William Sidney Warren, M.D.
Addiction Medicine (Anesthesiology) Physician · Little Rock, AR
William Sidney Warren, M.D. is an addiction medicine (anesthesiology) physician with a practice address in Little Rock, Arkansas, and NPI 1467547984, issued on Oct 3, 2006. Check the license (Arkansas C6145, as entered in NPPES) on the Arkansas State Medical Board; the Medicare figures below come from public CMS files.
- Name
- William Sidney Warren
- Credential
- M.D.
- Primary taxonomy
- Addiction Medicine (Anesthesiology) Physician 207LA0401X
- License number
- C6145 AR
Self-reported in NPPES; status is on the state search - Practice location
- 425 W Capitol Ave Ste 1535, Little Rock, AR 72201
- Phone
- (501) 448-6663
- Enumerated
- Oct 3, 2006
- Record last updated
- Jun 24, 2023
- Fax
- (501) 448-6663
- Entity
- Type 1 · individual
Verify William Sidney Warren in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersArkansas State Medical Board
Search for license C6145Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
90% fewer Medicare Part D claims than the average addiction medicine (anesthesiology) physician in 2024
34 Medicare Part D claims, against an average of 345 among the 58 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.
Most prescribed
- Buprenorphine-Naloxone22 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.
Addiction Medicine (Anesthesiology) Physician providers in Arkansas
There are 1 addiction medicine (anesthesiology) physician records in Arkansas.
All 1 in Arkansas → Every provider in Little Rock → Addiction Medicine (Anesthesiology) Physician nationwide →
Common questions
What is William Sidney Warren, M.D.'s NPI number?
William Sidney Warren, M.D.'s National Provider Identifier (NPI) is 1467547984, issued on Oct 3, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William Sidney Warren, M.D. located?
The NPPES record lists a practice address at 425 W Capitol Ave Ste 1535, Little Rock, AR, 72201. Phone: (501) 448-6663. Providers update this record themselves, so call before visiting.
How can I verify William Sidney Warren, M.D.'s license?
NPPES lists Arkansas license number C6145, as entered by the provider. Search the Arkansas State Medical Board at https://armedicalboard.adh.arkansas.gov/public/verify/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William Sidney Warren, M.D. prescribe under Medicare Part D?
In 2024, William Sidney Warren, M.D. had 34 Medicare Part D claims; the average among addiction medicine (anesthesiology) physician prescribers was 345. 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.