NPI registry status
Active
2026 NPPES data Addiction Medicine (Family Medicine) Physician NPI 1790849685 M.D.
Verify on CMS → Fred Vonstieff, M.D.
Addiction Medicine (Family Medicine) Physician in Concord, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 799 in Addiction Medicine (Family Medicine) Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
858
Medicare Part D claims · 138 beneficiaries · Addiction Medicine (Family Medicine) Physician avg: 1K
Generic prescribing
94%
generic claims · 6% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$27.24
1 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2024
What the federal data shows
Fred Vonstieff, M.D. filed 858 Medicare Part D claims in 2024 as an Addiction Medicine (Family Medicine) Physician in Concord, California, prescribing 94% generic.
- 858
- Part D claims, 2024
- 94%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥72nd
- pct by Part D claim volume (lower-bound band)
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.
Federal trust snapshot
What official records show about Fred Vonstieff, M.D.
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1790849685), first enumerated 12/21/2006.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 858 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
1 CMS Care Compare hospital affiliation on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- Reported
Industry payment transparency
$27.24 in reported industry payments (1 transfers) in 2024 under the federal Sunshine Act — disclosed transfers of value, not a quality rating.
Source: CMS Open Payments
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not Fred Vonstieff, M.D.'s individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
Compare Vonstieff with other Addiction Medicine (Family Medicine) Physician providers
Same primary specialty, same federal CMS NPPES roster.
Also enrolled in California
- Dr. Matthew Abinante, DO, MPH Huntington Beach, CA
- Dr. Paul Abramson, M.D. San Francisco, CA
- Dr. Kami Adibi, M.D. Los Angeles, CA
- Dr. Belis Aladag, MD, MPH, FASAM Walnut Creek, CA
- Dr. Marianne Aldridge, M.D. Loma Linda, CA
- Dr. Abdul Mureed Alim, MD Modesto, CA
Other specialties in Concord: Behavior Technician (6,277) · Behavior Analyst (302) · Mental Health Counselor (260) · Marriage & Family Therapist (236)
CMS NPPES provider registry desk
NPI 1790849685 · Addiction Medicine (Family Medicine) Physician
NPI-10 · ENUM-LEGACY · TAX-NARROW · RX-LIGHT · BOOK-THIN · PHOTO-ENUM
- NPI-10 1790849685
- ENUM-LEGACY 2006
- TAX-NARROW 799
- RX-LIGHT 858
- BOOK-THIN 111 in California
- PHOTO-ENUM Manuel Thomas, MD · 2006
Fred Vonstieff, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
858 ≥ 72nd percentile 72% of 1,416,883 prescribers are in lower value bands
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.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
Fred Vonstieff, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Fred Vonstieff, M.D.?
Quality data not reportedPrimary specialty
Addiction Medicine (Family Medicine) Physician
Medicare Part D claims
858 28% vs specialty avg
Specialty distribution in California
How Addiction Medicine (Family Medicine) Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Addiction Medicine (Family Medicine) Physician. Verify directly:
How MIPS and board certification work
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).
Practice Address
Provider Details
| NPI | 1790849685 |
|---|---|
| Specialty | Addiction Medicine (Family Medicine) Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 12/21/2006 |
Hospital and facility affiliations
Facilities where Fred Vonstieff, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Fred J Von Stieff MD A Professional Corporation
Concord, CA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
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 Fred Vonstieff, M.D.. Source: openpaymentsdata.cms.gov.
Total received
$27
Largest payer
ITI, Inc. (d/b/a Intra-Cellular Therapies, Inc.)
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 Fred Vonstieff, M.D.. To verify Fred Vonstieff, M.D.'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 · Generic-heavy
Fred Vonstieff, M.D. - brand share 6.0%
Addiction Medicine (Family Medicine) Physician average
6% brand-name claims vs 94% generic, on 858 2024 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 2024.
858
Total Claims
$62K
Total Drug Cost
138
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 1,820.733
- Total Day Supply
- 53,206
- Brand vs Generic
- 6% brand / 94% generic
- Brand Drug Cost
- $41K
- Generic Drug Cost
- $21K
Patient Demographics
- Average Patient Age
- 68.1 years
- Avg HCC Risk Score
- 1.53
- Gender Split
- 46% female / 54% male
- Age Distribution
- <65: 31, 65-74: 77, 75-84: N/A, 85+: N/A
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What Fred Vonstieff, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2024
- Trazodone Hcl
Trazodone Hcl
75 claims
- Gabapentin
Gabapentin
68 claims
- Famotidine
Famotidine
64 claims
- Hydroxyzine Pamoate
Hydroxyzine Pamoate
64 claims
- Naltrexone Hcl
Naltrexone Hcl
57 claims
- Pantoprazole Sodium
Pantoprazole Sodium
34 claims
- Quetiapine Fumarate 28
Quetiapine Fumarate
28 claims
- Lisinopril 27
Lisinopril
27 claims
| Drug | Claims |
|---|---|
| Trazodone Hcl | 75 |
| Gabapentin | 68 |
| Famotidine | 64 |
| Hydroxyzine Pamoate | 64 |
| Naltrexone Hcl | 57 |
| Pantoprazole Sodium | 34 |
| Quetiapine Fumarate | 28 |
| Lisinopril | 27 |
| Atorvastatin Calcium | 26 |
| Escitalopram Oxalate | 24 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Addiction Medicine (Family Medicine) Physician in CA →
All providers in California →
Compare specialties →
Addiction Medicine (Family Medicine) Physician Overview
How Fred Vonstieff, M.D. fits within the Addiction Medicine (Family Medicine) Physician landscape nationally.
799
Addiction Medicine (Family Medicine) Physician Providers in US
49
States with Addiction Medicine (Family Medicine) Physician
1,187
Avg Claims per Provider
Fred Vonstieff, M.D.'s 858 claims are below the specialty average of 1,187.
Nationwide Addiction Medicine (Family Medicine) Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Vonstieff, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2006)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Addiction Medicine (Family Medicine) Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Vonstieff.
One of 111 Addiction Medicine (Family Medicine) Physician providers enrolled in California, 11 are shown on this page.
Dr. Karen Antwiler
M.D.
Cathedral City, CA
Dr. Dale Apodaca
M.D.
San Diego, CA
Dr. Alexandra Arenson
DO
Walnut Creek, CA
Dr. Jonathan Avalos
M.D.
Rialto, CA
Dr. Jerry Ayers
MD
San Diego, CA
Compare Addiction Medicine (Family Medicine) Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Fred Vonstieff, M.D.'s specialty? ▼
Fred Vonstieff, M.D. specializes in Addiction Medicine (Family Medicine) Physician and practices in Concord, California. Credentials: M.D..
How much does Fred Vonstieff, M.D. prescribe under Medicare Part D? ▼
In 2024, Fred Vonstieff, M.D. wrote 858 Medicare Part D claims totaling $62K in drug costs for 138 beneficiaries.
Where is Fred Vonstieff, M.D. located? ▼
Fred Vonstieff, M.D. is located at 2481 PACHECO ST, Concord, CA, 94520. Phone: (925) 680-8933.
What is Fred Vonstieff, M.D.'s NPI number? ▼
Fred Vonstieff, M.D.'s National Provider Identifier (NPI) is 1790849685, issued on 12/21/2006.
Does Fred Vonstieff, M.D. prescribe more brand-name or generic drugs? ▼
Fred Vonstieff, M.D.'s prescribing is 6% brand-name and 94% generic drugs by claim count, with $41K in brand drug costs.
How many Addiction Medicine (Family Medicine) Physician providers are there in the US? ▼
There are 799 Addiction Medicine (Family Medicine) Physician providers across 49 states in the US. The average Addiction Medicine (Family Medicine) Physician provider writes 1,187 Medicare Part D claims per year.
What drugs does Fred Vonstieff, M.D. prescribe most often? ▼
Based on 2024 Medicare Part D data, Fred Vonstieff, M.D.'s most frequently prescribed drugs include Trazodone Hcl, Gabapentin, Famotidine. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Fred Vonstieff, M.D. accept Medicare? ▼
Fred Vonstieff, M.D. appears in CMS Medicare data with 858 Part D claims and 138 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Fred Vonstieff, M.D.'s credentials? ▼
Fred Vonstieff, M.D.'s NPI is 1790849685 with credentials M.D.. 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
View source datasets and methodology notes
- 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 (2024). 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 August 2026 (NPPES) / 2024 (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
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of August 2026.