Derek Illastron, MD
NPI 1790949956 · Internal Medicine Physician · Kahului, HI
Enrolled with Medicare as Practitioner - Hospitalist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Derek Illastron, MD is a Internal Medicine Physician provider in Kahului, HI (NPI 1790949956).
Provider details
- NPI number
- 1790949956
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 235414 (MA)
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
17 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) | Beneficiaries |
|---|---|---|
| Amoxicillin/Potassium Clavbrand: Amoxicillin-Clavulanate Potass | 12 | 11 |
| Atorvastatin Calcium | 12 | — |
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
- 2008-07-16
- Last updated
- 2019-03-19
Frequently asked questions
- What is Derek Illastron's NPI number?
- Derek Illastron's National Provider Identifier (NPI) is 1790949956, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Derek Illastron's specialty?
- Derek Illastron is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Derek Illastron located?
- Derek Illastron's practice location on file with NPPES is 110 E Kaahumanu Ave, Kahului, HI 96732-2118.
- What is Derek Illastron's phone number?
- The practice phone number listed in the NPPES registry for Derek Illastron is (808) 242-6464.
- Does Derek Illastron accept Medicare?
- Derek Illastron is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Derek Illastron's NPI active?
- Yes — Derek Illastron's NPI (1790949956) is active in the NPPES registry as of the last update on 2019-03-19.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.