DailyMed Label: Phentolamine Mesylate

DailyMed Label: Phentolamine mesylate

2008

DailyMed Prescription

Phentolamine mesylate

Phentolamine mesylate

Novalar Pharmaceuticals

NDC: 1500-0101

Phentolamine mesylate is phenol,3-[[(4,5-dihydro-1 H -imidazol-2-yl)methyl](4-methyl-phenyl)amino]-, methanesulfonate (salt), a non-specific alpha adrenergic blocker. Phentolamine mesylate USP is a white to off-white, odorless crystalline powder with a molecular weight of 377.46. It is sparingly soluble in water, soluble in alcohol, and slightly soluble in chloroform. The empirical formulation is C 17 H 19 N 3 O•CH 4 O 3 S, and the chemical structure is: OraVerse (phentolamine mesylate) Injection is a clear, colorless, sterile, non pyrogenic, isotonic, preservative free solution. Each 1.7 mL cartridge contains 0.4 mg phentolamine mesylate, D-mannitol, edetate disodium, and sodium acetate. Either acetic acid or sodium hydroxide is used as necessary to adjust the pH.

OraVerse is indicated for reversal of the 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 is not recommended for use in children less than 6 years of age or weighing less than 15 kg (33 lbs). OraVerse is indicated 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 is not recommended for use in children less than 6 years of age or weighing less than 15 kg (33 lbs). ( 1 )

Amount of Local Anesthetic Administered Dose of OraVerse 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 ) 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] 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. Note: Do not administer OraVerse if the product is discolored or contains particulate matter. In pediatric patients weighing 15-30 kg, the maximum dose of OraVerse recommended is 1/2 cartridge (0.2 mg). (Note: Use in pediatric patients under 6 years of age or weighing less than 15 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 12 years of age.)

0.4 mg/1.7 mL solution per cartridge 0.4 mg/1.7 mL solution per cartridge ( 3 )

None. None ( 4 )

Myocardial infarction, cerebrovascular spasm, and cerebrovascular occlusion have been reported to occur following the intravenous or intramuscular administration of phentolamine, usually in association with marked hypotensive episodes or shock-like states which occasionally follow parenteral administration. Tachycardia and cardiac arrhythmias may occur with the use of phentolamine or other alpha-adrenergic blocking agents. ( 5.1 ) Myocardial infarction, cerebrovascular spasm, and cerebrovascular occlusion have been reported to occur following the parenteral administration of phentolamine. These events usually occurred in association with marked hypotensive episodes producing shock-like states. Tachycardia and cardiac arrhythmias may occur with the use of phentolamine or other alpha-adrenergic blocking agents. Although such effects are uncommon after administration of OraVerse, clinicians should be alert to the signs and symptoms of these events, particularly in patients with a prior history of cardiovascular disease.

In clinical trials, the most common adverse reaction with OraVerse that was greater than the control group was injection site pain.

There are no known drug interactions with OraVerse. 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.

Use in pediatric patients less than 6 years of age or <15 kg (33 lbs) is not recommended. ( 8.4 ) In pediatric patients weighing less than 30 kg (66 lbs), the maximum dose of OraVerse recommended is 1/2 cartridge (0.2 mg). ( 8.4 ) Pregnancy Category C There are no adequate and well-controlled studies in pregnant women. OraVerse should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Oral administration of phentolamine to pregnant rats and mice at doses at least 24 times the recommended dose (based on a 60 kg human) resulted in slightly decreased growth and slight skeletal immaturity of the fetuses. Immaturity was manifested by increased incidence of incomplete or unossified calcaneal and phalangeal nuclei of the hind limb and of incompletely ossified sternebrae. At oral phentolamine doses at least 60 times the recommended dose (based on a 60 kg human), a slightly lower rate of implantation was found in the rat. Phentolamine did not affect embryonic or fetal development in the rabbit at oral doses at least 20 times the recommended dose (based on a 60 kg human). No teratogenic or embryotoxic effects were observed in the rat, mouse, or rabbit studies. It is not known whether OraVerse is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when OraVerse is administered to a nursing woman. The unknown risks of limited infant exposure to phentolamine through breast milk following a single maternal dose should be weighed against the known benefits of breastfeeding. In clinical studies, pediatric patients between the ages of 3 and 17 years received OraVerse. The safety and effectiveness of OraVerse have been established in the age group 6-17 years. Effectiveness in pediatric patients below the age of 6 years has not been established. Use of OraVerse in patients between the ages of 6 and 17 years old is supported by evidence from adequate and well-controlled studies of OraVerse in adults, with additional adequate and well-controlled studies of OraVerse in pediatric patients ages 12-17 years old [Studies 1 (mandibular procedures) and 2 (maxillary procedures)] and ages 6-11 years old [Study 3 (mandibular and maxillary procedures)]. The safety, but not the efficacy, of OraVerse has been evaluated in pediatric patients under the age of 6 years old. Dosages in pediatric patients may need to be limited based on body weight. [see Dosage and Administration (2)] Of the total number of patients in clinical studies of OraVerse, 55 were 65 and over, while 21 were 75 and over. No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

OraVerse (phentolamine mesylate) Injection 0.4 mg/1.7 mL is supplied in a dental cartridge, in cartons of 10 and 50 cartridges. Each cartridge is individually packaged in a separate compartment of a 10 cartridge blister pack. NDC 1500-0101-01 NDC 1500-0101-02 Store at controlled room temperature, 20-25C (68-77F) with brief excursions permitted between 15-30C (59-86F) (see USP Controlled Room Temperature). Protect from direct heat and light. Do not permit to freeze. Manufactured by Novocol Pharmaceutical of Canada, Incorporated Cambridge, Ontario, Canada for Novalar Pharmaceuticals, Inc. San Diego, CA, 92130 US Patent Nos.: 6,764,678; 6,872,390; 7,229,630 Trademark of Novalar Pharmaceuticals, Inc.

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. Following OraVerse administration, phentolamine is 100% available from the submucosal injection site and peak concentrations are achieved 10-20 minutes after injection. Phentolamine systemic exposure increased linearly after 0.8 mg compared to 0.4 mg OraVerse intraoral submucosal injection. The terminal elimination half-life of phentolamine in the blood was approximately 2-3 hours. Pediatrics Following OraVerse administration, the phentolamine C max was higher (approximately 3.5-fold) in children who weighed between 15 and 30 kg (33 and 66 lbs) than in children who weighed more than 30 kg. However, phentolamine AUC was similar between the two groups. It is recommended that in children weighing 15-30 kg, the maximum dose of OraVerse should be limited to ½ cartridge (0.2 mg) (see Dosage and Administration section). The pharmacokinetics of OraVerse in adults and in children who weighed more than 30 kg (66 lbs) are similar after intraoral submucosal injection. OraVerse has not been studied in children under 3 years of age or weighing less than 15 kg (33 lbs). The pharmacokinetics of OraVerse after administration of more than 1 cartridge (0.4mg) has not been studied in children.

Carcinogenicity studies with OraVerse have not been conducted. Phentolamine was not mutagenic in the in-vitro bacterial reverse mutation (Ames) assay. In the in-vitro chromosomal aberration study in Chinese hamster ovary cells, numerical aberrations were slightly increased after a 4-hour exposure to phentolamine without metabolic activation and structural aberrations were slightly increased after a 4-hour exposure to phentolamine with metabolic activation only at the highest concentrations tested, but neither numerical nor structural aberrations were increased after a 20-hour exposure without metabolic activation. Phentolamine was not clastogenic in two in-vivo mouse micronucleus assays. At doses up to 150 mg/kg (143 times human therapeutic exposure levels at the C max ), phentolamine mesylate was shown to have no adverse effects on male fertility in the rat.

The safety and efficacy of OraVerse when used for reversal of soft-tissue anesthesia (STA), i.e., anesthesia of the lips and tongue following a dental procedure that required local anesthesia containing a vasoconstrictor, were evaluated in the following clinical studies. The efficacy of OraVerse on reversal of local anesthesia of the teeth, mandible and maxilla has not been assessed. Two Phase 3, double-blinded, randomized, multi-center, controlled studies were conducted in dental patients who had mandibular (Study 1) or maxillary (Study 2) restorative or periodontal maintenance procedures and who had received a local anesthetic that contained a vasoconstrictor. The primary endpoint was time to normal lip sensation as measured by patient reported responses to lip palpation. The secondary endpoints included patients’ perception of altered function, sensation and appearance, and their actual functional deficits in smiling, speaking, drinking and drooling, as assessed by both the patient and an observer blinded to the treatment. In the mandibular study, the time to recovery of tongue sensation was also a secondary endpoint. Patients were stratified by type and amount of anesthetic administered. OraVerse was administered at a cartridge ratio of 1:1 to local anesthetic. The control was a sham injection. OraVerse reduced the median time to recovery of normal sensation in the lower lip by 85 minutes (55%) compared to control. The median time to recovery of normal sensation in the upper lip was reduced by 83 minutes (62%). The differences between these times for both studies are depicted in Kaplan-Meier plots for time to normal lip sensation in Figures 1 and 2. Within 1 hour after administration of OraVerse, 41% of patients reported normal lower lip sensation as compared to 7% in the control group, and 59% of patients in the OraVerse group reported normal upper lip sensation as compared to 12% in the control group. Figure 1: Kaplan-Meier Plot of Time to Recovery of Normal Sensation in the Lower Lip (ITT Analysis Data Set) Figure 2: Kaplan-Meier Plot of Time to Recovery of Normal Sensation in the Upper Lip (ITT Analysis Data Set) In Study 1 (mandibular), OraVerse accelerated: a) the recovery of the perception of normal appearance and function by 60 minutes (40%), b) the recovery of normal function by 60 (50%) minutes, and c) the recovery of normal sensation in the tongue by 65 minutes (52%). In Study 2 (maxillary), the recovery of the perception of normal appearance and function was reduced by 60 minutes (50%) and the recovery of normal function was reduced by 45 minutes (43%). Study 3, a pediatric, Phase 2, double-blinded, randomized, multi-center, controlled study was conducted in dental patients who had received 2% lidocaine with 1:100,000 epinephrine. Dental patients (n=152, ages 4-11 years) received 1/2 cartridge of local anesthetic if they weighed ≥15 kg but <30 kg, and one-half or one full cartridge if they weighed ≥30 kg at a cartridge ratio of 1:1 to local anesthetic. The median time to normal lip sensation in patients 6 to 11 years of age who were trainable in the lip-palpation procedures, for mandibular and maxillary procedures combined, was reduced by 75 minutes (56%). Within 1 hour after administration of OraVerse, 44 patients (61%) reported normal lip sensation, while only 9 patients (21%) randomized to the control group reported normal lip sensation. In this study, neither the patients’ perception of their appearance or ability to function nor their actual ability to function was evaluated.