Healthcare provider profile · identity verified

Mark Christopher Gillis, MD

Family Practice · ITASCA, IL · NPI 1992806509

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 Calcium926268
Levothyroxine SodiumLevothyroxine Sodium440118
Amlodipine BesylateAmlodipine Besylate394115
LisinoprilLisinopril389105
Losartan PotassiumLosartan Potassium24465
Metoprolol SuccinateMetoprolol Succinate24076
Rosuvastatin CalciumRosuvastatin Calcium19961
Pantoprazole SodiumPantoprazole Sodium18064
Metformin Hcl ErMetformin Hcl16152
AlprazolamAlprazolam15836
LorazepamLorazepam15539
SimvastatinSimvastatin14439
Tamsulosin HclTamsulosin Hcl14444
OmeprazoleOmeprazole13050
Sertraline HclSertraline Hcl12638
Alendronate SodiumAlendronate Sodium11340
AllopurinolAllopurinol10834
HydrochlorothiazideHydrochlorothiazide10833
Metoprolol TartrateMetoprolol Tartrate10430
Hydrocodone-AcetaminophenHydrocodone/Acetaminophen8621
MeloxicamMeloxicam8640
Zolpidem TartrateZolpidem Tartrate8526
GabapentinGabapentin8329
FurosemideFurosemide8127
Lisinopril-HydrochlorothiazideLisinopril/Hydrochlorothiazide7923
Amlodipine Besylate-BenazeprilAmlodipine Besylate/Benazepril7521
AtenololAtenolol7519
Tramadol HclTramadol Hcl7318
Metformin HclMetformin Hcl6522
Potassium ChloridePotassium Chloride6323
ClopidogrelClopidogrel Bisulfate6017
Albuterol Sulfate HfaAlbuterol Sulfate5527
Pravastatin SodiumPravastatin Sodium5417
Glipizide ErGlipizide5215
ClonazepamClonazepam5112
Duloxetine HclDuloxetine Hcl5114
FinasterideFinasteride4916
FamotidineFamotidine4817
Trazodone HclTrazodone Hcl4416
CarvedilolCarvedilol4316
Escitalopram OxalateEscitalopram Oxalate4315
ValsartanValsartan4313
AzithromycinAzithromycin4138
Triamterene-HydrochlorothiazidTriamterene/Hydrochlorothiazid4111
EzetimibeEzetimibe3913
Nifedipine ErNifedipine3711
Fluoxetine HclFluoxetine Hcl36suppressed
Montelukast SodiumMontelukast Sodium3611
Venlafaxine Hcl ErVenlafaxine Hcl3311
GlimepirideGlimepiride32suppressed
BumetanideBumetanide3111
Citalopram HbrCitalopram Hydrobromide31suppressed
Dextroamphetamine-Amphet ErDextroamphetamine/Amphetamine31suppressed
Benazepril HclBenazepril Hcl30suppressed
Bupropion XlBupropion Hcl30suppressed
Triamcinolone AcetonideTriamcinolone Acetonide3019
Amitriptyline HclAmitriptyline Hcl29suppressed
EstradiolEstradiol27suppressed
FenofibrateFenofibrate27suppressed
Fluticasone PropionateFluticasone Propionate2613
Losartan-HydrochlorothiazideLosartan/Hydrochlorothiazide26suppressed
ValacyclovirValacyclovir Hcl2615
Cyclobenzaprine HclCyclobenzaprine Hcl25suppressed
Pioglitazone HclPioglitazone Hcl25suppressed
SynthroidLevothyroxine Sodium25suppressed
EliquisApixaban23suppressed
IrbesartanIrbesartan23suppressed
Valsartan-HydrochlorothiazideValsartan/Hydrochlorothiazide22suppressed
JardianceEmpagliflozin21suppressed
SpironolactoneSpironolactone21suppressed
PrednisonePrednisone2015
Sumatriptan SuccinateSumatriptan Succinate20suppressed
Warfarin SodiumWarfarin Sodium20suppressed
Acetaminophen-CodeineAcetaminophen With Codeine19suppressed
CelecoxibCelecoxib19suppressed
Esomeprazole MagnesiumEsomeprazole Magnesium19suppressed
Terazosin HclTerazosin Hcl19suppressed
Ibandronate SodiumIbandronate Sodium18suppressed
LansoprazoleLansoprazole18suppressed
Paroxetine HclParoxetine Hcl18suppressed
Diclofenac SodiumDiclofenac Sodium17suppressed
Doxazosin MesylateDoxazosin Mesylate17suppressed
Doxycycline MonohydrateDoxycycline Monohydrate1717
HydrocortisoneHydrocortisone17suppressed
Nitrofurantoin Mono-MacroNitrofurantoin Monohyd/M-Cryst1715
TemazepamTemazepam17suppressed
Alfuzosin Hcl ErAlfuzosin Hcl16suppressed
Amoxicillin-Clavulanate PotassAmoxicillin/Potassium Clav1612
MethylprednisoloneMethylprednisolone1616
Enalapril MaleateEnalapril Maleate14suppressed
EszopicloneEszopiclone14suppressed
Fluticasone-SalmeterolFluticasone Propion/Salmeterol14suppressed
LovastatinLovastatin14suppressed
Oxybutynin Chloride ErOxybutynin Chloride14suppressed
Isosorbide Mononitrate ErIsosorbide Mononitrate13suppressed
Meclizine HclMeclizine Hcl13suppressed
PregabalinPregabalin13suppressed
Propranolol Hcl ErPropranolol Hcl13suppressed
Verapamil ErVerapamil Hcl13suppressed
CephalexinCephalexin1211
Hydralazine HclHydralazine Hcl12suppressed
Ondansetron OdtOndansetron12suppressed
Oxycodone-AcetaminophenOxycodone Hcl/Acetaminophen12suppressed
TestosteroneTestosterone12suppressed
Advair HfaFluticasone Propion/Salmeterol11suppressed
Mometasone FuroateMometasone Furoate11suppressed

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