William Brian Greiser, MD
Emergency Medicine Physician · Trinidad, CO
William Brian Greiser, MD is an emergency medicine physician with a practice address in Trinidad, Colorado, and NPI 1720114408, issued on Feb 26, 2007. Check the license (Colorado 36079, as entered in NPPES) on the Colorado Medical Board; the Medicare figures below come from public CMS files.
- Name
- William Brian Greiser
- Credential
- MD
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License number
- 36079 CO
Self-reported in NPPES; status is on the state search - Practice location
- 410 Benedicta Ave, Trinidad, CO 81082
- Phone
- (800) 893-9698
- Enumerated
- Feb 26, 2007
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 1,434 in Colorado → Look up another NPI →
Also registered at 410 Benedicta Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- James Conrad, M.D.Surgery Physician1316983083
- Teresa Coombs, RNDiabetes Educator Registered Nurse1063911832
- Summer FarisPsychiatric/Mental Health Registered Nurse1225664485
- Charles MasewiczPhysical Therapist1871428664
- Jesse Mullins, PTAPhysical Therapy Assistant1316148158
- Leona MyersRegistered Nurse1801682430
Verify William Brian Greiser in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersColorado Medical Board
Search for license 36079Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
50% more Medicare Part D claims than the average emergency medicine physician in 2024
339 Medicare Part D claims for 128 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D. Brand-name drugs were 4% of claims. 89 claims were for opioids.
Most prescribed
- Oxycodone Hcl53 claims
- Hydrocodone-Acetaminophen26 claims
- Prednisone13 claims
- Ciprofloxacin Hcl11 claims
- Ibuprofen11 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.
William Brian Greiser among 1,434 emergency medicine physician records in Colorado
William Brian Greiser, MD is one of 1,434 emergency medicine physician records with a practice address in Colorado. 77% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 43% of them.
- NPI issued2007 · 43% of these records are older, 47% newer
- In a Medicare fileYes · 77% of these records are
- In the CMS Doctors and Clinicians fileNo · 57% of these records are
- Record last updated2007 · 59% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a Colorado practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Emergency Medicine Physician providers in Colorado
There are 1,434 emergency medicine physician records in Colorado.
All 1,434 in Colorado → Every provider in Trinidad → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Chad Davis, M.D.Walsenburg, CO 810891922081090
- Jonathan Dobin, M.D.Walsenburg, CO 810891295180362
- Ginger Dunnam-Smith, M.D.Walsenburg, CO 810891710905997
- Thomas Faulhaber, M.D.Walsenburg, CO 810891912914466
- Greg Hosler, MDWalsenburg, CO 810891679714745
- Michael Mills, M.D.Walsenburg, CO 810891700806007
- Jonathan Moran, DOWalsenburg, CO 810891902244734
- Fred Williams, MDWalsenburg, CO 810891013987973
Common questions
What is William Brian Greiser, MD's NPI number?
William Brian Greiser, MD's National Provider Identifier (NPI) is 1720114408, issued on Feb 26, 2007. An NPI identifies a provider in billing; it is not a license.
Where is William Brian Greiser, MD located?
The NPPES record lists a practice address at 410 Benedicta Ave, Trinidad, CO, 81082. Phone: (800) 893-9698. Providers update this record themselves, so call before visiting.
How can I verify William Brian Greiser, MD's license?
NPPES lists Colorado license number 36079, as entered by the provider. Search the Colorado Medical Board at https://dpo.colorado.gov/Medical. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William Brian Greiser, MD prescribe under Medicare Part D?
In 2024, William Brian Greiser, MD had 339 Medicare Part D claims for 128 beneficiaries; the average among emergency medicine physician prescribers was 226. 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.