NPPES file of Aug 9, 2026

Frederick Sebastian Fleszler, MD

Nephrology Physician · Allentown, PA

Frederick Sebastian Fleszler, MD is a nephrology physician with a practice address in Allentown, Pennsylvania, and NPI 1588758353, issued on Oct 3, 2006. Check the license (Pennsylvania MD428393, as entered in NPPES) on the Pennsylvania Department of State (PALS); the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1588758353
Name
Frederick Sebastian Fleszler
Credential
MD
Primary taxonomy
Nephrology Physician 207RN0300X
License numbers
MD428393 PA
25MA08358900 NJ
Self-reported in NPPES; status is on the state search
Practice location
1230 S Cedar Crest Blvd Stes 301, 302, 304, Allentown, PA 18103
Phone
(610) 432-4529
Enumerated
Oct 3, 2006
Record last updated
May 31, 2022
Fax
(610) 432-2206
Medicare enrollment
Enrolled (PECOS I20080620000498); accepts Medicare assignment
Telehealth
Offers telehealth (CMS)
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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Also registered at 1230 S Cedar Crest Blvd Stes 301, 302, 304

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Tayyab Ali, MDNephrology Physician1710986559
  2. Audrey Anatalio, PA-CMedical Physician Assistant1316581259
  3. Cheryl Bitting, CRNPFamily Nurse Practitioner1891888301
  4. Ravindra Bollu, M.D.Nephrology Physician1194716845
  5. Margaret Duffy, MDNephrology Physician1518233881
  6. Eric Fels, D.O.Nephrology Physician1821089590

Verify Frederick Sebastian Fleszler in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersPennsylvania Department of State (PALS)
    Search for license MD428393    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the Pennsylvania license search

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8% more Medicare Part D claims than the average nephrology physician in 2024

1,580 Medicare Part D claims for 205 beneficiaries, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D.

  1. Frederick Fleszler1,580
  2. Specialty average1,465

Most prescribed

  1. Amlodipine Besylate187 claims
  2. Calcitriol150 claims
  3. Lisinopril123 claims
  4. Losartan Potassium114 claims
  5. Valsartan73 claims
  6. Spironolactone67 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

  1. Kidney Care Specialists LLCAllentown, PA
  2. Valley Kidney Specialists, P.C.Allentown, PA

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Nephrology Physician providers in Pennsylvania

There are 651 nephrology physician records in Pennsylvania.

All 651 in Pennsylvania → Every provider in Allentown →

Other nephrology physician records in Pennsylvania

  1. Muhammad Abdulbasit, MD, FACPWilkes Barre, PA1265704225
  2. Mohamed Anwar Abdus Samad, MDYork, PA1285983684
  3. Samer Abou Chehade, M.DErie, PA1730744020
  4. Blaise AbramovitzPittsburgh, PA1093150922
  5. Parvaneh Abtahi, MDWyomissing, PA1245213099
  6. Azza AbubakerPhiladelphia, PA1821732298
  7. Scott Adler, MDPhiladelphia, PA1295986792
  8. Sandeep Aggarwal, M.D.Philadelphia, PA1548420326
  9. Gautam Agrawal, M.D , M.P.HGreensburg, PA1063737070
  10. Ravi Agrawal, M.B.B.SBethlehem, PA1396973178

Common questions

What is Frederick Sebastian Fleszler, MD's NPI number?

Frederick Sebastian Fleszler, MD's National Provider Identifier (NPI) is 1588758353, issued on Oct 3, 2006. An NPI identifies a provider in billing; it is not a license.

Where is Frederick Sebastian Fleszler, MD located?

The NPPES record lists a practice address at 1230 S Cedar Crest Blvd Stes 301, 302, 304, Allentown, PA, 18103. Phone: (610) 432-4529. Providers update this record themselves, so call before visiting.

How can I verify Frederick Sebastian Fleszler, MD's license?

NPPES lists Pennsylvania license number MD428393, as entered by the provider. Search the Pennsylvania Department of State (PALS) at https://www.pals.pa.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.

How much does Frederick Sebastian Fleszler, MD prescribe under Medicare Part D?

In 2024, Frederick Sebastian Fleszler, MD had 1,580 Medicare Part D claims for 205 beneficiaries; the average among nephrology physician prescribers was 1,465. 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.

Written with AI tools from the named public files; every figure is computed from those files (how it is made).

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.