Issam A. Oneyssi, M.D.
Internal Medicine Physician · Southbridge, MA
Issam A. Oneyssi, M.D. is an internal medicine physician with a practice address in Southbridge, Massachusetts, and NPI 1528026622, issued on May 1, 2006. Check the license (Massachusetts 76569, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Issam A. Oneyssi
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 76569 MA
Self-reported in NPPES; status is on the state search - Practice location
- 100 South St, Southbridge, MA 01550
- Phone
- (508) 765-9771
- Enumerated
- May 1, 2006
- Record last updated
- Oct 2, 2025
- Fax
- (508) 909-7735
- Medicaid ID
- 3103641 MA
- Medicare enrollment
- Enrolled (PECOS I20040408000747); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 6,825 in Massachusetts → Look up another NPI →
Also registered at 100 South St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Dianne Aguirre, PAPhysician Assistant1659874121
- Joseph Amegah, M SMental Health Counselor1972625358
- Cheryl Amodeo, RNCase Management Registered Nurse1821134172
- Alan Anderson, C.R.N.A.Certified Registered Nurse Anesthetist1891713160
- Mary Banda, MDInternal Medicine Physician1265481311
- Janet Baum, M.D.Diagnostic Radiology Physician1053392944
Verify Issam A. Oneyssi in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 76569Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
92% fewer Medicare Part D claims than the average internal medicine physician in 2024
268 Medicare Part D claims for 117 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims.
Most prescribed
- Cefpodoxime Proxetil39 claims
- Prednisone23 claims
- Amlodipine Besylate12 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: $287.74
2 payments; by number, the most common kind was food and beverage; the largest payer was Davol Inc. The 50,334 providers of this specialty with any payment received $1,303.06 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.
Bills Medicare through one group practice
- Umass Memorial Medical Group IncSouthbridge, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Issam A. Oneyssi among 6,825 internal medicine physician records in Massachusetts
Issam A. Oneyssi, M.D. is one of 6,825 internal medicine physician records with a practice address in Massachusetts. 75% 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 12% of them.
- NPI issued2006 · 12% of these records are older, 54% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated1990 · median 2004 among the 4,103 with a school on file
- Record last updated2025 · 64% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
14 internal medicine physician records list a practice address in Southbridge
They are 14 of the 546 NPPES records with a practice address in Southbridge, and 6,825 internal medicine physician records in Massachusetts.
All 6,825 in Massachusetts → Every provider in Southbridge → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Mary Banda, MDSouthbridge, MA 015501265481311
- Nizam DinSouthbridge, MA 015501861659625
- William Dunn, D.O.Southbridge, MA 015501043246978
- Patrick Duplan, MDSouthbridge, MA 015501124656285
- Vladas Litani, MDSouthbridge, MA 015501528072360
- Suresh Mamidala, M.DSouthbridge, MA 015501437394350
- Adam Paszkowski, M.D.Southbridge, MA 015501306872452
- Francis Powers, M.D.Southbridge, MA 015501811905516
Common questions
What is Issam A. Oneyssi, M.D.'s NPI number?
Issam A. Oneyssi, M.D.'s National Provider Identifier (NPI) is 1528026622, issued on May 1, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Issam A. Oneyssi, M.D. located?
The NPPES record lists a practice address at 100 South St, Southbridge, MA, 01550. Phone: (508) 765-9771. Providers update this record themselves, so call before visiting.
How can I verify Issam A. Oneyssi, M.D.'s license?
NPPES lists Massachusetts license number 76569, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Issam A. Oneyssi, M.D. prescribe under Medicare Part D?
In 2024, Issam A. Oneyssi, M.D. had 268 Medicare Part D claims for 117 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.