Phentolamine

12.1 Mechanism of Action The mechanism by which OraVerse accelerates reversal of soft-tissue anesthesia and the associated functional deficits is not fully understood. Phentolamine mesylate, the active ingredient in OraVerse, produces an alpha-adrenergic block of relatively short duration resulting in vasodilatation when applied to vascular smooth muscle. In an animal model, OraVerse increased local blood flow in submucosal tissue of the dog when given after an intraoral injection of lidocaine 2% with 1:100,000 epinephrine.

1. INDICATONS AND USAGE OraVerse an alpha adrenergic blocker, is indicated for adult and pediatric patients ages 3 years and older for the reversal of soft-tissue anesthesia, i.e., anesthesia of the lip and tongue, and the associated functional deficits resulting from an intraoral submucosal injection of a local anesthetic containing a vasoconstrictor. OraVerse, an alpha adrenergic blocker, is indicated for adult and pediatric patients ages 3 years and older for the reversal of soft-tissue anesthesia, i.e., anesthesia of the lip and tongue, and the associated functional deficits resulting from an intraoral submucosal injection of a local anesthetic containing a vasoconstrictor. ( 1 )

2. DOSAGE AND ADMINISTRATION Amount of Local Anesthetic Administered Dose of OraVerse 1 / 4 Cartridge 1 / 4 Cartridge (0.1 mg) ½ Cartridge ½ Cartridge (0.2 mg) 1 Cartridge 1 Cartridge (0.4 mg) 2 Cartridges 2 Cartridges (0.8 mg) OraVerse is administered using the same location(s) and same technique(s) (infiltration or block injection) used for the administration of local anesthetic. ( 2.1 ) 2.1 General Dosing information The recommended dose of OraVerse is based on the number of cartridges of local anesthetic with vasoconstrictor administered: Amount of Local Anesthetic Administered Dose of OraVerse [mg] Dose of OraVerse [Cartridge(s)] 1 / 4 Cartridge 0.1 1 / 4 ½ Cartridge 0.2 ½ 1 Cartridge 0.4 1 2 Cartridges 0.8 2 OraVerse should be administered following the dental procedure using the same location(s) and technique(s) (infiltration or block injection) employed for the administration of the local anesthetic. Chemically disinfect the carpule cap by wiping with either isopropyl alcohol (91%) or ethyl alcohol (70%). Many commercially available brands of isopropyl (rubbing) alcohol, as well as solutions of ethyl alcohol not of U.S.P. grade, contain denaturants that are injurious to rubber and therefore are not to be used. Inspect carpules visually prior to administration and do not use if particulate matter, discoloration, cracks in the glass, protruding plungers or other defects are observed. Note: Do not administer OraVerse if particulate matter, discoloration, cracks in the glass, protruding plungers or other defects are observed. 2.2 Dosing in Special Populations In pediatric patients weighing between ≥15 kg and <30 kg, the maximum dose of OraVerse recommend is ½ cartridge (0.2 mg). (Note: Use in pediatric patients under 3years of age or weighing less than15 kg (33 lbs) is not recommended. A dose of more than 1 cartridge [0.4 mg] of OraVerse has not been studied in children less than 4 years of age.)

6. ADVERSE REACTIONS In clinical trials, the most common adverse reaction with OraVerse that was greater than the control group was injection site pain. The most common adverse reaction with OraVerse (incidence ≥5% and > control) is injection-site pain. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Septodont at 1-888-888-1441 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Dental patients were administered a dose of either 0.2, 0.4 or 0.8mg of OraVerse. The majority of adverse reactions were mild and resolved within 48 hours. There were no serious adverse reactions and no discontinuations due to adverse reactions. Table 1 lists adverse reactions where the frequency was greater than or equal to 3% in any OraVerse dose group and was equal to or exceeded that of the control group. Table 1: Adverse Reactions with Frequency Greater Than or Equal to 3% and Equal to or Exceeding Control Adverse Event OraVerse Control 0.2 mg (N = 83) 0.4 mg (N = 284) 0.8 mg (N = 51) Total (N = 418) Total (N = 359) N (%) N (%) N (%) N (%) N (%) Patients with AEs 15 (18) 82 (29) 20 (39) 117 (28) 96 (27) Tachycardia 0 (0) 17 (6) 2 (4) 19 (5) 20 (6) Bradycardia 0 (0) 5 (2) 2 (4) 7 (2) 1 (0.3) Injection site pain 5 (6) 15 (5) 2 (4) 22 (5) 14 (4) Post procedural pain 3 (4) 17 (6) 5 (10) 25 (6) 23 (6) Headache 0 (0) 10 (4) 3 (6) 13 (3) 14 (4) An examination of population subgroups did not reveal a differential adverse reaction incidence on the basis of age, gender, or race. Results from the pain assessments in Study 1 and Study 2, involving mandibular and maxillary procedures, respectively, indicated that the majority of dental patients in both OraVerse and control groups experienced no or mild oral pain, with less than 10% of patients in each group reporting moderate oral pain with a similar distribution between the OraVerse and control groups. No patient experienced severe pain in these studies. Study 4 included 150 pediatric patients between 2-5 years of age who received a dose of either ¼ cartridge (0.1 mg), ½ cartridge (0.2 mg) or 1 cartridge (0.4 mg) of OraVerse or sham injection (placebo). Safety in patients in Study 4 was similar to safety in older patients described above. Post-procedural revealed that oral pain was reported in the OraVerse group with a higher frequency (10.1%) than the placebo group (3.9%). The proportion of patients in the OraVerse and placebo groups was comparable with respect to the highest severity of pain experienced: 30.4% of OraVerse patients and 30% of placebo patients reported no pain; 43.1% of OraVerse patients and 45.0% of placebo patients reported mild pain; 19.0% of OraVerse subjects and 17.5% of placebo patients reported moderate pain; and 15.2% of OraVerse patients and 15.0% of placebo patients reported severe pain. 6.2 Adverse Reactions in Clinical Trials Adverse reactions reported by less than 3% but at least 2 dental patients receiving OraVerse and occurring at a greater incidence than those receiving control, included diarrhea, facial swelling, increased blood pressure/hypertension, injection site reactions, jaw pain, oral pain, paresthesia, pruritus, tenderness, upper abdominal pain and vomiting. The majority of these adverse reactions were mild and resolved within 48 hours. The few reports of paresthesia were mild and transient and resolved during the same time period. 6.3 Post Marketing Adverse Reactions Reports from Literature and Other Sources The following adverse reactions have been identified during postapproval parenteral use of phentolamine mesylate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Acute and prolonged hypotensive episodes and cardiac arrhythmias have been reported with the use of phentolamine. In addition, weakness, dizziness, flushing, orthostatic hypotension, and nasal stuffiness have occurred.

7. DRUG INTERACTIONS There are no known drug interactions with OraVerse. 7.1 Lidocaine and Epinephrine When OraVerse was administered as an intraoral submucosal injection 30 minutes after injection of a local anesthetic, 2% lidocaine HCl with 1:100,000 epinephrine, the lidocaine concentration increased immediately after OraVerse intraoral injection. Lidocaine AUC and Cmax values were not affected by administration of OraVerse. OraVerse administration did not affect the PK of epinephrine.