P. Gunanayagam, MD
NPI 1811075997 · Internal Medicine Physician · Antioch, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
P. Gunanayagam, MD is a Internal Medicine Physician provider in Antioch, CA (NPI 1811075997).
Provider details
- NPI number
- 1811075997
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A82707 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
21 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. 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 does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 21 | $110 |
Typical Medicare-allowed amounts for these services range $110–$110 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 95 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 559 | 212 |
| Amlodipine Besylate | 370 | 141 |
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 362 | 72 |
| Gabapentin | 226 | 77 |
| Atenolol | 206 | 82 |
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 203 | 100 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-11-02
- Last updated
- 2021-12-13
Frequently asked questions
- What is P. Gunanayagam's NPI number?
- P. Gunanayagam's National Provider Identifier (NPI) is 1811075997, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is P. Gunanayagam's specialty?
- P. Gunanayagam is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is P. Gunanayagam located?
- P. Gunanayagam's practice location on file with NPPES is 3400 Delta Fair Blvd, Antioch, CA 94509-4004.
- What is P. Gunanayagam's phone number?
- The practice phone number listed in the NPPES registry for P. Gunanayagam is (925) 779-5000.
- Does P. Gunanayagam accept Medicare?
- P. Gunanayagam is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is P. Gunanayagam's NPI active?
- Yes — P. Gunanayagam's NPI (1811075997) is active in the NPPES registry as of the last update on 2021-12-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.