NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1851457717 M.D.
Verify on CMS → Jean Shlyak, M.D.
Internal Medicine Physician in Northbrook, Illinois.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 172,737 in Internal Medicine Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
8K
Medicare Part D claims · 301 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
86%
generic claims · 13% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
What the federal data shows
Jean Shlyak, M.D. filed 8,000 Medicare Part D claims in 2023 as an Internal Medicine Physician in Northbrook, Illinois, prescribing 86% generic.
- 8K
- Part D claims, 2023
- 86%
- generic prescribing
- ≥97th
- pct by Part D claim volume (lower-bound band)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Jean Shlyak, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
8,000 ≥ 97th percentile 97% of 1,370,886 prescribers are in lower value bands
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2023
◑
Board-eligible specialty (heuristic, not verified)
Jean Shlyak, M.D. practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Jean Shlyak, M.D.?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
8,000 195% vs specialty avg
Specialty distribution in Illinois
How Internal Medicine Physician compares to other specialties among Illinois providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Internal Medicine Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Jean Shlyak, M.D. appears in the CMS NPPES registry as an Internal Medicine Physician provider holding M.D. credentials at 3000 DUNDEE RD STE 215, Northbrook, IL, 60062, with a listed phone of (847) 390-8550. NPI 1851457717 was issued on 12/28/2006.
Medicare Part D records for calendar year 2023 show 8,000 prescription claims written by this provider, covering 301 Medicare beneficiaries and totaling roughly $582K in drug spend, split 13% brand-name and 86% generic by claim count, with an opioid prescribing rate of 0.8%.
Internal Medicine Physician is a high-volume specialty nationwide, with 172,737 enrolled providers across 56 states and an average of 2,716 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1851457717 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | M.D. |
| Gender | Female |
| NPI Issued | 12/28/2006 |
License & disciplinary context - Illinois IDFPR 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~42K Illinois medical licensees in 2023 - they are NOT specific to Jean Shlyak, M.D.. To verify Jean Shlyak, M.D.'s current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases
IDFPR publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Illinois disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Typical
Jean Shlyak, M.D. - brand share 13.0%
Internal Medicine Physician average
13% brand-name claims vs 86% generic, on 8,000 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
8,000
Total Claims
$582K
Total Drug Cost
301
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 11,835
- Total Day Supply
- 347,303
- Brand vs Generic
- 13% brand / 86% generic
- Brand Drug Cost
- $450K
- Generic Drug Cost
- $130K
- Opioid Claims
- 66 (0.8% rate)
- Antibiotic Claims
- 91
Patient Demographics
- Average Patient Age
- 76.7 years
- Avg HCC Risk Score
- 1.13
- Gender Split
- 67% female / 33% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Jean Shlyak, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Levothyroxine Sodium
Levothyroxine Sodium
680 claims
- Amlodipine Besylate
Amlodipine Besylate
461 claims
- Omeprazole
Omeprazole
308 claims
- Lorazepam 231
Lorazepam
231 claims
- Allopurinol 216
Allopurinol
216 claims
- Metformin Hcl 205
Metformin Hcl
205 claims
- Losartan Potassium 179
Losartan Potassium
179 claims
- Propranolol Hcl 177
Propranolol Hcl
177 claims
| Drug | Claims |
|---|---|
| Levothyroxine Sodium | 680 |
| Amlodipine Besylate | 461 |
| Omeprazole | 308 |
| Lorazepam | 231 |
| Allopurinol | 216 |
| Metformin Hcl | 205 |
| Losartan Potassium | 179 |
| Propranolol Hcl | 177 |
| Atorvastatin Calcium | 168 |
| Gabapentin | 153 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Internal Medicine Physician Overview
How Jean Shlyak, M.D. fits within the Internal Medicine Physician landscape nationally.
172,737
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider
Jean Shlyak, M.D.'s 8,000 claims are above the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in Illinois
Other clinicians with the same primary specialty enrolled in Illinois, drawn from the same CMS NPPES roster as Shlyak.
One of 8,383 Internal Medicine Physician providers enrolled in Illinois, 5 are shown here.
Dr. Hasan Abad
D.O.
Chicago, IL
Dr. Peter Abadeer
D.O.
Bloomington, IL
Dr. Pamela Abadi
D.O.
Winfield, IL
Dr. Motaz Abas
MD
Peoria, IL
Dr. Estefania Abasolo Lopez
MD
Chicago, IL
Compare Internal Medicine Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Illinois medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Internal Medicine Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Jean Shlyak, M.D.'s specialty? ▼
Jean Shlyak, M.D. specializes in Internal Medicine Physician and practices in Northbrook, Illinois. Credentials: M.D..
How much does Jean Shlyak, M.D. prescribe under Medicare Part D? ▼
In 2023, Jean Shlyak, M.D. wrote 8,000 Medicare Part D claims totaling $582K in drug costs for 301 beneficiaries.
Where is Jean Shlyak, M.D. located? ▼
Jean Shlyak, M.D. is located at 3000 DUNDEE RD STE 215, Northbrook, IL, 60062. Phone: (847) 390-8550.
What is Jean Shlyak, M.D.'s NPI number? ▼
Jean Shlyak, M.D.'s National Provider Identifier (NPI) is 1851457717, issued on 12/28/2006.
Does Jean Shlyak, M.D. prescribe more brand-name or generic drugs? ▼
Jean Shlyak, M.D.'s prescribing is 13% brand-name and 86% generic drugs by claim count, with $450K in brand drug costs.
Does Jean Shlyak, M.D. prescribe opioids? ▼
Yes, Jean Shlyak, M.D. had 66 opioid claims in 2023 with an opioid prescribing rate of 0.8%.
How many Internal Medicine Physician providers are there in the US? ▼
There are 172,737 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does Jean Shlyak, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Jean Shlyak, M.D.'s most frequently prescribed drugs include Levothyroxine Sodium, Amlodipine Besylate, Omeprazole. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Jean Shlyak, M.D. accept Medicare? ▼
Jean Shlyak, M.D. appears in CMS Medicare data with 8,000 Part D claims and 301 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Jean Shlyak, M.D.'s credentials? ▼
Jean Shlyak, M.D.'s NPI is 1851457717 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.