Dr. John E Greifenkamp , MD
Internal Medicine β’ Longview, TX
707 Hollybrook Dr
Longview, TX 756052410
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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Dr. John Greifenkamp is listed in NPPES under Internal Medicine.
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NPI assigned on March 2, 2006; this date does not establish years in practice.
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Published CMS data list 48 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024. Published rows only; this is not a quality measure.
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Published Part D records, 2024:
- Clopidogrel (Clopidogrel Bisulfate) β 21 prescription fills, including refills.
- Carvedilol β 14 prescription fills, including refills.
- Amlodipine Besylate β 13 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See the full table Β· Guide: How to read Medicare Part D prescriber data
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Fewer Part D prescriptions than 85% of clinicians listed under Internal Medicine in Longview, TX (2024, 78 clinicians with data). Median for this group: 256. Middle half: 92 to 6,437.
Fewer Part D prescriptions than 85% of clinicians listed under Internal Medicine in Texas (2024, 5,674 clinicians with data). Median for this group: 828. Middle half: 121 to 4,824.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part D prescriptions went from 196 in 2020 to 48 in 2024.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2020β2024.
Practice Location & Contact Primary Location
707 Hollybrook Dr
Longview, TX 756052410
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
What Public CMS Data Show
Internal Medicine: NPPES taxonomy is a reported classification, not proof of board certification.
30-day fills
86 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
$538 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 β by Provider and Drug, 2024.
Open Payments general payments, program year 2025
All general payments: $147.76 across 2 records.
By nature of payment
- Food and Beverage: $147.76 across 2 records.
Reporting-company totals
- Alnylam Pharmaceuticals Inc.: $133.10 across 1 record.
- Philips North America LLC: $14.66 across 1 record.
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).
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.
Medicare assignment not listed
CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.
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, βDoes your provider accept Medicare as full payment?β
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Compared with the same specialty in Longview and Texas
Billing and prescribing volume is not a quality rating.
Medicare Part D prescriptions
Fewer Part D prescriptions than 85% of clinicians listed under Internal Medicine in Longview, TX (2024, 78 clinicians with data). Median for this group: 256. Middle half: 92 to 6,437.
Fewer Part D prescriptions than 85% of clinicians listed under Internal Medicine in Texas (2024, 5,674 clinicians with data). Median for this group: 828. Middle half: 121 to 4,824.
Part D drug cost
A lower Part D drug cost than 80% of clinicians listed under Internal Medicine in Longview, TX (2024, 78 clinicians with data). Median for this group: $15,088. Middle half: $1,085 to $464,881.
A lower Part D drug cost than 85% of clinicians listed under Internal Medicine in Texas (2024, 5,674 clinicians with data). Median for this group: $64,859. Middle half: $4,211 to $436,775.
99 active clinicians are listed under Internal Medicine with a practice address in Longview, TX (9,191 in Texas).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Longview
20.2% of these 99 clinicians have the CMS telehealth indicator.
76.8% of these 99 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 D prescriptions
Medicare Part D prescriptions decreased 76% from 196 in 2020 to 48 in 2024.
- 2020: 196
- 2021: 207
- 2022: 120
- 2023: 111
- 2024: 48
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30-day fills
30-day fills decreased 69% from 276 in 2020 to 86 in 2024.
- 2020: 276
- 2021: 283
- 2022: 159
- 2023: 157
- 2024: 86
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Part D drug cost
Part D drug cost decreased 98% from $35,462 in 2020 to $538 in 2024.
- 2020: $35,462
- 2021: $24,920
- 2022: $18,633
- 2023: $13,303
- 2024: $538
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Industry payments (Open Payments)
Industry payments (Open Payments) went from $30.62 in 2024 to $147.76 in 2025.
- 2024: $30.62
- 2025: $147.76
Sources: 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 Β· 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 β December 31, 2025): fewer than 11 records totaling $147.76.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Alnylam Pharmaceuticals Inc. |
Food and Beverage
In-kind items and services
|
AMVUTTRA | General | $133.10 |
| Philips North America LLC |
Food and Beverage
Cash or cash equivalent
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MCOT | General | $14.66 |
Source: CMS Open Payments, program year 2025, released June 30, 2026.
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 |
|---|---|---|---|---|---|
| Clopidogrel | Clopidogrel Bisulfate | 21 | 1,290 | $308.29 | β |
| Carvedilol | Carvedilol | 14 | 840 | $164.59 | β |
| Amlodipine Besylate | Amlodipine Besylate | 13 | 450 | $65.42 | β |
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.
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.)
Nurse Practitioner - Family
Family Nurse Practitioner
Internal Medicine
Doctor of Medicine (M.D.)
Internal Medicine - Rheumatology
Doctor of Medicine (M.D.)
Family Medicine
Doctor of Medicine (M.D.)
Nurse Practitioner - Family
Family Nurse Practitioner (Certified)
Career & Practice History
NPI enumerated March 02, 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 August 2026.
NPI Administrative Meta
Other Internal Medicine Providers in Longview
- Dr. Malasha Khan, MD
- Dr. Madhu Chiluveri, MD
- Dr. Carl Earnest, MD
- Dr. Sreeman Jampana, MD
- Dr. Jeffrey Hart, MD
- Dr. Allessia Wilson, MD
Mailing Address
707 Hollybrook Dr
Longview, TX 756052410
Phone: 9037576042