Clinical pharmacology of local anaesthetics

Comparative Outcome of Lidocaine Versus Bupivacaine for Cervical Medial Branch Block in Chronic Cervical Facet Arthropathy: A Randomized Double-Blind Study

OBJECTIVE

This study evaluated the effect of prolonged concordant response and functional clinical improvement between lidocaine and bupivacaine for cervical medial branch block (CMBB) in chronic cervical facet syndrome.

METHODS

Sixty-two patients diagnosed with chronic cervical facet syndrome were randomized into either lidocaine or bupivacaine groups. The therapeutic CMBB was performed under ultrasound guidance. Either 2% lidocaine or 0.5% bupivacaine with a volume of 0.5-1 mL per level was injected according to the patient's pain symptoms. The patients, pain assessor, and pain specialist were blinded. The primary outcome was the duration of pain reduction by at least 50%. The Numerical Rating Scale of 0-10 and the Neck Disability Index questionnaire were recorded.

RESULTS

There was no significant difference in the duration of 50% and 75% pain reduction and Neck Disability Index between the lidocaine and bupivacaine groups. Lidocaine provided significant pain reduction up to 16 weeks (P < 0.05) and significant improvement in neck functional outcomes up to 8 weeks (P < 0.01) compared to the baseline. While bupivacaine yielded significant pain alleviation for up to 8 weeks for pain upon neck mobilization (P < 0.05) and demonstrated notable improvement in neck function up to 4 weeks (P < 0.01) compared to the baseline.

CONCLUSION

CMBB using lidocaine or bupivacaine provided clinical benefits in prolonged analgesic effect and improving neck functions for chronic cervical facet syndrome. Lidocaine illustrated better performance and could be considered a local anesthetic of choice regarding the prolonged concordance response.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

BACKGROUND

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

METHODS

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

RESULTS

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

CONCLUSIONS

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

BACKGROUND

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

METHODS

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

RESULTS

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

CONCLUSIONS

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Updates on Wound Infiltration Use for Postoperative Pain Management: A Narrative Review

Local anesthetic wound infiltration (WI) provides anesthesia for minor surgical procedures and improves postoperative analgesia as part of multimodal analgesia after general or regional anesthesia. Although pre-incisional block is preferable, in practice WI is usually done at the end of surgery. WI performed as a continuous modality reduces analgesics, prolongs the duration of analgesia, and enhances the patient’s mobilization in some cases. WI benefits are documented in open abdominal surgeries (Caesarean section, colorectal surgery, abdominal hysterectomy, herniorrhaphy), laparoscopic cholecystectomy, oncological breast surgeries, laminectomy, hallux valgus surgery, and radical prostatectomy. Surgical site infiltration requires knowledge of anatomy and the pain origin for a procedure, systematic extensive infiltration of local anesthetic in various tissue planes under direct visualization before wound closure or subcutaneously along the incision. Because the incidence of local anesthetic systemic toxicity is 11% after subcutaneous WI, appropriate local anesthetic dosing is crucial. The risk of wound infection is related to the infection incidence after each particular surgery. For WI to fully meet patient and physician expectations, mastery of the technique, patient education, appropriate local anesthetic dosing and management of the surgical wound with “aseptic, non-touch” technique are needed.

Validity of the lipid sink as a mechanism for the reversal of local anesthetic systemic toxicity: a physiologically based pharmacokinetic model study

BACKGROUND

In vitro observations support the lipid sink theory of therapeutic action by confirming the capacity of lipid emulsions to successfully uptake bupivacaine from aqueous media. However, competing hypotheses and some in/ex vivo small animal studies suggest that a metabolic or positive inotropic effect underlies the dramatic effects of lipid therapy. Controlled clinical tests to establish causality and mechanism of action are an impossibility. In an effort to quantitatively probe the merits of a "sink" mechanism, a physiologically based pharmacokinetic model has been developed that considers the binding action of plasma lipid.

METHODS

The model includes no fitting parameters and accounts for concentration dependence of plasma protein and lipid:anesthetic binding as well as the metabolism of the lipid scavenger. Predicted pharmacokinetics were validated by comparison with data from healthy volunteers administered a nontoxic dose of bupivacaine. The model was augmented to simulate lipid therapy and extended to the case of accidental IV infusion of bupivacaine at levels known to cause systemic toxicity.

RESULTS

The model yielded quantitative agreement with available pharmacokinetic data. Simulated lipid infusion following an IV overdose was predicted to yield (1) an increase in total plasma concentration, (2) a decrease in unbound concentration, and (3) a decrease in tissue content of bupivacaine.

CONCLUSIONS

Results suggest that the timescale on which tissue content is reduced varies from organ to organ, with the concentration in the heart falling by 11% within 3 min. This initial study suggests that, in isolation, the lipid sink is insufficient to guarantee a reversal of systemic toxicity.

Medial branch neurotomy in low back pain

INTRODUCTION

This study aimed to assess the effectiveness of pulsed radiofrequency medial branch dorsal ramus neurotomy in patients with facet joint syndrome.

METHODS

From January 2008 to April 2010, 92 patients with facet joint syndrome diagnosed by strict inclusion criteria and controlled diagnostic blocks undergone medial branch neurotomy. We did not exclude patients with failed back surgery syndrome (FBSS). Electrodes (20G) with 5-mm active tip were placed under fluoroscopy guide parallel to medial branch. Patients were followed up by physical examination and by Visual Analog Scale and Oswestry Disability Index at 1, 6, and 12 months.

RESULTS

In all cases, pain improvement was statistically significant and so quality of life. Three non-FBSS patients had to undergo a second neurotomy because of non-satisfactory pain decrease. Complications were reported in no case.

CONCLUSIONS

Medial branch radiofrequency neurotomy has confirmed its well-established effectiveness in pain and quality of life improvement as long as strict inclusion criteria be fulfilled and nerve ablation be accomplished by parallel electrode positioning. This statement can be extended also to FBSS patients.

Do not use epinephrine in digital blocks: myth or truth? Part II. A retrospective review of 1111 cases

BACKGROUND

Epinephrine in digital blocks has been condemned by traditional medical theory. The authors provide a retrospective review of 1111 cases involving digital block anesthesia with epinephrine in conjunction with an extensive literature review.

METHODS

The authors conducted a retrospective review of 1111 cases involving digital and hand surgery. Observations were made concerning the location of and indication for surgery, age, sex, type of block used, type and dose of anesthetic, use of epinephrine and concentration, use of a tourniquet, follow-up, and complications. Dorsal and transthecal techniques were used exclusively. Patients with vascular compromise did not receive epinephrine and were excluded from the study.

RESULTS

One thousand one hundred eleven cases were reviewed, distributed among 692 male patients and 419 female patients. Sites of surgery ranged throughout the hand and all fingers for a variety of indications. Five hundred patients received injections of 1% plain lidocaine with a dosage range of 2 to 10 cc and an average of 5.7 cc. Six hundred eleven patients received injections of 1% lidocaine with epinephrine (1:100,000) in a dose range of 0.5 to 10 cc and an average dose of 4.33 cc. Nine hundred eighty-six patients (88.75 percent) followed up in the clinic. No patients suffered from digital gangrene in the epinephrine group.

CONCLUSIONS

After reviewing 1111 cases, there were no complications associated with the use of epinephrine in digital blocks. The authors suggest that correct application of epinephrine in digital blocks is appropriate, and defend its use.

Evaluation of the tail formalin test in mice as a new model to assess local analgesic effects

Opioids are effective topical analgesics in the radiant heat tailflick assay and display synergistic interactions with a number of other classes of drugs. To determine whether these actions extend to other types of nociception, we examined the actions of topical morphine and lidocaine in a tail formalin assay in the mouse. Formalin responses in the tail were similar to those seen in the hind paw, but were limited to licking. Unlike the traditional hind paw assay, the time-course of nociceptive behavior in the tail was monophasic; lasting 40-60 min. Morphine, MK-801 and acetylsalicylic acid (ASA) were active systemically in the tail formalin assay with potencies similar to those seen in the second phase of the paw formalin test. Both morphine and lidocaine were active topically in the tail formalin assay, although their time-course of action appeared to be shorter than that of the formalin. However, morphine displayed ceiling effect not seen when it was administered systemically. Lidocaine also had a ceiling effect. When given together, the response to the combination was supra-additive, consistent with our prior studies showing synergy in the radiant heat tailflick assay. These studies validate the formalin assay in the tail and support the topical actions of opioids and other drugs in a second pain model. They also suggest supra-additive interactions between morphine and lidocaine similar to those previously seen. The tail formalin assay will be valuable in assessing the activity of topical drugs.

Prilocaine plasma levels and methemoglobinemia in patients undergoing tumescent liposuction involving less than 2,000 ml

BACKGROUND

As a reaction to reported adverse outcomes after lidocaine infiltration in tumescent liposuction, prilocaine has gained increasing popularity. Previous studies investigating large-volume liposuction procedures found maximum prilocaine levels and methemoglobinemia up to 12 h postoperatively, suggesting that liposuction should be performed as a hospital procedure only. The aim of this study was to determine prilocaine plasma levels and methemoglobinemia in patients after low- to average-volume liposuction for the purpose of defining the required postoperative surveillance period.

METHODS

In 25 patients undergoing liposuction involving less than 2,000 ml prilocaine levels and methemoglobinemia were measured over 4 h postoperatively. Liposuction was conducted after the tumescent technique using a 0.05% hypotonic prilocaine solution with epinephrine.

RESULTS

The average prilocaine dose was 6.8 + 0.8 mg/kg, with a maximum dose of 15 mg/kg. The peak prilocaine plasma level of 0.34 mug/ml occurred 3 h after the infiltration. The mean methemoglobinemia at this time point was 0.65%. Only one patient demonstrated a slightly elevated methemoglobin level of 1.4%, but lacked any clinical signs of methemoglobinemia. The prilocaine recovery in the aspirate averaged 36 +/- 4%, indicating that a large amount is removed by suctioning.

CONCLUSIONS

The patients did not experience high plasma levels of prilocaine or methemoglobinemia undergoing liposuction involving less than 2,000 ml using a 0.05% hypotonic prilocaine solution. The authors therefore conclude that this procedure can be performed safely with a monitoring period of 12 h.

Optimum Pain Relief With Continuous Epidural Infusion of Local Anesthetics Shortens the Duration of Zoster-Associated Pain

OBJECTIVE

To investigate effects of continuous epidural infusion (CEI) of 0.5% bupivacaine added to intermittent epidural boluses (IEB) on the duration of zoster-associated pain (ZAP), as compared with continuous infusion of normal saline placebo added to IEB.

DESIGN

A prospective, double-blind, randomized, placebo-controlled study.

SETTING

A university hospital and an affiliated clinic in Japan from 1996 through 1999.

PATIENTS

56 immunocompetent herpes zoster (HZ) patients, 50 years or older, within 10 days of rash onset and with severe pain and eruption.

INTERVENTIONS

Patients were hospitalized and randomly allocated into 2 groups. CEI group given CEI of 0.5% bupivacaine (0.5-1.0 mL/h) plus IEB of 0.5% bupivacaine 4 times daily (n = 29). IEB group given normal saline infusion plus IEB of 0.5% bupivacaine 4 times daily (n = 27). All patients received oral acyclovir 800 mg, 5 times daily, for 7 days.

OUTCOME MEASURES

The number of days required for complete cessation of ZAP and the proportion of subjects with allodynia beyond 30 days.

RESULTS

The median time to cessation of ZAP was significantly shorter in the CEI group than in the IEB group (29 days vs. 40 days, P = 0.002). The number of patients whose allodynia persisted beyond 30 days of treatment was significantly lower in the CEI group than in the IEB group (10% vs. 37%, P = 0.027).

CONCLUSIONS

CEI of 0.5% bupivacaine plus IEB was associated with a shorter duration of ZAP and fewer patients with allodynia beyond 30 days, compared with IEB plus normal saline infusion. Patients at high risk for developing postherpetic neuralgia (PHN) can be managed with intensive therapies at the early stage of disease, such as CEI, which maintains effective analgesia and may reduce the burden of PHN.

Do not use epinephrine in digital blocks: myth or truth?

The purpose of this study was to examine the role for epinephrine augmentation of digital block anesthesia by safely prolonging its duration of action and providing a temporary hemostatic effect. After obtaining approval from the review board of the authors' institution, 60 digital block procedures were performed in a prospective randomized double-blinded study. The digital blocks were performed using the dorsal approach. All anesthetics were delivered to treat either posttraumatic injuries or elective conditions. Of the 60 digital block procedures, 31 were randomized to lidocaine with epinephrine and 29 to plain lidocaine. Of the procedures performed using lidocaine with epinephrine, one patient required an additional injection versus five of the patients who were given plain lidocaine (p = 0.098). The need for control of bleeding required digital tourniquet use in 20 of 29 block procedures with plain lidocaine and in 9 of 31 procedures using lidocaine with epinephrine (p < 0.002). Two patients experienced complications after plain lidocaine blocks, while no complications occurred after lidocaine with epinephrine blocks (p = 0.23). By prolonging lidocaine's duration of action, epinephrine may prevent the need for an additional injection and prolong post-procedure pain relief. This study demonstrated that the temporary hemostatic effect of epinephrine decreased the need for, and thus the potential risk of, using a digital tourniquet (p < 0.002). As the temporary vasoconstrictor effect is reversible, the threat of complication from vasoconstrictor-induced ischemia is theoretical.

Specificity of diagnostic nerve blocks: a prospective, randomized study of sciatica due to lumbosacral spine disease

Temporary nerve blocks using local anesthetic are employed extensively in the evaluation of pain problems, particularly lumbosacral spine disease. Their specificity and sensitivity in localizing anatomic sources of pain have never been studied formally, however, and so their diagnostic and prognostic value is questionable. There have been anecdotal reports of relief of pain by temporary blocks directed to areas of pain referral, as opposed to areas of documented underlying pathology; but there has been no study to define the frequency or magnitude of this effect. We have examined the specificity and sensitivity of a battery of local anesthetic blocks in a series of 33 patients with a chief complaint of sciatica, attributable in all cases to spinal disease (radiculopathy, with some clinical features of arthropathy). As determined by blinded patient analog ratings in randomized sequence, three different nerve blocks were significantly more effective than control lumbar subcutaneous injection of an identical volume of 3 ml of 0.5% bupivacaine (P < 0.05). Not only paraspinal lumbosacral root blocks and medial branch posterior primary ramus blocks (at or proximal to the pathology), but also sciatic nerve blocks (distal or collateral to the pathology) produced temporary relief in a majority of patients. This confirmed the study hypothesis that false positive results are common, and specificity is low. For sciatic nerve blocks, specificity was between 24% and 36%. Patterns of responses specific to the established diagnosis of radiculopathy (i.e., root block most effective) had sensitivities between 9% and 42%. Statistical analysis of clinical and technical prognostic factors revealed that the only association with pain relief by any block were the effects of other blocks. The strongest association was between relief by sciatic nerve block and relief by medial branch posterior primary ramus (facet) block (P = 0.001, odds ratio 16.0). There were no associations between the results of blocks and clinical findings (history, physical examination, diagnostic imaging) in these patients, chosen for their homogeneous clinical presentation and absence of functional signs. Our findings indicate a limited role for uncontrolled local anesthetic blocks in the diagnostic evaluation of sciatica and referred pain syndromes in general. Negative blocks or a pattern of responses may have some predictive value, but isolated, positive blocks are non-specific. This lack of specificity may, however, be advantageous in therapeutic applications.

Comparative local anaesthetic blocks in the diagnosis of cervical zygapophysial joint pain

The utility of randomised, double-blind, controlled, comparative local anaesthetic blocks for the diagnosis of cervical, zygapophysial joint pain was studied in 47 patients with chronic neck pain following whiplash injury. Each patient was investigated with radiologically controlled blocks of the medial branches of the cervical, dorsal rami to anaesthetise the target cervical, zygapophysial joint. The blocks were performed using either lignocaine or bupivacaine, randomly allocated, and the patients' responses were assessed in a double-blind fashion. Any positive response was subsequently assessed by repeating the block with the complementary anaesthetic. Only those patients experiencing a longer period of pain relief from the bupivacaine were considered to have true-positive responses. Forty-four patients had pain relief from two blocks at a single level, of whom 34 had longer pain relief from bupivacaine. This result is unlikely to have occurred by chance (P = 0.0002). The durations of pain relief obtained from the anaesthetics were consistent with the known characteristics of these drugs with bupivacaine lasting significantly longer than lignocaine (P = 0.0003). A subgroup of 13 patients were identified with unexpected, prolonged responses to one or both of the anaesthetics. Comparative, diagnostic blocks are a valid technique in the identification of painful zygapophysial joints, and constitute an implementable alternative to normal saline controls.

Modification of pain on injection of propofol--a comparison between lignocaine and procaine

Pain on injection of propofol was assessed in a controlled, randomised study of 273 patients. They received either lignocaine 10 mg, procaine 10 mg or isotonic saline 0.5 ml, 15 seconds before the injection of propofol into a vein on the back of the hand. The incidence of pain on injection in the control group (51%) was comparable with other studies. Lignocaine and procaine both significantly reduced the pain (35% and 34% respectively, p less than 0.05) but there was no statistical difference between these two groups.

Interscalene brachial plexus blockade with lidocaine in chronic renal failure--a pharmacokinetic study

Plasma lidocaine concentrations, latency of onset, and duration of anaesthesia, were determined after interscalene brachial plexus block in 16 patients presenting for elective upper limb surgery. Eight patients had normal renal function and eight had chronic renal failure, as determined by creatinine clearance. Significantly higher plasma lidocaine levels were recorded ten minutes after infiltration in patients with chronic renal failure (p less than 0.05). Cmax plasma levels for normal patients (5.6 +/- 1.1 micrograms.ml-1) and for patients with chronic renal failure (6.6 +/- 1.6 micrograms.ml-1) were not significantly different. The latency of onset and duration of anaesthesia were similar in both groups. One per cent lidocaine solution may be administered to patients with normal and impaired renal function to provide effective brachial plexus blockade for short surgical procedures.

Layered closure of lacerations

The cause, depth, and location of a laceration are major determining factors in its treatment. In all cases, the wound must be completely cleansed with irrigation under pressure and then examined radiographically if necessary and debrided. Successful repair depends on understanding and using the principles of wound healing. The skin's greatest strength is in the dermal layer, and the best repair results when the entire depth of the dermis is accurately approximated to the entire depth of the opposite dermis. Accurate coaptation of the epidermis gives a polished effect to the repair but does not contribute to its strength. Fat and muscle do not support sutures. Full-thickness sutures may safely be used only on palmar and plantar surfaces. With an extensive laceration or one near a joint, a splint or sling may be needed. The wound should be examined a couple of days after suture placement for signs of infection.

[Continuous peridural anesthesia in children less than 2 years old]

Continuous epidural anaesthesia was carried out in 23 children (age 13.9 +/- 6 months, weight 9.09 +/- 2.5 kg) scheduled for long surgical procedure (soft tissue release for club-foot, "pull-through" for Hirschsprung disease, various genito-urinary procedures). The lumbar epidural space was punctured under general anaesthesia with a 19 G Tuohy needle. A graduated 24 G polyurethane catheter was then inserted and fixed. The local anaesthetic used was bupivacaine 0.25% (0.71 +/- 0.02 ml X kg-1), with or without 1:200,000 adrenaline. Five and 10 min after injection of bupivacaine, heart rate was significantly decreased (p less than 0.05) when compared with pre-induction values, but systolic blood pressure did not change. No other haemodynamic changes occurred. Analgesia was sufficient in all but two cases at incision. Mean duration of surgical procedure was 143 +/- 9.2 min. The time of the first reinjection was significantly longer if bupivacaine with adrenaline was used (116 +/- 2.34 min), when compared with bupivacaine without adrenaline (68.9 +/- 3.92 min) (p less than 0.001). No systemic analgesic was needed during the surgical procedure and anaesthesia was maintained either with halothane (inspiratory fraction less than 0.5%) or enflurane (inspiratory fraction less than 0.8%). All children were extubated at the end of the surgical procedure. The catheter was maintained in 16 children for postoperative analgesia. The first postoperative injection was given 7.1 +/- 0.45 h later. The catheter remained in situ 26.7 +/- 4.1 h. No complication was observed. Thus, during surgery, the need for systemic analgesia was avoided and a rapid and safe postoperative recovery was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Bupivacaine: a long-lasting local anesthetic for dentistry

Bupivacaine, a long-acting amide local anesthetic, is a chemical analogue of mepivacaine with high lipid-solubility and protein-binding characteristics. These properties contribute to bupivacaine's greater potency and anesthetic duration as compared to other local anesthetics used in dentistry. The prolonged anesthesia it produces has been shown to limit postoperative pain following third molar extractions and endodontic procedures. Bupivacaine 0.5% with 1:200,000 epinephrine provides a safe and valuable alternative to the anesthetic agents presently available in dentistry.