Doctor profile · Federal record

Dr. Mary Nielsen, M.D.

Psychiatry Physician · Clayton, MO

  • NPI 1972645240
  • 19 yrs on file
  • Female
  • Solo practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
225 S Meramec Ave, Suite 932T
Clayton, MO 631053511
(314) 721-7550
fax (314) 863-2114

Credentials & registration

NPPES · NUCC
NPI registered
February 2007 — 19 yrs on file
Profile last updated
July 8, 2007
Specialty taxonomy
2084P0800X — NUCC code
State license (1)
Missouri #MDR7P10
Medicaid
MO #F31343

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1972645240. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
416
Distinct HCPCS
2
Medicare allowed
$31,910
HCPCS Description Services Patients Avg allowed
90833 Psychotherapy with evaluation and management visit, 30 minutes 227 25 $68
99213 Established patient office or other outpatient visit, 20-29 minutes 189 24 $88

In context: peer comparison

Among 1 peers in this city , average services per provider: 208. This provider delivers 2.0× the peer median.

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
306
Patients
0
Total drug cost
$12,664
Drug Type Claims Patients Total cost
Quetiapine Fumarate Generic 41 0 $529
Alprazolam Generic 27 0 $362
Mirtazapine Generic 27 0 $1,547
Trazodone Hcl Generic 25 0 $382
Bupropion Xl (Bupropion Hcl) Brand 23 0 $964
Clonazepam Generic 22 0 $261
Duloxetine Hcl Generic 19 0 $450
Chlordiazepoxide Hcl Generic 17 0 $680
Escitalopram Oxalate Generic 17 0 $238
Aripiprazole Generic 16 0 $228

Frequently asked questions

Auto-generated from federal data
What is Dr. Mary Nielsen's medical specialty?
Dr. Mary Nielsen practices Psychiatry Physician in Clayton, MO.
Where does Dr. Mary Nielsen practice?
Dr. Mary Nielsen practices at 225 S Meramec Ave, Clayton, MO 631053511. Office phone: 3147217550.
What is Dr. Mary Nielsen's NPI?
Dr. Mary Nielsen's National Provider Identifier (NPI) is 1972645240, issued by NPPES.
What procedures does Dr. Mary Nielsen commonly perform?
Top Medicare-reported procedures in 2023: Psychotherapy with evaluation and management visit (HCPCS 90833); Established patient office or other outpatient visit (HCPCS 99213). Source: CMS Medicare Physician & Other Practitioners file.