2026 NPPES data Adult Medicine Physician NPI 1598750473 D.O
Verify on CMS →

TAMARA MAHER, D.O

Adult Medicine Physician in LOS ALAMITOS, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
7K
Medicare Part D claims · 430 beneficiaries · Adult Medicine Physician avg: 3K
Generic prescribing
88%
generic claims · 12% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$1.0K
48 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

TAMARA MAHER, D.O filed 7,174 Medicare Part D claims in 2023 as a Adult Medicine Physician in LOS ALAMITOS, California, prescribing 88% generic.

7K
Part D claims, 2023
88%
generic prescribing
$1.0K
industry payments (Sunshine Act)

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

TAMARA MAHER, D.O's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

7,174 Top 4% higher than 96% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2,000–2,200: 213,991 prescribers (16%). This entry sits in this band. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source CMS Medicare Part D Prescriber Public Use File · 2023

Board-eligible specialty (heuristic — not verified)

TAMARA MAHER, D.O practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about TAMARA MAHER, D.O?

Quality data not reported

NPI registry status

Active

Issued 09/15/2005

NPI 1598750473

Primary specialty

Adult Medicine Physician

Niche

2,481 US NPIs in this specialty

Medicare Part D claims

7,174 156% vs specialty avg

2023 prescription claims

Specialty avg: 2,807

Specialty distribution in California

How Adult Medicine Physician compares to other specialties among California providers

California providers

Adult Medicine Physician share within California

1. Adult Medicine Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Adult Medicine Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Adult Medicine Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Adult Medicine Physician ABMS/AOA estimate

Est. board-certified rate (Adult Medicine Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Adult Medicine Physician) — ABMS / AOA estimate

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

TAMARA MAHER, D.O appears in the CMS NPPES registry as a Adult Medicine Physician provider holding D.O credentials at 10861 CHERRY ST, LOS ALAMITOS, CA, 90720, with a listed phone of (562) 431-9200. NPI 1598750473 was issued on 09/15/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what MAHER most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 7,174 prescription claims written by this provider, covering 430 Medicare beneficiaries and totaling roughly $980K in drug spend, split 12% brand-name and 88% generic by claim count, with an opioid prescribing rate of 2.0%. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Adult Medicine Physician is a narrow specialty nationwide, with 2,481 enrolled providers across 52 states and an average of 2,807 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

10861 CHERRY ST
LOS ALAMITOS, CA 90720

Provider Details

NPI 1598750473
Specialty Adult Medicine Physician
Credentials D.O
Gender Female
NPI Issued 09/15/2005

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for TAMARA MAHER, D.O. Source: openpaymentsdata.cms.gov.

Total received

$1.0K

Largest payer

AstraZeneca Pharmaceuticals LP

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

License & disciplinary context — California MBC 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 — they are NOT specific to TAMARA MAHER, D.O. To verify TAMARA MAHER, D.O's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Typical

TAMARA MAHER, D.O — brand share 12.0%
Specialty average (est.)

12% brand-name claims vs 88% generic, on 7,174 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

7,174
Total Claims
$980K
Total Drug Cost
430
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
16,408
Total Day Supply
478,250
Brand vs Generic
12% brand / 88% generic
Brand Drug Cost
$729K
Generic Drug Cost
$244K
Opioid Claims
142 (2.0% rate)
Antibiotic Claims
323

Patient Demographics

Average Patient Age
75.9 years
Avg HCC Risk Score
1.23
Gender Split
73% female / 27% male
Age Distribution
<65: 21, 65-74: 173, 75-84: 170, 85+: 66

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What TAMARA MAHER, D.O prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Rosuvastatin Calcium
502
Amlodipine Besylate
307
Losartan Potassium
269
Levothyroxine Sodium
262
Atorvastatin Calcium
220
Ezetimibe
162
Escitalopram Oxalate
137
Losartan-Hydrochlorothiazide
Losartan/Hydrochlorothiazide
129
Pravastatin Sodium
126
Metformin Hcl
102

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Adult Medicine Physician Overview

How TAMARA MAHER, D.O fits within the Adult Medicine Physician landscape nationally.

2,481
Adult Medicine Physician Providers in US
52
States with Adult Medicine Physician
2,807
Avg Claims per Provider

TAMARA MAHER, D.O's 7,174 claims are above the specialty average of 2,807.

Nearby Adult Medicine Physician Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as MAHER.

Compare Adult Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is TAMARA MAHER, D.O's specialty?
TAMARA MAHER, D.O specializes in Adult Medicine Physician and practices in LOS ALAMITOS, California. Credentials: D.O.
How much does TAMARA MAHER, D.O prescribe under Medicare Part D?
In 2023, TAMARA MAHER, D.O wrote 7,174 Medicare Part D claims totaling $980K in drug costs for 430 beneficiaries.
Where is TAMARA MAHER, D.O located?
TAMARA MAHER, D.O is located at 10861 CHERRY ST, LOS ALAMITOS, CA, 90720. Phone: (562) 431-9200.
What is TAMARA MAHER, D.O's NPI number?
TAMARA MAHER, D.O's National Provider Identifier (NPI) is 1598750473, issued on 09/15/2005.
Does TAMARA MAHER, D.O prescribe more brand-name or generic drugs?
TAMARA MAHER, D.O's prescribing is 12% brand-name and 88% generic drugs by claim count, with $729K in brand drug costs.
Does TAMARA MAHER, D.O prescribe opioids?
Yes, TAMARA MAHER, D.O had 142 opioid claims in 2023 with an opioid prescribing rate of 2.0%.
How many Adult Medicine Physician providers are there in the US?
There are 2,481 Adult Medicine Physician providers across 52 states in the US. The average Adult Medicine Physician provider writes 2,807 Medicare Part D claims per year.
What drugs does TAMARA MAHER, D.O prescribe most often?
Based on 2023 Medicare Part D data, TAMARA MAHER, D.O's most frequently prescribed drugs include Rosuvastatin Calcium, Amlodipine Besylate, Losartan Potassium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does TAMARA MAHER, D.O accept Medicare?
TAMARA MAHER, D.O appears in CMS Medicare data with 7,174 Part D claims and 430 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify TAMARA MAHER, D.O's credentials?
TAMARA MAHER, D.O's NPI is 1598750473 with credentials D.O. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology