Why Particles in an Injectable Are a Different Category of ProblemThis is the part worth understanding, because it explains why a single lot recall carries language this serious. Solid particles introduced there travel with the blood until they reach a vessel narrower than they are, and then they stop. That company's notice to the FDA warned of "blockage of blood vessels and life-threatening blood clot events." One lot of papaverine hydrochloride injection, USP, 60 mg per 2 mL single-dose vials, lot 25202, NDC 0517-4002-25, expiring November 30, 2026. Most patients received this drug in a clinical setting and would not have the lot number.