Maria Theresa Ammermann, NP
Family Nurse Practitioner · Downey, CA
Maria Theresa Ammermann, NP is a family nurse practitioner with a practice address in Downey, California, and NPI 1750594131, issued on May 8, 2007. Check the license (California 12398, as entered in NPPES) with the California board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Maria Theresa Ammermann
- Credential
- NP
- Primary taxonomy
- Family Nurse Practitioner 363LF0000X
- License number
- 12398 CA
Self-reported in NPPES; status is on the state search - Practice location
- 9353 Imperial Hwy, Downey, CA 90242
- Phone
- (562) 657-2944
- Enumerated
- May 8, 2007
- Record last updated
- Dec 2, 2021 (not updated in 5 years: call before relying on the address or phone)
- Fax
- (562) 657-2446
- Medicare enrollment
- Enrolled (PECOS I20090502000011); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest family nurse practitioner records → All 16,966 in California → Look up another NPI →
Also registered at 9353 Imperial Hwy
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Maria Theresa Ammermann in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich California board licenses this profession
Search for license 12398Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
34% fewer Medicare Part D claims than the average family nurse practitioner in 2024
860 Medicare Part D claims for 494 beneficiaries, against an average of 1,305 among the 140,557 providers of this specialty who prescribed in Part D. 250 claims were for opioids.
Most prescribed
- Gabapentin235 claims
- Pregabalin126 claims
- Hydrocodone-Acetaminophen108 claims
- Duloxetine Hcl66 claims
- Oxycodone-Acetaminophen43 claims
- Ibuprofen33 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.
Bills Medicare through one group practice
- Southern California Permanente Medical GroupDowney, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Maria Theresa Ammermann among 16,966 family nurse practitioner records in California
Maria Theresa Ammermann, NP is one of 16,966 family nurse practitioner records with a practice address in California. 67% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 7% of them.
- NPI issued2007 · 7% of these records are older, 87% newer
- In a Medicare fileYes · 67% of these records are
- In the CMS Doctors and Clinicians fileYes · 40% of these records are
- Graduated2001 · median 2019 among the 6,793 with a school on file
- Record last updated2021 · 42% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363LF0000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
94 family nurse practitioner records list a practice address in Downey
They are 94 of the 3,607 NPPES records with a practice address in Downey, and 16,966 family nurse practitioner records in California.
All 16,966 in California → Every provider in Downey → Family Nurse Practitioner nationwide →
The 8 family nurse practitioner records with the nearest ZIP codes
- Wendy AndreuDowney, CA 902421174935464
- Brenda BernalDowney, CA 902421649646738
- Jardine Cordero-Pagunsan, NP-CDowney, CA 902421053639914
- Monina Distor-Castro, RN, FNP-BCDowney, CA 902421528379690
- Leilani Hermosura-Bautista, RN, NP-CDowney, CA 902421396953758
- Gail Lew, NURSE PRACTITIONERDowney, CA 902421184835415
- Lily Lim, NPDowney, CA 902421396966636
- Tony Nguyen, FNP-CDowney, CA 902421790151074
Common questions
What is Maria Theresa Ammermann, NP's NPI number?
Maria Theresa Ammermann, NP's National Provider Identifier (NPI) is 1750594131, issued on May 8, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Maria Theresa Ammermann, NP located?
The NPPES record lists a practice address at 9353 Imperial Hwy, Downey, CA, 90242. Phone: (562) 657-2944. Providers update this record themselves, so call before visiting.
How can I verify Maria Theresa Ammermann, NP's license?
NPPES lists California license number 12398, as entered by the provider. Search the California board that licenses this profession; the NPPES record confirms identity only.
How much does Maria Theresa Ammermann, NP prescribe under Medicare Part D?
In 2024, Maria Theresa Ammermann, NP had 860 Medicare Part D claims for 494 beneficiaries; the average among family nurse practitioner prescribers was 1,305. 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.