Timmothy Merrigan, M.D.
NPI 1063442945 · Family Medicine Physician · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Timmothy Merrigan, M.D. is a Family Medicine Physician provider in Walnut Creek, CA (NPI 1063442945).
Provider details
- NPI number
- 1063442945
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- A63055 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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 · 72 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 843 | 284 |
| Hydrochlorothiazide | 396 | 126 |
| Amlodipine Besylate | 359 | 122 |
| Losartan Potassium | 260 | 85 |
| Lisinopril | 243 | 84 |
| Levothyroxine Sodium | 221 | 73 |
| Famotidine | 179 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-07-04
- Last updated
- 2022-02-11
Frequently asked questions
- What is Timmothy Merrigan's NPI number?
- Timmothy Merrigan's National Provider Identifier (NPI) is 1063442945, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Timmothy Merrigan's specialty?
- Timmothy Merrigan is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Timmothy Merrigan located?
- Timmothy Merrigan's practice location on file with NPPES is 320 Lennon Ln, Walnut Creek, CA 94598-2419.
- What is Timmothy Merrigan's phone number?
- The practice phone number listed in the NPPES registry for Timmothy Merrigan is (924) 906-2326.
- Does Timmothy Merrigan accept Medicare?
- Timmothy Merrigan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Timmothy Merrigan's NPI active?
- Yes — Timmothy Merrigan's NPI (1063442945) is active in the NPPES registry as of the last update on 2022-02-11.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.