Healthcare provider profile · identity verified

Karl C Larson, M.D.

Family Practice · OSHKOSH, WI · NPI 1063528529

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 Calcium23776
Losartan PotassiumLosartan Potassium21865
Amlodipine BesylateAmlodipine Besylate21470
Rosuvastatin CalciumRosuvastatin Calcium16744
LisinoprilLisinopril16251
Metoprolol SuccinateMetoprolol Succinate15149
Levothyroxine SodiumLevothyroxine Sodium12636
GabapentinGabapentin12442
OmeprazoleOmeprazole11333
HydrochlorothiazideHydrochlorothiazide10630
FurosemideFurosemide9938
Tamsulosin HclTamsulosin Hcl9830
Albuterol Sulfate HfaAlbuterol Sulfate9732
EliquisApixaban8829
Metoprolol TartrateMetoprolol Tartrate8425
Pantoprazole SodiumPantoprazole Sodium8426
Oxycodone HclOxycodone Hcl7621
Metformin HclMetformin Hcl7423
Tramadol HclTramadol Hcl7429
PrednisonePrednisone7148
Sertraline HclSertraline Hcl6315
Trazodone HclTrazodone Hcl5819
Pravastatin SodiumPravastatin Sodium5214
AllopurinolAllopurinol5117
Hydrocodone-AcetaminophenHydrocodone/Acetaminophen4716
CarvedilolCarvedilol4512
Fluticasone PropionateFluticasone Propionate4527
Metformin Hcl ErMetformin Hcl4012
Fluoxetine HclFluoxetine Hcl37suppressed
ChlorthalidoneChlorthalidone3615
Potassium ChloridePotassium Chloride3617
SimvastatinSimvastatin3615
MeloxicamMeloxicam3416
Zolpidem TartrateZolpidem Tartrate3411
Duloxetine HclDuloxetine Hcl3314
SpironolactoneSpironolactone33suppressed
BumetanideBumetanide3211
Escitalopram OxalateEscitalopram Oxalate31suppressed
Alendronate SodiumAlendronate Sodium30suppressed
Fluticasone-SalmeterolFluticasone Propion/Salmeterol30suppressed
CefdinirCefdinir2923
Diclofenac SodiumDiclofenac Sodium2914
ClopidogrelClopidogrel Bisulfate28suppressed
Venlafaxine Hcl ErVenlafaxine Hcl28suppressed
LorazepamLorazepam2714
LovastatinLovastatin27suppressed
Triamcinolone AcetonideTriamcinolone Acetonide2611
FinasterideFinasteride25suppressed
Lantus SolostarInsulin Glargine,hum.Rec.Anlog25suppressed
AlprazolamAlprazolam2415
Amoxicillin-Clavulanate PotassAmoxicillin/Potassium Clav2422
Glipizide ErGlipizide24suppressed
ClonazepamClonazepam23suppressed
Cyclobenzaprine HclCyclobenzaprine Hcl2311
JardianceEmpagliflozin22suppressed
Pramipexole DihydrochloridePramipexole Di-Hcl22suppressed
GlimepirideGlimepiride21suppressed
Bupropion XlBupropion Hcl20suppressed
Doxazosin MesylateDoxazosin Mesylate20suppressed
Citalopram HbrCitalopram Hydrobromide19suppressed
EzetimibeEzetimibe19suppressed
FamotidineFamotidine19suppressed
GlipizideGlipizide19suppressed
Wixela InhubFluticasone Propion/Salmeterol19suppressed
SynthroidLevothyroxine Sodium18suppressed
Buspirone HclBuspirone Hcl17suppressed
Tresiba Flextouch U-200Insulin Degludec17suppressed
Doxycycline HyclateDoxycycline Hyclate1613
Ondansetron HclOndansetron Hcl16suppressed
Amlodipine Besylate-BenazeprilAmlodipine Besylate/Benazepril15suppressed
Quetiapine FumarateQuetiapine Fumarate15suppressed
AtenololAtenolol14suppressed
Benazepril HclBenazepril Hcl14suppressed
PregabalinPregabalin14suppressed
TemazepamTemazepam14suppressed
Trelegy ElliptaFluticasone/Umeclidin/Vilanter14suppressed
Warfarin SodiumWarfarin Sodium14suppressed
Clotrimazole-BetamethasoneClotrimazole/Betamethasone Dip1311
Dextroamphetamine-AmphetamineDextroamphetamine/Amphetamine13suppressed
Advair HfaFluticasone Propion/Salmeterol12suppressed
Azelastine HclAzelastine Hcl12suppressed
IbuprofenIbuprofen12suppressed
LevetiracetamLevetiracetam12suppressed
Montelukast SodiumMontelukast Sodium12suppressed
Sulfamethoxazole-TrimethoprimSulfamethoxazole/Trimethoprim1211
AmoxicillinAmoxicillin11suppressed
Anoro ElliptaUmeclidinium Brm/Vilanterol Tr11suppressed
CephalexinCephalexin11suppressed
FluconazoleFluconazole11suppressed
HydroxyureaHydroxyurea11suppressed
Pioglitazone HclPioglitazone Hcl11suppressed
ValacyclovirValacyclovir 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