Mark Shaffer, M.D.
NPI 1255436804 · Internal Medicine Physician · La Mesa, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Shaffer, M.D. is a Internal Medicine Physician provider in La Mesa, CA (NPI 1255436804).
Provider details
- NPI number
- 1255436804
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- C42649 (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
19 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 · 8 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Levothyroxine Sodium | 60 | 16 |
| Tamsulosin Hcl | 34 | — |
| Atorvastatin Calcium | 27 | 13 |
| Apixabanbrand: Eliquis | 23 | 11 |
| Donepezil Hcl | 16 | — |
| Pantoprazole Sodium | 15 | — |
| Finasteride |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-09-14
- Last updated
- 2010-09-02
Frequently asked questions
- What is Mark Shaffer's NPI number?
- Mark Shaffer's National Provider Identifier (NPI) is 1255436804, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Shaffer's specialty?
- Mark Shaffer is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Shaffer located?
- Mark Shaffer's practice location on file with NPPES is 7877 Parkway Dr, La Mesa, CA 91942-2000.
- What is Mark Shaffer's phone number?
- The practice phone number listed in the NPPES registry for Mark Shaffer is (619) 461-3717.
- Does Mark Shaffer accept Medicare?
- Mark Shaffer is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Shaffer's NPI active?
- Yes — Mark Shaffer's NPI (1255436804) is active in the NPPES registry as of the last update on 2010-09-02.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.