title: Local and systemic toxicity of intraoral submucosal injections of phentolamine mesylate (OraVerse).
abstract: OraVerse, an injectable formulation of phentolamine mesylate (PM), was recently approved by the U.S. Food and Drug Administration (FDA) for reversal of anesthesia of the lip and tongue and associated functional deficits resulting from an intraoral submucosal injection of a local anesthetic containing a vasoconstrictor. Because PM had not been approved previously for submucosal administration, 2 Good Laboratory Practices (GLP) studies in dogs designed to investigate systemic toxicity and the local effects of single and repeated dosing of OraVerse on the inferior alveolar nerve and branches of the superior alveolar nerve and adjacent soft tissues after local administration were conducted. Systemic toxicity was measured by preinjection and postinjection clinical examinations, clinical chemistry, and gross and microscopic examinations of major organs after necropsy. No evidence of systemic toxicity was detected. Local nerve and adjacent tissue damage was assessed by conventional histopathology. Nerve degeneration was evident in 1 animal. Mild perineural inflammation adjacent to the inferior alveolar nerve and inflammatory exudates were observed in submucosal tissues in several animals. No changes were observed in the nerves at injection sites of dogs from any dose group that were considered directly related to the test articles. These data reveal that single and repeated intraoral administrations of OraVerse are well tolerated in beagle dogs.
authors.affiliation: University of Washington School of Dentistry, Seattle, Washington, USA. rbruth@u.washington.edu
authors.forename: Bruce
authors.initials: B
authors.lastname: Rutherford
authors.forename: Jillynne R
authors.initials: JR
authors.lastname: Zeller
authors.forename: Daryl
authors.initials: D
authors.lastname: Thake
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000633:toxicity*; D000779:Anesthetics, Local / Q000037:antagonists & inhibitors; D000818:Animals; D003389:Cranial Nerve Diseases / Q000139:chemically induced; D004285:Dogs; D006400:Hematocrit; D006454:Hemoglobins / Q000187:drug effects; D007267:Injections; D008340:Mandibular Nerve / Q000187:drug effects; D008442:Maxillary Nerve / Q000187:drug effects; D009061:Mouth Mucosa / Q000187:drug effects; D009410:Nerve Degeneration / Q000139:chemically induced; D009412:Nerve Fibers / Q000187:drug effects; D009443:Neuritis / Q000139:chemically induced; D009929:Organ Size; D010646:Phentolamine / Q000008:administration & dosage / Q000633:toxicity*; D011897:Random Allocation; D014018:Tissue Distribution; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000633:toxicity
chemical_list: D000317:Adrenergic alpha-Antagonists; D000779:Anesthetics, Local; D006454:Hemoglobins; D014665:Vasodilator Agents; D010646:Phentolamine