William Prey, M.D.
NPI 1366542953 · Psychiatry Physician · San Francisco, CA
Enrolled with Medicare as Order and Referring Only - Psychiatry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Prey, M.D. is a Psychiatry Physician provider in San Francisco, CA (NPI 1366542953).
Provider details
- NPI number
- 1366542953
- Entity type
- Individual
- Primary specialty
- Psychiatry PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- G45386 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
19 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 53 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Lamotrigine | 170 | 31 |
| Lorazepam | 148 | 27 |
| Trazodone Hcl | 86 | 19 |
| Baclofen | 67 | 13 |
| Vortioxetine Hydrobromidebrand: Trintellix | 51 | — |
| Suvorexantbrand: Belsomra | 50 | — |
| Duloxetine Hcl | 47 | — |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$222 across 8 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-09-23
- Last updated
- 2007-07-08
Frequently asked questions
- What is William Prey's NPI number?
- William Prey's National Provider Identifier (NPI) is 1366542953, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Prey's specialty?
- William Prey is listed in the NPPES registry with a primary specialty of Psychiatry Physician (Allopathic & Osteopathic Physicians).
- Where is William Prey located?
- William Prey's practice location on file with NPPES is 2345 California St, San Francisco, CA 94115-2747.
- What is William Prey's phone number?
- The practice phone number listed in the NPPES registry for William Prey is (415) 346-8599.
- Does William Prey accept Medicare?
- William Prey is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Prey's NPI active?
- Yes — William Prey's NPI (1366542953) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.