NPI registry status
Active
2026 NPPES data Ambulatory Care Pharmacist NPI 1922457191 PHARMD
Verify on CMS → Michelle Castillones, PHARMD
Ambulatory Care Pharmacist in San Rafael, 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 3,473 in Ambulatory Care Pharmacist, 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
3K
Medicare Part D claims · 615 beneficiaries · Ambulatory Care Pharmacist avg: 492
Generic prescribing
82%
generic claims · 14% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Michelle Castillones, PHARMD filed 3,128 Medicare Part D claims in 2023 as a Ambulatory Care Pharmacist in San Rafael, California, prescribing 82% generic.
- 3K
- Part D claims, 2023
- 82%
- generic prescribing
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.
Michelle Castillones, PHARMD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
3,128 Top 11% higher than 89% of 1,370,886 prescribers
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
What does the federal data show about Michelle Castillones, PHARMD?
Quality data not reportedPrimary specialty
Ambulatory Care Pharmacist
Medicare Part D claims
3,128 6× vs specialty avg
Specialty distribution in California
How Ambulatory Care Pharmacist 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 Ambulatory Care Pharmacist. 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).
Michelle Castillones, PHARMD appears in the CMS NPPES registry as a Ambulatory Care Pharmacist provider holding PHARMD credentials at 1650 LOS GAMOS DR STE 270, San Rafael, CA, 94903, with a listed phone of (415) 482-6819. NPI 1922457191 was issued on 06/08/2016.
Medicare Part D records for calendar year 2023 show 3,128 prescription claims written by this provider, covering 615 Medicare beneficiaries and totaling roughly $278K in drug spend, split 14% brand-name and 82% generic by claim count.
Ambulatory Care Pharmacist is a narrow specialty nationwide, with 3,473 enrolled providers across 52 states and an average of 492 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
Provider Details
| NPI | 1922457191 |
|---|---|
| Specialty | Ambulatory Care Pharmacist |
| Credentials | PHARMD |
| Gender | Female |
| NPI Issued | 06/08/2016 |
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 Michelle Castillones, PHARMD. To verify Michelle Castillones, PHARMD'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
Michelle Castillones, PHARMD - brand share 14.0%
Ambulatory Care Pharmacist average
14% brand-name claims vs 82% generic, on 3,128 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.
3,128
Total Claims
$278K
Total Drug Cost
615
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 9,788
- Total Day Supply
- 293,525
- Brand vs Generic
- 14% brand / 82% generic
- Brand Drug Cost
- $238K
- Generic Drug Cost
- $36K
Patient Demographics
- Average Patient Age
- 70.6 years
- Avg HCC Risk Score
- 1.09
- Gender Split
- 41% female / 59% male
- Age Distribution
- <65: 22, 65-74: 479, 75-84: 114, 85+: 0
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Michelle Castillones, PHARMD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
669 claims
- Metformin Hcl Er
Metformin Hcl Er
321 claims
- Metformin Hcl 237
Metformin Hcl
237 claims
- Lisinopril 223
Lisinopril
223 claims
- Glipizide 146
Glipizide
146 claims
- Losartan Potassium 144
Losartan Potassium
144 claims
- Glimepiride 114
Glimepiride
114 claims
- Amlodipine Besylate 111
Amlodipine Besylate
111 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 669 |
| Metformin Hcl Er Metformin Hcl | 321 |
| Metformin Hcl | 237 |
| Lisinopril | 223 |
| Glipizide | 146 |
| Losartan Potassium | 144 |
| Glimepiride | 114 |
| Amlodipine Besylate | 111 |
| Rosuvastatin Calcium | 96 |
| Jardiance Empagliflozin | 87 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Ambulatory Care Pharmacist Overview
How Michelle Castillones, PHARMD fits within the Ambulatory Care Pharmacist landscape nationally.
3,473
Ambulatory Care Pharmacist Providers in US
52
States with Ambulatory Care Pharmacist
492
Avg Claims per Provider
Michelle Castillones, PHARMD's 3,128 claims are above the specialty average of 492.
Nearby Ambulatory Care Pharmacist Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Castillones.
Clare Adams
Mission Viejo, CA
Kristine Adzhemyan
Los Angeles, CA
Dr. Omar Ahmed
PHARMD
San Rafael, CA
Dr. Soo Ahn
PHARM.D.
Simi Valley, CA
Dr. Genevieve Aichelman
PHARM.D.
Lemoore, CA
Compare Ambulatory Care Pharmacist nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the California medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Ambulatory Care Pharmacist peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Michelle Castillones, PHARMD's specialty? ▼
Michelle Castillones, PHARMD specializes in Ambulatory Care Pharmacist and practices in San Rafael, California. Credentials: PHARMD.
How much does Michelle Castillones, PHARMD prescribe under Medicare Part D? ▼
In 2023, Michelle Castillones, PHARMD wrote 3,128 Medicare Part D claims totaling $278K in drug costs for 615 beneficiaries.
Where is Michelle Castillones, PHARMD located? ▼
Michelle Castillones, PHARMD is located at 1650 LOS GAMOS DR STE 270, San Rafael, CA, 94903. Phone: (415) 482-6819.
What is Michelle Castillones, PHARMD's NPI number? ▼
Michelle Castillones, PHARMD's National Provider Identifier (NPI) is 1922457191, issued on 06/08/2016.
Does Michelle Castillones, PHARMD prescribe more brand-name or generic drugs? ▼
Michelle Castillones, PHARMD's prescribing is 14% brand-name and 82% generic drugs by claim count, with $238K in brand drug costs.
How many Ambulatory Care Pharmacist providers are there in the US? ▼
There are 3,473 Ambulatory Care Pharmacist providers across 52 states in the US. The average Ambulatory Care Pharmacist provider writes 492 Medicare Part D claims per year.
What drugs does Michelle Castillones, PHARMD prescribe most often? ▼
Based on 2023 Medicare Part D data, Michelle Castillones, PHARMD's most frequently prescribed drugs include Atorvastatin Calcium, Metformin Hcl Er, Metformin Hcl. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Michelle Castillones, PHARMD accept Medicare? ▼
Michelle Castillones, PHARMD appears in CMS Medicare data with 3,128 Part D claims and 615 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Michelle Castillones, PHARMD's credentials? ▼
Michelle Castillones, PHARMD's NPI is 1922457191 with credentials PHARMD. 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 (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
Compiled from official public sources by the PlainDoctor editorial team.