DAVID CASTELLANOS, PAC appears in the CMS NPPES registry as a Medical Physician Assistant provider holding PAC credentials at 451 JUNCTION RD, MADISON, WI, 53717, with a listed phone of (608) 265-1600. NPI 1295375798 was issued on 01/13/2020. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CASTELLANOS most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 1,197 prescription claims written by this provider, covering 327 Medicare beneficiaries and totaling roughly $142K in drug spend, split 14% brand-name and 86% generic by claim count, with an opioid prescribing rate of 1.7%. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Medical Physician Assistant is a mid-sized specialty nationwide, with 40,527 enrolled providers across 55 states and an average of 1,077 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.