Levobupivacaine: a new safer long acting local anaesthetic agent

The Options for Neuraxial Drug Administration

Neuraxial drug administration, i.e., the injection of drugs into the epidural or intrathecal space to produce anesthesia or analgesia, is a technique developed more than 120 years ago. Today, it still is widely used in daily practice in anesthesiology and in acute and chronic pain therapy. A multitude of different drugs have been introduced for neuraxial injection, only a part of which have obtained official approval for that indication. A broad understanding of the pharmacology of those agents is essential to the clinician to utilize them in a safe and efficient manner. In the present narrative review, we summarize current knowledge on neuraxial anatomy relevant to clinical practice, including pediatric anatomy. Then, we delineate the general pharmacology of neuraxial drug administration, with particular attention to specific aspects of epidural and intrathecal pharmacokinetics and pharmacodynamics. Furthermore, we describe the most common clinical indications for neuraxial drug administration, including the perioperative setting, obstetrics, and chronic pain. Then, we discuss possible neurotoxic effects of neuraxial drugs, and moreover, we detail the specific properties of the most commonly used neuraxial drugs that are relevant to clinicians who employ epidural or intrathecal drug administration, in order to ensure adequate treatment and patient safety in these techniques. Finally, we give a brief overview on new developments in neuraxial drug therapy.

Comparison Between the Effects of Bupivacaine and Levobupivacaine for Spinal Anesthesia on QT Dispersion

BACKGROUND

Bupivacaine and Levobupivacaine are frequently used local anesthetic drugs in spinal anesthesia practice. Both agents have arrhythmic effects on the heart. However, there is no clear information about which agent is more arrhythmogenic.

OBJECTIVE

The aim of this article is to investigate the effects of bupivacaine and its S (-)-enantiomer, levobupivacaine, on cardiac arrhythmias in patients.

METHODS

The study included 40 patients scheduled for inguinal hernia surgery. Patients were randomly divided into the following two groups using a sealed envelope method: Group I, the bupivacaine group (n = 20); and Group II, the levobupivacaine group (n = 20). The QT values were taken preoperatively and during the 10th of the spinal block, the 10th of the surgical incision, and the 10th postoperative minute. Additionally, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), oxygen saturation (SO₂), and heart rate (HR) values, in addition to motor block (Bromage scale) levels and durations, were recorded for each patient.

RESULTS

HR values measured at 10 min after spinal block were significantly higher than the baseline values in the levobupivacaine group (p < 0.05). The corrected QT interval (QTc) values increased significantly at 10 minutes after spinal block and at 10 min postoperatively in the bupivacaine group (p < 0.05). QTd and QTcd measurements were taken at the 10th minute of spinal anesthesia, the 10th minute of the incision, and the 10th minute postoperatively. When compared to the levobupivacaine group, a statistically significant increase was found in the bupivacaine group (p < 0.05).

CONCLUSION

Levobupivacaine allows greater hemodynamic stability, while bupivacaine affects QTc and QTd measurement times more. As such, we believe that levobupivacaine may be a better alternative to bupivacaine during clinical practice, particularly in patients with cardiac problems.

Comparison of General Anesthesia (Sevoflurane) and Spinal Anesthesia (Levobupivacaine) Methods on QT Dispersion in Inguinal Hernia Operations

Introduction Arrhythmias are one of the most frequently seen issues during surgical operations. In this study, we investigated and compared the effects on the QT dispersion of patients when using a method of volatile inhalation mask anesthesia with sevoflurane (VIMA: Group I) and when spinal anesthesia was performed with levobupivacaine (Group II). Methods The study included 40 patients who had American Society of Anesthesiology scores of I-II (ASA I-II), were aged from 18 to 65 years, and were scheduled for inguinal hernia operations. Approval of the university ethics committee was obtained before the study began. All patients had measurements taken for non-invasive blood pressure, including systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP), heart rate (HR), and oxygen saturation (SO2) values. The QT intervals were measured using the 12-derivation electrocardiogram (ECG) device (Cardiofax V). Our study was performed with randomization using the closed envelope method. Results When the percentage differences of the HR values from the initial period in both groups were compared, we observed significant differences between the groups, with increases in the VIMA group at the second period as well as increases in the VIMA group at the fourth, fifth, sixth, seventh, and ninth periods but decreases in the spinal anesthesia group for these periods. There were statistically significant differences between the two groups at the third and fifth periods when the percentage differences of the QTc values from the initial period were compared. We observed increases in the spinal anesthesia group. Conclusion In our study, we suggest that the tendency toward arrhythmia may be reduced by choosing general anesthesia with sevoflurane rather than levobupivacaine in patients with cardiac complaints who are undergoing regional anesthesia and/or taking medication that affects QT intervals.

Pharmacodynamics and Pharmacokinetics of Levobupivacaine Used for Epidural Anesthesia in Patients with Liver Dysfunction

The objective of this study was to study the pharmacodynamics and pharmacokinetics of levobupivacaine used for epidural anesthesia in patients with liver dysfunction. Twenty patients aged 20-60, American Society of Anesthesiologists (ASA) graded I-III according to the ASA guidelines, scheduled for elective upper abdominal surgery, were included in the study. They were divided into two groups of ten each. In group I, the patients with liver dysfunction were included, whereas group II was composed of those with normal liver function. In both groups, anesthesia was induced by general anesthesia combined with epidural block, given by T 8-9 interspace injection of 1.8 mg kg(-1) levobupivacaine (0.75 %) with 5 μg mL(-1) of adrenaline in 1.5 min. The sensory and motor blockade indices were recorded for 30 min after the injection. The plasma concentration of levobupivacaine was determined by high performance liquid chromatography from 0 to 1440 min after the injection and pharmacokinetics of the drug were calculated. The onset and recovery time from the sensory block in the two groups were similar with no significant difference (P > 0.05). The maximum spread of anesthetic effect, the number of spinal segments regressed, onset time, and degree of motor block after the injection were also insignificantly different in the two groups. The plasma levobupivacaine concentration/time curve of the liver dysfunction (group I) was significantly higher than that of the controls (group II). In the liver dysfunction patients, the volume of distribution (V/F) was significantly increased, the elimination rate, i.e., half-life (t 1/2β ), was prolonged, and the elimination rate constants (K 12 and K 10) were significantly decreased (P < 0.05 or P < 0.01). The patients with liver dysfunction injected with 0.75 % levobupivacaine exhibited normal onset and recovery time of the sensory and motor blocks within 30 min. However, in these patients, the metabolism of levobupivacaine was significantly slower as evidenced by the higher blood concentration of the drug than in cases with normal functioning liver.

Comparison of analgesic and systemic effects of bupivacaine, methadone, or bupivacaine/methadone administered epidurally in conscious sheep

OBJECTIVE

The aim of this study was to evaluate the combination of bupivacaine and methadone administered epidurally in sheep.

METHODS

Six healthy female mixed-breed sheep weighing 35-46 kg and aged 12-18 months were included. Each sheep was assigned to receive three treatments: 0.5 mg/kg 0.25% bupivacaine (BP), 0.3 mg/kg 1% methadone (MT) or 0.25 mg/kg bupivacaine and 0.15 mg/kg methadone (BPMT). All drugs were injected into the lumbosacral space through an epidural catheter. Each animal received each treatment at random. Heart rate, arterial blood pressure (systolic, diastolic and mean), respiratory rate, rectal temperature, analgesia, sedation and motor block were determined before treatment and at predetermined intervals.

RESULTS

The duration of analgesia was 240, 220, and 180 min for BP, MT and BPMT, respectively (P < 0.05). Motor block for all agents was mild to moderate. None or the treatments significantly altered the heart rate, blood pressure or respiratory rate.

CONCLUSION

Our findings suggest that lumbosacral epidural administration of bupivacaine, methadone or a combination of the two drugs can provide perioperative analgesia in sheep as part of their management for surgical procedures in the flank and hindlimbs.

Efficacy of Intra-articular Local Anesthetics in Total Knee Arthroplasty

Pain management after total knee arthroplasty (TKA) remains among the most important challenges for patients with TKA. Intra-articular local anesthetic has been shown to reduce postoperative pain following TKA. However, studies report conflicting results. This meta-analysis evaluated the efficacy and safety of single-dose intra-articular local anesthetics for pain control after TKA. Databases (Cochrane Central Register of Controlled Trials, Embase, PubMed, Web of Science, and Chinese Biomedical Databases) were searched to identify randomized, controlled trials comparing local anesthetic with placebo in patients undergoing TKA. Data were extracted independently by 2 researchers using a standardized form. Risk of bias was assessed with the use of the Cochrane Collaboration's tool for assessing the risk of bias by 2 observers. Relative risk, standardized mean difference, and corresponding 95% confidence interval were calculated. Seventeen trials met the inclusion criteria, for a total of 1338 participants. The results showed that, compared with the placebo group, the single local anesthetic group had a significant lower pain score with rest at 4, 8, 24, and 48 hours; less opioid consumption at 24, 48, and 72 hours postoperatively; and greater range of motion at 24, 48, and 72 hours. There were no significant differences between the 2 groups in length of hospital stay, nausea and vomiting, pruritus, sedation, or deep venous thrombosis. The study findings showed that pain relief after TKA was significantly better with intra-articular local anesthetic than with placebo.

Comparison of preincisional infiltrated levobupivacaine and ropivacaine for acute postoperative pain relief after septorhinoplasty

BACKGROUND

To maintain a high standard of patient care, it is essential to provide adequate pain management in patients who undergo nasal surgery. Levobupivacaine and ropivacaine are relatively new long-acting local anesthetics.

OBJECTIVE

The aim of this study was to compare the analgesic effect and blood loss of preincisional levobupivacaine HCl 0.25% and ropivacaine HCl 0.375% in patients undergoing septorhinoplasty.

METHODS

Sixty American Society of Anesthesiologists (ASA) I and II patients (18-55 years old) who were scheduled for elective open technique septorhinoplasty under general anesthesia were recruited for this study. The anesthetic technique was standardized for both groups. Preoperative and postoperative hemoglobin levels were recorded for all patients. Patients were assigned randomly to 1 of 2 study groups, and preincisional surgical field infiltration with 5 mL of 0.5% levobupivacaine plus 5 mL of 0.9% saline (group L; n = 30) or 5 mL of 0.75% ropivacaine plus 5 mL of 0.9% saline (group R; n = 30) was performed by the same surgeon. The degree of pain was measured by visual analogue scale (VAS) for pain and recorded at multiple time points in all patients after surgery.

RESULTS

The analgesic effect at 2 hours in the postanesthesia care unit (PACU) and at 24 hours postoperatively did not differ significantly between the 2 local anesthetics (P > 0.05). Pain scores of patients decreased after the 24 hours in levobupivacaine group and ropivacaine group when compared with 0-minute VAS values, and this was statistically significant (P < 0.05). No significant difference was observed between groups with respect to the preoperative and postoperative hemoglobin (P = 0.767 and 0.824, respectively) values.

CONCLUSIONS

Local tissue infiltration with 0.25% levobupivacaine or 0.375% ropivacaine is similarly effective in reducing the postoperative pain associated with septorhinoplasty.

Intrathecal bupivacaine or levobupivacaine: which should be used for elderly patients?

OBJECTIVES

To compare two intrathecal anaesthetics, bupivacaine and levobupivacaine, for their effects on motor and sensory blockade and haemodynamics in patients aged ≥ 65 years undergoing transurethral resection of the prostate (TUR-P) or transurethral resection of the urinary bladder (TUR-M).

METHODS

Patients scheduled to undergo TUR-P or TUR-M were randomized to receive either 3 ml (15 mg) 0.5% isobaric levobupivacaine (group L) or 3 ml (15 mg) of 0.5% hyperbaric bupivacaine (group B) for spinal anaesthesia. The onset time, maximum level and time to reach the maximum level of sensory and motor blockade were recorded. Changes to haemodynamic parameters were also recorded.

RESULTS

The study randomized 100 patients: 57 to group L and 43 to group B. Levobupivacaine did not cause any significant changes in haemodynamic parameters, including systolic blood pressure, and showed a similar sensory block onset time compared with bupivacaine, but it had a significantly longer motor block onset time compared with bupivacaine.

CONCLUSION

These current findings suggest that levobupivacaine can be used as a substitute for bupivacaine for spinal anaesthesia in elderly patients ≥ 65 years of age undergoing elective TUR-P or TUR-M operations.

Investigation of effects of levobupivacaine injection to rabbit knee joint on histopathologic changes of joint cartilage tissue and changes of serum biochemical parameters

The aim of this study is to evaluate the effects of intra-articular levobupivacaine on rabbit knee articular cartilage and certain biochemical parameters in the blood. A total of 24 New Zealand rabbits were included to study. Blood sampling was carried out in all animals on the first day, then the subjects were randomly allocated either to the control group (Group C, n = 9) or to the levobupivacaine group (Group L, n = 15). Group C underwent each two intra-articular injections of saline, 0.25 mL into the right knee and 0.50 mL into the left one. Group L was injected 0.25 mL (1.25 mg) of levobupivacaine into the right knee and 0.50 mL (2.5 mg) into the left one. The groups were divided randomly into three. Tissue and blood samples for histologic and biochemical examination were collected from Groups C1 and L1 on the first, C2 and L2 on the second, and C3 and L3 on the tenth day of the study. Interleukin-1β (IL-1 β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) levels were analyzed. No statistically significant differences could be detected when comparing either left or right joints within the same groups and with Group C and L (P > 0.05). Significant elevations of biochemical parameters were found in Group C. It is concluded that levobupivacaine does not lead to significant histologic changes in rabbit articular cartilage. Significant elevations of biochemical parameters being generally found in the C Group, it is thought that such elevations are not linked to levobupivacaine. Intra-articular levobupivacaine may be a safe alternative for use in post-operative analgesia.

Efficacy and safety of 0.5% levobupivacaine versus 0.5% bupivacaine for peribulbar anesthesia

Background

This randomized double-blind study examined the use of a new anesthetic agent, levobupivacaine 0.5%, which is the S(−)-enantiomer of a racemic mixture of bupivacaine, for peribulbar anesthesia and compared it with racemic bupivacaine 0.5% alone or in combination with hyaluronidase 10 IU/mL.

Methods

A total of 160 patients undergoing ophthalmic surgery were randomized into four groups (n = 40 each) to receive inferotemporal peribulbar injection of levobupivacaine 0.5% (group L), racemic bupivacaine 0.5% (group B), levobupivacaine + hyaluronidase 10 IU/mL (group LH), or racemic bupivacaine + hyaluronidase 10 IU/mL (group BH) by two anesthetists and two ophthalmologists in a ratio of 25% each. Ocular akinesia and orbicularis oculi function were evaluated using a three-point scale; a value < 5 points was considered as requiring surgery, and movements were re-evaluated the day following surgery to confirm regression of the block.

Results

The time to onset (12 ± 2.6 minutes versus 13 ± 2.8 minutes) and duration of anesthesia (185 ± 33.2 minutes versus 188 ± 35.7 minutes) were similar between groups L and B. Complete akinesia (score 0) was obtained more frequently when hyaluronidase was used in addition to the anesthetic, with occurrences of 72.5% versus 57.5% in group LH versus L, respectively, and 67.5% versus 45% in group BH versus B. Moderate hypotension (<30% of baseline) was observed in four patients (10%) in group L, two (5.0%) in group B, one (2.5%) in group LH, and three (7.5%) in group BH. The time to onset was significantly different between groups L and BH, B and BH, and LH and BH, and the duration of anesthesia differed significantly between groups B and LH, B and BH, and L and LH. The akinesia score differed significantly between groups L and LH and between groups B and LH (P = 0.043 and P = 0.018, respectively), and the number of patients with a score of 0 differed significantly between groups B and LH and between groups B and BH (P = 0.004 and P = 0.017, respectively).

Conclusion

Levobupivacaine is a long-lasting local anesthetic with limited cardiotoxicity and neurotoxicity, and may be considered the landmark for vitreoretinal surgery in elderly patients.

A pharmacokinetic standard for babies and adults

The pharmacokinetic behavior of medicines used in humans follows largely predictable patterns across the human age range from premature babies to elderly adults. Most of the differences associated with age are in fact due to differences in size. Additional considerations are required to describe the processes of maturation of clearance processes and postnatal changes in body composition. Application of standard approaches to reporting pharmacokinetic parameters is essential for comparative human pharmacokinetic studies from babies to adults. A standardized comparison of pharmacokinetic parameters obtained in children and adults is shown for 46 drugs. Appropriate size scaling shows that children (over 2 years old) are similar to adults. Maturation changes are generally completed within the first 2 years of postnatal life; consequently babies may be considered as immature children, whereas children are just small adults.

Levobupivacaine differentially suppresses platelet aggregation by modulating calcium release in a dose-dependent manner

OBJECTIVE

Levobupivacaine, an amide local anesthetic widely used in regional anesthesia, is reported in recent studies that it is a potent inhibitor of platelet functions. However, the concentrations of levobupivacaine were limitedly estimated in these reports. Additionally, the mechanisms by which it affects platelet function and blood coagulation is still not entirely known. The purpose of this study was to further investigate its effects on platelet function and the possible signaling mechanisms under various concentrations of levobupivacaine.

METHODS

Blood samples collected from healthy volunteers were separated into whole blood, platelet-rich-plasma and washed platelets. The effect of levobupivacaine on platelet aggregation was studied using platelet function analyzer (PFA-100) and platelet aggregometer. Agonist-induced platelet adenosine triphosphate (ATP) release, cytosolic calcium mobilization, thromboxane B2 (TxB2) secretion and platelet P-selectin translocation under various concentrations of levobupivacaine were investigated.

RESULTS

Our results indicated that levobupivacaine possessed negative effect on platelet aggregation. The closure times of (PFA-100) were lengthened and the agonist-induced platelet aggregation was significantly attenuated by levobupivacaine even at a low dose (50 μgml(-1)). Pretreatment with levobupivacaine produced significant changes in agonist-induced platelet P-selectin translocation, ATP release, thromboxane A2 (TxA2) production, and calcium mobilization in a dose-dependent manner. The p38 mitogen-activated protein kinases (MAPK), protein kinase C (PKC) δ subtype, cytosolic phospholipase A2 (cPLA2), and protein kinase B (PKB or Akt) were involved in collagen-induced platelet signaling, which would be responsible for antiplatelet effects of levobupivacaine.

CONCLUSION

We explored possible targets of levobupivacaine on platelets aggregation signaling mechanisms. Our data revealed that p38 MAPK, PKC δ subtype, cPLA2, and Akt were pathways involved in collagen-induced platelet signaling, which might be responsible for antiplatelet effects of levobupivacaine. Our study did provide direct evidence bolstering the critical mechanisms of levobupivacaine within different contexts. Additionally, levobupivacaine imposed a negative effect on platelet aggregation through multiple signaling pathways.

Can a periarticular levobupivacaine injection reduce postoperative opiate consumption during primary hip arthroplasty?

BACKGROUND

Several reports have confirmed the ability of intraoperative periarticular injections to control pain after THA. However, these studies used differing combinations of analgesic agents and the contribution of each, including the local anesthetic agent, is uncertain. Understanding the independent effects of the various agents could assist in improved pain management after surgery.

QUESTIONS/PURPOSES

We therefore determined the ability of intraoperative periarticular infiltration of levobupivacaine to (1) reduce postoperative pain, (2) reduce postoperative morphine requirements, and (3) reduce the incidence of nausea and urinary retention.

PATIENTS AND METHODS

A double-blinded, randomized, placebo-controlled trial of patients undergoing primary THAs was performed. Patients were randomized to receive a periarticular infiltration of 150 mg levobupivacaine in 60 mL 0.9% saline (n = 45) or a placebo consisting of 60 mL 0.9% saline (n = 46). We obtained a short-form McGill pain score, visual analog scale (VAS), and morphine requirements via patient-controlled analgesia (PCA) as primary measures. Postoperative antiemetic requirements and need for catheterization for urinary retention were determined as secondary measures.

RESULTS

Subjectively reported pain scores and the overall intensity scores were similar for both groups in the postoperative period. At the same time the mean morphine consumption was less in the levobupivacaine group, most notable in the first 12 hours after surgery: treatment group 11.5 mg vs control group 21.2 mg. We observed no differences in the frequency of postoperative nausea and vomiting or urinary retention.

CONCLUSIONS

Our observations suggest periarticular injection of levobupivacaine can supplement available postoperative analgesic techniques and reduce postoperative morphine requirements after THA.

LEVEL OF EVIDENCE

Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The efficacy and safety of levobupivacaine administered by lumbosacral epidural route in conscious sheep

The aim of this study was to evaluate 3 doses of levobupivacaine (LB) epidurally administered in sheep. Six adult male 24-36 month-old sheep received levobupivacaine at 3 doses, LB05 (0.05 mg/kg), LB15 (0.15 mg/kg), and LB25 (0.25mg/kg), and saline solution into the lumbosacral epidural space. Heart rate, arterial blood pressure (systolic, diastolic, and mean), respiratory rate, rectal, and skin temperature, local anesthesia, and ataxia were determined before treatment and at predetermined intervals. The duration of local anesthesia was 30±5 min, 145±27 min, and 290±18 min for LB05, LB15, and LB25, respectively (P<0.05). Ataxia determined for LB05, LB15, or LB25 was similar to the anesthetic times. There was an increase in heart rate and reduction in arterial pressure in LB25 (P<0.05), whereas LB05 or LB15 did not affect these parameters. Lumbosacral epidural levobupivacaine is an appropriate choice for local anesthesia in sheep.

Structure, function, regulation and polymorphism and the clinical significance of human cytochrome P450 1A2

Human CYP1A2 is one of the major CYPs in human liver and metabolizes a number of clinical drugs (e.g., clozapine, tacrine, tizanidine, and theophylline; n > 110), a number of procarcinogens (e.g., benzo[a]pyrene and aromatic amines), and several important endogenous compounds (e.g., steroids). CYP1A2 is subject to reversible and/or irreversible inhibition by a number of drugs, natural substances, and other compounds. The CYP1A gene cluster has been mapped on to chromosome 15q24.1, with close link between CYP1A1 and 1A2 sharing a common 5'-flanking region. The human CYP1A2 gene spans almost 7.8 kb comprising seven exons and six introns and codes a 515-residue protein with a molecular mass of 58,294 Da. The recently resolved CYP1A2 structure has a relatively compact, planar active site cavity that is highly adapted for the size and shape of its substrates. The architecture of the active site of 1A2 is characterized by multiple residues on helices F and I that constitutes two parallel substrate binding platforms on either side of the cavity. A large interindividual variability in the expression and activity of CYP1A2 has been observed, which is largely caused by genetic, epigenetic and environmental factors (e.g., smoking). CYP1A2 is primarily regulated by the aromatic hydrocarbon receptor (AhR) and CYP1A2 is induced through AhR-mediated transactivation following ligand binding and nuclear translocation. Induction or inhibition of CYP1A2 may provide partial explanation for some clinical drug interactions. To date, more than 15 variant alleles and a series of subvariants of the CYP1A2 gene have been identified and some of them have been associated with altered drug clearance and response and disease susceptibility. Further studies are warranted to explore the clinical and toxicological significance of altered CYP1A2 expression and activity caused by genetic, epigenetic, and environmental factors.

Brain penetration of local anaesthetics in the rat: Implications for experimental neuroscience

Multiple experimental neuroscience techniques rely on the use of general anaesthesia to minimize the discomfort associated to animal restraint and to achieve a more effective control of relevant physiological parameters. In order to minimise potential interference on brain neuronal activity, such studies are typically conducted at low anaesthetic doses. This practice is often coupled to peripheral infiltration of local anaesthetics to provide supplementary analgesia and prevent sub-threshold activation of pain pathways that may confound central measurements of brain function. However, little is known of the effect of peripheral anaesthesia on central measurements of brain activity in small laboratory animal species. In order to begin to address this question, we measured total and free brain exposure of five different local anaesthetics following subcutaneous infiltration of analgesic doses in a surgical protocol widely used in rodent neuroimaging and electrophysiology studies. Notably, all the anaesthetics exhibited detectable total and free brain concentrations at all the time points examined. Lidocaine and mepivacaine showed the highest free brain exposures (>525 ng/g), followed by bupivacaine and ropivacaine (>70 ng/g). The ester-type local anaesthetic tetracaine produced the lowest free brain exposure (<8.6 ng/g). Our data suggest that peripheral administration of local anaesthetics in small laboratory animals could result in pharmacologically active brain exposures that might influence and confound central measurements of brain function. The use of the ester-type anaesthetic tetracaine produced considerably lower brain exposure, and may represent a viable experimental option when local anaesthesia is required.

Ropivacaine vs. levobupivacaine combined with sufentanil for epidural analgesia after lung surgery

BACKGROUND AND OBJECTIVES

There are no clinical studies that compare epidural infusion of ropivacaine and levobupivacaine in patients undergoing lung surgery. The aim of this prospective, randomized double-blind study was to evaluate the efficacy and safety of two commercially available solutions of ropivacaine (0.2% w/v) and levobupivacaine (0.125% w/v) when administered by continuous epidural infusion together with sufentanil in patients undergoing lung surgery.

METHODS

After obtaining informed consent, 54 patients, ASA physical status I-III undergoing lung resection, were enrolled. Patients were randomly assigned to two groups in which analgesia was performed by continuous thoracic epidural infusion of ropivacaine 0.2% w/v (Group R) or levobupivacaine 0.125% w/v (Group L) with or without sufentanil 1 microg mL(-1). After a test and a loading dose of each drug for the respective group, continuous epidural infusion, set at 5 mL h(-1), began. General anaesthesia was standardized. In the recovery room, patients were provided with intravenous morphine patient-controlled analgesia. Visual analogue scale at rest and when coughing, rescue patient-controlled analgesia morphine amount, haemodynamics, sensory and motor block, sedation, nausea and vomiting, patient satisfaction score, were evaluated within 48 h.

RESULTS

The two groups were similar regarding patient characteristics, quality of analgesia, level of sensory block, morphine consumption and satisfaction score. Postoperative haemodynamic profile was stable in all the patients. Minor side-effects occurred with a similar incidence. Motor block was not seen.

CONCLUSIONS

Equivalent volumes of ropivacaine (0.2% w/v) and levobupivacaine (0.125% w/v) provided similar static and dynamic analgesia with similar incidence of minor side-effects after thoracotomy.

The efficacy of local anaesthetic for pain after iliac bone harvesting: a randomised controlled trial

INTRODUCTION

Autogenous bone grafting is commonly used in reconstructive surgery but postoperative pain from the donor site can be severe, delaying early mobilisation and preventing discharge from hospital.

METHOD

An RCT of levobupivacaine infusion (16.25mg/h for 24h) of iliac crest wounds versus placebo. Postoperative pain was recorded immediately on returning to the ward, then at 1, 2, 3, 4, 5, 6h, morning and evening on subsequent days until discharge, and at the 7-day clinic appointment. Mobility was recorded twice daily and at 7days.

RESULTS

Of 46 evaluable patients, 25 were randomised to levobupivacaine and 21 to placebo. Mean pain scores for (i) average pain from initial assessment to 6h; (ii) 1day in the morning; (iii) 1day in the evening; (iv) at 2days; and (v) follow-up were all statistically significant in favour of lower pain scores in the levobupivicaine group (p-values all <0.01). Comparison between the study groups for mobility found 6 patients unable to get out of bed in the placebo group and none in the local anaesthetic group at the initial assessment (Fisher's exact test p-value=0.005), and 2 patients at 24h. Patients in the local anaesthetic group were always more mobile and this was statistically significant even at 7days for gait disturbance, limp, deviation of gait and unequalness of stride. There were no complications relating to the infusion system.

CONCLUSIONS

Local anaesthetic significantly reduced postoperative pain and improved mobility. We recommend that surgeons use a local anaesthetic infusion to improve the postoperative experience for their patients undergoing iliac crest grafting.

Fentanyl and clonidine as adjunctive analgesics with levobupivacaine in paravertebral analgesia for breast surgery

The addition of fentanyl or clonidine to levobupivacaine was evaluated in patients undergoing breast surgery under general anaesthesia with intra- and postoperative paravertebral analgesia. Patients were randomly allocated to four groups: Group L received 19 ml bolus levobupivacaine 0.25% plus 1 ml saline followed by an infusion of levobupivacaine 0.1%; Group LF received 19 ml bolus levobupivacaine 0.25% plus fentanyl 50 microg followed by an infusion of levobupivacaine 0.05% with fentanyl 4 microg x ml(-1); Group LC received 19 ml bolus levobupivacaine 0.25% plus clonidine 150 microg followed by an infusion of levobupivacaine 0.05% with clonidine 3 microg x ml(-1); Group C (control) received general anaesthesia without paravertebral analgesia. All groups received postoperative i.v. morphine patient controlled analgesia (PCA). Although mean (SD) postoperative PCA morphine consumption was decreased in LF [7.9 (4.1) mg] and LC [5.9 (3.5) mg]vs L [27.7 (8.6) mg] or C patients [21.7 (5.5) mg], p < 0.01, paravertebral fentanyl and clonidine were associated with significantly increased vomiting and hypotension, respectively.

The comparative hemodynamic effects of intravenous IQB-9302 and bupivacaine in anesthetized rats

BACKGROUND

The new local anesthetic IQB-9302 is an amide derivative bearing a cyclopropyl group, with remarkable long duration of action and relative low toxicity. In trying to characterize further its safety profile, the current study compared the hemodynamic effects of different concentrations of bupivacaine and IQB-9302 with saline.

METHODS

Two groups of eight anesthetized Sprague-Dawley rats were given 0.1, 0.3, 1, 3, and 10 mg/kg of intravenous (i.v.) IQB-9302 or bupivacaine at 20-min intervals; control animals received saline only. Arterial blood pressure and heart rate were monitored during the following 20 min.

RESULTS

Both bupivacaine and IQB-9302 reduced heart rate: for bupivacaine, -73.8 beats per min (bpm) (SD: 103.8) and -132.5 bpm (SD: 140.7) at 1 and 3 mg/kg, respectively; for IQB-9302, the reduction amounted to -40.8 bpm (SD: 14.2) and -113.5 bpm (SD: 94.2) at 1 and 3 mg/kg, respectively (baseline range, 318.7-438.2 bpm). The two drugs also produced a comparable increase in the mean arterial blood pressure; bupivacaine increased it by 8.7 mmHg (SD: 6.6) and 12.6 mmHg (SD: 15.4) at 1 and 3 mg/kg, respectively, and IQB-9302, 18.7 mmHg (SD: 21.1) and 20.7 mmHg (SD: 20.5) at 1 and 3 mg/kg, respectively (baseline range, 47.4-134.1 mmHg). All rats treated with 10 mg/kg of either drug died after a drop in heart rate and mean arterial blood pressure.

CONCLUSION

IQB-9302 had hemodynamic effects similar to those of bupivacaine in anesthetized rats. The clinical relevance of these effects warrants further investigation.

Efficacy and safety of caudal injection of levobupivacaine, 0.25%, in children under 2 years of age undergoing inguinal hernia repair, circumcision or orchidopexy

BACKGROUND

Levobupivacaine is the S(-)-enantiomer of racemic bupivacaine. Evidence suggests that it is less cardiotoxic than racemic bupivacaine and the R(+)-enantiomer, dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine.

METHODS

This was an open study designed to assess the efficacy and safety of 0.25% levobupivacaine administered as a caudal injection at a dose of 2 mg.kg(-1) to 49 paediatric patients aged less than 2 years old undergoing circumcision (group 1), or hernia repair or orchidopexy (group 2).

RESULTS

Adequate analgesia (an increase of <20% in pulse or respiratory rate compared with baseline and an absence of gross movement on application of surgical stimulus) was achieved in 43/48 patients evaluable for efficacy (89.6%). All 22 patients in the circumcision group had adequate analgesia, and two of these patients did not require additional analgesia. The mean time to the use of additional analgesia was 7.3 h. Only one event (a mild rash) was considered possibly related to study medication.

CONCLUSIONS

Levobupivacaine is a promising new local anaesthetic agent for pain management in paediatric patients and appears to offer similar anaesthetic efficacy to racemic bupivacaine with a potentially improved tolerability profile.

Putting chirality to work: the strategy of chiral switches

Most of the new drugs reaching the market today are single enantiomers, rather than the racemic mixtures that dominated up to ten years ago. Many of the new single-enantiomer drugs were developed as such, but there are also important examples of new single-enantiomer drugs derived from 'chiral switches' of established racemates. Indeed, a well-timed chiral switch can offer enhanced therapy and further profitability as a 'line extension' of a major racemic drug with patents that are expiring.

Electrophysiologic cardiac effects of the new local anesthetic IQB-9302 and of bupivacaine in the anesthetised dog

BACKGROUND

Local anesthetics are not free from potentially fatal complications. Therefore every new local anesthetic should be tested to demonstrate a lower, or at least similar, degree of toxicity over clinically used analogs. Most toxic effects from local anesthetics affect the cardiac electrophysiologic function, so the aim of this study was to characterize the electrophysiologic effects of a new long-acting local anesthetic (IQB-9302, Ciprocaine), and compare them with those of bupivacaine in the anesthetized dog.

METHODS

Eight Beagle dogs received three increasing infusion doses of either IQB-9302 or bupivacaine. Under isoflurane anesthesia, dogs were instrumented to monitor cardiovascular (cardiac output, arterial and venous blood pressures) and cardiac electrophysiologic data (sinus and atrioventricular (AV) node function, atrial, nodal and ventricular conduction times, and refractoriness).

RESULTS

Only the highest dose of both drugs induced hemodynamic or electrophysiologic alterations: cardiac output and heart rate were reduced while blood pressures remained unchanged. Atrial and intranodal conduction times and atrial refractoriness increased similarly with both anesthetics, but to a slightly lesser extent with IQB-9302. Significant increases in His-Purkinje and intraventricular conduction times were the most severe noxious effects and occurred only with large doses of either drug. IQB-9302 was slightly less toxic than bupivacaine and, unlike this latter drug, potentially fatal arrhythmias were not induced.

CONCLUSION

IQB-9302 has hemodynamic and cardiac electrophysiologic effects similar to those caused by bupivacaine. Nevertheless, slightly less toxic effects were derived from IQB-9302 administration than with bupivacaine, and, unlike the latter, the former might be less proarrhytmogenic. The new long-acting local anesthetic IQB-9302 may offer clinical advantages compared with bupivacaine.

Cardiac and CNS toxicity of levobupivacaine: strengths of evidence for advantage over bupivacaine

Bupivacaine is currently the most widely used long-acting local anaesthetic. Its uses include surgery and obstetrics; however, it has been associated with potentially fatal cardiotoxicity, particularly when given intravascularly by accident. Levobupivacaine, a single enantiomer of bupivacaine, has recently been introduced as a new long-acting local anaesthetic with a potentially reduced toxicity compared with bupivacaine. Numerous preclinical and clinical studies have compared levobupivacaine with bupivacaine and in most but not all studies there is evidence that levobupivacaine is less toxic. Advantages for levobupivacaine are seen on cardiac sodium and potassium channels, on isolated animal hearts and in whole animals, anaesthetised or awake. In particular the intravascular dose of levobupivacaine required to cause lethality in animals is consistently higher compared with bupivacaine. In awake sheep, for example, almost 78% more levobupivacaine was required to cause death. In contrast, in anaesthetised dogs no differences were seen in the incidence of spontaneous or electrical stimulation- induced ventricular tachycardia and fibrillations among animals exposed to levobupivacaine or bupivacaine. The reversibility of levobupivacaine-induced cardiotoxicity has also been assessed. Some data point to an advantage of levobupivacaine over bupivacaine but this potential advantage was not confirmed in a recent study in anaesthetised dogs. Three clinical studies have been conducted using surrogate markers of both cardiac and CNS toxicity. In these studies levobupivacaine or bupivacaine were given by intravascular injection to healthy volunteers. Levobupivacaine was found to cause smaller changes in indices of cardiac contractility and the QTc interval of the electrocardiogram and also to have less depressant effect on the electroencephalogram. Assuming that levobupivacaine has the same local anaesthetic potency as bupivacaine, then, all things being equal, it is difficult to argue that levobupivacaine should not displace bupivacaine as the long-acting local anaesthetic of choice. It would appear, however, that levobupivacaine has not yet significantly displaced bupivacaine from the markets in which it is sold. This may be due to a lack of perceived safety benefit and/or consideration of the additional costs that are associated with switching to levobupivacaine, which is approximately 57% more expensive than bupivacaine. If the price of levobupivacaine were closer to bupivacaine then the argument to switch to levobupivacaine would undoubtedly be much stronger. With the continued clinical use of levobupivacaine the database available to make comparisons will increase and this may allow cost-benefit arguments to be made more forcefully for levobupivacaine in the future.

Levobupivacaine versus racemic bupivacaine for spinal anesthesia

Levobupivacaine is the pure S(-)-enantiomer of racemic bupivacaine but is less toxic to the heart and central nervous system. Although it has recently been introduced for routine obstetric and nonobstetric epidural anesthesia, comparative clinical studies on its intrathecal administration are not available. We therefore performed this prospective randomized double-blinded study to evaluate the anesthetic potencies and hemodynamics of intrathecal levobupivacaine compared with racemic bupivacaine. Eighty patients undergoing elective hip replacement received either 3.5 mL levobupivacaine 0.5% isobaric or 3.5 mL bupivacaine 0.5% isobaric. Sensory blockade was verified with the pinprick test; motor blockade was documented by using a modified Bromage score. Hemodynamic variables (e.g., blood pressure, heart rate, pulse oximetry) were also recorded. Intergroup differences between levobupivacaine and bupivacaine were insignificant both with regard to the onset time and the duration of sensory and motor blockade (11 +/- 6 versus 13 +/- 8 min; 10 +/- 7 versus 9 +/- 7 min; 228 +/- 77 versus 237 +/- 88 min; 280 +/- 84 versus 284 +/- 80 min). Both groups showed slight reductions in heart rate and mean arterial pressure, but there was no intergroup difference in hemodynamics. We conclude that intrathecal levobupivacaine is equal in efficacy to, but less toxic than, racemic bupivacaine.

IMPLICATIONS

Levobupivacaine, the pure S(-)-enantiomer of racemic bupivacaine is an equally effective local anesthetic for spinal anesthesia compared with racemic bupivacaine.

Levobupivacaine: a review of its pharmacology and use as a local anaesthetic

Based on findings that the cardiotoxicity infrequently observed with racemic bupivacaine shows enantioselectivity, i.e. it is more pronounced with the R(+)-enantiomer, the S(-)-enantiomer (levobupivacaine) has been developed for clinical use as a long acting local anaesthetic. The majority of in vitro, in vivo and human pharmacodynamic studies of nerve block indicate that levobupivacaine has similar potency to bupivacaine. However, levobupivacaine had a lower risk of cardiovascular and CNS toxicity than bupivacaine in animal studies. In human volunteers, levobupivacaine had less of a negative inotropic effect and, at intravenous doses >75 mg, produced less prolongation of the QTc interval than bupivacaine. Fewer changes indicative of CNS depression on EEG were evident with levobupivacaine. Levobupivacaine is long acting with a dose-dependent duration of anaesthesia. The onset of action is < or = 15 minutes with various anaesthetic techniques. In studies of surgical anaesthesia in adults, levobupivacaine provided sensory block for up to 9 hours after epidural administration of < or = 202.5 mg, 6.5 hours after intrathecal 15 mg, and 17 hours after brachial plexus block with 2 mg/kg. Randomised, double-blind clinical studies established that the anaesthetic and/or analgesic effects of levobupivacaine were largely similar to those of bupivacaine at the same dose. Sensory block tended to be longer with levobupivacaine than bupivacaine, amounting to a difference of 23 to 45 minutes with epidural administration and approximately 2 hours with peripheral nerve block. With epidural administration, levobupivacaine produced less prolonged motor block than sensory block. This differential was not seen with peripheral nerve block. Conditions satisfactory for surgery and good pain management were achieved by use of local infiltration or peribulbar administration of levobupivacaine. Levobupivacaine was generally as effective as bupivacaine for pain management during labour, and was effective for the management of postoperative pain, especially when combined with clonidine, morphine or fentanyl. The tolerability profiles of levobupivacaine and bupivacaine were very similar in clinical trials. No clinically significant ECG abnormalities or serious CNS events occurred with the doses used. The most common adverse event associated with levobupivacaine treatment was hypotension (31%).

CONCLUSIONS

Levobupivacaine is a long acting local anaesthetic with a clinical profile closely resembling that of bupivacaine. However, current preclinical safety and toxicity data show an advantage for levobupivacaine over bupivacaine. Clinical data comparing levobupivacaine with ropivacaine are needed before the role of the drug can be fully established. Excluding pharmacoeconomic considerations, levobupivacaine is an appropriate choice for use in place of bupivacaine.