestyramineCholestyramine (With Sugar)17suppressed
Clonidine HclClonidine Hcl17suppressed
Oxycodone HclOxycodone Hcl17suppressed
RamiprilRamipril17suppressed
DutasterideDutasteride16suppressed
Ultra-Fine Mini Pen NeedlePen Needle, Diabetic16suppressed
Glipizide ErGlipizide15suppressed
PremarinEstrogens, Conjugated15suppressed
Escitalopram OxalateEscitalopram Oxalate14suppressed
Oxybutynin ChlorideOxybutynin Chloride14suppressed
Tresiba Flextouch U-200Insulin Degludec14suppressed
DiazepamDiazepam13suppressed
Fluoxetine HclFluoxetine Hcl13suppressed
Paroxetine HclParoxetine Hcl13suppressed
Quetiapine FumarateQuetiapine Fumarate13suppressed
Sulfamethoxazole-TrimethoprimSulfamethoxazole/Trimethoprim1313
Alendronate SodiumAlendronate Sodium12suppressed
Atrovent HfaIpratropium Bromide12suppressed
Clindamycin PhosphateClindamycin Phosphate12suppressed
FenofibrateFenofibrate12suppressed
Memantine HclMemantine Hcl12suppressed
Novolog FlexpenInsulin Aspart12suppressed
Triamterene-HydrochlorothiazidTriamterene/Hydrochlorothiazid12suppressed
Benazepril HclBenazepril Hcl11suppressed
Dextroamphetamine-AmphetamineDextroamphetamine/Amphetamine11suppressed
LansoprazoleLansoprazole11suppressed
Oxybutynin Chloride ErOxybutynin Chloride11suppressed
Soliqua 100-33Insulin Glargine/Lixisenatide11suppressed
Trazodone HclTrazodone Hcl11suppressed

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.

YearGeneral PaymentsMain payerExplicit productsCompany overlapsPart D coverage
2025
2024 Complete

Questions to ask

Questions you could discuss with your doctor

These are general questions generated from reviewed templates. They are not personalized medical advice.

Sources and limitations

How to read this page

Loaded source releases

DatasetYearPublicationSource
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