Effect of intrathecal tramadol administration on postoperative pain after transurethral resection of prostate

Effects of Ketamine and Tramadol As Adjuvants to Bupivacaine in Spinal Anesthesia for Unilateral Open Ovarian Cystectomy: A Randomized Controlled Trial

BACKGROUND

Spinal anesthesia offers numerous advantages and desirable features. However, it is associated with various side effects related to local anesthetic agents used. Reducing the dose of local anesthetic in spinal anesthesia can help minimize side effects but may lead to a diminished analgesic effect or failure of anesthesia. Therefore, adding an adjuvant may enhance the benefits while mitigating side effects.

OBJECTIVE

This study aimed to evaluate the effects of ketamine and tramadol as adjuvants to bupivacaine on the duration of spinal analgesia. The objectives were to compare the three groups and prove their analgesic effects, safety, and superiority. The primary outcomes were the duration of spinal analgesia, as well as the onset and duration of both sensory and motor blocks. Secondary outcomes included the heart rate, mean arterial pressure, and the incidence of undesired effects such as nausea, vomiting, sedation, shivering, and postoperative headache.

METHODS

In this double-blind randomized controlled trial, 120 female patients undergoing elective open unilateral ovarian cystectomy under spinal anesthesia were studied. The inclusion criteria included patients aged 16-45 years with a physical status classified as American Society of Anesthesiologists (ASA) class I and II. Patients were randomly allocated into three groups: group B (n=40) received only bupivacaine, group BK (n=40) received bupivacaine mixed with preservative-free ketamine, and group BT (n=40) received bupivacaine mixed with preservative-free tramadol.

RESULTS

The mean duration of spinal analgesia, measured in minutes, showed significant differences (P < 0.001) between group BK (165 ± 4) and group B (170 ± 5). There was also a significant difference between group BT (313 ± 8) and group B (170 ± 5) (P < 0.001). Additionally, significant differences were observed between group BK (165 ± 4) and group BT (313 ± 8) (P < 0.001).

CONCLUSION

The administration of 25 mg of ketamine and 25 mg of tramadol as adjuvants to bupivacaine in spinal anesthesia significantly affected the postoperative duration of analgesia. Tramadol prolonged the duration of spinal anesthesia, while ketamine shortened it. The use of both adjuvants did not result in undesired effects.

Intrathecal nalbuphine vs. buprenorphine as an adjuvant in lower limb orthopedic surgeries: a prospective randomized controlled study

This study aimed to compare the efficacy of intrathecal nalbuphine and buprenorphine as an adjuvant to heavy bupivacaine (0.5%) for spinal anesthesia in lower limb orthopedic surgeries to improve the quality of spinal anesthesia (onset, duration, and side effects) and prolongation of postoperative analgesia. Sixty patients were recruited into this single-centered, double-blinded, hospital-based, prospective, comparative study conducted in 2017–2018. They were randomly and equally (n = 30) allocated into two groups: nalbuphine group which received 0.5 mL (0.8 mg) of nalbuphine with 3 mL of heavy (0.5%) hyperbaric bupivacaine and buprenorphine group which received 0.5 mL (60 mg) of buprenorphine with 3 mL of heavy hyperbaric bupivacaine. Intraoperatively, onset and duration of blockade (motor and sensory), and time for first dose of rescue analgesia were recorded in both groups at regular intervals. Heart rate, blood pressure, Visual Analogue Scale score and side effects were also recorded postoperatively for 12 hours. The demographic parameters, time of onset of sensory block and motor block, and duration of motor block were comparable between nalbuphine and buprenorphine groups. The duration of sensory block in the buprenorphine group was longer than in the nalbuphine group. Time to the first dose of rescue analgesia was delayed in buprenorphine group as compared to nalbuphine group. In both groups maximum patients achieved maximum height of sensory block at 90 minutes. There were significant differences in the mean heart rate and blood pressure between buprenorphine and nalbuphine groups. Nalbuphine group patients achieved a Visual Analogue Scale score > 4 earlier as compared to buprenorphine group. Few side effects were observed in both groups. Intrathecal buprenorphine is a better adjuvant to 0.5% bupivacaine in the spinal anesthesia for lower limb orthopedic surgeries, as it provides longer sensory block and delayed administration of first dose of rescue analgesia with negligible side-effects. The study was approved by Institutional Ethics Committee of Krishna Institute of Medical Sciences (approval number: KIMSDU/IEC/03/2017) on November 23, 2017.

Prospective Randomized Control Trial Comparing Effect of Dexamethasone Versus Fentanyl as Adjuvants to Intrathecal Bupivacaine for Orthopedic Surgery

Introduction Spinal anesthesia is the most consistent block for lower limb orthopedic surgeries. We conducted this randomized prospective study to evaluate comparative efficacy of intrathecal dexamethasone with fentanyl and normal saline as adjuvants to hyperbaric bupivacaine in spinal anesthesia administered to patients scheduled for lower limb orthopedic surgery. Materials and methods 105 patients scheduled for lower limb orthopedic surgeries under spinal anesthesia were included in this clinical trial. After randomization, patients received an intrathecal injection of hyperbaric bupivacaine (12.5 mg) with 4 mg of dexamethasone in group I, hyperbaric bupivacaine (12.5 mg) with 25 ug fentanyl with 0.5 ml of normal saline in group II and hyperbaric bupivacaine (12.5 mg) with normal saline (1 ml) in group III, so as to make volume of drug equal in all three groups. The observer evaluated the sensory and motor blocks and other parameters like time to self-void, stay in post-anesthesia care unit (PACU) and complications.  Results The total duration of sensory blockade was found to be 311.43, 197.86 and 115.29 minutes and motor blockade of 223.43, 163.86 and 83.0 minutes in groups I, II and III respectively. The PACU stay was 233.14, 173.86 and 93.00 minutes in groups I, II and III, respectively. The average time to self-void was 400.00, 315.29 and 203.00 in three groups, respectively. Conclusion Intrathecal dexamethasone seemed to be an effective adjuvant to spinal bupivacaine as it prolongs the duration of analgesia, stable hemodynamic profile with minimal side effects. Further studies are required to evaluate the optimum dose and long-term safety of intrathecal dexamethasone.

Review of adjuvants to local anesthetics in peripheral nerve blocks: Current and future trends

In recent anesthetic practice, peripheral nerve blocks (PNBs) are used extensively for surgical anesthesia and nonsurgical analgesia. PNBs offer many benefits over other anesthetic techniques in a certain population of patients, and in some specific clinical setting, that may contribute to faster and safer pain relief, increased patient satisfaction, reduced hospital stay, and decreased overall healthcare cost. The technique involves the injection of the anesthetic in the vicinity of a specific nerve or bundle of nerves to block the sensation of pain transmitting to a specific portion of the body. However, the length of analgesia when a single anesthetic is used for PNB may not last long. Therefore, the practice of adding an additional agent called adjuvant has been evolved to prolong the analgesic effect. There are many such adjuvants available that are clinically being used for this purpose imparting great efficacy and safety to the anesthetic process. The adjuvants molecules are generally classified as opioids, alpha-2 agonist, steroids, etc. Most of them are safe to use and show little or no adverse event related to neurotoxicity and tissue damage. Although there is extensive use of such adjuvants in the clinical field, none of the molecules is approved by the FDA and is used as an off-label drug. The risk to benefit ratio must be assessed while using such an agent. This review will try to delineate the basic need of adjuvant in peripheral nerve block and will discuss the advantages and limitations of using different adjuvants and will discuss the future prospect of such application.

Evaluation of Anesthetic and Analgesic Effects of Intrathecal Administration of Tramadol vs Fentanyl

Objectives:

The aim of this study was to examine the anesthetic and analgesic effects of intrathecal tramadol compared with intrathecal fentanyl added to bupivacaine and that of a placebo added to bupivacaine in patients undergoing elective transurethral procedures.

Methods:

The anesthetic and analgesic efficacy of intrathecal tramadol hydrochloride (HCL) was assessed against a local anesthetic in this prospective, double-blind, randomized study of 146 American Society of Anesthesiologists classification I-III patients who underwent an elective transurethral procedure. A lumbar intrathecal block was performed using bupivacaine heavy 0.5 % combined with either tramadol HCL, fentanyl, or saline for surgery. Each group received 12.5 mg bupivacaine with 50 μg (1 mL) fentanyl, 12.5 mg bupivacaine with 10 mg (1 mL) tramadol, or 12.5 mg bupivacaine with 1 mL preservative-free saline.

Results:

The saline group experienced more pain than patients in the tramadol HCL and fentanyl groups (p<0.05). The mean time to regression of the sensory block to the S1-2 segment was significantly longer in the fentanyl group compared with the tramadol and saline groups (p<0.05). The incidence of complications was similar.

Conclusion:

Fentanyl added to a local anesthetic provided longer postoperative analgesia compared with tramadol added to a local anesthetic.

Adjuvants to local anesthetics: Current understanding and future trends

Although beneficial in acute and chronic pain management, the use of local anaesthetics is limited by its duration of action and the dose dependent adverse effects on the cardiac and central nervous system. Adjuvants or additives are often used with local anaesthetics for its synergistic effect by prolonging the duration of sensory-motor block and limiting the cumulative dose requirement of local anaesthetics. The armamentarium of local anesthetic adjuvants have evolved over time from classical opioids to a wide array of drugs spanning several groups and varying mechanisms of action. A large array of opioids ranging from morphine, fentanyl and sufentanyl to hydromorphone, buprenorphine and tramadol has been used with varying success. However, their use has been limited by their adverse effect like respiratory depression, nausea, vomiting and pruritus, especially with its neuraxial use. Epinephrine potentiates the local anesthetics by its antinociceptive properties mediated by alpha-2 adrenoreceptor activation along with its vasoconstrictive properties limiting the systemic absorption of local anesthetics. Alpha 2 adrenoreceptor antagonists like clonidine and dexmedetomidine are one of the most widely used class of local anesthetic adjuvants. Other drugs like steroids (dexamethasone), anti-inflammatory agents (parecoxib and lornoxicam), midazolam, ketamine, magnesium sulfate and neostigmine have also been used with mixed success. The concern regarding the safety profile of these adjuvants is due to its potential neurotoxicity and neurological complications which necessitate further research in this direction. Current research is directed towards a search for agents and techniques which would prolong local anaesthetic action without its deleterious effects. This includes novel approaches like use of charged molecules to produce local anaesthetic action (tonicaine and n butyl tetracaine), new age delivery mechanisms for prolonged bioavailability (liposomal, microspheres and cyclodextrin systems) and further studies with other drugs (adenosine, neuromuscular blockers, dextrans).

A Comparative Study of Analgesic Effect of Intrathecal Nalbuphine and Fentanyl as Adjuvant in Lower Limb Orthopaedic Surgery

INTRODUCTION

Intrathecal opioids when added to local anaesthetics decrease their dosage and provide haemodynamic stability. Nalbuphine is an agonist-antagonist and acts on kappa receptors providing analgesia.

AIM

The study aims to compare the analgesic efficacy of fentanyl with that of two doses of nalbuphine when used with injection bupivacaine heavy in spinal anaesthesia.

MATERIALS AND METHODS

A randomised, double blinded, prospective study on 90 patients of ASA I and II undergoing lower limb orthopaedic surgery under subarachnoid block was done. Patients were randomly allocated into three groups (n=30). Each group received 12.5 mg of 0.5% of injection bupivacaine heavy along with either 25 μg of 0.5 ml fentanyl (Group F) or 0.8 mg of 0.5 ml nalbuphine (Group NL) or 1.6 mg of 0.5 ml nalbuphine (Group NH). Characteristics of sensory and motor blocks, haemodynamic changes, duration and quality of analgesia, adverse effects, sedation, VRS score and analgesic requirement were studied at different time interval intraoperatively and till 24 hours of block.

RESULTS

The duration of analgesia (in minute) was 441±119.69 in NL Group, 450±103.38 in NH Group and 300.0±88.53 in Group F (p=0.05). There was no significant difference regarding block characteristics and haemodynamic parameters. Total 24 hours analgesic requirement was titrated by analgesic score which was 2.25±0.7 (NH Group), 1.875±0.83 (NL Group) and 3.375±1.77 (F Group) p=0.0186 by ANOVA. The adverse effects of NL Group were least.

CONCLUSION

There was no significant advantage of intrathecal fentanyl or 1.6 mg nalbuphine over low dose 0.8 mg nalbuphine.

Intrathecal ropivacaine with or without tramadol for lower limb orthopedic surgeries

BACKGROUND AND AIM

Preservative free tramadol has been used as an adjuvant to intrathecal bupivacaine. However, the effect of the addition of tramadol on intrathecal isobaric ropivacaine has never been studied.

MATERIAL AND METHODS

This prospective, randomized, double-blind study was conducted in 50 adult male American Society of Anesthesiologists grade I or II patients, aged 18-60 years, being operated for unilateral femur fractures. An epidural catheter was inserted in L2-L3 interspace and subarachnoid block was given in L3-L4 space. The patients were randomized to receive 0.5 mL normal saline (group R) or 0.5 mL (25 mg) preservative free tramadol (group RT) with 2.5 mL of 0.75% intrathecal ropivacaine. Hemodynamic parameters, sensory level, motor block, sedation and side-effects were recorded. Statistical analysis was done using Student's t-test, Chi-square test, Fischer's exact test and repeated measures ANOVA.

RESULTS

The time of sensory block onset was 9.2 ± 4.9 min and 8.6 ± 5.3 min (P = 0.714) in group R and group RT, respectively. The motor block onset was also comparable in both the groups (P = 0.112). The duration of sensory block was 147.2 ± 37.4 min in group R and 160.4 ± 40.9 min in group RT (P = 0.252). The median maximum block height achieved in both the groups was T6 and the time to achieve the maximum block was also comparable statistically (P = 0.301).

CONCLUSION

The addition of intrathecal tramadol 25 mg to the isobaric ropivacaine does not alter the block characteristics produced by intrathecal ropivacaine alone.

Epidural nalbuphine for postoperative analgesia in orthopedic surgery

BACKGROUND

The challenging task of postoperative pain relief comes within the realm of the anesthesiologist. Combined spinal epidural (CSE) anesthesia can be used as the sole technique for carrying out surgical procedures and managing postoperative pain using various drug regimes. Epidural administration of opioids in combination with local anesthetic agents in low dose offers new dimensions in the management of postoperative pain.

AIMS

Comparative evaluation of bupivacaine hydrochloride with nalbuphine versus bupivacaine with tramadol for postoperative analgesia in lower limb orthopedic surgeries under CSE anesthesia to know the quality of analgesia, incidence of side effects, surgical outcome and level of patient satisfaction.

SETTINGS AND DESIGN

A prospective, randomized and double-blind study was conducted involving 80 patients of American Society of Anesthesiologists physical status I and II coming for elective lower limb orthopedic surgeries carried under spinal anesthesia.

MATERIALS AND METHODS

Anesthesia was given with 0.5% of 2.5 ml bupivacaine intrathecally in both the groups. Epidurally 0.25% bupivacaine along with 10 mg nalbuphine (group A) or tramadol 100 mg (group B) diluted to 2 ml to make a total volume of 10 ml was administered at sensory regression to T10.

STATISTICAL ANALYSIS

The data were collected, compiled and statistically analyzed with the help of MS Excel, EPI Info 6 and SPSS to draw the relative conclusions.

RESULTS AND CONCLUSIONS

The mean duration of analgesia in group A was 380 ± 11.49 min and in group B was 380 ± 9.8 min. The mean sedation score was found to be more in group B than group A. The mean patient satisfaction score in group A was 4.40 ± 0.871 and in group B was 3.90 ± 1.150 which was found to be statistically significant (P < 0.05). We concluded that the addition of nalbuphine with bupivacaine was effective for postoperative analgesia in terms of quality of analgesia and patient satisfaction score as compared to tramadol.

Reinforcement of subarachnoid block by epidural volume effect in lower abdominal surgery: A comparison between fentanyl and tramadol for efficacy and block properties

Background:

Epidural volume extension (EVE) is claimed to increase the block height and decrease the dose requirement for intrathecal drug. However, almost all studies have been done in obstetric population and none actually compares the effect of additional drugs added to epidural volume.

Materials and Methods:

Seventy-five (ASA I and II) patients scheduled for lower abdominal surgery were randomly divided into three groups. All groups received intrathecal 10 mg bupivacaine; two groups received additional 10 ml of normal saline epidurally with 25 mg tramadol or 25 mg of fentanyl. Groups were than compared for maximal block height, rate of sensory block regression to T10, and motor block regression to Bromage scale of 0. Time to first analgesia and adverse effects were also compared among the three groups.

Materials and Methods:

Seventy-five (ASA I and II) patients scheduled for lower abdominal surgery were randomly divided into three groups. All groups received intrathecal 10 mg bupivacaine; two groups received additional 10 ml of normal saline epidurally with 25 mg tramadol or 25 mg of fentanyl. Groups were than compared for maximal block height, rate of sensory block regression to T10, and motor block regression to Bromage scale of 0. Time to first analgesia and adverse effects were also compared among the three groups.

Results:

Groups with EVE had statistically significant higher block height, with a significant faster regression that the control group. However, both fentanyl and tramadol groups were inseparable in respect to motor or sensory block regression. Fentanyl group had maximal time to first analgesia, followed by tramadol and control groups. Hemodynamic alterations were also more common in EVE groups.

Conclusion:

EVE can increase the block height significantly, but it seems to be limited only to the physical property of additional volume in epidural space and fentanyl or tramadol do not seem to differ in their ability to alter block properties.

Analgesic effects of intrathecal tramadol in patients undergoing caesarean section: a randomised, double-blind study

BACKGROUND

Intrathecal tramadol combined with local anaesthetics has been used for postoperative analgesia following lower abdominal and perineal surgery. The present study evaluated the effect of intrathecal tramadol on spinal block characteristics and neonatal outcome after elective caesarean section.

METHODS

Eighty full-term parturients scheduled for elective caesarean section were randomly divided into two groups. In the fentanyl group, patients received intrathecal 0.5% bupivacaine 10 mg with fentanyl 10 μg; in the tramadol group, patients were given the same dose of bupivacaine with tramadol 10 mg. Sensory and motor block characteristics, duration of postoperative analgesia, maternal side effects, and neonatal outcome were compared.

RESULTS

One patient in the tramadol group and two patients in the fentanyl group were excluded from data analysis. Median [interquartile range] duration of postoperative analgesia in the tramadol and the fentanyl groups was 300 [240-360] min and 260 [233-300] min respectively (P = 0.02). The incidence of shivering was lower in patients who received tramadol (5%) than those who had fentanyl (32%) (P = 0.003). Apgar scores, umbilical cord acid-base measurement and neurologic and adaptive capacity scores were comparable between the two groups.

CONCLUSION

Compared to intrathecal fentanyl 10 μg, tramadol 10 mg, as an adjunct to bupivacaine for subarachnoid block for caesarean section, showed a longer duration of analgesia with a reduced incidence of shivering.

Addition of intrathecal Dexamethasone to Bupivacaine for spinal anesthesia in orthopedic surgery

OBJECTIVES

Spinal anesthesia has the advantage that profound nerve block can be produced in a large part of the body by the relatively simple injection of a small amount of local anesthetic. Intrathecal local anesthetics have limited duration. Different additives have been used to prolong spinal anesthesia. The effect of corticosteroids in prolonging the analgesic effects of local anesthetics in peripheral nerves is well documented. The purpose of this investigation was to determine whether the addition of dexamethasone to intrathecal bupivacaine would prolong the duration of sensory analgesia or not.

METHODS

We conducted a randomized, prospective, double-blind, case-control, clinical trial. A total of 50 patients were scheduled for orthopedic surgery under spinal anesthesia. The patients were randomly allocated to receive 15 mg hyperbaric bupivacaine 0.5% with 2 cc normal saline (control group) or 15 mg hyperbaric bupivacaine 0.5% plus 8 mg dexamethasone (case group) intrathecally. The patients were evaluated for quality, quantity, and duration of block; blood pressure, heart rate, nausea, and vomiting or other complications.

RESULTS

There were no signification differences in demographic data, sensory level, and onset time of the sensory block between two groups. Sensory block duration in the case group was 119±10.69 minutes and in the control group was 89.44±8.37 minutes which was significantly higher in the case group (P<0.001). The duration of analgesia was 401.92±72.44 minutes in the case group; whereas it was 202±43.67 minutes in the control group (P<0.001). The frequency of complications was not different between two groups.

CONCLUSION

This study has shown that the addition of intrathecal dexamethasone to bupivacaine significantly improved the duration of sensory block in spinal anesthesia without any changes in onset time and complications.

Addition of intrathecal Dexamethasone to Bupivacaine for spinal anesthesia in orthopedic surgery

Objectives:

Spinal anesthesia has the advantage that profound nerve block can be produced in a large part of the body by the relatively simple injection of a small amount of local anesthetic. Intrathecal local anesthetics have limited duration. Different additives have been used to prolong spinal anesthesia. The effect of corticosteroids in prolonging the analgesic effects of local anesthetics in peripheral nerves is well documented. The purpose of this investigation was to determine whether the addition of dexamethasone to intrathecal bupivacaine would prolong the duration of sensory analgesia or not.

Methods:

We conducted a randomized, prospective, double-blind, case-control, clinical trial. A total of 50 patients were scheduled for orthopedic surgery under spinal anesthesia. The patients were randomly allocated to receive 15 mg hyperbaric bupivacaine 0.5% with 2 cc normal saline (control group) or 15 mg hyperbaric bupivacaine 0.5% plus 8 mg dexamethasone (case group) intrathecally. The patients were evaluated for quality, quantity, and duration of block; blood pressure, heart rate, nausea, and vomiting or other complications.

Results:

There were no signification differences in demographic data, sensory level, and onset time of the sensory block between two groups. Sensory block duration in the case group was 119±10.69 minutes and in the control group was 89.44±8.37 minutes which was significantly higher in the case group (P<0.001). The duration of analgesia was 401.92±72.44 minutes in the case group; whereas it was 202±43.67 minutes in the control group (P<0.001). The frequency of complications was not different between two groups.

Conclusion:

This study has shown that the addition of intrathecal dexamethasone to bupivacaine significantly improved the duration of sensory block in spinal anesthesia without any changes in onset time and complications.

Advances in perioperative pain management: use of medications with dual analgesic mechanisms, tramadol & tapentadol

Recovery from ambulatory surgical procedures can be limited by postoperative pain. Inadequate analgesia may delay or prevent patient discharge and can result in readmission. More frequently, postoperative pain produces discomfort and interrupts sleep, contributing to postoperative fatigue. The development of effective analgesic regimens for the management of postoperative pain is a priority especially in patients with impaired cardiorespiratory, hepatic, or renal function. Tramadol and tapentadol hydrochloride are novel in that their analgesic actions occur at multiple sites. Both agents are reported to be mu-opioid receptor agonists and monoamine-reuptake inhibitors. In contrast to pure opioid agonists, both drugs are believed to have lower risks of respiratory depression, tolerance, and dependence. The Food and Drug Administration has approved both drugs for the treatment of moderate-to-severe acute pain in adults. This article provides an evidence-based account of the role of tramadol and tapentadol in modern clinical practice.

Tramadol added to bupivacaine does not prolong analgesia of continuous psoas compartment block

The primary aim of our study was to evaluate the quality and duration of analgesia when tramadol was added to 0.25% bupivacaine for continuous psoas compartment block (CPCB) using visual analog pain scores. Thirty patients were prospectively randomized into two equal groups (n = 15). Visual analog scale pain score was not significantly different between the groups during the 48-hour follow-up period. Rescue analgesic consumption, nausea and vomiting, and the satisfaction scores were comparable between the groups (P > 0.05). Success with catheter placement adjacent to the lumbar plexus was 100%, and none of the patients developed any catheter-related complications. In conclusion, tramadol does not provide a clinically significant analgesic action as an adjunct to 0.25% bupivacaine for CPCB.

Altered antinociceptive efficacy of tramadol over time in rats with painful peripheral neuropathy

Pain due to peripheral nerve injury or disease is a dynamic process, such that the mechanism that underlies it alters over time. Tramadol has been reported to be analgesic in clinical neuropathic pain, with varying levels of efficacy due to a patient population that has had neuropathic pain for a wide range of time. In order to address and examine the issue, the antinociceptive efficacy of tramadol over time was tested in rats with a chronic constriction injury (CCI) of the left sciatic nerve. Rats developed a robust hind paw hypersensitivity to innocuous mechanical stimulation ipsilateral to CCI surgery. Subcutaneous injection of tramadol in rats two weeks after CCI surgery dose-dependently attenuated mechanical hypersensitivity, which was abolished with the mu-opioid receptor antagonist naloxone but not the alpha(2)-adrenoceptor antagonist yohimbine. Systemic tramadol also attenuated mechanical hypersensitivity four weeks after CCI surgery, but the efficacy significantly diminished at this time point. In addition, the effect of tramadol at this later time point could be reduced with yohimbine as well as naloxone. These data demonstrate that the efficacy of tramadol depends in part on the duration of nerve injury-evoked nociception, and that its antinociceptive mechanism changes over time. Alteration in antinociceptive mechanism over time may explain the inconsistency in efficacy of this and other analgesic drugs in chronic pain patients.

Tramadol as adjunct to psoas compartment block with levobupivacaine 0.5%: a randomized double-blinded study

BACKGROUND

Tramadol has been administered peripherally to prolong analgesia after brachial plexus and neuraxial blocks. Our aim was to evaluate the systemic and perineural effects of tramadol as an analgesic adjunct to psoas compartment block (PCB) with levobupivacaine.

METHODS

In a randomized, prospective, double-blinded trial, 60 patients (ASA I-III), aged 49-88 yr, undergoing primary total hip or knee arthroplasty underwent PCB and subsequent bupivacaine spinal anaesthesia. Patients were randomized into three groups. Each patient received PCB with levobupivacaine 0.5%, 0.4 ml kg(-1). The control group (group L, n=21) received i.v. saline, the systemic tramadol group (group IT, n=19) received i.v. tramadol 1.5 mg kg(-1) and the perineural tramadol group (group T, n=20) received i.v. saline and PCB with tramadol 1.5 mg kg(-1). Postoperatively patients received regular paracetamol 6-hourly and diclofenac sodium 12-hourly. Time to first morphine analgesia, 24-hour morphine consumption, sensory block, pain and sedation scores and haemodynamic parameters were recorded.

RESULTS

Time (h) to first morphine analgesia was similar in the three groups [mean (SD)]: group L, 11.2 (6.6); group T, 14.5 (8.0); group IT, 14.6 (6.8); P=0.35. Twenty-four-hour cumulative morphine (mg) consumption was also similar in the three groups [group L, 21.9 (10.1); group T, 19.8 (6.7), group IT, 16.5 (9.5)], as were durations of sensory and motor block. There were no differences in the incidence of adverse effects except that patients in group IT were more sedated at 14 h than group L (P=0.02).

CONCLUSION

We conclude that our data do not support a clinically important local anaesthetic or peripheral analgesic effect of tramadol as adjunct to PCB with levobupivacaine 0.5%.