William Kassler, MD
NPI 1538162672 · Internal Medicine Physician · Manchester, NH
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Kassler, MD is a Internal Medicine Physician provider in Manchester, NH (NPI 1538162672).
Provider details
- NPI number
- 1538162672
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 10716 (NH)
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
21 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 · 2 distinct drugs on file.
| Drug | Part D claims (2024) |
|---|---|
| Metformin Hcl | 17 |
| Amlodipine Besylate | 15 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Registry dates
- Enumerated
- 2005-05-23
- Last updated
- 2013-12-04
Frequently asked questions
- What is William Kassler's NPI number?
- William Kassler's National Provider Identifier (NPI) is 1538162672, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Kassler's specialty?
- William Kassler is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Kassler located?
- William Kassler's practice location on file with NPPES is 1415 Elm St, Manchester, NH 03101-1325.
- What is William Kassler's phone number?
- The practice phone number listed in the NPPES registry for William Kassler is (603) 626-9500.
- Does William Kassler accept Medicare?
- William Kassler is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Kassler's NPI active?
- Yes — William Kassler's NPI (1538162672) is active in the NPPES registry as of the last update on 2013-12-04.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.