Joan Mcmahon, MD
NPI 1467403345 · Internal Medicine Physician · Lewistown, MT
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Joan Mcmahon, MD is a Internal Medicine Physician provider in Lewistown, MT (NPI 1467403345).
Provider details
- NPI number
- 1467403345
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- MED-PHYS-LIC-9666 (MT)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 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 · 48 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Levothyroxine Sodium | 142 | 51 |
| Atorvastatin Calcium | 109 | 37 |
| Lisinopril | 86 | 36 |
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 55 | 21 |
| Gabapentin | 51 | 16 |
| Hydrochlorothiazide | 49 | 20 |
| Omeprazole |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-05-15
- Last updated
- 2024-06-19
- Certified
- 2024-06-19
Frequently asked questions
- What is Joan Mcmahon's NPI number?
- Joan Mcmahon's National Provider Identifier (NPI) is 1467403345, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Joan Mcmahon's specialty?
- Joan Mcmahon is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Joan Mcmahon located?
- Joan Mcmahon's practice location on file with NPPES is 408 Wendell Ave, Lewistown, MT 59457-2261.
- What is Joan Mcmahon's phone number?
- The practice phone number listed in the NPPES registry for Joan Mcmahon is (406) 535-1502.
- Does Joan Mcmahon accept Medicare?
- Joan Mcmahon is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Joan Mcmahon's NPI active?
- Yes — Joan Mcmahon's NPI (1467403345) is active in the NPPES registry as of the last update on 2024-06-19.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.