NPPES file of Aug 9, 2026

California Medicare prescriber rankings

143,204 California prescribers billed $27.3 billion in Medicare Part D drugs in 2024, the largest total of any state. Opioids were 3.29 of every 100 of those claims (CMS), below the national 3.52.

CMS Medicare Part D Prescribers, 2024; CMS NPPES · method · Verify with CMS →

Written with AI tools from the named public files; every figure is computed from those files (how it is made).
  • Prescribers143,204
  • Part D drug cost$27.3 billion
  • Average per prescriber$190,777
  • Wrote an opioid (CMS)79,990 (55.87%)
  • Opioid claims per 100 claims (CMS)3.29

Reading the California tables

California's 143,204 prescribers wrote 151,834,237 Part D claims in 2024, about $190,777 in drug cost per prescriber. A high total usually reflects specialty practice, such as cancer, rheumatology or HIV care, or vaccines: 2 of the 50 largest totals are mostly vaccines, which pharmacies often bill under a standing order naming one clinician. These are billing tables, not quality ratings. PlainDoctor does not rank named prescribers by opioid share; the state's opioid figures above come from CMS's own totals.

The 50 highest Part D drug-cost totals

Prescriber (NPPES taxonomy)Drug costClaims
1Armaghan AzadFamily Medicine Physicianmostly vaccines, often billed by pharmacies under a standing order naming this clinician$108.8 million537,707
2Vlad NusinovichInternal Medicine Physician$21.2 million79,089
3Rahul NaikHematology & Oncology Physician$19.2 million4,658
4Sergei GrandoDermatology Physician$19.1 million3,589
5Samir MacwanNeuromuscular Medicine (Psychiatry & Neurology) Physician$19.0 million2,207
6Misty MahaffeyNurse Practitioner$18.5 million2,378
7Michael BazelEmergency Medicine Physician$18.4 million64,983
8Ronald WittelesAdvanced Heart Failure and Transplant Cardiology Physician$17.9 million3,519
9Ari BaronSpecialist$16.4 million2,751
10Triet NguyenOphthalmology Physician$16.4 million16,686
11Jonathan EskenaziNeurology Physician$16.3 million19,403
12Srikanth NaramalaRheumatology Physician$15.9 million7,829
13Gerald HoRheumatology Physician$15.8 million19,575
14Boris BagdasarianHematology & Oncology Physician$15.6 million3,271
15Jennifer TresserPharmacist$15.4 million22,932
16Dong Phuong NguyenPharmacist Clinician (PhC)/ Clinical Pharmacy Specialist$15.3 million2,188
17Marc RiedlAllergy & Immunology Physician$15.2 million1,009
18Mark BaratsNephrology Physician$14.8 million59,388
19Alexander Del RosarioInternal Medicine Physician$14.7 million16,954
20Christina BiPharmacist$14.5 million1,543
21Bikramjit AhluwaliaRheumatology Physician$14.3 million23,044
22Daisy-Scarlett MaccallumFamily Medicine Physicianmostly vaccines, often billed by pharmacies under a standing order naming this clinician$13.7 million63,064
23Byung LeeHematology & Oncology Physician$13.5 million3,076
24Seleaina ThomasFamily Nurse Practitioner$13.0 million6,019
25Sivagini GaneshPulmonary Disease Physician$12.9 million2,290
26Weber ChenHematology & Oncology Physician$12.8 million2,580
27Namita SoodPulmonary Disease Physician$12.6 million3,026
28Kelvin MaiInternal Medicine Physician$12.4 million76,192
29Sadiq AltamimiClinical Neurophysiology Physician$12.3 million7,568
30Michael BenjaminHematology & Oncology Physician$12.3 million1,835
31Ann StapletonInfectious Disease Physician$12.3 million9,673
32Samy MetyasRheumatology Physician$12.2 million13,050
33Lucy UngPharmacist$12.1 million3,006
34Michael CarrollHematology & Oncology Physician$12.1 million2,173
35Robert VescioHematology & Oncology Physician$12.1 million1,866
36Marcus UreyAdvanced Heart Failure and Transplant Cardiology Physician$12.0 million5,574
37Katrina LamStudent in an Organized Health Care Education/Training Program$11.9 million2,776
38Shelley ShapiroPulmonary Disease Physician$11.7 million1,607
39Warren BantaHematology & Oncology Physician$11.6 million2,921
40Mark AvdalovicPulmonary Disease Physician$11.5 million2,458
41Mihran ShirinianHematology & Oncology Physician$11.3 million2,733
42Bertrand TuanSpecialist$11.3 million2,119
43Waheed MuradHematology & Oncology Physician$11.1 million2,314
44Eddie HuSpecialist$11.1 million2,988
45Tsovinar TekkelianClinical Cardiac Electrophysiology Physician$11.0 million80,155
46Victor CarabelloNephrology Physician$10.9 million10,630
47James BerensonResearch Study Specialist$10.9 million1,975
48Michelle KittlesonAdvanced Heart Failure and Transplant Cardiology Physician$10.9 million8,631
49Eric CheungHematology & Oncology Physician$10.8 million3,229
50Vagharshak PilossyanFamily Medicine Physician$10.8 million99,093

Source: CMS Medicare Part D Prescribers by Provider, 2024 (data.cms.gov), matched to CMS NPPES by NPI; vaccine share from the prescriber's top drugs in the CMS by-provider-and-drug file. Specialty is the taxonomy the clinician reported to NPPES.

Common questions

How many Medicare prescribers are in California?

California has 143,204 Medicare Part D prescribers who filed 151,834,237 claims totaling $27.3 billion in drug costs.

What is the opioid prescribing rate in California?

Opioids were 3.29 of every 100 Medicare Part D claims written by California prescribers in 2024, against 3.52 nationally (CMS). 79,990 of the state's 143,181 Part D prescribers in CMS's geography file (55.87%) wrote at least one opioid.

Checking a prescriber

Open the prescriber's record for the full NPI entry and prescribing detail, then confirm the license on the state board search. The Part D file covers Medicare Part D only; commercial, Medicaid, VA and cash prescriptions are not in it.

Prescriber rankings in other states

  1. Alabama
  2. Alaska
  3. American Samoa
  4. Arizona
  5. Arkansas
  6. California
  7. Colorado
  8. Connecticut
  9. Delaware
  10. District of Columbia
  11. Florida
  12. Georgia
  13. Guam
  14. Hawaii
  15. Idaho
  16. Illinois
  17. Indiana
  18. Iowa
  19. Kansas
  20. Kentucky
  21. Louisiana
  22. Maine
  23. Maryland
  24. Massachusetts
  25. Michigan
  26. Minnesota
  27. Mississippi
  28. Missouri
  29. Montana
  30. Nebraska
  31. Nevada
  32. New Hampshire
  33. New Jersey
  34. New Mexico
  35. New York
  36. North Carolina
  37. North Dakota
  38. Northern Mariana Islands
  39. Ohio
  40. Oklahoma
  41. Oregon
  42. Pennsylvania
  43. Puerto Rico
  44. Rhode Island
  45. South Carolina
  46. South Dakota
  47. Tennessee
  48. Texas
  49. Utah
  50. Vermont
  51. Virgin Islands
  52. Virginia
  53. Washington
  54. West Virginia
  55. Wisconsin
  56. Wyoming

National prescriber rankings · All rankings

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 Medicare Part D data year 2024 (CMS).