FAUSTO J CASTILLO MAIRENA, M.D. appears in the CMS NPPES registry as a Student in an Organized Health Care Education/Training Program provider holding M.D. credentials at 5405 W HILLSDALE AVE, VISALIA, CA, 93291, with a listed phone of (559) 556-5591. NPI 1780115972 was issued on 03/21/2017. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CASTILLO MAIRENA 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 2,805 prescription claims written by this provider, covering 462 Medicare beneficiaries and totaling roughly $354K in drug spend, split 16% brand-name and 84% generic by claim count, with an opioid prescribing rate of 4.2%. 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.

Student in an Organized Health Care Education/Training Program is a high-volume specialty nationwide, with 331,761 enrolled providers across 55 states and an average of 459 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.