Russell M. Greif, D.O.
Internal Medicine Physician · Lancaster, CA
Russell M. Greif, D.O. is an internal medicine physician with a practice address in Lancaster, California, and NPI 1669519765, issued on Jan 30, 2007. Check the license (California 20A5410, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Russell M. Greif
- Credential
- D.O.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A5410 CA
Self-reported in NPPES; status is on the state search - Practice location
- 44241 15TH St W, Lancaster, CA 93534
- Phone
- (661) 726-6490
- Enumerated
- Jan 30, 2007
- Record last updated
- Dec 13, 2011 (not updated in 15 years: call before relying on the address or phone)
- Fax
- (661) 726-6494
- Medicaid IDs
- 020A54100 CA
DOAX54100 CA - Medicare enrollment
- Enrolled (PECOS I20100915000042); accepts Medicare assignment
- Medical or professional school
- College Of Osteo Med Of The Pacific At Pomona, 1986
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
Also registered at 44241 15TH St W
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Rachel Allen, NPFamily Nurse Practitioner1104327881
- Katrina Baker, MDObstetrics & Gynecology Physician1538154836
- Jackson Fu, MDObstetrics & Gynecology Physician1871581637
- Laura Galeazzi, A.C.N.P.Acute Care Nurse Practitioner1982006748
- Karen Tison, M.D.Ophthalmology Physician1164476248
Verify Russell M. Greif in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A5410Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
6% fewer Medicare Part D claims than the average internal medicine physician in 2024
2,989 Medicare Part D claims for 192 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 19% of claims.
Most prescribed
- Rosuvastatin Calcium195 claims
- Amlodipine Besylate175 claims
- Atorvastatin Calcium131 claims
- Lisinopril119 claims
- Synthroid105 claims
- Losartan Potassium96 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.
Industry payments in 2024: $634.05
11 payments; by number, the most common kind was food and beverage; the largest payer was GlaxoSmithKline, LLC. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
55 internal medicine physician records list a practice address in Lancaster
They are 55 of the 4,273 NPPES records with a practice address in Lancaster, and 17,696 internal medicine physician records in California.
All 55 in Lancaster → All 17,696 in California → Every provider in Lancaster →
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- Samuel Abarte, M.D.Chula Vista, CA1578535498
- Alexander Abary, MDLong Beach, CA1104995919
- Luba Abascal, MDSan Francisco, CA1023180874
- Michael Abate, MDSacramento, CA1548248131
- Wali Abawi, D.O.Joshua Tree, CA1104362268
Common questions
What is Russell M. Greif, D.O.'s NPI number?
Russell M. Greif, D.O.'s National Provider Identifier (NPI) is 1669519765, issued on Jan 30, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Russell M. Greif, D.O. located?
The NPPES record lists a practice address at 44241 15TH St W, Lancaster, CA, 93534. Phone: (661) 726-6490. Providers update this record themselves, so call before visiting.
How can I verify Russell M. Greif, D.O.'s license?
NPPES lists California license number 20A5410, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Russell M. Greif, D.O. prescribe under Medicare Part D?
In 2024, Russell M. Greif, D.O. had 2,989 Medicare Part D claims for 192 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.