Dr. John Dennis O Brien, MD
- Part D claims, 2019
- 24
- Industry payments
- $326
- Affiliated sites
- 1
- Medical group
- 1
- State license
- 1
- Practice address
- 410 N 12th St, Oskaloosa, IA 52577
- Practice phone
- Call (641) 672-3360
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Mahaska Health - Primary Care - Oskaloosa (N 12th St)
Multi-specialty group site · Oskaloosa, Iowa
Find Dr. O Brien's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. John Dennis O Brien is a pediatrician in Oskaloosa, Iowa
Dr. O Brien practices at Mahaska Health - Primary Care - Oskaloosa (N 12th St) in Oskaloosa, Iowa.
Dr. O Brien's NPI, 1497740203, was assigned on September 19, 2005. Dr. O Brien holds Iowa license 29352.
- NPI
- 1497740203NPI Registry (opens in a new tab)
- NPI enumeration date
- September 19, 2005
- NPI status
- Active
- Practice phone
- (641) 672-3360
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. John Dennis O Brien practices at 2 locations in Oskaloosa, Iowa
Dr. O Brien's primary practice is Mahaska Health - Primary Care - Oskaloosa (N 12th St), at 410 N 12th St, Oskaloosa, IA 52577. The practice phone is (641) 672-3360. The NPI Registry lists Dr. O Brien's practice address as 1229 C E Ave, Oskaloosa, IA 52577.
- Mahaska Health - Primary Care - Oskaloosa (N 12th St)Primary410 N 12th St, Oskaloosa, IA 52577Phone(641) 672-3360
- NPI Registry address1229 C E Ave, Oskaloosa, IA 52577 · Mahaska CountyPhone(641) 672-3360
Sources: NPPES NPI Registry (CMS); Dmand AI Affiliation Data; Doctors and Clinicians National Downloadable File (CMS); and Dmand AI Practice Data
Dr. John Dennis O Brien is affiliated with 1 site of care and 1 medical group
Dr. O Brien's primary practice is Mahaska Health - Primary Care - Oskaloosa (N 12th St) in Oskaloosa, Iowa. The medical group on file is Mahaska Health.
Sources: Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dmand AI tracks the EHR system at Dr. John Dennis O Brien's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. O Brien practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Mahaska Health - Primary Care - Oskaloosa (N 12th St) | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. John Dennis O Brien is one of 377 pediatricians in Iowa
Pediatrics is Dr. O Brien's primary specialty in the NPI Registry, under taxonomy code 208000000X. Dr. O Brien is licensed in Iowa.
Specialties and state licenses
- Pediatrics, IowaPrimary
Pediatricians near Dr. O Brien
Counts of pediatricians with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. John Dennis O Brien's patients have a median age of 16
Across all payers, Dmand AI patient panel data puts Dr. O Brien's median patient age at 16, with 37% women.
Dr. O Brien's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 16
Patient panel by sex, all payers
- Women37%
- Men58%
Source: Dmand AI Patient Panel Data
Dr. John Dennis O Brien wrote 24 Medicare Part D claims in 2019
In 2019, Dr. O Brien wrote 24 Medicare Part D claims. Every claim was for a generic drug. They cover 2 drugs, with $1,417 in total drug cost.
Dr. O Brien's most prescribed drugs by claims, 2019
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Source: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026
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Dr. John Dennis O Brien received $326 in industry payments from 2016 to 2022
CMS Open Payments shows 19 general payments to Dr. O Brien from 17 drug and device companies from 2016 to 2022. Food and beverage make up the largest share, 100% of the total. Novo Nordisk Inc paid the most, $32.
General payments to Dr. O Brien by program year, 2016 to 2022
Companies that paid Dr. O Brien the most, 2016 to 2022
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. John Dennis O Brien's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Affiliation DataDoctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDoctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. John Dennis O Brien
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. John Dennis O Brien's NPI number?
Dr. John Dennis O Brien's NPI number is 1497740203. It was assigned on September 19, 2005, and it is active in the NPI Registry.
What kind of doctor is Dr. John Dennis O Brien?
Dr. John Dennis O Brien is a pediatrician in Oskaloosa, Iowa. The primary specialty in the NPI Registry is Pediatrics Physician (taxonomy code 208000000X).
Where does Dr. John Dennis O Brien practice?
Dr. O Brien practices at 410 N 12th St, Oskaloosa, IA 52577. Dr. O Brien also practices at 1229 C E Ave, Oskaloosa, IA 52577. Dr. O Brien's primary practice is Mahaska Health - Primary Care - Oskaloosa (N 12th St) in Oskaloosa, Iowa.
What is Dr. John Dennis O Brien's office phone number?
The practice phone on file for Dr. O Brien is (641) 672-3360.
What is Dr. John Dennis O Brien's medical license number?
Dr. O Brien holds Iowa license 29352.
What medical group is Dr. John Dennis O Brien part of?
Dr. O Brien is linked to Mahaska Health.
What drugs does Dr. John Dennis O Brien prescribe most?
In 2019 Medicare Part D data, Dr. O Brien's most prescribed drugs by claims were Nadolol and Paroxetine HCl.
Has Dr. John Dennis O Brien received payments from drug or device companies?
CMS Open Payments shows $326 in general payments to Dr. O Brien from 17 companies from 2016 to 2022. The largest total came from Novo Nordisk Inc.
How long has Dr. John Dennis O Brien been practicing?
Dr. O Brien's NPI was assigned in 2005.
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