John Allen, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 22 S GREENE ST, Baltimore, MD, 21201, with a listed phone of (672) 141-5156. NPI 1023436839 was issued on 03/31/2014. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Allen 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 1,759 prescription claims written by this provider, covering 219 Medicare beneficiaries and totaling roughly $215K in drug spend, split 13% brand-name and 86% generic by claim count, with an opioid prescribing rate of 3.4%. 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.

Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 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.