Maria Kostantacos, APRN, FNP
Family Nurse Practitioner · Janesville, WI
Maria Kostantacos, APRN, FNP is a family nurse practitioner with a practice address in Janesville, Wisconsin, and NPI 1538493614, issued on Sep 23, 2009. Check the license (Wisconsin 5492-33, as entered in NPPES) with the Wisconsin board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Maria Kostantacos
- Credential
- APRN, FNP
- Primary taxonomy
- Family Nurse Practitioner 363LF0000X
- License numbers
- 5492-33 WI
148040 WI
041343430 IL
Self-reported in NPPES; status is on the state search - Practice location
- 1010 N Washington St, Janesville, WI 53548
- Phone
- (608) 741-3800
- Enumerated
- Sep 23, 2009
- Record last updated
- Oct 2, 2013 (not updated in 13 years: call before relying on the address or phone)
- Fax
- (608) 741-3838
- Medicare enrollment
- Enrolled (PECOS I20140113000392); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest family nurse practitioner records → All 2,814 in Wisconsin → Look up another NPI →
Also registered at 1010 N Washington St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Maria Kostantacos in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Wisconsin board licenses this profession
Search for license 5492-33Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
93% fewer Medicare Part D claims than the average family nurse practitioner in 2024
89 Medicare Part D claims for 51 beneficiaries, against an average of 1,305 among the 140,557 providers of this specialty who prescribed in Part D. 39 claims were for opioids.
Most prescribed
- Oxycodone Hcl33 claims
- Amoxicillin-Clavulanate Potass11 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 one group practice
- Mercy Health System CorporationHarvard, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Maria Kostantacos among 2,814 family nurse practitioner records in Wisconsin
Maria Kostantacos, APRN, FNP is one of 2,814 family nurse practitioner records with a practice address in Wisconsin. 74% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2009, is newer than 16% of them.
- NPI issued2009 · 16% of these records are older, 82% newer
- In a Medicare fileYes · 74% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated2013 · median 2019 among the 1,740 with a school on file
- Record last updated2013 · 42% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363LF0000X and a Wisconsin practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Family Nurse Practitioner providers in Wisconsin
There are 2,814 family nurse practitioner records in Wisconsin.
All 2,814 in Wisconsin → Every provider in Janesville → Family Nurse Practitioner nationwide →
The 8 family nurse practitioner records with the nearest ZIP codes
- Katlin Cheatham, APRNJanesville, WI 535481336851294
- Jessica Green, APNPJanesville, WI 535481124537774
- Julie Martin, APRN, FNPJanesville, WI 535481770030561
- Nicole Salter Braun, APRN, FNP-BCJanesville, WI 535481497896955
- Susan Schleicher, APNPJanesville, WI 535481194094052
- Oxana Valk, APNJanesville, WI 535481164935789
- Jennifer Wimmer, APNP, FNP-CJanesville, WI 535481043693344
- Kathryn Wroblewski, NP-CJanesville, WI 535481043929680
Common questions
What is Maria Kostantacos, APRN, FNP's NPI number?
Maria Kostantacos, APRN, FNP's National Provider Identifier (NPI) is 1538493614, issued on Sep 23, 2009. An NPI identifies a provider in billing; it is not a license.
Where is Maria Kostantacos, APRN, FNP located?
The NPPES record lists a practice address at 1010 N Washington St, Janesville, WI, 53548. Phone: (608) 741-3800. Providers update this record themselves, so call before visiting.
How can I verify Maria Kostantacos, APRN, FNP's license?
NPPES lists Wisconsin license number 5492-33, as entered by the provider. Search the Wisconsin board that licenses this profession; the NPPES record confirms identity only.
How much does Maria Kostantacos, APRN, FNP prescribe under Medicare Part D?
In 2024, Maria Kostantacos, APRN, FNP had 89 Medicare Part D claims for 51 beneficiaries; the average among family nurse practitioner prescribers was 1,305. 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.