Guadalupe S. Sitjar, MD
Internal Medicine Physician · Gurnee, IL
Guadalupe S. Sitjar, MD is an internal medicine physician with a practice address in Gurnee, Illinois, and NPI 1497870315, issued on Mar 20, 2007. Check the license on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Guadalupe S. Sitjar
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- Practice location
- 135 North Greenleaf, Gurnee, IL 60031
- Phone
- (847) 336-9159
- Enumerated
- Mar 20, 2007
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (847) 336-9159
- Medicare enrollment
- Enrolled (PECOS I20101102000187); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 7,238 in Illinois → Look up another NPI →
Verify Guadalupe S. Sitjar in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional RegulationCheck the board
- 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
63% fewer Medicare Part D claims than the average internal medicine physician in 2024
1,185 Medicare Part D claims for 102 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 18% of claims.
Most prescribed
- Atorvastatin Calcium79 claims
- Amlodipine Besylate59 claims
- Furosemide56 claims
- Eliquis41 claims
- Losartan Potassium36 claims
- Carvedilol34 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.
Bills Medicare through 2 group practices
- Infinite Care Home Physicians LLCDes Plaines, IL
- Physicians House CallsPark Ridge, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Guadalupe S. Sitjar among 7,238 internal medicine physician records in Illinois
Guadalupe S. Sitjar, MD is one of 7,238 internal medicine physician records with a practice address in Illinois. 73% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 39% of them.
- NPI issued2007 · 39% of these records are older, 55% newer
- In a Medicare fileYes · 73% of these records are
- In the CMS Doctors and Clinicians fileYes · 50% of these records are
- Graduated1970 · median 2003 among the 3,580 with a school on file
- Record last updated2007 · 47% 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 Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
28 internal medicine physician records list a practice address in Gurnee
They are 28 of the 846 NPPES records with a practice address in Gurnee, and 7,238 internal medicine physician records in Illinois.
All 7,238 in Illinois → Every provider in Gurnee → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Vivek Arora, M.D.Gurnee, IL 600311194712638
- Melissa Chen, M.D.Gurnee, IL 600311942261516
- Regan Christopoulos, MDGurnee, IL 600311740231596
- Efren Estrella, M.D.Gurnee, IL 600311053341172
- Mohammad Kagzi, MDGurnee, IL 600311659347409
- Jason Kramer, M.D.Gurnee, IL 600311093746927
- James Monahan, MDGurnee, IL 600311760478499
- Joseph Mun, MDGurnee, IL 600311588635940
Common questions
What is Guadalupe S. Sitjar, MD's NPI number?
Guadalupe S. Sitjar, MD's National Provider Identifier (NPI) is 1497870315, issued on Mar 20, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Guadalupe S. Sitjar, MD located?
The NPPES record lists a practice address at 135 North Greenleaf, Gurnee, IL, 60031. Phone: (847) 336-9159. Providers update this record themselves, so call before visiting.
How can I verify Guadalupe S. Sitjar, MD's license?
Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Guadalupe S. Sitjar, MD prescribe under Medicare Part D?
In 2024, Guadalupe S. Sitjar, MD had 1,185 Medicare Part D claims for 102 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.