Mary Onderdonk, DNP, CRNP
Gerontology Nurse Practitioner · Towson, MD
Mary Onderdonk, DNP, CRNP is a gerontology nurse practitioner with a practice address in Towson, Maryland, and NPI 1245802156, issued on Jul 12, 2021. Check the license (Maryland R234428, as entered in NPPES) with the Maryland board that licenses this profession; the Medicare figures below come from public CMS files.
- Name
- Mary Onderdonk
- Credential
- DNP, CRNP
- Primary taxonomy
- Gerontology Nurse Practitioner 363LG0600X
- License number
- R234428 MD
Self-reported in NPPES; status is on the state search - Practice location
- 6701 N Charles St Ste 4105, Towson, MD 21204
- Phone
- (443) 849-6255
- Enumerated
- Jul 12, 2021
- Record last updated
- Aug 30, 2021 (not updated in 5 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest gerontology nurse practitioner records → All 199 in Maryland → Look up another NPI →
Also registered at 6701 N Charles St Ste 4105
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Michelle KirwanAdult Health Nurse Practitioner1952892051
Verify Mary Onderdonk in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWhich Maryland board licenses this profession
Search for license R234428Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
90% fewer Medicare Part D claims than the average gerontology nurse practitioner in 2024
141 Medicare Part D claims for 75 beneficiaries, against an average of 1,369 among the 6,165 providers of this specialty who prescribed in Part D. 14 claims were for opioids.
Most prescribed
- Haloperidol18 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.
Mary Onderdonk among 199 gerontology nurse practitioner records in Maryland
Mary Onderdonk, DNP, CRNP is one of 199 gerontology nurse practitioner records with a practice address in Maryland. 69% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2021, is newer than 66% of them.
- NPI issued2021 · 66% of these records are older, 28% newer
- In a Medicare fileYes · 69% of these records are
- In the CMS Doctors and Clinicians fileNo · 49% of these records are
- Record last updated2021 · 46% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 363LG0600X and a Maryland practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gerontology Nurse Practitioner providers in Maryland
There are 199 gerontology nurse practitioner records in Maryland.
All 199 in Maryland → Every provider in Towson → Gerontology Nurse Practitioner nationwide →
The 8 gerontology nurse practitioner records with the nearest ZIP codes
- Dmitry Bederak, DNP, CRNPBaltimore, MD 212041194490250
- Nicole Hormes, CRNPTowson, MD 212041033930870
- Michelle Kalendek, CRNPTowson, MD 212041942278858
- Paula Kowalewski, C.R.N.P.Baltimore, MD 212041306893474
- Kathryn Loschiavo, CRNPTowson, MD 212041225182652
- Uchechi Nze, NPTowson, MD 212041699475244
- Katherine Robbins, DNP, CRNP, AGPCNP-BCTowson, MD 212041235901596
- Valdane Robinson, CRNPTowson, MD 212041245631241
Common questions
What is Mary Onderdonk, DNP, CRNP's NPI number?
Mary Onderdonk, DNP, CRNP's National Provider Identifier (NPI) is 1245802156, issued on Jul 12, 2021. An NPI identifies a provider in billing; it is not a license.
Where is Mary Onderdonk, DNP, CRNP located?
The NPPES record lists a practice address at 6701 N Charles St Ste 4105, Towson, MD, 21204. Phone: (443) 849-6255. Providers update this record themselves, so call before visiting.
How can I verify Mary Onderdonk, DNP, CRNP's license?
NPPES lists Maryland license number R234428, as entered by the provider. Search the Maryland board that licenses this profession; the NPPES record confirms identity only.
How much does Mary Onderdonk, DNP, CRNP prescribe under Medicare Part D?
In 2024, Mary Onderdonk, DNP, CRNP had 141 Medicare Part D claims for 75 beneficiaries; the average among gerontology nurse practitioner prescribers was 1,369. 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.