Karl Christian Sonntag, MD
Internal Medicine Physician · Saint Louis, MO
Karl Christian Sonntag, MD is an internal medicine physician with a practice address in Saint Louis, Missouri, and NPI 1164029146, issued on Oct 3, 2020. Check the license (Missouri 2023047698, as entered in NPPES) on the Missouri Board of Registration for the Healing Arts; the Medicare figures below come from public CMS files.
- Name
- Karl Christian Sonntag
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 2023047698 MO
Self-reported in NPPES; status is on the state search - Practice location
- 6420 Clayton RD, Saint Louis, MO 63117
- Phone
- (314) 768-8373
- Enumerated
- Oct 3, 2020
- Record last updated
- Jun 2, 2026
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 2,604 in Missouri → Look up another NPI →
Also registered at 6420 Clayton RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Karl Christian Sonntag in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMissouri Board of Registration for the Healing Arts
Search for license 2023047698Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
92% fewer Medicare Part D claims than the average internal medicine physician in 2024
269 Medicare Part D claims for 30 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Carvedilol18 claims
- Amlodipine Besylate15 claims
- Gabapentin14 claims
- Atorvastatin Calcium13 claims
- Ozempic11 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.
Karl Christian Sonntag among 2,604 internal medicine physician records in Missouri
Karl Christian Sonntag, MD is one of 2,604 internal medicine physician records with a practice address in Missouri. 77% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2020, is newer than 75% of them.
- NPI issued2020 · 75% of these records are older, 21% newer
- In a Medicare fileYes · 77% of these records are
- In the CMS Doctors and Clinicians fileNo · 55% of these records are
- Record last updated2026 · 48% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Missouri practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
941 internal medicine physician records list a practice address in Saint Louis
They are 941 of the 27,605 NPPES records with a practice address in Saint Louis, and 2,604 internal medicine physician records in Missouri.
All 2,604 in Missouri → Every provider in Saint Louis → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- David Abbott, MDRichmond Heights, MO 631171568448850
- Monika Aplyn, M.D.Saint Louis, MO 631171336195247
- Kathleen Brunts, M.D.Saint Louis, MO 631171851382204
- Danita Cole, MDSaint Louis, MO 631171639152374
- Mohammad Emami, MDSaint Louis, MO 631171598712671
- Snehal Gandhi, M.D.Saint Louis, MO 631171184608689
- William Guyol, MDSaint Louis, MO 631171396738019
- Alka Kapoor, MDSaint Louis, MO 631171639122633
Common questions
What is Karl Christian Sonntag, MD's NPI number?
Karl Christian Sonntag, MD's National Provider Identifier (NPI) is 1164029146, issued on Oct 3, 2020. An NPI identifies a provider in billing; it is not a license.
Where is Karl Christian Sonntag, MD located?
The NPPES record lists a practice address at 6420 Clayton RD, Saint Louis, MO, 63117. Phone: (314) 768-8373. Providers update this record themselves, so call before visiting.
How can I verify Karl Christian Sonntag, MD's license?
NPPES lists Missouri license number 2023047698, as entered by the provider. Search the Missouri Board of Registration for the Healing Arts at https://www.fsmb.org/contact-a-state-medical-board/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Karl Christian Sonntag, MD prescribe under Medicare Part D?
In 2024, Karl Christian Sonntag, MD had 269 Medicare Part D claims for 30 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.