Mary Nielsen, M.D.
NPI 1972645240 · Psychiatry Physician · Clayton, MO
Mary Nielsen, M.D. is a Psychiatry Physician provider in Clayton, MO (NPI 1972645240).
Provider details
- NPI number
- 1972645240
- Entity type
- Individual
- Primary specialty
- Psychiatry PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Female
- Sole proprietor
- Yes
- License
- MDR7P10 (MO)
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 · 19 distinct drugs on file.
| Drug | Part D claims (2024) |
|---|---|
| Quetiapine Fumarate | 48 |
| Alprazolam | 33 |
| Trazodone Hcl | 30 |
| Methylphenidate Hcl | 28 |
| Clonazepam | 28 |
| Bupropion Hclbrand: Bupropion Xl | 24 |
| Mirtazapine | 19 |
| Zolpidem Tartrate | 15 |
| Aripiprazole |
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-02-13
- Last updated
- 2007-07-08
Frequently asked questions
- What is Mary Nielsen's NPI number?
- Mary Nielsen's National Provider Identifier (NPI) is 1972645240, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mary Nielsen's specialty?
- Mary Nielsen is listed in the NPPES registry with a primary specialty of Psychiatry Physician (Allopathic & Osteopathic Physicians).
- Where is Mary Nielsen located?
- Mary Nielsen's practice location on file with NPPES is 225 S Meramec Ave, Clayton, MO 63105-3511.
- What is Mary Nielsen's phone number?
- The practice phone number listed in the NPPES registry for Mary Nielsen is (314) 721-7550.
- Is Mary Nielsen's NPI active?
- Yes — Mary Nielsen's NPI (1972645240) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.