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Internal Medicine in Mason City, Iowa

Data updated monthly · Last refresh September 2026

39 Internal Medicine providers practice in Mason City, and 36% received drug or device company payments in 2025. Listings are drawn from federal public records and are not endorsements.

Internal Medicine providers in Mason City

Listed alphabetically. Payment figures come from the federal Open Payments program, which requires drug and device companies to report what they pay physicians for consulting, speaking, meals, travel and royalties. A disclosed payment is a financial relationship, not evidence of wrongdoing, and many totals reflect a single meal. Figures cover calendar year 2025.

Dr. Adam Hoffmann, DO
Mason City, IA · $1,638 in drug and device payments (2025) · (641) 494-5300
Dr. Ali Mardan, PHD, MD, RPVI, FACP
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-8001
Dr. Amy Tesar, DO
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6999
Dr. Bruce Harlan, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 422-6999
Dr. Burt Humburg, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-7000
Dr. Daniel Pennington, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 422-6999
Dr. David Popp, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6999
Dr. Dejan Spaseski, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-7000
Dr. Dominick Myers, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-7000
Dr. Etee Patel, MD
Mason City, IA · $151 in drug and device payments (2025) · (641) 428-7000
Dr. Evelyn Inga
Mason City, IA · $209 in drug and device payments (2025) · (641) 428-6000
Dr. Fnu Dayawa Da Agoons, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6615
Dr. Hersi Moallin
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6000
Dr. Jacob Obholz, DO
Mason City, IA · $80 in drug and device payments (2025) · (641) 428-5700
Dr. Jake Mullenbach, DO
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6000
Dr. Janice Kirsch, MD
Mason City, IA · No drug or device payments recorded (2025) · Telehealth · (641) 422-6000
Dr. Jashan Gill, MD
Mason City, IA · $1,351 in drug and device payments (2025) · (641) 494-5300
Dr. J.d. Thoreson, M.D.
Mason City, IA · No drug or device payments recorded (2025) · (641) 494-5350
Dr. John Pflugi, DO
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6900
Dr. Jose Morales Oliva, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-5700
Dr. Luke Carlson, MD
Mason City, IA · $38 in drug and device payments (2025) · (641) 428-5700
Dr. Mark Johnson, MD
Mason City, IA · $28,199 in drug and device payments (2025) · (641) 428-7799
Dr. Mary Zahnle, MDI
Mason City, IA · $62 in drug and device payments (2025) · (641) 428-5700
Dr. Matthew Hardee, D.O.
Mason City, IA · $21 in drug and device payments (2025) · (641) 428-5700
Dr. Melissa Frame, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6000
Dr. Muhammad Tahir, M.D.
Mason City, IA · $1,032 in drug and device payments (2025) · (641) 494-5300
Dr. Neena Singh, M.D.
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-7951
Dr. Nithin Karnan, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-5700
Dr. Patrick Dunlay, DO
Mason City, IA · No drug or device payments recorded (2025) · (641) 422-6999
Dr. Phillip Alscher, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 422-6999
Dr. Pratha Shettigar, MD
Mason City, IA · $79 in drug and device payments (2025) · (641) 428-5700
Dr. Richard Trimble, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 422-6999
Dr. Smitha Kanak, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 494-3000
Dr. Tanvi Deshpande, MD
Mason City, IA · $64 in drug and device payments (2025) · (641) 428-5700
Dr. Umer Mukhtar, MD
Mason City, IA · No drug or device payments recorded (2025) · Telehealth · (641) 428-6615
Dr. Vaughan Cipperly, MD
Mason City, IA · $278 in drug and device payments (2025) · (641) 428-6300
Dr. William Riesen, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-5700
Dr. Yuvaraj Thangaraj, MD
Mason City, IA · No drug or device payments recorded (2025) · (641) 428-6999
Dr. Zachary Fuller, DO
Mason City, IA · $5 in drug and device payments (2025) · (641) 428-5700

Conditions Internal Medicine providers in Mason City, Iowa commonly treat

Patients often search by condition rather than specialty. These are conditions typically managed by Internal Medicine providers. Individual practices vary, so confirm with the provider before booking.

Common questions

How many Internal Medicine providers are in Mason City, Iowa?

There are 39 Internal Medicine providers with active NPI records practicing in Mason City, according to federal NPPES data refreshed monthly.

How many Internal Medicine providers in Mason City received drug or device company payments?

14 of 39 (36%) received at least one payment from a drug or device company in 2025, according to the federal Open Payments program.

What conditions do Internal Medicine providers in Mason City treat?

Internal Medicine providers in Mason City commonly treat high blood pressure, type 2 diabetes, high cholesterol, preventive care, chronic disease management and related conditions. Individual practices vary, so confirm with the provider before booking.

Where does this data come from?

Provider records come from the federal NPPES registry and CMS Doctors and Clinicians files. Payment figures come from the CMS Open Payments program for calendar year 2025. The directory refreshes monthly.

All specialties in Mason City Internal Medicine across Iowa

Sources: NPPES (CMS), Doctors and Clinicians national files, CMS Open Payments 2025. Updated monthly. Records are public federal data and are not verified credentials, licensure checks, or endorsements. This directory is informational and not medical advice. How we build this directory.