Nathan Tonlaar, M.D. appears in the CMS NPPES registry as a Radiation Oncology Physician provider holding M.D. credentials at 2055 S FREMONT AVE, Springfield, MO, 65804, with a listed phone of (417) 820-2468. NPI 1811284375 was issued on 07/06/2011. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Tonlaar 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 272 prescription claims written by this provider, covering 120 Medicare beneficiaries and totaling roughly $4K in drug spend, with an opioid prescribing rate of 21.7%. 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.

Radiation Oncology Physician is a mid-sized specialty nationwide, with 6,018 enrolled providers across 52 states and an average of 186 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.