NPI registry status
Active
2026 NPPES data General Practice Physician NPI 1124307814 MD
Verify on CMS → Guillermo Pastrana Maisonet, 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 16,725 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
5K
Medicare Part D claims · 287 beneficiaries · General Practice Physician avg: 3K
Generic prescribing
85%
generic claims · 15% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$1.3K
17 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
What the federal data shows
Guillermo Pastrana Maisonet, MD filed 4,682 Medicare Part D claims in 2023 as a General Practice Physician in San Juan, Puerto Rico, prescribing 85% generic.
- 5K
- Part D claims, 2023
- 85%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥93rd
- 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.
Guillermo Pastrana Maisonet, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
4,682 ≥ 93rd percentile 93% of 1,370,886 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 · 2023
✓
Board certification likely (heuristic, not verified)
Guillermo Pastrana Maisonet, MD 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 Guillermo Pastrana Maisonet, MD?
Quality data not reportedPrimary specialty
General Practice Physician
Medicare Part D claims
4,682 63% vs specialty avg
Specialty distribution in Puerto Rico
How General Practice Physician compares to other specialties among Puerto Rico 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 General Practice 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).
Guillermo Pastrana Maisonet, MD appears in the CMS NPPES registry as a General Practice Physician provider holding MD credentials at 505 AVE HOSTOS, San Juan, PR, 00918, with a listed phone of (787) 902-6631. NPI 1124307814 was issued on 08/11/2011.
Medicare Part D records for calendar year 2023 show 4,682 prescription claims written by this provider, covering 287 Medicare beneficiaries and totaling roughly $481K in drug spend, split 15% brand-name and 85% generic by claim count, with an opioid prescribing rate of 0.6%.
General Practice Physician is a mid-sized specialty nationwide, with 16,725 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
Provider Details
| NPI | 1124307814 |
|---|---|
| Specialty | General Practice Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 08/11/2011 |
Hospital and facility affiliations
Facilities where Guillermo Pastrana Maisonet, MD 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.
Pastrana Toledo Medical Group, LLC
San Juan, PR
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 Guillermo Pastrana Maisonet, MD. Source: openpaymentsdata.cms.gov.
Total received
$1.3K
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.
Brand vs generic prescribing mix · Typical
Guillermo Pastrana Maisonet, MD - brand share 15.0%
General Practice Physician average
15% brand-name claims vs 85% generic, on 4,682 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.
4,682
Total Claims
$481K
Total Drug Cost
287
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 9,195
- Total Day Supply
- 266,221
- Brand vs Generic
- 15% brand / 85% generic
- Brand Drug Cost
- $400K
- Generic Drug Cost
- $79K
- Opioid Claims
- 28 (0.6% rate)
- Antibiotic Claims
- 118
Patient Demographics
- Average Patient Age
- 69.0 years
- Avg HCC Risk Score
- 1.41
- Gender Split
- 62% female / 38% male
- Age Distribution
- <65: 51, 65-74: 162, 75-84: 63, 85+: 11
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Guillermo Pastrana Maisonet, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Gabapentin
Gabapentin
286 claims
- Ezetimibe
Ezetimibe
185 claims
- Famotidine
Famotidine
183 claims
- Atorvastatin Calcium
Atorvastatin Calcium
180 claims
- Losartan Potassium
Losartan Potassium
170 claims
- Rosuvastatin Calcium
Rosuvastatin Calcium
159 claims
- Levocetirizine Dih…
Levocetirizine Dihydrochloride
151 claims
- Levothyroxine Sodium
Levothyroxine Sodium
123 claims
| Drug | Claims |
|---|---|
| Gabapentin | 286 |
| Ezetimibe | 185 |
| Famotidine | 183 |
| Atorvastatin Calcium | 180 |
| Losartan Potassium | 170 |
| Rosuvastatin Calcium | 159 |
| Levocetirizine Dihydrochloride | 151 |
| Levothyroxine Sodium | 123 |
| Simvastatin | 120 |
| Metformin Hcl | 115 |
* 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 Guillermo Pastrana Maisonet, MD fits within the General Practice Physician landscape nationally.
16,725
General Practice Physician Providers in US
56
States with General Practice Physician
2,872
Avg Claims per Provider
Guillermo Pastrana Maisonet, MD's 4,682 claims are above 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 Pastrana Maisonet.
Dr. Veronica Abraham
MD
San Juan, PR
Dr. Manuel Abraham Gonzalez
M.D.
San Juan, PR
Dr. Jennifer Abraham Vega
MD
San Juan, PR
Dr. Jose M. Abreu Guzman
M.D.
Manati, PR
Dr. Steven Abreu Reyes
M.D.
Las Piedras, PR
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.
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Frequently Asked Questions
What is Guillermo Pastrana Maisonet, MD's specialty? ▼
Guillermo Pastrana Maisonet, MD specializes in General Practice Physician and practices in San Juan, Puerto Rico. Credentials: MD.
How much does Guillermo Pastrana Maisonet, MD prescribe under Medicare Part D? ▼
In 2023, Guillermo Pastrana Maisonet, MD wrote 4,682 Medicare Part D claims totaling $481K in drug costs for 287 beneficiaries.
Where is Guillermo Pastrana Maisonet, MD located? ▼
Guillermo Pastrana Maisonet, MD is located at 505 AVE HOSTOS, San Juan, PR, 00918. Phone: (787) 902-6631.
What is Guillermo Pastrana Maisonet, MD's NPI number? ▼
Guillermo Pastrana Maisonet, MD's National Provider Identifier (NPI) is 1124307814, issued on 08/11/2011.
Does Guillermo Pastrana Maisonet, MD prescribe more brand-name or generic drugs? ▼
Guillermo Pastrana Maisonet, MD's prescribing is 15% brand-name and 85% generic drugs by claim count, with $400K in brand drug costs.
Does Guillermo Pastrana Maisonet, MD prescribe opioids? ▼
Yes, Guillermo Pastrana Maisonet, MD had 28 opioid claims in 2023 with an opioid prescribing rate of 0.6%.
How many General Practice Physician providers are there in the US? ▼
There are 16,725 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 Guillermo Pastrana Maisonet, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Guillermo Pastrana Maisonet, MD's most frequently prescribed drugs include Gabapentin, Ezetimibe, Famotidine. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Guillermo Pastrana Maisonet, MD accept Medicare? ▼
Guillermo Pastrana Maisonet, MD appears in CMS Medicare data with 4,682 Part D claims and 287 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Guillermo Pastrana Maisonet, MD's credentials? ▼
Guillermo Pastrana Maisonet, MD's NPI is 1124307814 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
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
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 May 2026.