Reversal of soft-tissue local anesthesia with phentolamine mesylate in adolescents and adults

Inferior alveolar nerve block anesthesia in children: The effect of ibuprofen and phentolamine mesylate on pain perception

CONTEXT

For successfully managing pediatric dental patients, local anesthesia is essential to eliminate pain during or after the operative period. An early recovery from soft-tissue anesthesia after an inferior alveolar nerve block (IANB) should benefit a young child patient by avoiding the risk of inadvertently biting the soft tissues.

AIMS

Hence, the purpose of the study was to (1) evaluate and compare the efficacy of pre- and postoperative ibuprofen on pain perception in children who undergo IANB anesthesia with or without the use of PM and (2) evaluate the average time required for reversal of anesthesia symptoms using phentolamine mesylate.

METHODS

The present study was a randomized, clinical trial performed among 60 children between 6 and 8 years of age using a convenient sampling method. The children were randomly assigned into four equal groups of 15 each using the computer-generated randomization sequence. IANB anesthesia was performed using 2% lignocaine with 1:100,000 epinephrine, and a mandibular primary molar pulpotomy was performed on each group. Group 1: the ibuprofen tablet was taken 1 h before the onset of the procedure. Group 2: ibuprofen tablet 30 min after the pulpotomy procedure. Group 3: the ibuprofen tablet was taken 1 h before the onset of the procedure, and the Phentolamine mesylate (PM) injection was administered. Group 4: immediately after the pulpotomy, the PM injection was administered, and an ibuprofen tablet was taken 30 min after the pulpotomy procedure. All children were assessed for the duration of soft-tissue anesthesia, their behavior scores and pain rating, as well as the incidence of postoperative self-inflicted injuries.

STATISTICAL ANALYSIS USED

A one-way ANOVA was used to compare the average time needed for the reversal of anesthetic symptoms between groups. The effects of phentolamine, local anesthetics, and ibuprofen on the child's behavior and pain scores were compared using the Student's t-test. For the study, P < 0.05 was accepted as statistically significant.

RESULTS

The time needed for the full reversal of anesthetic symptoms to manifest on the tongue and lip was substantially reduced by the injection of phentolamine (P < 0.001). The use of phentolamine for reversal or the intake of ibuprofen pre- or postoperatively did not exhibit any significant variation in the behavior, pain experience, or incidence of self-inflicted injuries in the child.

CONCLUSION

It is evident that although phentolamine injections shorten the duration of anesthesia, the adjunctive use of pre- or postoperative ibuprofen did not significantly alter pain scores.

EFFECTIVENESS OF PHENTOLAMINE MESYLATE IN REVERSAL OF LOCAL ANESTHESIA: SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

The aim of the present paper is to summarize the effectiveness of Phentolamine mesylate on the reversal of local anesthesia (LA).

METHODOLOGY

Seven electronic databases were searched for randomized clinical trials in patients who received LA (population) and either received a Phentolamine injection (intervention) after LA compared to placebo or sham (control) to cause a return of normal sensation (outcome). Risk of bias assessment was performed using Cochrane risk of bias assessment tool 2.0. The hazard ratio (HR) was calculated as the event (time to return to the normal sensation) was a time-dependent event, as well as the weighted mean difference (WMD), was computed. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of the evidence.

RESULTS

Ten studies met our inclusion criteria and were included in this review. After pooling the results quantitatively, the value of the HR in the tongue was 0.56 (95% CI: 0.41-0.75, P<.001); in lower lip, the value was 0.56 (95% CI: 0.38-0.83, P = .004) and for upper lip, the value was 0.50 (95% CI: 0.31-0.80, P = .004). The WMD for the time to return for normal sensation was -47.71 min for the tongue (95% CI: -73.63 to -21.80 min, P<.001), -73.29 min for lower lip (95% CI: -88.41 to -58.16 min, P<.001) and -86.86 min for upper lip (95% CI: -101.16 to -72.57 min, P<.001). There is a high certainty of evidence that patients who have been administered local anesthesia may achieve faster recovery of normal sensation in tongue, and moderate certainty of evidence for return of normal sensation in lower lip and upper lip, if Phentolamine was administered after the local anesthesia. The adverse effects were reported in a few studies and were minor, not necessitating any medical intervention.

CONCLUSIONS

Phentolamine might be a useful adjunct in patients who desire an earlier return of normal sensation and function after local anesthesia. Future research should be directed to study the cost-effectiveness or dental patient-reported outcomes of Phentolamine after local anesthetic injections.

Effectiveness and Tolerability of a New Formulation of a Topical Anesthetic in Reduction of Pain and Parents’ Satisfaction in Pediatric Dentistry

The aim of the present study was to test a new topical anesthetic gel with a different formulation (10% lidocaine, 10% prilocaine) to analyze its effectiveness in pain control, during the subsequent injection of local anesthetic, and the presence of any side effects. Methods: The study’s research design was a randomized controlled clinical trial on 300 children, aged 5–8 years, divided into two groups, each of 150 patients, according to pre-injection procedures (presence or absence of topical anesthesia). The injection pain was analyzed using the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability Scale (FLACC). At the end of the procedures, patients’ parents’ satisfaction was recorded. The data were analyzed using the Student’s T test, Mann–Whitney U test and Chi-square test. Results: There were statistically significant differences between the two groups both in the PRS and FLACC ratings. Both in subjective and objective pain evaluations, significantly higher pain ratings were observed in the group without topical anesthesia. There was also a statistically significant difference in terms of patients’ parents’ judgment, as in the group with the use of topical anesthetic the level of parental satisfaction is statistically higher. Conclusion: The experimental anesthetic has proved very effective in its use as a topical gel in both pain measurement scales, thus validating its use on the oral mucosa, for its pharmacological and psychological effect, in the total absence of local and systemic side effects.

Use of Phentolamine Mesylate in Implant Surgery: Analysis of Adverse Effects and Haemodynamic Changes

The clinical application of phentolamine mesylate (PM) as an anaesthetic reversal agent has been documented in the paediatric population and in conservative dentistry, but no studies have been conducted regarding dental implant surgery. A prospective randomised study was conducted on 60 patients eligible for mandibular implant treatment, randomly divided between a control group (CG) and an experimental group (EG), to whom PM was administered. Haemodynamic changes, adverse effects and patient satisfaction were assessed. No statistically significant differences in haemodynamic changes and postoperative pain were found between CG and EG (p < 0.05), except for systolic blood pressure (SBP), which increased slightly in EG, without posing a risk to patients. There were no differences in the occurrence of adverse effects between the two groups, except for greater difficulty in chewing and biting (p < 0.05) in CG and greater pain in the injection area (p = 0.043) in EG. Among EG patients, 83.3% reported that they would request PM again for future dental treatment. The use of PM offers an alternative to implant surgery, thereby increasing patients' quality of life without increasing the risks.

Efficacy of phentolamine mesylate in reducing the duration of various local anesthetics

Background

To evaluate changes in the effectiveness of phentolamine mesylate in combination with different local anesthetics (LAs) and vasoconstrictors. A prospective randomized double-blind study was conducted with 90 patients divided into three groups, with each group being administered one of three different LAs: lidocaine 2% 1/80,000, articaine 4% 1/200,000, and bupivacaine 0.5% 1/200,000.

Methods

We compared treatments administered to the mandible involving a LA blockade of the inferior alveolar nerve. Results were assessed by evaluating reduction in total duration of anesthesia, self-reported patient comfort using the visual analog pain scale, incidence rates of the most common adverse effects, overall patient satisfaction, and patient feedback.

Results

The differences among the three groups were highly significant (P < 0.001); time under anesthesia was especially reduced for both the lip and tongue with bupivacaine. The following adverse effects were reported: pain at the site of the anesthetic injection (11.1%), headaches (6.7%), tachycardia (1.1%), and heavy bleeding after treatment (3.3%). The patients' feedback and satisfaction ratings were 100% and 98.9%, respectively.

Conclusions

Efficient reversal of LAs is useful in dentistry as it allows patients to return to normal life more readily and avoid common self-injuries sometimes caused by anesthesia. Phentolamine mesylate reduced the duration of anesthesia in the three studied groups, with the highest reduction reported in the bupivacaine group (from 460 min to 230 min for the lip and 270 min for the tongue [P < 0.001]).

Reversing the Effects of 0.5% Bupivacaine Using Phentolamine Mesylate: A Preliminary Randomized Controlled Clinical Trial

Phentolamine mesylate is the only commercially available dental local anesthetic reversal agent. It has been proven safe and effective for reversing most local anesthetics used in dentistry but was never tested with bupivacaine. The aim of this project was to evaluate the effectiveness of 0.4-mg phentolamine mesylate in reversing an inferior alveolar nerve block (IANB) with 0.5% bupivacaine, 1:200,000 epinephrine. Sixty-six participants were recruited and were administered an IANB with bupivacaine. After confirmation of anesthesia, they were randomized into 1 of 2 groups (phentolamine mesylate or control). Participants in the phentolamine mesylate group received a second injection with 1.7-mL OraVerse (0.4-mg phentolamine mesylate), while participants in the control group received a second injection with 1.7-mL sterile saline water. Participants were trained to self-assess sensation (lower lip and tongue) and function (drinking, speaking, and smiling), which they did every 20 minutes, and they recorded the time when sensation/function returned to normal. Comparative analysis was completed using independent sample t-tests, univariate linear regressions, and Pearson chi-square. Forty-three participants were randomized, and 34 completed the study (phentolamine mesylate, n = 15; control, n = 19). There was a statistically significant difference between the 2 treatment groups for return of normal sensation to the lower lip (mean difference of 2 hours and 17 minutes; P = .027) and the tongue (mean difference of 1 hour and 35 minutes; P = .046) in favor of the phentolamine mesylate group. The results indicate that phentolamine mesylate hastens the return to normal sensation of an IANB with bupivacaine.

Effect of phentolamine mesylate on regression of lidocaine-epinephrine epidural anaesthesia in sheep

OBJECTIVE

To determine the impact of epidural phentolamine on the duration of anaesthesia following epidural injection of lidocaine-epinephrine.

STUDY DESIGN

Blinded randomized experimental study.

ANIMALS

A group of 12 adult ewes weighing 25.7 ± 2.3 kg and aged 8-9 months.

METHODS

All sheep were administered epidural lidocaine (approximately 4 mg kg^-1) and epinephrine (5 μg mL^-1). Of these, six sheep were randomized into three epidural treatments, separated by 1 week, administered 30 minutes after lidocaine-epinephrine: SAL: normal saline, PHE1: phentolamine (1 mg) and PHE2: phentolamine (2 mg). The other six sheep were administered only epidural lidocaine-epinephrine: treatment LIDEP. Each injection was corrected to 5 mL using 0.9% saline. Noxious stimuli were pinpricks with a hypodermic needle and skin pinch with haemostatic forceps to determine the onset and duration of sensory and motor block. Heart rate, noninvasive mean arterial pressure (MAP), respiratory rate and rectal temperature were recorded.

RESULTS

The onset times were not different among treatments. Duration of sensory block was significantly shorter in SAL (57.5 ± 6.2 minutes), PHE1 (60.7 ± 9.0 minutes) and PHE2 (62.0 ± 6.7 minutes) than in LIDEP (81.7 ± 13.4 minutes) (p < 0.05). Duration of motor blockade was significantly shorter in PHE1 (59.4 ± 5.4 minutes) and PHE2 (54.3 ± 4.0 minutes) than in SAL (84.8 ± 7.0 minutes) and LIDEP (91.5 ± 18.2 minutes) (p < 0.01). MAP in PHE2 was decreased at 10 minutes after administration of phentolamine (p < 0.05).

CONCLUSION AND CLINICAL RELEVANCE

Epidural administration of 5 mL normal saline after epidural injection of lidocaine-epinephrine reduced the duration of sensory but not motor block in sheep. Epidural administration of phentolamine diluted to the final volume of 5 mL diminished both the duration of sensory and motor block in sheep administered epidural lidocaine-epinephrine.

Assessment of photobiomodulation therapy by an 8l0-nm diode laser on the reversal of soft tissue local anesthesia in pediatric dentistry: a preliminary randomized clinical trial

During the injection of local anesthesia in pediatric dental procedures, from the injection time until the elimination of tissue anesthesia, inevitable problems were reported. According to the encouraging results of previous studies addressing the positive effects of laser therapy on increasing the microcirculation, we aimed to investigate the clinical effect of photobiomodulation therapy on the reversal of soft tissue anesthesia in children. Using a split-mouth design, 34 children aged 4 to 8 years old, candidate for receiving local infiltration injection at both right and left side in mandible, were enrolled in the study. The mandibular right and left quadrants were randomly assigned to groups of laser or sham laser: in laser side, patients received 810-nm laser irradiation, and in the sham laser group, the patients had the laser in off mode at 45 min after injection with an interval of 7-10 days between two sessions of each quadrant treatments. The degree of anesthesia was evaluated using the palpation technique alternately every 15 min. Data were analyzed using paired sample t test and multiple linear regression test. The mean duration of anesthesia expressed in minutes was equal to 145.15 ± 23.27 and 188.82 ± 12.31 for the laser group and sham laser group, respectively. There was a significant difference in duration of anesthesia between two groups (P < 0.001). Considering the results and limitations of the present study, photobiomodulation therapy by 810-nm diode laser can be proposed as a non-invasive method in order to reduce the duration of anesthesia in pediatric patients.

Phentolamine Mesylate May be a Safe and Effective Option to Reduce Discomfort and Time to Recovery After Dental Care With Local Anesthesia

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Effectiveness and safety of phentolamine mesylate in routine dental care. Daubländer M, Liebaug F, Niedeggen G, Theobald K, Kürzinger M-L. J Am Dent Assoc 2017; 148(3):149-56.

SOURCE OF FUNDING

The study was funded by Sanofi-Aventis Deutschland, Berlin, Germany TYPE OF STUDY/DESIGN: Two study designs were used: a prospective noninterventional, postauthorization efficacy (controlled observational) study, and a prospective noninterventional uncontrolled observational study.

Reversing the effects of 2% Lidocaine: A randomized controlled clinical trial

OBJECTIVES

Prolonged soft tissue anesthesia following a dental appointment is a complaint that is frequently reported by patients. Soft tissue anesthesia generally exceeds the duration of pulpal anesthesia by a few hours. This can lead to difficulties with smiling, drinking, speaking and lip/cheek biting following dental appointments. Phentolamine Mesylate (PM) is a pharmacological agent capable of reducing the duration of soft tissue anesthesia following dental treatments. Many clinical trials supporting its efficacy have used sham injections compared to injections with PM. The present study aims to evaluate the effect of PM on the duration of soft tissue anesthesia compared to a control injection of saline water.

METHODS

This randomized controlled trial recruited 40 participants above 18 years of age. Following an inferior alveolar nerve block using 1.8 ml of Lidocaine 2%, 1:100 000 epinephrine, participants were randomized into one of 2 groups. The test group received an injection of 0.4 mg PM (OraVerse). Participants in the control group received an injection of sterile saline water. Participants were trained in self-assessing their anesthesia, which they did until return to normal sensation.

RESULTS

Thirty-six participants completed the study. PM significantly reduced the duration of soft tissue anesthesia in the lower lip (104 vs 170 min, p = .001), and tongue (83 vs 134 min, p = .004) compared to the control injection. No serious adverse events were encountered. The only adverse events observed were post-operative pain and discomfort.

CONCLUSIONS

Phentolamine Mesylate hastens the return to normal soft tissue sensation and function by approximately one hour compared to a control injection of water.

CLINICAL SIGNIFICANCE

Phentolamine Mesylate can be considered a safe and effective way of reducing the duration of soft tissue anesthesia following a dental appointment. This controlled clinical trial is registered at the National Institutes of Health (ClinicalTrials.gov) #NCT02861378.

The Effect of Phentolamine on Reversing Soft Tissue Anesthesia: An Oral Health Technology Assessment Report

Long-lasting numbness of soft tissues such as lips, tongue, and cheeks after dental anesthesia is not only unpleasant but has the potential to cause self-inflicted damage to the numb tissue. Phentolamine mesylate, when injected in vicinity to the site of local anesthesia, accelerates the absorption of local anesthesia. Dental use of this drug was approved in the United States and Canada in 2008 and 2014, respectively. The rapidly increasing popularity of this novel technology (intraoral phentolamine injections) warrants a health technology assessment for clinicians. A medical librarian conducted a systematic literature search (up to March 1, 2016) for any clinical study involving intraoral phentolamine injection. Meta-analysis of the efficacy data from 4 clinical studies supports the role of intraoral phentolamine injections in shortening the duration of numbness after local anesthesia. No publication bias was found in the selected studies. The selected studies identified no serious adverse events other than pain at the site of injection and some postprocedural pain. Our cost-effectiveness analysis shows phentolamine mesylate to be an effective treatment modality when compared with no treatment, sham, or placebo injection. Phentolamine mesylate incurs an additional cost (in US dollars) of $0.13 to $0.16 per minute of reversing the soft tissue local anesthesia and $0.38 to $0.46, when compared with sham or placebo injection, after a noninvasive dental procedure. The literature lacked substantial evidence in favor of clinical benefits, such as a decrease in self-inflicted injuries. Only a subgroup of the dental patient population undergoing specific dental procedures would benefit from accelerated recovery from numbness. Knowledge Transfer Statement: Intraoral phentolamine to reverse numbness is a new intervention with ambiguous utility. With consideration of cost and patient preference, evidence generated by this report may be used in clinical decision making and case selection for this intervention.

Effect of a trial pharmaceutical solution on reversing sensations after using lidocain: An animal study

Introduction:

Local anesthesia has a paramount role in any branches of medical sciences specially dentistry. Soft tissue irritations and lips biting are adverse side-effects in some cases. This study tried out to represent a new pharmaceutical solution in returning sensations faster.

Materials and Methods:

Five New Zealand laboratory rabbits were anesthetized with 1 cc Ketamine and Xilosine intramuscularly in thigh site. Electrodes were attached to the palms and wrists. Then, 0.2 cc lidocain 2% was injected in forearm origin in order to block median proximal nerve in both forelegs. The nerves conduction study (NCS) was recorded before and after lidocain injection, plus 30 min and once again 1 h after calcium gloconate 10%, dextrose 50%, citric acid solution injection. The recorded data were analyzed using Wilcoxon test and using SPSS software (version 11.5) at significant level of 0.05.

Results:

The NCS of left and right forearms was 1.4 ± 1.35 mV and 0.48 ± 0.45 mV. According to the statistical test, there was no significant difference between two groups (P > 0.05).

Conclusion:

Calcium gloconate 10%, dextrose 50%, citric acid solution did not reverse the effect of anesthetic drugs. Possible reasons were pressure to the nerves, which were caused by drug volume, and low sample size.

Advances in dental local anesthesia techniques and devices: An update

Although local anesthesia remains the backbone of pain control in dentistry, researches are going to seek new and better means of managing the pain. Most of the researches are focused on improvement in the area of anesthetic agents, delivery devices and technique involved. Newer technologies have been developed that can assist the dentist in providing enhanced pain relief with reduced injection pain and fewer adverse effects. This overview will enlighten the practicing dentists regarding newer devices and methods of rendering pain control comparing these with the earlier used ones on the basis of research and clinical studies available.

Pharmacology of local anesthetics used in oral surgery

This article provides a comprehensive review of the pharmacology of local anesthetics as a class, and provides details of the individual drugs available in dental cartridges. Maximum recommended doses of local anesthetics and vasoconstrictors are presented for healthy adult and pediatric patients, and for patients with cardiovascular system impairments. Various complications and reasons for failure of local anesthesia effectiveness are discussed, and current and future trends in local anesthesia are presented to provide an overview of current research in local anesthesia.

OraVerse: Reverses Numbness After Dental Procedures

The lingering numbness that can last anywhere from 3 to 5 h after a routine dental procedure is often an unnecessary, inconvenient hassle. Patients may find that their ability to speak, smile, eat and drink is impaired, and may even have uncontrollable drooling. The effects of local dental anesthetics can now be reversed. That's because OraVerse, an anesthetic reversal agent, can return the patient to normal sensation and function in about half the time. OraVerse which is U.S. Food and Drug Administration approved is a safe and effective form of phentolamine mesylate, a vasodilator that has been used in several other medical applications since 1952. OraVerse injection - the first and only proven safe and effective product of its kind can quickly reverse the effects of local dental anesthetics, so patient can carry on without impairment of talk, smile and drink after dental procedures. Studies also have shown that there are no known drug interactions and no evident toxicity or contraindications for using OraVerse.

Contribution of dentist anesthesiologists to dental anesthesiology research

In order to determine if dentist anesthesiologists (DAs) actively contribute to research in the field of anesthesiology, and thus contribute new knowledge to the field, an extensive literature search was accomplished. DAs make up only 1.5% of dentists who actively contribute to anesthesia research but account for 10% of publications. To determine if the impact of DA research was similar to the American Dental Association (ADA) recognized specialties, h-indices of noted researchers in other specialties were compared to the h-indices of noted DA researchers. The results show that the impact of top DA researchers in dental anesthesiology is similar to the impact of top dental specialty researchers, despite lack of academic departments in dental schools where a large percentage of dental research is completed. Dentist anesthesiologists actively contribute to the research in anesthesiology for dentistry and thus, actively contribute to new knowledge in the field.

Phentolamine mesylate for accelerating recovery from lip and tongue anesthesia

Phentolamine mesylate, at dosages from 0.4 to 0.8 mg in adults and adolescents and at dosages from 0.2 to 0.4 mg in children aged 4 to 11 years, has been proven to be safe and effective for the reversal of soft tissue anesthesia (lip and tongue numbness) and the associated functional deficits resulting from a local dental anesthetic injection containing a vasoconstrictor. Its ability to block a-adrenergic receptors on blood vessels induces vasodilation and enhances the redistribution of the local anesthetic away from the injection site. The low dosages administered for dental local anesthetic reversal in all likelihood accounts for the lack of significant cardiovascular effects that are associated with the medical use of the drug for hypertensive conditions associated with catecholamine excess.

Local and systemic toxicity of intraoral submucosal injections of phentolamine mesylate (OraVerse)

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.

Pharmacokinetics of lidocaine with epinephrine following local anesthesia reversal with phentolamine mesylate

Phentolamine mesylate accelerates recovery from oral soft tissue anesthesia in patients who have received local anesthetic injections containing a vasoconstrictor. The proposed mechanism is that phentolamine, an alpha-adrenergic antagonist, blocks the vasoconstriction associated with the epinephrine used in dental anesthetic formulations, thus enhancing the systemic absorption of the local anesthetic from the injection site. Assessments of the pharmacokinetics of lidocaine and phentolamine, and the impact of phentolamine on the pharmacokinetics of lidocaine with epinephrine were performed to characterize this potentially valuable strategy. The blood levels of phentolamine were determined following its administration intraorally and intravenously. Additionally, the effects of phentolamine mesylate on the pharmacokinetics of intraoral injections of lidocaine with epinephrine were evaluated. Sixteen subjects were enrolled in this phase 1 trial, each receiving 4 drug treatments: 1 cartridge lidocaine/epinephrine followed after 30 minutes by 1 cartridge phentolamine (1L1P), 1 cartridge phentolamine administered intravenously (1Piv), 4 cartridges lidocaine/epinephrine followed after 30 minutes by 2 cartridges phentolamine (4L2P), and 4 cartridges lidocaine/epinephrine followed by no phentolamine (4L). Pharmacokinetic parameters estimated for phentolamine, lidocaine, and epinephrine included peak plasma concentration (Cmax), time to peak plasma concentration (Tmax), area under the plasma concentration-time curve from 0 to the last time point (AUClast) or from time 0 to infinity (AUCinf), elimination half-life (t1/2), clearance (CL), and volume of distribution (Vd). The phentolamine Tmax occurred earlier following the intravenous administration of 1Piv (7 minutes than following its submucosal administration in treatment 1L1P (15 minutes) or 4L2P (11 minutes). The phentolamine t1/2, CL, and Vd values were similar for 1L1P, 1Piv, and 4L2P. The Tmax for lidocaine occurred later and the Cmax for lidocaine was slightly higher when comparing the 4L2P treatment and the 4L treatment. The phentolamine-induced delay of the lidocaine Tmax likely represents phentolamine's ability to accelerate the systemic absorption of lidocaine from oral tissues into the systemic circulation.