California Medicare Prescriber Rankings
139,399 prescribers · $26963.3M total drug cost · Verify with CMS →
California is represented in the CMS Medicare Part D Prescriber Public Use File (calendar year 2023) by 139,399 prescribers, who collectively wrote 145,161,763 prescription claims totaling $26963.3M in drug costs. Averaged across the state roster, that works out to roughly $193K in Part D drug cost per prescriber. The Part D PUF covers only Medicare Part D, prescriptions filled through commercial insurance, Medicaid, VA, TriCare, or cash payment are excluded, and CMS suppresses any prescriber-drug-beneficiary combination with fewer than 11 beneficiaries for patient privacy, which means the tables below understate low-volume activity and omit some specialty clinics entirely. According to the CMS Medicare Part D Prescriber data and the National Provider Identifier Registry, covering 2023 prescribing for more than 1 million U.S. clinicians since the benefit began in January 2006, you can search and compare here, every figure traces to its source in our methodology.
The opioid prescribing picture in California is anchored by an average prescriber-level opioid rate of 5.7% against the national average of 6.4%, with 43845 prescribers in the state having written at least one Part D opioid claim during 2023. Opioid rate is calculated by CMS as opioid claims divided by total claims for that prescriber, so a low-volume pain specialist can show a high rate while a high-volume primary-care physician writing occasional short-course scripts shows a low rate, raw rate alone does not indicate clinical appropriateness, and CMS explicitly cautions against using the PUF for quality judgments. The top-cost tables spotlight prescribers whose 2023 Part D drug spend was highest in California; these are typically oncologists, rheumatologists, and specialists managing high-cost biologics, not an indicator of over-prescribing.
Drill into any provider in the rankings below to see their full NPPES record, credentials, and detailed prescribing breakdown including brand/generic mix, beneficiary demographics, and most-prescribed drugs. Important: PlainDoctor presents the CMS Medicare Part D Prescriber PUF exactly as published, without editorial ranking or quality judgment. These tables are a data-transparency resource, not medical advice, not an indictment, not a quality ranking, and not a substitute for clinical judgment. Opioid prescribing decisions are nuanced medical acts, and a high PUF rate reflects only the composition of a specific prescriber's 2023 Medicare Part D claims, not patient outcomes, treatment necessity, or compliance with CDC opioid prescribing guidelines. Always verify credentials through the NPPES NPI Registry and the California medical board before drawing conclusions.
Top Prescribers by Drug Cost
Highest Opioid Prescribing Rates
Frequently Asked Questions
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Compare Prescriber Rankings in Nearby States
Other states with CMS Medicare Part D Prescriber PUF rankings for side-by-side context.
Data from CMS Medicare Part D Prescriber Public Use File (Calendar Year 2023); providers identified by NPI from the CMS NPPES registry. PlainDoctor presents this data factually without editorial judgment. Methodology · About
How to read California Medicare prescriber data
The rankings on this page are drawn from the CMS Medicare Part D Prescriber Public Use File and cover providers who submitted prescription drug claims for Medicare Part D beneficiaries in California. High-cost prescribers are not inherently problematic, a high total drug cost most often reflects specialty practice in cancer care, rheumatology, neurology, or HIV/AIDS where the standard of care involves expensive brand-name or biologic medications. Low-cost prescribers serving a primarily elderly primary-care population may prescribe generics almost exclusively, producing a small cost figure that says nothing about the quality of care they provide.
The opioid prescribing rate shows the share of a provider's Medicare Part D claims that were for opioid medications. Context is critical here: pain management specialists, palliative care physicians, and oncologists legitimately maintain higher opioid rates because their patients require it for symptom management. A high opioid rate from a family medicine physician in a county with no pain specialists may also reflect appropriate care for patients who have no other options. These rankings are a transparency resource for researchers and policymakers, not a quality judgment on individual providers.
State-level prescribing patterns in California reflect the state's age distribution, the prevalence of Medicare Advantage versus traditional Medicare, the density of teaching hospitals, and rural versus urban geography. States with older populations and lower Medicare Advantage penetration typically show higher per-capita Part D claims because traditional Medicare beneficiaries generate more claims data than those enrolled in integrated managed-care plans. States with large academic medical centers show more specialty prescribing; states with dispersed rural populations show proportionally more primary-care generalist prescribing.
For any provider appearing in these lists, the PlainDoctor detail page (accessible by clicking the provider name) shows their full NPI record, specialty taxonomy, practice address, and credential history from NPPES. The Part D prescribing data itself is published by CMS with a roughly 18-month lag; the most recent file covers calendar year 2023. For real-time prescribing status or licensure verification, contact the California state medical board or use the CMS NPI Registry directly.
Compare to other states
Medicare Part D prescriber distribution varies dramatically by state due to differences in population age, Medicare Advantage penetration, regional medical-school training pipelines, and rural-versus-urban geography. Browse the equivalent rankings for California, Texas, Florida, New York, Pennsylvania, Ohio, Illinois, Georgia, North Carolina, Michigan, and Washington for the high-volume states. Or jump directly to the prescriber rankings hub and all PlainDoctor rankings.
For specialty-level analysis (which clinician types prescribe most under Medicare Part D), see the top specialties ranking. For population-adjusted comparisons (per-capita prescriber availability), see the top states by provider count page.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-20.