Frederick Richard Stack, MD
Internal Medicine Physician · Sioux City, IA
Frederick Richard Stack, MD is an internal medicine physician with a practice address in Sioux City, Iowa, and NPI 1548256977, issued on Sep 21, 2005. Check the license (Iowa MD-46368, as entered in NPPES) on the Iowa Board of Medicine; the Medicare figures below come from public CMS files.
- Name
- Frederick Richard Stack
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License numbers
- MD-46368 IA
24459 AZ
91977 MT
Self-reported in NPPES; status is on the state search - Practice location
- 801 5TH St, Sioux City, IA 51101
- Phone
- (712) 279-2010
- Enumerated
- Sep 21, 2005
- Record last updated
- Jan 28, 2026
- Fax
- (712) 279-2034
- Medicaid ID
- 436693002 AZ
- Medicare enrollment
- Enrolled (PECOS I20210122002608); accepts Medicare assignment
- Medical or professional school
- University Of Nebraska College Of Medicine, 1991
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 871 in Iowa → Look up another NPI →
Also registered at 801 5TH St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Ahmed AbdulrahmanHospitalist Physician1972252856
- Monsurat AdelekePsychiatric/Mental Health Nurse Practitioner1669308433
- Ali Aljuhani, LMSWClinical Social Worker1366918062
- Ashley Anderson, PMHNP-BCPsychiatric/Mental Health Nurse Practitioner1881499242
- Peter Anderson, M.D.Internal Medicine Physician1114967858
- Sydney Backstrom, PHARMDPharmacist1407713357
Verify Frederick Richard Stack in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIowa Board of Medicine
Search for license MD-46368Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
90% fewer Medicare Part D claims than the average internal medicine physician in 2024
315 Medicare Part D claims for 138 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 20 claims were for opioids.
Most prescribed
- Prednisone25 claims
- Amlodipine Besylate13 claims
- Amoxicillin-Clavulanate Potass13 claims
- Cefdinir12 claims
- Atorvastatin Calcium11 claims
- Clopidogrel11 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
4 hospitals and group practices
- Benefis Hospitals IncGreat Falls, MT · Acute Care Hospitals2 of 5 stars
- Banner-University Medical GroupTucson, AZ
- Eastern Maine Medical CenterBangor, ME
- Pines Health ServicesCaribou, ME
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through); hospitals matched to CMS Hospital General Information (Care Compare) (data.cms.gov). Star ratings are CMS hospital ratings, not ratings of this provider.
Frederick Richard Stack among 871 internal medicine physician records in Iowa
Frederick Richard Stack, MD is one of 871 internal medicine physician records with a practice address in Iowa. 70% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 89% newer
- In a Medicare fileYes · 70% of these records are
- In the CMS Doctors and Clinicians fileYes · 44% of these records are
- Graduated1991 · median 2008 among the 386 with a school on file
- Record last updated2026 · 46% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Iowa practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
20 internal medicine physician records list a practice address in Sioux City
They are 20 of the 1,486 NPPES records with a practice address in Sioux City, and 871 internal medicine physician records in Iowa.
All 871 in Iowa → Every provider in Sioux City → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Peter Anderson, M.D.Sioux City, IA 511011114967858
- Amy Callaghan, DOSioux City, IA 511011215924964
- Steven Feeney, M.D.Sioux City, IA 511011649208604
- Neha Mehta, M.D.Sioux City, IA 511011346774940
- Manju Pillai, MDSioux City, IA 511011275843575
- Sandeep Pulimi, MDSioux City, IA 511011730429408
- Anukul Roy, MDSioux City, IA 511011568625796
- Rodrigo Torres, M.D.Sioux City, IA 511011952390189
Common questions
What is Frederick Richard Stack, MD's NPI number?
Frederick Richard Stack, MD's National Provider Identifier (NPI) is 1548256977, issued on Sep 21, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Frederick Richard Stack, MD located?
The NPPES record lists a practice address at 801 5TH St, Sioux City, IA, 51101. Phone: (712) 279-2010. Providers update this record themselves, so call before visiting.
How can I verify Frederick Richard Stack, MD's license?
NPPES lists Iowa license number MD-46368, as entered by the provider. Search the Iowa Board of Medicine at https://dial.iowa.gov/about-dial/boards-and-commissions/medicine. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Frederick Richard Stack, MD prescribe under Medicare Part D?
In 2024, Frederick Richard Stack, MD had 315 Medicare Part D claims for 138 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.