Gregorio J. Guillen, M.D
Geriatric Medicine (Internal Medicine) Physician · Perth Amboy, NJ
Gregorio J. Guillen, M.D is a geriatric medicine (internal medicine) physician with a practice address in Perth Amboy, New Jersey, and NPI 1538252226, issued on Oct 2, 2006. Check the license (New Jersey MA56159, as entered in NPPES) on the New Jersey State Board of Medical Examiners; the Medicare figures below come from public CMS files.
- Name
- Gregorio J. Guillen
- Credential
- M.D
- Primary taxonomy
- Geriatric Medicine (Internal Medicine) Physician 207RG0300X
- License number
- MA56159 NJ
Self-reported in NPPES; status is on the state search - Practice location
- 400 State St. Suite 2, Perth Amboy, NJ 08861
- Phone
- (732) 442-6020
- Enumerated
- Oct 2, 2006
- Record last updated
- Aug 6, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (732) 442-1995
- Medicaid ID
- 6523706 NJ
- Medicare enrollment
- Enrolled (PECOS I20050207000626); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest geriatric medicine (internal medicine) physician records → All 165 in New Jersey → Look up another NPI →
Also registered at 400 State St. Suite 2
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Solania Rios, P.A.Medical Physician Assistant1376774307
Verify Gregorio J. Guillen in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersNew Jersey State Board of Medical Examiners
Search for license MA56159Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
3.6 times the Medicare Part D claims of the average geriatric medicine (internal medicine) physician in 2024
15,087 Medicare Part D claims for 848 beneficiaries, against an average of 4,246 among the 3,116 providers of this specialty who prescribed in Part D. Brand-name drugs were 18% of claims. 212 claims were for opioids.
Most prescribed
- Atorvastatin Calcium829 claims
- Omeprazole516 claims
- Amlodipine Besylate495 claims
- Metoprolol Succinate364 claims
- Gabapentin322 claims
- Metformin Hcl312 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $1,761.02
105 payments; by number, the most common kind was food and beverage; the largest payer was AstraZeneca Pharmaceuticals LP. The 1,004 providers of this specialty with any payment received $1,720.82 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Gregorio J. Guillen among 165 geriatric medicine (internal medicine) physician records in New Jersey
Gregorio J. Guillen, M.D is one of 165 geriatric medicine (internal medicine) physician records with a practice address in New Jersey. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 8% of them.
- NPI issued2006 · 8% of these records are older, 42% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileYes · 64% of these records are
- Graduated1982 · median 1996 among the 106 with a school on file
- Record last updated2013 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0300X and a New Jersey practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Geriatric Medicine (Internal Medicine) Physician providers in New Jersey
There are 165 geriatric medicine (internal medicine) physician records in New Jersey.
All 165 in New Jersey → Every provider in Perth Amboy → Geriatric Medicine (Internal Medicine) Physician nationwide →
The 8 geriatric medicine (internal medicine) physician records with the nearest ZIP codes
- Mukesh Singh, M.DSomerset, NJ 088731679555189
- Zahira Shamsi, M.DMiddlesex, NJ 088461962501304
- Renukamba Gubbi, M.D.Hillsborough, NJ 088441255363719
- Caprice MartinEdison, NJ 088371336098375
- Jayashree Satwalekar, M.D.Edison, NJ 088371275589806
- Gustavo Cruz Giniebra, NPManville, NJ 088351215721188
- Abhijit Chatterjee, MDMonroe Township, NJ 088311487692836
- Tori Gartmond, MDMonroe Township, NJ 088311629539663
Common questions
What is Gregorio J. Guillen, M.D's NPI number?
Gregorio J. Guillen, M.D's National Provider Identifier (NPI) is 1538252226, issued on Oct 2, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Gregorio J. Guillen, M.D located?
The NPPES record lists a practice address at 400 State St. Suite 2, Perth Amboy, NJ, 08861. Phone: (732) 442-6020. Providers update this record themselves, so call before visiting.
How can I verify Gregorio J. Guillen, M.D's license?
NPPES lists New Jersey license number MA56159, as entered by the provider. Search the New Jersey State Board of Medical Examiners at https://newjersey.mylicense.com/verification/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Gregorio J. Guillen, M.D prescribe under Medicare Part D?
In 2024, Gregorio J. Guillen, M.D had 15,087 Medicare Part D claims for 848 beneficiaries; the average among geriatric medicine (internal medicine) physician prescribers was 4,246. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.