Karen L. Sonnenthal, N.P.
Nurse Practitioner · Walnut Creek, CA
Karen L. Sonnenthal, N.P. is a nurse practitioner with a practice address in Walnut Creek, California, and NPI 1942229463, issued on Jul 18, 2006. Check the license (California NP9432, as entered in NPPES) with the California board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Karen L. Sonnenthal
- Credential
- N.P.
- Primary taxonomy
- Nurse Practitioner 363L00000X
- License number
- NP9432 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1450 Treat Blvd, Walnut Creek, CA 94597
- Phone
- (925) 296-9720
- Enumerated
- Jul 18, 2006
- Record last updated
- Apr 2, 2014 (not updated in 12 years: call before relying on the address or phone)
- Fax
- (925) 296-9034
- Medicare enrollment
- Enrolled (PECOS I20050222000380); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest nurse practitioner records → All 8,223 in California → Look up another NPI →
Also registered at 1450 Treat Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Cynthia AshbrookAllergy & Immunology Physician1386786408
- Chanda Banwat, M.D.Internal Medicine Physician1750584389
Verify Karen L. Sonnenthal in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich California board licenses this profession
Search for license NP9432Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
3.6 times the Medicare Part D claims of the average nurse practitioner in 2024
4,037 Medicare Part D claims for 629 beneficiaries, against an average of 1,109 among the 54,319 providers of this specialty who prescribed in Part D. 171 claims were for opioids.
Most prescribed
- Atorvastatin Calcium223 claims
- Rosuvastatin Calcium196 claims
- Levothyroxine Sodium189 claims
- Amlodipine Besylate171 claims
- Lisinopril128 claims
- Hydrocodone-Acetaminophen114 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.
Industry payments in 2024: $106.28
5 payments; by number, the most common kind was food and beverage; the largest payer was Lilly USA, LLC. The 38,884 providers of this specialty with any payment received $791.64 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- John Muir Physician NetworkDanville, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Karen L. Sonnenthal among 8,223 nurse practitioner records in California
Karen L. Sonnenthal, N.P. is one of 8,223 nurse practitioner records with a practice address in California. 65% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 2% of them.
- NPI issued2006 · 2% of these records are older, 82% newer
- In a Medicare fileYes · 65% of these records are
- In the CMS Doctors and Clinicians fileYes · 42% of these records are
- Graduated1997 · median 2017 among the 3,425 with a school on file
- Record last updated2014 · 45% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363L00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
70 nurse practitioner records list a practice address in Walnut Creek
They are 70 of the 6,170 NPPES records with a practice address in Walnut Creek, and 8,223 nurse practitioner records in California.
All 8,223 in California → Every provider in Walnut Creek → Nurse Practitioner nationwide →
The 8 nurse practitioner records with the nearest ZIP codes
- Janette CarlinWalnut Creek, CA 945971992382246
- Allison Friede, NPWalnut Creek, CA 945971245794098
- Yajuan Leonard, APRNWalnut Creek, CA 945971336160456
- Helen Lu, FNPWalnut Creek, CA 945971639510332
- Maki Matsumura, NP-CWalnut Creek, CA 945971013316488
- Puja Sarna, NPWalnut Creek, CA 945971609322817
- Renita Vinluan-Fan, NPWalnut Creek, CA 945971265765754
- Sarah Berg, NPWalnut Creek, CA 945981427062975
Common questions
What is Karen L. Sonnenthal, N.P.'s NPI number?
Karen L. Sonnenthal, N.P.'s National Provider Identifier (NPI) is 1942229463, issued on Jul 18, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Karen L. Sonnenthal, N.P. located?
The NPPES record lists a practice address at 1450 Treat Blvd, Walnut Creek, CA, 94597. Phone: (925) 296-9720. Providers update this record themselves, so call before visiting.
How can I verify Karen L. Sonnenthal, N.P.'s license?
NPPES lists California license number NP9432, as entered by the provider. Search the California board that licenses this profession; the NPPES record confirms identity only.
How much does Karen L. Sonnenthal, N.P. prescribe under Medicare Part D?
In 2024, Karen L. Sonnenthal, N.P. had 4,037 Medicare Part D claims for 629 beneficiaries; the average among nurse practitioner prescribers was 1,109. 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.