Matthew Nienaber, D.O.
Internal Medicine Physician · Santa Monica, CA
Matthew Nienaber, D.O. is an internal medicine physician with a practice address in Santa Monica, California, and NPI 1033535182, issued on Mar 13, 2014. Check the license (California 20A14759, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Matthew Nienaber
- Credential
- D.O.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A14759 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1821 Wilshire Blvd Ste 100, Santa Monica, CA 90403
- Phone
- (310) 575-3100
- Enumerated
- Mar 13, 2014
- Record last updated
- May 28, 2026
- Fax
- (310) 575-3102
- Medicare enrollment
- Enrolled (PECOS I20170911003106); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 1821 Wilshire Blvd Ste 100
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Maryam Farazha, MDFamily Medicine Physician1063416840
- Shahrouz Ganjian, MDPediatrics Physician1457582934
- Laura GoldsmithNurse Practitioner1629624077
- Daniel Reiness, M.S. ED.Mental Health Counselor1639588742
Verify Matthew Nienaber in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A14759Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
12% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,803 Medicare Part D claims for 233 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 10% of claims. 154 claims were for opioids.
Most prescribed
- Atorvastatin Calcium202 claims
- Gabapentin94 claims
- Levothyroxine Sodium87 claims
- Hydrocodone-Acetaminophen80 claims
- Amlodipine Besylate79 claims
- Metformin Hcl76 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.
Industry payments in 2024: $329.41
14 payments; by number, the most common kind was food and beverage; the largest payer was AstraZeneca Pharmaceuticals LP. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Providence Saint Johns Medical FoundationSanta Monica, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Matthew Nienaber among 17,696 internal medicine physician records in California
Matthew Nienaber, D.O. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2014, is newer than 74% of them.
- NPI issued2014 · 74% of these records are older, 24% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2014 · median 2004 among the 11,065 with a school on file
- Record last updated2026 · 61% 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 California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
168 internal medicine physician records list a practice address in Santa Monica
They are 168 of the 5,151 NPPES records with a practice address in Santa Monica, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Santa Monica → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Harvey Alpern, MDSanta Monica, CA 904031235291741
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- James Dahlgren, M.D.Santa Monica, CA 904031487852117
- Monya De, MD, MPHSanta Monica, CA 904031275726655
- Teresa Dean, M.D.Santa Monica, CA 904031255538781
- Joel Isackson, MDSanta Monica, CA 904031285640680
- Stephen Kania, M.D.Santa Monica, CA 904031851594469
Common questions
What is Matthew Nienaber, D.O.'s NPI number?
Matthew Nienaber, D.O.'s National Provider Identifier (NPI) is 1033535182, issued on Mar 13, 2014. An NPI identifies a provider in billing; it is not a license.
Where is Matthew Nienaber, D.O. located?
The NPPES record lists a practice address at 1821 Wilshire Blvd Ste 100, Santa Monica, CA, 90403. Phone: (310) 575-3100. Providers update this record themselves, so call before visiting.
How can I verify Matthew Nienaber, D.O.'s license?
NPPES lists California license number 20A14759, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Matthew Nienaber, D.O. prescribe under Medicare Part D?
In 2024, Matthew Nienaber, D.O. had 2,803 Medicare Part D claims for 233 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.