Geraldine A. Ryan, M.D.
Internal Medicine Physician · O Fallon, MO
Geraldine A. Ryan, M.D. is an internal medicine physician with a practice address in O Fallon, Missouri, and NPI 1689640609, issued on Feb 28, 2006. Check the license (Missouri 100756, as entered in NPPES) on the Missouri Board of Registration for the Healing Arts; the Medicare figures below come from public CMS files.
- Name
- Geraldine A. Ryan
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 100756 MO
Self-reported in NPPES; status is on the state search - Practice location
- 9426 Phoenix Village Pkwy, O Fallon, MO 63368
- Phone
- (636) 561-5999
- Enumerated
- Feb 28, 2006
- Record last updated
- Apr 2, 2015 (not updated in 11 years: call before relying on the address or phone)
- Fax
- (636) 561-4746
- Medicare enrollment
- Enrolled (PECOS I20070525000044); accepts Medicare assignment
- Medical or professional school
- Saint Louis University School Of Medicine, 1988
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 2,604 in Missouri → Look up another NPI →
Also registered at 9426 Phoenix Village Pkwy
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Jeneffer Avalos Topete, PAPhysician Assistant1952062689
- Rabya Mian, MDAllergy & Immunology Physician1861608309
- Beth Zimmer, MDFamily Medicine Physician1548221823
Verify Geraldine A. Ryan 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 100756Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.2 times the Medicare Part D claims of the average internal medicine physician in 2024
6,874 Medicare Part D claims for 544 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 13% of claims. 100 claims were for opioids.
Most prescribed
- Atorvastatin Calcium555 claims
- Levothyroxine Sodium395 claims
- Losartan Potassium278 claims
- Omeprazole239 claims
- Metoprolol Succinate229 claims
- Amlodipine Besylate204 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: $511.68
23 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 50,334 providers of this specialty with any payment received $1,303.06 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 2 group practices
- Aging Well Health Care, LLCSaint Louis, MO
- Mercy Clinic East CommunitiesO Fallon, MO
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Geraldine A. Ryan among 2,604 internal medicine physician records in Missouri
Geraldine A. Ryan, M.D. 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 2006, is newer than 8% of them.
- NPI issued2006 · 8% of these records are older, 59% newer
- In a Medicare fileYes · 77% of these records are
- In the CMS Doctors and Clinicians fileYes · 55% of these records are
- Graduated1988 · median 2006 among the 1,443 with a school on file
- Record last updated2015 · 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).
17 internal medicine physician records list a practice address in O Fallon
They are 17 of the 1,225 NPPES records with a practice address in O Fallon, and 2,604 internal medicine physician records in Missouri.
All 2,604 in Missouri → Every provider in O Fallon → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Daniela Blum Morales, MDO Fallon, MO 633681730561069
- Gregory Genova, M.D.O Fallon, MO 633681750377941
- Naman Ghazal-Albar, MDO Fallon, MO 633681639144785
- Gary Gray, MDO Fallon, MO 633681497729826
- Brian Grus, MDO Fallon, MO 633681053421065
- Rajiv Sadana, MDO Fallon, MO 633681669423034
- Aaron Steimel, DOO Fallon, MO 633681659067874
- Alan Steube, DOO Fallon, MO 633681740857457
Common questions
What is Geraldine A. Ryan, M.D.'s NPI number?
Geraldine A. Ryan, M.D.'s National Provider Identifier (NPI) is 1689640609, issued on Feb 28, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Geraldine A. Ryan, M.D. located?
The NPPES record lists a practice address at 9426 Phoenix Village Pkwy, O Fallon, MO, 63368. Phone: (636) 561-5999. Providers update this record themselves, so call before visiting.
How can I verify Geraldine A. Ryan, M.D.'s license?
NPPES lists Missouri license number 100756, 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 Geraldine A. Ryan, M.D. prescribe under Medicare Part D?
In 2024, Geraldine A. Ryan, M.D. had 6,874 Medicare Part D claims for 544 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.