Ann Emerg Med
Cervical VertebraeCraniocerebral TraumaFractures, Bone
Dr. Mark Shaffer, MD
NPI1255436804
- Part D claims, 2024
- 383
- Publications
- 4
- Industry payments
- $233
- Affiliated sites
- 3
- Medical groups
- 3
- Practice address
- 541 V Avenue, National City, CA 91950
- Practice phone
- Call (619) 791-7900
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Castle Manor Nursing & Rehabilitation Center
Skilled Nursing Facility · National City, California
Find Dr. Shaffer's professional email, personal email and mobile number
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Dr. Mark Shaffer is an internist in National City, California
Dr. Shaffer practices at Castle Manor Nursing & Rehabilitation Center in National City, California.
Dr. Shaffer's NPI, 1255436804, was assigned on September 14, 2006. Dr. Shaffer graduated from Universidad Nacional Autonoma de Mexico in 1977. Dr. Shaffer holds California license C42649.
NPI and contact details
- NPI
- 1255436804NPI Registry (opens in a new tab)
- NPI enumeration date
- September 14, 2006
- NPI status
- Active
- Practice phone
- (619) 791-7900
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Medical school graduation
- 1977
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Affiliation Data
Dr. Mark Shaffer practices at Castle Manor Nursing & Rehabilitation Center in National City, California
Dr. Shaffer's primary practice is Castle Manor Nursing & Rehabilitation Center, at 541 V Avenue, National City, CA 91950 in San Diego County. The practice phone is (619) 791-7900.
- Castle Manor Nursing & Rehabilitation Center541 V Avenue, National City, CA 91950 · San Diego CountyPhone(619) 791-7900
Source: Dmand AI Affiliation Data
Dr. Mark Shaffer is affiliated with 3 sites of care and 3 medical groups
Dr. Shaffer's primary practice is Castle Manor Nursing & Rehabilitation Center in National City, California. The medical group on file is San Ysidro Health. Dmand AI also links Dr. Shaffer to 2 more group practices and clinics and 2 medical groups, each named with a free account.
Castle Manor Nursing & Rehabilitation CenterPrimary
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Mark Shaffer's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Shaffer practices, 3 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Castle Manor Nursing & Rehabilitation Center | Available with a free account |
| +2 more sites and 2 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Mark Shaffer is one of 16,751 internists in California
Internal medicine is Dr. Shaffer's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dmand AI has Dr. Shaffer's licenses on file in 3 states: California, Florida and Illinois.
Specialties and state licenses
- Internal medicine, CaliforniaPrimary
- Florida license
- Illinois license
Internists near Dr. Shaffer
Counts of internists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Mark Shaffer's patients have a median age of 88
Across all payers, Dmand AI patient panel data puts Dr. Shaffer's median patient age at 88, with 56% women.
Dr. Shaffer's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 88
Patient panel by sex, all payers
- Women56%
- Men44%
Source: Dmand AI Patient Panel Data
Dr. Mark Shaffer wrote 383 Medicare Part D claims in 2024
In 2024, Dr. Shaffer wrote 383 Medicare Part D claims for 72 patients. 83% of them were for generic drugs. CMS names the drug for 200 of them, across 8 drugs with 11 or more claims each, at $22,935 in total drug cost. In 2023, CMS named 327 claims across 15 drugs.
Part D claims, 2024383
Drugs named by CMS8
Total drug cost$22,935
Part D patients72
Dr. Shaffer's Part D claims by kind of drug, 2024
- Generic318 claims83%
- Brand-name and other65 claims17%
Dr. Shaffer's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 3272024: 20039%
Drugs named by CMS: 8 in 2024, 15 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
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Dr. Mark Shaffer has 4 publications on record
Dmand AI links 4 papers to Dr. Shaffer. The most frequent topics are Cervical Vertebrae. Dr. Shaffer has published most often in Ann Emerg Med. Dr. Shaffer's most frequent co-author is Jack Franaszek, MD.
Papers4
Topics Dr. Shaffer writes about most
- Cervical Vertebrae
Dr. Shaffer's most frequent co-authors
Recent publications by Dr. Shaffer
Ann Emerg Med
Cardiac TamponadeDrainageHeart Injuries
ComaPostureSkull Fractures
Cervical VertebraeEmergency Service, HospitalMethods
See who Dr. Shaffer researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Shaffer works with, so you can find a warm path to the right internists.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. Mark Shaffer received $233 in industry payments from 2017 to 2023
CMS Open Payments shows 3 general payments to Dr. Shaffer from 3 drug and device companies from 2017 to 2023. Food and beverage make up the largest share, 100% of the total. Neurocrine BioSciences, Inc. paid the most, $111.
General payments to Dr. Shaffer by program year, 2017 to 2023
Companies that paid Dr. Shaffer the most, 2017 to 2023
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Mark Shaffer graduated from Universidad Nacional Autonoma de Mexico
Dr. Shaffer graduated from Universidad Nacional Autonoma de Mexico in 1977.
- Medical school
Source: Dmand AI Professional Profile Data
Dr. Mark Shaffer accepts plans from 4 insurance carriers
Dr. Shaffer is in network with 4 carriers, including Elevance, Blue Cross Blue Shield of Massachusetts and HCSC. Medicare plans come from the most carriers, 4. Check the plan with the practice before a visit.
- Elevance
- Blue Cross Blue Shield of Massachusetts
- HCSC
- Molina
Plan types Dr. Shaffer accepts, by number of carriers
- Medicare4
- PPO3
- HMO2
- EPO1
- POS1
Source: Dmand AI Insurance Network Data
Sources for Dr. Mark Shaffer's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| Publications, topics and co-authors | PubMed (National Library of Medicine) (opens in a new tab)Dmand AI Research Linkage |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Mark Shaffer
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Mark Shaffer's NPI number?
Dr. Mark Shaffer's NPI number is 1255436804. It was assigned on September 14, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Mark Shaffer?
Dr. Mark Shaffer is an internist in National City, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Mark Shaffer practice?
Dr. Shaffer practices at 541 V Avenue, National City, CA 91950. Dr. Shaffer's primary practice is Castle Manor Nursing & Rehabilitation Center in National City, California. Dmand AI also links Dr. Shaffer to 2 group practices and clinics and 2 medical groups.
What is Dr. Mark Shaffer's office phone number?
The practice phone on file for Dr. Shaffer is (619) 791-7900.
What is Dr. Mark Shaffer's medical license number?
Dr. Shaffer holds California license C42649, one of the licenses on file in 3 states.
Which states has Dr. Mark Shaffer been licensed in?
Dmand AI has state licenses on file for Dr. Shaffer in California (1989 to 2027), Florida (1990 to 2000) and Illinois (1980 to 1993).
What medical group is Dr. Mark Shaffer part of?
Dr. Shaffer is linked to San Ysidro Health. Dmand AI links Dr. Shaffer to 2 more medical groups.
Where did Dr. Mark Shaffer go to medical school?
Dr. Shaffer graduated from Universidad Nacional Autonoma de Mexico in 1977.
What drugs does Dr. Mark Shaffer prescribe most?
In 2024 Medicare Part D data, Dr. Shaffer's most prescribed drugs by claims were Levothyroxine Sodium, Tamsulosin HCl and Atorvastatin Calcium.
Has Dr. Mark Shaffer received payments from drug or device companies?
CMS Open Payments shows $233 in general payments to Dr. Shaffer from 3 companies from 2017 to 2023. The largest total came from Neurocrine BioSciences, Inc.
Show 4 more questionsShow fewer questions
How long has Dr. Mark Shaffer been practicing?
Dr. Shaffer graduated from medical school in 1977, 49 years ago.
Does Dr. Mark Shaffer do research?
Dmand AI links 4 publications to Dr. Shaffer.
Who does Dr. Mark Shaffer publish with?
Dr. Shaffer's most frequent co-authors are Jack Franaszek, MD (1 shared paper).
What insurance does Dr. Mark Shaffer accept?
Dr. Shaffer is in network with 4 carriers, including Elevance, Blue Cross Blue Shield of Massachusetts and HCSC. Medicare plans come from the most carriers, 4. Check the plan with the practice before a visit.
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