Dr. William Chunghun Sim , MD
Internal Medicine • Downey, CA
11480 Brookshire Ave, 200
Downey, CA 902419998
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
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NPI assigned on September 19, 2006; this date does not establish years in practice.
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Published CMS data list 5,538 Original Medicare Part B services in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Published rows only; this is not a quality measure.
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Published Part B service records, 2024:
- 99349 — Residence visit for established patient with moderate level of medical decision making, per day: 1,647 service units.
- 99214 — Established patient outpatient office visit: 677 service units.
- 99213 — Established patient outpatient office visit: 640 service units.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Units differ by code; these are not visits or a measure of quality.
CPT® only copyright 2023 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2024). CPT notice
See all 17 records in the table · Guide: How to read Medicare Part B data
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Published CMS data list 37,524 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024. Published rows only; this is not a quality measure.
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Published Part D records, 2024:
- Atorvastatin Calcium — 2,063 prescription fills, including refills.
- Losartan Potassium — 1,669 prescription fills, including refills.
- Amlodipine Besylate — 1,383 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 275 records in the table · Guide: How to read Medicare Part D prescriber data
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More Medicare Part B services than 95% of clinicians listed under Internal Medicine in Downey, CA (2024, 33 clinicians with data). Median for this group: 325. Middle half: 52 to 764.
More Medicare Part B services than 95% of clinicians listed under Internal Medicine in California (2024, 8,010 clinicians with data). Median for this group: 547. Middle half: 197 to 1,237.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part B services went from 4,620 in 2020 to 5,538 in 2024.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2020–2024.
Practice Location & Contact Primary Location
11480 Brookshire Ave
200
Downey, CA 902419998
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
CMS Doctors and Clinicians lists 1 group name: Frischer Medical Group Inc. See the list
Source: CMS Doctors and Clinicians National Downloadable File, release date unavailable.
Listings do not confirm current availability, employment or a shared ownership network.
Medicare Profile & Education
Source: CMS Doctors and Clinicians National Downloadable File
Stanford University School Of Medicine
1990
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
787 people with Original Medicare in 2024
It gives a sense of how many people with Medicare this clinician treated that year.
Source: CMS, Medicare Physician & Other Practitioners – by Provider, 2024.
Medicare-allowed amount
About $535,185 in 2024
The total amount Medicare approved for these services in 2024. It includes what Medicare paid and what patients or their other insurance owed, such as the deductible and coinsurance.
It shows the total cost of this clinician's Original Medicare services under Medicare's fee rules.
What this does not show: Medicare-allowed amount
This is not the clinician's income. Part of it can go to a clinic or group practice, staff, equipment or drugs. It is not the price you will pay.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024.
Paid by Medicare
About $373,240 in 2024
The part of the Medicare-allowed amount that Medicare itself paid in 2024, after patients' deductibles and coinsurance.
The gap between the allowed amount and this number is roughly what patients and their other insurance paid.
What this does not show: Paid by Medicare
This is not the clinician's income and not a measure of quality.
Source: CMS, Medicare Physician & Other Practitioners – by Provider and Service, 2024.
30-day fills
55,798 standardized 30-day fills in 2024
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$3,393,626 in 2024
The total cost of these prescriptions in 2024, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers – by Provider and Drug, 2024.
Open Payments general payments, program year 2025
All general payments: $1,982.35 across 94 records.
By nature of payment
- Food and Beverage: $1,982.35 across 94 records.
Reporting-company totals (3 largest of 26)
- ABBVIE INC.: $478.66 across 21 records.
- AstraZeneca Pharmaceuticals LP: $164.09 across 8 records.
- Novo Nordisk Inc: $161.38 across 9 records.
A reported payment does not necessarily mean the financial relationship is improper and is not a measure of care quality. Clinicians can review and dispute these records.
Source: Calculated by T-MedInfo from CMS Open Payments general-payment records for program year 2025 (published June 30, 2026).
Years since graduation
36 years (graduated 1990)
CMS Doctors and Clinicians data list 1990 as the year this clinician finished professional school.
It tells you roughly how long ago the clinician finished school.
What this does not show: Years since graduation
It is not the number of years in practice, and more years does not mean better care.
Source: CMS Doctors and Clinicians National Downloadable File.
NPI first issued
2006
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Accepts Medicare assignment
CMS data list this clinician as accepting Medicare assignment. This means agreeing to take the Medicare-approved amount as full payment for covered services.
With Original Medicare, you usually pay only your deductible and coinsurance, and the office sends the claim to Medicare for you.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians; Medicare.gov, “Does your provider accept Medicare as full payment?”
Telehealth (some services)
Recent Medicare claims show this clinician provided some services by telehealth, such as a video or phone visit.
You may be able to have some visits without going to the office. Ask which visits can be done by telehealth.
What this does not show: Telehealth (some services)
It does not mean all services are offered by telehealth, or that telehealth is covered by your plan.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Enrolled in Medicare (PECOS)
Dr. Sim has a Medicare enrollment record in PECOS, the CMS system clinicians use to enroll so they can bill Medicare or order services for people with Medicare.
It does not show whether the clinician accepts assignment, is in your plan's network, or is taking new patients.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Can order Medicare-covered services
CMS lists Dr. Sim as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.
Medicare pays for these items and services only when they are ordered by an eligible clinician.
What this does not show: Can order Medicare-covered services
It does not mean the clinician offers these services directly.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Downey and California
Billing and prescribing volume is not a quality rating.
Medicare Part B services
More Medicare Part B services than 95% of clinicians listed under Internal Medicine in Downey, CA (2024, 33 clinicians with data). Median for this group: 325. Middle half: 52 to 764.
More Medicare Part B services than 95% of clinicians listed under Internal Medicine in California (2024, 8,010 clinicians with data). Median for this group: 547. Middle half: 197 to 1,237.
Medicare-allowed amount
A higher Medicare-allowed amount than 95% of clinicians listed under Internal Medicine in Downey, CA (2024, 33 clinicians with data). Median for this group: $38,363. Middle half: $4,243 to $84,868.
A higher Medicare-allowed amount than 95% of clinicians listed under Internal Medicine in California (2024, 8,010 clinicians with data). Median for this group: $57,305. Middle half: $20,387 to $125,671.
Paid by Medicare
A higher Medicare payment amount than 95% of clinicians listed under Internal Medicine in Downey, CA (2024, 33 clinicians with data). Median for this group: $30,399. Middle half: $3,240 to $63,005.
A higher Medicare payment amount than 95% of clinicians listed under Internal Medicine in California (2024, 8,010 clinicians with data). Median for this group: $43,389. Middle half: $14,879 to $95,775.
Medicare Part D prescriptions
More Part D prescriptions than 95% of clinicians listed under Internal Medicine in Downey, CA (2024, 82 clinicians with data). Median for this group: 422. Middle half: 121 to 3,652.
More Part D prescriptions than 95% of clinicians listed under Internal Medicine in California (2024, 10,854 clinicians with data). Median for this group: 1,235. Middle half: 145 to 4,223.
Part D drug cost
A higher Part D drug cost than 95% of clinicians listed under Internal Medicine in Downey, CA (2024, 82 clinicians with data). Median for this group: $19,569. Middle half: $3,463 to $211,674.
A higher Part D drug cost than 95% of clinicians listed under Internal Medicine in California (2024, 10,854 clinicians with data). Median for this group: $86,796. Middle half: $7,321 to $305,686.
116 active clinicians are listed under Internal Medicine with a practice address in Downey, CA (17,888 in California).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Downey
10.3% of these 116 clinicians have the CMS telehealth indicator.
62.9% of these 116 clinicians are listed by CMS as accepting Medicare assignment.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
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Medicare Part B services
Medicare Part B services increased 20% from 4,620 in 2020 to 5,538 in 2024.
- 2020: 4,620
- 2021: 3,456
- 2022: 4,643
- 2023: 4,892
- 2024: 5,538
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Medicare-allowed amount
Medicare-allowed amount increased 42% from $376,828 in 2020 to $535,185 in 2024.
- 2020: $376,828
- 2021: $308,277
- 2022: $459,414
- 2023: $504,133
- 2024: $535,185
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Paid by Medicare
Paid by Medicare increased 39% from $268,303 in 2020 to $373,240 in 2024.
- 2020: $268,303
- 2021: $218,352
- 2022: $331,244
- 2023: $353,856
- 2024: $373,240
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Medicare Part D prescriptions
Medicare Part D prescriptions increased 56% from 24,095 in 2020 to 37,524 in 2024.
- 2020: 24,095
- 2021: 19,098
- 2022: 24,871
- 2023: 31,115
- 2024: 37,524
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30-day fills
30-day fills increased 39% from 40,284 in 2020 to 55,798 in 2024.
- 2020: 40,284
- 2021: 34,961
- 2022: 41,819
- 2023: 48,578
- 2024: 55,798
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Part D drug cost
Part D drug cost increased 82% from $1,868,659 in 2020 to $3,393,626 in 2024.
- 2020: $1,868,659
- 2021: $1,652,194
- 2022: $2,193,441
- 2023: $3,110,165
- 2024: $3,393,626
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Industry payments (Open Payments)
Industry payments (Open Payments) increased 17% from $1,687.13 in 2021 to $1,982.35 in 2025.
- 2021: $1,687.13
- 2022: $1,058.04
- 2023: $1,273.20
- 2024: $1,888.70
- 2025: $1,982.35
Sources: CMS Medicare Physician & Other Practitioners (2024), CMS Medicare Part D Prescribers (2024), CMS Open Payments (2025), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo · Report an error.
Pharma & Medical Device Financial Disclosures
Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments
Program year 2025 (payments made January 1 – December 31, 2025): 94 records totaling $1,982.35.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
UBRELVY | General | $33.74 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
UBRELVY | General | $32.57 |
| Echosens North America, Inc. |
Food and Beverage
Cash or cash equivalent
|
Fibroscan | General | $32.10 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
UBRELVY | General | $31.50 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
UBRELVY | General | $31.09 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
Wegovy | General | $31.05 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
LINZESS | General | $30.56 |
| Amgen Inc. |
Food and Beverage
In-kind items and services
|
Repatha | General | $30.50 |
| Sumitomo Pharma America, Inc. |
Food and Beverage
In-kind items and services
|
GEMTESA | General | $29.81 |
| Pfizer Inc. |
Food and Beverage
In-kind items and services
|
NURTEC ODT | General | $28.90 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
|
JARDIANCE | General | $28.76 |
| Otsuka America Pharmaceutical, Inc. |
Food and Beverage
In-kind items and services
|
REXULTI | General | $28.71 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
UBRELVY | General | $27.99 |
| Phathom Pharmaceuticals, Inc. |
Food and Beverage
Cash or cash equivalent
|
VOQUEZNA | General | $27.71 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
LINZESS | General | $27.11 |
| Boehringer Ingelheim Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
|
JARDIANCE | General | $27.11 |
| Boehringer Ingelheim Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
|
JARDIANCE | General | $27.02 |
| GlaxoSmithKline, LLC. |
Food and Beverage
In-kind items and services
|
TRELEGY ELLIPTA | General | $26.90 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
LINZESS | General | $26.76 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
Ozempic | General | $26.37 |
| Dexcom, Inc. |
Food and Beverage
In-kind items and services
|
Dexcom G6 Transmitter | General | $26.34 |
| Amgen Inc. |
Food and Beverage
In-kind items and services
|
OTEZLA | General | $25.96 |
| Boehringer Ingelheim Pharmaceuticals, Inc. |
Food and Beverage
In-kind items and services
|
JARDIANCE | General | $25.60 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
UBRELVY | General | $25.59 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
|
KISUNLA | General | $25.49 |
(top 25 shown)
Source: CMS Open Payments, program year 2025, released June 30, 2026.
Performed Procedures & Service Volume
CPT® is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016–2023 American Medical Association. All rights reserved. Applicable FARS/HHSARS apply. Descriptions of CPT codes are the AMA's CPT Consumer Friendly Descriptors as published by CMS in the Medicare Physician & Other Practitioners – by Provider and Service data, 2017–2024; they are plain-language summaries, not for clinical coding or documentation. HCPCS Level II codes and descriptions are from CMS. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
| HCPCS Code | Services | Patients | Submitted Charge | Medicare Allowed |
|---|---|---|---|---|
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99349
Residence visit for established patient with moderate level of medical decision making, per day, if using time, at least 40 minutes
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1,647 | 315 | $450.00 | $134.23 |
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99214
Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more
|
677 | 331 | $200.00 | $139.55 |
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99213
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more
|
640 | 238 | $150.00 | $99.17 |
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99348
Residence visit for established patient with low level of medical decision making, per day, if using time, at least 30 minutes
|
564 | 235 | $300.00 | $80.88 |
|
J1010
Injection, methylprednisolone acetate, 1 mg
|
510 | 11 | $2.00 | $0.13 |
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G0181
Physician or allowed practitioner supervision of a patient receiving medicare-covered services provided by a participating home health agency (patient not present) requiring complex and multidisciplinary care modalities involving regular physician or allow
|
423 | 245 | $250.00 | $112.83 |
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J3301
Injection, triamcinolone acetonide, not otherwise specified, 10 mg
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379 | 62 | $10.00 | $0.96 |
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99490
Chronic care management services, first 20 minutes of clinical staff time directed by health care professional, per calendar month
|
215 | 30 | $150.00 | $67.70 |
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99345
Residence visit for new patient with high level of medical decision making, per day, if using time, at least 75 minutes
|
125 | 125 | $300.00 | $212.84 |
|
96372
Injection of drug or substance under skin or into muscle
|
109 | 58 | $50.00 | $15.87 |
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20610
Aspiration and/or injection of fluid from large joint
|
53 | 36 | $145.00 | $74.31 |
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93000
Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report
|
51 | 46 | $50.00 | $15.70 |
|
81002
Urinalysis, manual test
|
47 | 29 | $15.00 | $3.41 |
|
99215
Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more
|
39 | 34 | $250.00 | $195.12 |
|
99212
Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more
|
27 | 23 | $125.00 | $62.26 |
|
99204
New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more
|
20 | 20 | $275.00 | $180.81 |
|
G0439
Annual wellness visit, includes a personalized prevention plan of service (pps), subsequent visit
|
12 | 12 | $250.00 | $141.17 |
Source: CMS Part B by Provider and Service, 2024; services under 11 beneficiaries omitted by CMS. Privacy limits
Submitted charges are billed amounts, not a price quote for your visit.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2024.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Atorvastatin Calcium | Atorvastatin Calcium | 2,063 | 103,588 | $20,351.27 | 400 |
| Losartan Potassium | Losartan Potassium | 1,669 | 86,711 | $14,073.40 | 319 |
| Amlodipine Besylate | Amlodipine Besylate | 1,383 | 65,810 | $6,839.18 | 265 |
| Metformin Hcl | Metformin Hcl | 1,224 | 61,089 | $7,442.05 | 243 |
| Levothyroxine Sodium | Levothyroxine Sodium | 1,215 | 75,423 | $14,718.27 | 245 |
| Metoprolol Succinate | Metoprolol Succinate | 1,005 | 54,811 | $13,738.45 | 200 |
| Pantoprazole Sodium | Pantoprazole Sodium | 800 | 37,992 | $8,832.05 | 155 |
| Omeprazole | Omeprazole | 795 | 39,468 | $9,365.77 | 166 |
| Linzess | Linaclotide | 768 | 24,599 | $439,941.29 | 132 |
| Donepezil Hcl | Donepezil Hcl | 750 | 23,029 | $6,040.45 | 96 |
| Gabapentin | Gabapentin | 710 | 25,304 | $9,997.42 | 112 |
| Tamsulosin Hcl | Tamsulosin Hcl | 683 | 30,162 | $12,880.05 | 131 |
| Potassium Chloride | Potassium Chloride | 674 | 25,579 | $17,851.82 | 132 |
| Memantine Hcl | Memantine Hcl | 650 | 20,990 | $30,093.19 | 92 |
| Montelukast Sodium | Montelukast Sodium | 583 | 27,525 | $7,905.13 | 108 |
| Doxazosin Mesylate | Doxazosin Mesylate | 562 | 31,091 | $10,574.04 | 119 |
| Furosemide | Furosemide | 543 | 22,509 | $2,442.46 | 118 |
| Memantine Hcl Er | Memantine Hcl | 472 | 14,402 | $50,313.45 | 65 |
| Eliquis | Apixaban | 453 | 17,451 | $343,990.04 | 70 |
| Famotidine | Famotidine | 444 | 17,941 | $4,516.81 | 77 |
| Meloxicam | Meloxicam | 428 | 13,854 | $2,064.32 | 93 |
| Glipizide Er | Glipizide | 416 | 23,420 | $4,359.74 | 88 |
| Clopidogrel | Clopidogrel Bisulfate | 391 | 19,040 | $4,152.42 | 77 |
| Prednisone | Prednisone | 385 | 5,726 | $1,481.62 | 186 |
| Nitrofurantoin Mono-Macro | Nitrofurantoin Monohyd/M-Cryst | 377 | 5,970 | $11,921.27 | 152 |
(top 25 shown)
Source: CMS Part D by Provider and Drug, 2024; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
NUCC Taxonomy Code: 207R00000X
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Additional State Medicaid & Healthcare Payer Identifiers
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSPRACTITIONER - INTERNAL MEDICINE
I20100311000876
CA
5698800910
Sources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Medicare Group Practice Enrollments
Source: CMS Doctors and Clinicians National Downloadable File
Frischer Medical Group Inc
11480 Brookshire Ave, Downey, CA 902415021
Phone: 5628060874
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine
Doctor of Medicine (M.D.)
Career & Practice History
NPI enumerated September 19, 2006.
No changes to the name, practice address, taxonomy or NPI status in this record have been observed in the monthly NPPES data files from January 2017 to November 2026.
NPI Administrative Meta
Other Internal Medicine Providers in Downey
- Dr. Sameer Amin, MD
- Dr. Jose Anguiano, MD
- Dr. Kim Chong, MD
- Dr. Muhammad Anees, MD
- Dr. Wang Ji, MD
- Triyug Malla Thakuri
Mailing Address
11480 Brookshire Ave, 200
Downey, CA 902419998
Phone: 5628060874