2026 NPPES data General Practice Physician NPI 1053921023 MD
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Alexandra Rivera Castro, MD

General Practice Physician in San Juan, Puerto Rico. This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers — including 16,677 in General Practice 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
89
Medicare Part D claims · 35 beneficiaries · General Practice Physician avg: 3K
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Alexandra Rivera Castro, MD filed 89 Medicare Part D claims in 2023 as a General Practice Physician in San Juan, Puerto Rico.

89
Part D claims, 2023

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.

Alexandra Rivera Castro, MD's Medicare Part D volume vs every U.S. prescriber

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

89 0th percentile higher than 0% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). This entry sits in this band. 200–400: 182,923 prescribers (13%). Above this entry. 400–600: 90,619 prescribers (7%). Above this entry. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. 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)

Alexandra Rivera Castro, MD 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 Alexandra Rivera Castro, MD?

Quality data not reported

NPI registry status

Active

Issued 08/05/2020

NPI 1053921023

Primary specialty

General Practice Physician

Mid-sized

16,677 US NPIs in this specialty

Medicare Part D claims

89 97% vs specialty avg

2023 prescription claims

Specialty avg: 2,872

Specialty distribution in Puerto Rico

How General Practice Physician compares to other specialties among Puerto Rico providers

Puerto Rico providers

Largest specialties in Puerto Rico (% of in-state providers)

General Practice Physician — 10%General Practice Physician10%Student in an Organized Health Care Education/Training Program — 8.9%Student in an Organized Health Care Education/Training Program8.9%Pharmacist — 8%Pharmacist8%Pharmacy Technician — 5.1%Pharmacy Technician5.1%Clinical Psychologist — 4.7%Clinical Psychologist4.7%Clinical Social Worker — 4.2%Clinical Social Worker4.2%
Largest specialties in Puerto Rico (% of in-state providers)

Specialty board-certification context

Estimated specialty board-certified rate — General Practice Physician (ABMS / AOA reference)

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

Est. board-certified rate (General Practice Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (General Practice 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).

Alexandra Rivera Castro, MD appears in the CMS NPPES registry as a General Practice Physician provider holding MD credentials at CARR 22 BARRIO MONACILLOS HOSPITAL ONCOLOGICO, San Juan, PR, 00935, with a listed phone of (787) 763-4149. NPI 1053921023 was issued on 08/05/2020. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Rivera Castro 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 89 prescription claims written by this provider, covering 35 Medicare beneficiaries and totaling roughly $5K in drug spend. 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.

General Practice Physician is a mid-sized specialty nationwide, with 16,677 enrolled providers across 56 states and an average of 2,872 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

CARR 22 BARRIO MONACILLOS HOSPITAL ONCOLOGICO
San Juan, PR 00935

Provider Details

NPI 1053921023
Specialty General Practice Physician
Credentials MD
Gender Female
NPI Issued 08/05/2020

Medicare Part D Prescribing Data

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

89
Total Claims
$5K
Total Drug Cost
35
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
89
Total Day Supply
1,088
Generic Drug Cost
$1K

Patient Demographics

Average Patient Age
77.5 years
Avg HCC Risk Score
2.13
Gender Split
49% female / 51% male

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Gabapentin
20
Levetiracetam
11

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

General Practice Physician Overview

How Alexandra Rivera Castro, MD fits within the General Practice Physician landscape nationally.

16,677
General Practice Physician Providers in US
56
States with General Practice Physician
2,872
Avg Claims per Provider

Alexandra Rivera Castro, MD's 89 claims are below the specialty average of 2,872.

Nearby General Practice Physician Providers in Puerto Rico

Other clinicians with the same primary specialty enrolled in Puerto Rico, drawn from the same CMS NPPES roster as Rivera Castro.

Compare General Practice Physician 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 Puerto Rico medical board — federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby General Practice Physician 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.

Frequently Asked Questions

What is Alexandra Rivera Castro, MD's specialty?
Alexandra Rivera Castro, MD specializes in General Practice Physician and practices in San Juan, Puerto Rico. Credentials: MD.
How much does Alexandra Rivera Castro, MD prescribe under Medicare Part D?
In 2023, Alexandra Rivera Castro, MD wrote 89 Medicare Part D claims totaling $5K in drug costs for 35 beneficiaries.
Where is Alexandra Rivera Castro, MD located?
Alexandra Rivera Castro, MD is located at CARR 22 BARRIO MONACILLOS HOSPITAL ONCOLOGICO, San Juan, PR, 00935. Phone: (787) 763-4149.
What is Alexandra Rivera Castro, MD's NPI number?
Alexandra Rivera Castro, MD's National Provider Identifier (NPI) is 1053921023, issued on 08/05/2020.
How many General Practice Physician providers are there in the US?
There are 16,677 General Practice Physician providers across 56 states in the US. The average General Practice Physician provider writes 2,872 Medicare Part D claims per year.
What drugs does Alexandra Rivera Castro, MD prescribe most often?
Based on 2023 Medicare Part D data, Alexandra Rivera Castro, MD's most frequently prescribed drugs include Gabapentin, Levetiracetam. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Alexandra Rivera Castro, MD accept Medicare?
Alexandra Rivera Castro, MD appears in CMS Medicare data with 89 Part D claims and 35 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Alexandra Rivera Castro, MD's credentials?
Alexandra Rivera Castro, MD's NPI is 1053921023 with credentials MD. 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

Compiled from official public sources by the PlainDoctor editorial team.