EMILY CASTILLO, ARNP appears in the CMS NPPES registry as a Nurse Practitioner provider holding ARNP credentials at 55 W TIETAN ST, WALLA WALLA, WA, 99362, with a listed phone of (509) 525-3720. NPI 1114261229 was issued on 11/15/2012. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CASTILLO 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 4,289 prescription claims written by this provider, covering 379 Medicare beneficiaries and totaling roughly $2.8 million in drug spend, split 53% brand-name and 47% generic by claim count. 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.

Nurse Practitioner is a high-volume specialty nationwide, with 87,227 enrolled providers across 56 states and an average of 1,084 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.