Tramadol: a review of its use in perioperative pain

Laparoscopic surgery: a narrative review of pharmacotherapy in pain management

Laparoscopic surgery is widespread, and an increasing number of surgeries are performed laparoscopically. Early pain after laparoscopy can be similar or even more severe than that after open surgery. Thus, proactive pain management should be provided. Pain after laparoscopic surgery is derived from multiple origins; therefore, a single agent is seldom sufficient. Pain is most effectively controlled by a multimodal, preventive analgesia approach, such as combining opioids with non-opioid analgesics and local anaesthetics. Wound and port site local anaesthetic injections decrease abdominal wall pain by 1-1.5 units on a 0-10 pain scale. Inflammatory pain and shoulder pain can be controlled by NSAIDs or corticosteroids. In some patient groups, adjuvant drugs, ketamine and α2-adrenergic agonists can be helpful, but evidence on gabapentinoids is conflicting. In the present review, the types of pain that need to be taken into account while planning pain management protocols and the wide range of analgesic options that have been assessed in laparoscopic surgery are critically assessed. Recommendations to the clinician will be made regarding how to manage acute pain and how to prevent persistent postoperative pain. It is important to identify patients at the highest risk for severe and prolonged post-operative pain, and to have a proactive strategy in place for these individuals.

Comparison of the analgesic efficacy of oral ketorolac versus intramuscular tramadol after third molar surgery: A parallel, double-blind, randomized, placebo-controlled clinical trial

BACKGROUND

Preemptive analgesia is considered an alternative for treating the postsurgical pain of third molar removal. The aim of this study was to evaluate the preemptive analgesic efficacy of oral ketorolac versus intramuscular tramadol after a mandibular third molar surgery.

MATERIAL AND METHODS

A parallel, double-blind, randomized, placebo-controlled clinical trial was carried out. Thirty patients were randomized into two treatment groups using a series of random numbers: Group A, oral ketorolac 10 mg plus intramuscular placebo (1 mL saline solution); or Group B, oral placebo (similar tablet to oral ketorolac) plus intramuscular tramadol 50 mg diluted in 1 mL saline solution. These treatments were given 30 min before the surgery. We evaluated the time of first analgesic rescue medication, pain intensity, total analgesic consumption and adverse effects.

RESULTS

Patients taking oral ketorolac had longer time of analgesic covering and less postoperative pain when compared with patients receiving intramuscular tramadol.

CONCLUSIONS

According to the VAS and UAC results, this study suggests that 10 mg of oral ketorolac had superior analgesic effect than 50 mg of tramadol when administered before a mandibular third molar surgery.

Molecular and histological changes in cerebral cortex and lung tissues under the effect of tramadol treatment

Tramadol abuse is one of the most frequent health problems in Egypt and worldwide. In most cases, tramadol abused by men face a problem with premature ejaculation. Tramadol like other opioids induces a decrease in plasma antioxidant levels, which may reflect a failure of the antioxidant defense mechanism against oxidative damage. The present work aimed to study the possible deleterious effects of oral administration of tramadol on brain and lung tissues in rats. Twenty adult male albino rats were divided into two groups; a control administered with normal saline and tramadol-treated (40mg/kg b.w.) group for 20 successive days. At the end of experimental period, blood was collected and specimens from brains and lungs were taken for histopathological and molecular studies. Malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) activities were measured in serum of control and tramadol-treated groups. Brain and lung specimens were histopathological evaluated using light microscopy. The expression levels of apoptotic related genes; Bcl-2, Bax and Caspase-3 were study in brain and lung tissues using RT-PCR analysis. We recorded a significant increase MDA level, while antioxidant enzymes; GSH, SOD and CAT were significantly decreased after tramadol-treatment. The obtained results revealed that tramadol induced a remarkable histomorphological changes in rats' brains (cerebral cortex and hippocampus) and severe histopathological changes in rats' lung when compared to that of control. On molecular level, the expression of the pro-apoptotic Bax and Caspase-3 showed a significant increase whereas the anti-apoptotic Bcl-2 decreased markedly indicating that tramadol is harmful at cellular level and can induce apoptotic changes in brain tissues. Our data confirmed the risk of increased oxidative stress, neuronal and pulmonary damage due to tramadol abuse. Although tramadol is reported to be effective in pain management, its toxicity should be kept in mind.

Worldwide research productivity on tramadol: a bibliometric analysis

BACKGROUND

Pain management and safe use of analgesics is an important medical issue. Tramadol is an old analgesic with controversial properties. Evaluation of worldwide scientific output on tramadol has not been explored. Therefore, the main objective of this study was to give a bibliometric overview of global research productivity on tramadol.

METHODS

SciVerse Scopus was used to retrieve and quantitatively and qualitatively analyze worldwide publications on tramadol.

RESULTS

A total of 2059 original and review research articles on tramadol were retrieved from Scopus. Forty-six documents (2.23 %) were published in Anesthesia and Analgesia Journal whereas 30 (1.46 %) were published in Arzneimittel Forschung Drug Research Journal. Retrieved tramadol documents were published from 71 countries and appeared in 160 peer reviewed journals. Although the United States of America (259; 12.86 %) had the largest contribution to tramadol publications; the contribution by other countries like Turkey (232; 11.27) India (189; 8.09 %) and Germany (176; 8.56 % was not far away from that of USA. The most productive institution was Grunenthal, Germany (47; 2.28 %) followed by Tehran University of Medical Sciences, Iran (29; 1.41 %), and, Ortho-McNeil Pharmaceutical Incorporated, USA (25; 1.21 %). Of the 2059 documents, there were 370 documents about dependence. The leading institution in documents pertaining to tramadol dependence was Grunenthal GmbH (18; 4.86 %) followed by Ortho-McNeil Pharmaceutical Incorporated (17; 4.59 %).

CONCLUSIONS

The current study showed that there is an obvious interest in tramadol research. More efforts are needed to clarify the abuse potential and safety profile of tramadol to help in determining the legal status of tramadol. Collaboration among pharmaceutical industry, clinical researchers and academic institutions can improve research quantity and quality on tramadol.

Comparison of pharmacokinetics of tramadol between young and middle-aged dogs

This study aimed to compare the pharmacokinetics of tramadol between young and middle-aged dogs. Tramadol (4 mg/kg) was administered intravenously (IV) to young and middle-aged dogs (2 and 8–10 years, respectively). Plasma concentrations of tramadol were measured using high-performance liquid chromatography (HPLC), and its pharmacokinetics best fit a two-compartment model. The volume of distribution (V_d), elimination half-life (t_1/2,β) and total body clearance (CL_tot) of the young group were 4.77 ± 1.07 l/kg, 1.91 ± 0.26 hr and 29.9 ± 7.3 ml/min/kg, respectively, while those of the middle-aged group were 4.73 ± 1.43 l/kg, 2.39 ± 0.97 hr and 23.7 ± 5.4 ml/min/kg, respectively. Intergroup differences in the t_1/2,β and CL_tot were significant (P<0.05). In conclusion, tramadol excretion was significantly prolonged in middle-aged dogs.

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.

A comparative study of intravenous paracetamol and intravenous tramadol for postoperative analgesia in laparotomies

Background:

Pain in the perioperative setting or thereafter plays a significant role in delaying an otherwise successful recovery. Hence, mitigation of such postoperative pain assumes importance. Among the various agents employed for such mitigation, opioids and non-steroidal anti-inflammatory drugs have for some time taken center stage. However, alas they are not without their share of adverse effects. This study was undertaken with the purpose of elucidating the efficacy of intravenous (IV) paracetamol as compared to IV tramadol in mitigating postoperative pain while observing its effect on hemodynamic stability and the presence of adverse drug reactions, if any.

Materials and Methods:

A total of 60 randomized cases aged ranges from 20 to 60 years of both sexes divided into two groups (each for paracetamol and tramadol) scheduled for laparotomies were administered IV paracetamol and tramadol for postoperative pain relief and assessed with visual analog scale (VAS) score and variations in vital parameters to ascertain extent of pain relief and post-operative nausea vomiting (PONV).

Results:

Data so collected was statistically interpreted, and observations extrapolated. Save for a perceptible decline in PONV with paracetamol group compared with tramadol group with a statistically significant P < 0.001, nothing statistically significant was observed in any other parameter, including VAS scores between either group.

Conclusion:

IV paracetamol is a safer alternative to tramadol with lesser PONV in the postoperative period translates into the lesser duration of hospitalization and hence earlier discharge.

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.

Crystal structure of {[2-hy-droxy-2-(3-meth-oxy-phen-yl)cyclo-hex-yl]meth-yl}di-methyl-ammonium benzoate

The title compound, C16H26NO2 (+)·C7H5O2 (-), is a benzoate salt of the painkiller Tramadol. The six-membered cyclo-hexane ring of the cation adopts a slightly distorted chair conformation and carries OH and 3-meth-oxy-phenyl substituents at the 2-position and a protonated methyl-aza-niumylmethyl group at the 3-position. In addition, a weak intra-molecular C-H⋯O hydrogen bond is observed in the cation. In the crystal, weak O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds link the components into chains along [010]. A C-H⋯π contact is also observed.

Patient's satisfaction after outpatient forefoot surgery: Study of 619 cases

INTRODUCTION

The number of outpatient surgical procedures performed in France on the forefoot has grown rapidly in recent years.

OBJECTIVES

The goal of this study was to evaluate experience and satisfaction of patients undergoing outpatient foot surgery using a telephone questionnaire developed for this purpose.

MATERIAL AND METHODS

In 2012 and 2013, every patient who was admitted to the day surgery unit at our hospital for an open procedure on their forefoot was called the morning after the procedure. A nurse went through the 14-item questionnaire with the patient. The same perioperative protocol, written instructions and treatment were used for all patients.

RESULTS

Six hundred nineteen patients were included. The questionnaire response rate was 89% (n=540). Isolated hallux valgus surgery was performed on 319 patients (61%); 107 patients (20%) underwent hallux valgus surgery with lateral metatarsal osteotomy; 57 patients (10.5%) underwent first metatarsophalangeal fusion and 47 patients (8.5%) underwent a procedure on the lateral rays only. In the postoperative phase, 65% reported having satisfactory sleep quality, 32% had experienced nausea, 16% had experienced vomiting and 17% had experienced bleeding. Eighty percent of patients experienced pain (VAS ≥ 1); 80% of these patients had their pain relieved by the prescribed treatment and 4% had not taken it. Nearly all the patients (99%) were satisfied with the outpatient care; the overall satisfaction score was 9.4 out of 10. There was a significant relationship between the type of procedure and vomiting, pain, bleeding and fever.

DISCUSSION

Outpatient care is becoming more common in response to economic challenges. The development of outpatient foot surgery appears to have satisfied the vast majority of operated patients. However, adjustments should be made to improve their tolerance to the pain management protocol. Although the logistics of performing follow-up call can be complicated, the patients appreciate receiving this call the next day. The call also seems to reassure both the patients and care providers.

Practice of Pain Management by Indian Healthcare Practitioners: Results of a Paper Based Questionnaire Survey

Objective. Understanding factors while selecting an analgesic and its usage pattern by Indian healthcare practitioners (HCPs). Methods. Questionnaire-based survey was conducted among six healthcare specialties. Results. Total 448 HCPs participated. Patient's age (72.8%, 74.4%, 87.5%, and 78.9%) and duration of therapy (70.8%, 66.2%, 69.6%, and 73.6%) were main attributes for selecting an opioid according to general practitioners (GPs), dentists, consulting physicians (CPs), and surgeons, respectively. Patient's age was important factor while selecting NSAID according to 77.60%, 66.91%, and 84.20% of GPs, dentists, surgeons, respectively. For mild pain, paracetamol was the choice according to 77%, 78.57% and 74% of GPs, CPs, and surgeons, respectively. For moderate pain, 77%, 87.50%, 68%, and 80.30% of GPs, CPs, surgeons and orthopedicians, respectively, preferred the use of paracetamol + tramadol combination. For moderate pain, NSAID + paracetamol and paracetamol+diclofenac were used by 68.94% and 47.73% of orthopedicians, respectively. Lack of pain clinic (38.8%) in city was commonly cited reason for not referring patients to pain clinics. Conclusion. Patient's age, duration of therapy, comorbid conditions, frequency of dosing, and severity of pain are important parameters while selecting analgesics. Paracetamol and its combinations are commonly used for mild and moderate pain, respectively. Pain clinics currently have limited presence in India.

Differential Consequences of Tramadol in Overdosing: Dilemma of a Polymorphic Cytochrome P450 2D6-Mediated Substrate

Tramadol is a centrally acting opioid analgesic that is prone to polymorphic metabolism via cytochrome P450 (CYP) 2D6. The generation of the active metabolite, O-desmethyltramadol, which occurs through the CYP 2D6 pathway, significantly contributes to the drug's activity. However, dosage adjustments of tramadol are typically not practiced in the clinic when treating patients who are homozygous extensive metabolizers, heterozygous extensive metabolizers, or poor metabolizers. In the event of a tramadol overdose, the consequences may be influenced importantly by the genotype or phenotype status of the subject. Depending on the individual subject's CYP 2D6 status, one may see excessive miotic-related toxicity driven by the excessive availability of O-desmethyltramadol or one may manifest mydriatic-related toxicity driven by the excessive availability of tramadol. This report provides pharmacokinetic perspectives in situations of tramadol overdosing.

Fentanyl versus tramadol with levobupivacaine for combined spinal-epidural analgesia in labor

Background:

Neuraxial labor analgesia using new local anesthetics such as levobupivacaine has become very popular by virtue of the safety and lesser motor blockade caused by these agents. Combined spinal-epidural analgesia (CSEA) has become the preferred method for labor analgesia as it combines benefits of both spinal analgesia and flexibility of the epidural catheter. Adding opioids to local anesthetic drugs provide rapid onset and prolonged analgesia but may be associated with several maternal and fetal adverse effects. The purpose of this study is to compare fentanyl and tramadol used in CSEA in terms of duration of analgesia and frequency of the adverse fetomaternal outcome.

Materials and Methods:

A total of 60 primiparas with a singleton pregnancy in active labor were given CSEA after randomly allocating them in two groups of 30 each. Group I received intrathecal 2.5 mg levobupivacaine + 25 μg fentanyl followed by epidural top ups of 20 ml 0.125% solution of the same combination. Group II received 25 mg tramadol instead of fentanyl. Epidural top ups were given when parturient complained of two painful contractions (visual analogue scale ≥ 4). Data collected were demographic profile of the patients, analgesic qualities, side- effects and the fetomaternal outcome.

Results:

Patients in Group II had significantly prolonged analgesia (145 ± 9 minutes) than in Group I (95 ± 7 minutes). Patients receiving fentanyl showed rapid onset of analgesia, but there were more incidence of side-effects like shivering, pruritus, transient fetal bradycardia, hypotension, nausea and vomiting. Only side-effect in the tramadol group was nausea and vomiting. During labor, maternal satisfaction was excellent.

Conclusions:

Adding tramadol to local anesthetic provides prolonged analgesia with minimal side effects. Fentanyl, when used as adjuvant to local anesthetic, has a rapid onset of analgesia but has certain fetomaternal side-effects.

Effect of tramadol on metamizol pharmacokinetics and pharmacodynamics after single and repeated administrations in arthritic rats

Combined administration of certain doses of opioid compounds with a non-steroidal anti-inflammatory drug can produce additive or supra-additive effects while reducing unwanted effects. We have recently reported that co-administration of metamizol with tramadol produces antinociceptive effect potentiation, after acute treatment. However, none information about the effect produced by the combination after chronic or repeated dose administration exists. The aims of this study were to investigate whether the antinociceptive synergism produced by the combination of metamizol and tramadol (177.8 + 17.8 mg/kg, s.c. respectively) is maintained after repeated treatment and whether the effects observed are primarily due to pharmacodynamic interactions or may be related to pharmacokinetics changes. Administration of metamizol plus tramadol acute treatment significantly enhanced the antinociceptive effect of the drugs given alone (P < 0.05). Nevertheless, this effect decreased about 53% after the chronic treatment (3 doses per day, for 4 days). No pharmacokinetic interaction between metamizol and tramadol was found under acute treatment (P > 0.05). The mechanism involved in the synergism of the antinociceptive effect observed with the combination of metamizol and tramadol in single dose cannot be attributed to a pharmacokinetic interaction, and other pharmacodynamic interactions have to be considered. On the other hand, when metamizol and tramadol were co-administered under repeated administrations, a pharmacokinetic interaction and tolerance development occurred. Differences found in metamizol active metabolites’ pharmacokinetics (P < 0.05) were related to the development of tolerance produced by the combination after repeated doses. This work shows an additional preclinical support for the combination therapy. The clinical utility of this combination in a suitable dose range should be evaluated in future studies.

Plasma concentrations, analgesic and physiological assessments in horses with chronic laminitis treated with two doses of oral tramadol

REASONS FOR PERFORMING STUDY

Laminitis is a painful disease for which adequate pain management remains a challenging and largely unmet medical need.

OBJECTIVES

To investigate plasma concentrations, analgesic and physiological effects of 2 doses of tramadol in horses with chronic laminitis.

STUDY DESIGN

Nonrandomised trial.

METHODS

Four horses with naturally occurring chronic laminitis received 5 mg/kg bwt and then 10 mg/kg bwt tramadol orally every 12 h for one week with a one-week washout between. Noninvasive arterial blood pressure, heart and respiratory rates, intestinal sounds and forelimb off-loading frequency were evaluated before and during treatments. Plasma tramadol and metabolite (M1 and M2) concentrations were measured on predetermined days and times after the morning dosing.

RESULTS

Forelimb off-loading frequency decreased significantly with 10 mg/kg bwt (40%, P = 0.02) but not with 5 mg/kg bwt (9%, P = 0.4). Physiological variables did not change significantly with either treatment. For 5 and 10 mg/kg bwt treatments, respectively, individual maximum plasma concentrations (μg/l) ranged from 329 to 728 and 628 to 1330 (tramadol), 12-24 and 32-80 (M1), and 90-157 and 239-362 (M2). Respective median area under the concentration vs. time curves (h μg/l) were 727 and 1426, 33 and 88, 303 and 1003.

CONCLUSIONS

Twice daily oral tramadol at 10 mg/kg bwt may produce analgesic plasma levels in horses with chronic laminitis.

Advances in exotic mammal clinical therapeutics

It is important that veterinarians treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety, efficacy and welfare issues. Sustained release formulations of commonly used drugs as well as newer routes for administration of therapeutic agents allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded, therefore research studies are warranted regarding potential problems associated with these formulations.

Epigenetics in the perioperative period

The perioperative period is characterized by profound changes in the body's homoeostatic processes. This review seeks to address whether epigenetic mechanisms may influence an individual's reaction to surgery and anaesthesia. Evidence from animal and human studies suggests that epigenetic mechanisms can explain many facets of susceptibility to acute and chronic pain, making them potential therapeutic targets. Modern pain management is still based upon opiates, and both the developmental expression of opioid receptors and opioid-induced hyperalgesia have been linked to epigenetic mechanisms. In general, opiates seem to increase global DNA methylation levels. This is in contrast to local anaesthetics, which have been ascribed a global demethylating effect. Even though no direct investigations have been carried out, the potential influence of epigenetics on the inflammatory response that follows surgery seems a promising area for research. There is a considerable body of evidence that supports the involvement of epigenetics in the complex process of wound healing. Epigenetics is an important emerging research topic in perioperative medicine, with a huge potential to positively influence patient outcome.

Tramadol for postoperative pain treatment in children

BACKGROUND

According to current recommendations a multimodal approach is believed to be the gold standard for postoperative pain treatment in children. However, several surveys in the last few years demonstrated that postoperative pain in children is still a serious problem, mainly because opioids are avoided. One of the reasons for this is the fear of severe adverse events following opioid administration. Tramadol is a weak mu-opioid agonist and inhibits reuptake of noradrenaline and serotonin (5HT). Because of a relatively wide therapeutic window and a ceiling effect with a lower risk for severe adverse events (for example respiratory depression) tramadol is a widely used opioid in children. However, the exact efficacy and occurrence of adverse events following tramadol (in comparison with placebo or other opioids) for postoperative pain treatment in children and adolescents are currently not clear.

OBJECTIVES

To assess the effectiveness and side effect profile of tramadol for postoperative pain relief in children and adolescents undergoing different surgical procedures.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 6), MEDLINE via PubMed (January 1966 to July 2014) and EMBASE via Ovid (January 1947 to July 2014). There were no restrictions regarding language or date of publication. The reference lists of all included trials were checked for additional studies.

SELECTION CRITERIA

All randomised controlled clinical trials investigating the perioperative administration of tramadol compared to placebo or other opioids for postoperative pain treatment in children and adolescents were included.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the study eligibility, performed the data extraction and assessed the risk of bias of included trials.

MAIN RESULTS

Twenty randomised controlled trials involving 1170 patients were included in this systematic review. The overall risk of bias in included trials was assessed as unclear, because concealment of allocation processes and blinding of outcome assessors were poorly described. Due to inconsistent outcome reporting, data from 17 included trials could be pooled for some endpoints only. Eight trials compared tramadol administration with placebo and five trials found that the need for rescue analgesia in the postoperative care unit (PACU) was reduced in children receiving tramadol (RR 0.40; 95% CI 0.20 to 0.78; low quality evidence). Only one trial investigated the number of patients with moderate to severe pain, but a non-validated pain scale was used (very low quality evidence). Four trials compared morphine with tramadol administration. There was no clear evidence of difference in the need for rescue analgesia in the PACU (RR 1.25; 95% CI 0.83 to 1.89; low quality evidence) with tramadol compared with morphine. No trials could be pooled for the outcome 'number of patients with moderate to severe pain'. Three trials were included for the comparison of tramadol with nalbuphine. There was no clear evidence for the need for rescue analgesia in the PACU (RR 0,63; 95% CI 0.16 to 2.45; low quality evidence). Only one trial reported the number of patients with moderate to severe pain, but used a non-validated pain scale (very low quality evidence). Two out of six included trials, which compared pethidine with tramadol, reported the number of children with a need for rescue analgesia within the PACU and showed no clear evidence (RR 0.93; 95% CI 0.43 to 2.02; very low quality evidence). Two trials reported the number of patients with moderate to severe pain and showed a lower RR in patients treated with tramadol (RR 0.64; 95% CI 0.36 to 1.16; low quality evidence). Only one trial was included, which compared tramadol with fentanyl, reporting the number of patients with the need for rescue analgesia (very low quality evidence). Generally, adverse events were poorly reported. Most data could be pooled for the comparison with placebo focusing on the RR for postoperative nausea and vomiting (PONV) in the postoperative care unit and 24 h postoperation. Children treated with tramadol, compared to placebo, did not show clear evidence of benefit for PONV in the postoperative care unit (RR 0.84; 95% CI 0.28 to 2.52; moderate quality evidence) and 24 h postoperation (RR 0.78; 95% CI 0.54 to 1.12; moderate quality evidence).

AUTHORS' CONCLUSIONS

The overall evidence regarding tramadol for postoperative pain in children is currently low or very low and should be interpreted with caution due to small studies and methodological problems (different validated and non-validated pain scales with different pain triggers, missing sample size calculations and missing intention-to-treat analysis). Nevertheless, we demonstrated that tramadol administration might provide appropriate analgesia when compared to placebo; this is based on results showing reduced rescue analgesia in children treated with tramadol compared to placebo. In contrast, the evidence regarding the comparison with other opioids (for example morphine) was uncertain. Adverse events were only poorly reported, so an accurate risk-benefit analysis was not possible.

Postoperative pain management

Postoperative pain is a very important issue for several patients. Indifferent of the surgery type or method, pain management is very necessary. The relief from suffering leads to early mobilization, less hospital stay, reduced hospital costs, and increased patient satisfaction. An individual approach should be applied for pain control, rather than a fix dose or drugs. Additionally, medical, psychological, and physical condition, age, level of fear or anxiety, surgical procedure, personal preference, and response to agents given should be taken into account. The major goal in the management of postoperative pain is minimizing the dose of medications to lessen side effects while still providing adequate analgesia. Again a multidisciplinary team approach should be pursued planning and formulating a plan for pain relief, particularly in complicated patients, such as those who have medical comorbidities. These patients might appear increase for analgesia-related complications or side effects.

A Comparative Study of the Efficacy of IV Dexketoprofen, Lornoxicam, and Diclophenac Sodium on Postoperative Analgesia and Tramadol Consumption in Patients Receiving Patient-Controlled Tramadol

OBJECTIVE

This study was designed to compare the effects of dexketoprofen, lornoxicam, and diclophenac sodium on postoperative analgesia and tramadol consumption in patients receiving postoperative patient-controlled tramadol after a major abdominal surgery.

METHODS

Eighty patients were randomized to receive one of the four study drugs. Patients in group dexketoprofen (DT) received IV 50 mg dexketoprofen, group lornoxicam (LR) received IV 8 mg lornoxicam, group diclophenac sodium (DS) received 75 mg IV diclophenac sodium and group saline (S) received 0.9% saline in 2 mL syringes, 20 min before the end of anaesthesia. A standardized (1 mg kg(-1)) dose of tramadol was routinely administered to all patients as the loading dose at the end of surgery. Postoperatively, whenever patients requested, they were allowed to use a tramadol patient-controlled analgesia device giving a bolus dose (0.2 mg kg(-1)) of tramadol. Pain, discomfort, and sedation scores, cumulative tramadol consumption, supplemental meperidine requirement, and side effects were recorded.

RESULTS

Visual rating scale and patient discomfort scores were significantly lower in DT, LR and DS groups compared to those in in group S (p<0.001). Cumulative tramadol consumption was significantly lower in non-steroidal anti-inflammatory drug (NSAID)-treated groups at each study period after the second postoperative hour than in group S (p<0.001). Supplemental meperidine requirement was significantly higher in group S at each study period after postoperative 30 min than in NSAID-treated groups (p<0.01).

CONCLUSION

After major abdominal surgery, adding IV diclophenac, lornoxicam or dexketoprofen to patient-controlled tramadol resulted in lower pain scores, smaller tramadol consumption, less rescue supplemental analgesic requirement, and fewer side effects compared with the tramadol alone group.

Effect of combining tramadol and morphine in adult surgical patients: a systematic review and meta-analysis of randomized trials

The role for tramadol in multimodal postsurgical analgesic strategies remains unclear. We undertook a systematic review to evaluate the utility of combining tramadol with morphine after surgery. We searched the MEDLINE, EMBASE, LILAC, Cochrane, and Clinical Trial Register databases for randomized, controlled studies comparing tramadol with placebo or active control in patients undergoing surgery. Fourteen studies (713 patients) were included. There was a limited but significant postoperative morphine-sparing effect, with a weighted mean difference (WMD) of -6.9 (95% confidence interval -11.3 to -2.5) mg. This effect was not associated with a decrease in morphine-related adverse effects. No difference in the incidence of nausea, vomiting, sedation, or shivering was observed. There was no decrease in pain intensity at 24 h; the WMD was -0.9 (-7.2; 5.2) on a 100 mm visual analogue scale at 24 h. We found no significant clinical benefit from the combination of i.v. tramadol and morphine after surgery.

Pharmacokinetics of tramadol following intravenous and oral administration in male rhesus macaques (Macaca mulatta)

Recently, tramadol and its active metabolite, O-desmethyltramadol (M1), have been studied as analgesic agents in various traditional veterinary species (e.g., dogs, cats, etc.). This study explores the pharmacokinetics of tramadol and M1 after intravenous (IV) and oral (PO) administration in rhesus macaques (Macaca mulatta), a nontraditional veterinary species. Rhesus macaques are Old World monkeys that are commonly used in biomedical research. Effects of tramadol administration to monkeys are unknown, and research veterinarians may avoid inclusion of this drug into pain management programs due to this limited knowledge. Four healthy, socially housed, adult male rhesus macaques (Macaca mulatta) were used in this study. Blood samples were collected prior to, and up to 10 h post-tramadol administration. Serum tramadol and M1 were analyzed using liquid chromatography-mass spectrometry. Noncompartmental pharmacokinetic analysis was performed. Tramadol clearance was 24.5 (23.4-32.7) mL/min/kg. Terminal half-life of tramadol was 111 (106-127) min IV and 133 (84.9-198) min PO. Bioavailability of tramadol was poor [3.47% (2.14-5.96%)]. Maximum serum concentration of M1 was 2.28 (1.88-2.73) ng/mL IV and 11.2 (9.37-14.9) ng/mL PO. Sedation and pruritus were observed after IV administration.

Tramadol can selectively manage moderate pain in children following European advice limiting codeine use

The European Medicine Agency recommendations limiting codeine use in children have created a void in managing moderate pain. We review the evidence on the pharmacokinetic, pharmacodynamic and safety profile of tramadol, a possible substitute for codeine.

CONCLUSION

Tramadol appears to be safe in both paediatric inpatients and outpatients. It may be appropriate to limit the current use of tramadol to monitored settings in children with risk factors for respiratory depression, subject to further safety evidence.

Evaluation of thermal antinociceptive effects after oral administration of tramadol hydrochloride to American kestrels (Falco sparverius)

OBJECTIVE

To evaluate the thermal antinociceptive and sedative effects and duration of action of tramadol hydrochloride after oral administration to American kestrels (Falco sparverius).

ANIMALS

12 healthy 3-year-old American kestrels.

PROCEDURES

Tramadol (5, 15, and 30 mg/kg) and a control suspension were administered orally in a masked randomized crossover experimental design. Foot withdrawal response to a thermal stimulus was determined 1 hour before (baseline) and 0.5, 1.5, 3, 6, and 9 hours after treatment. Agitation-sedation scores were determined 3 to 5 minutes before each thermal stimulus test.

RESULTS

The lowest dose of tramadol evaluated (5 mg/kg) significantly increased the thermal foot withdrawal thresholds for up to 1.5 hours after administration, compared with control treatment values, and for up to 9 hours after administration, compared with baseline values. Tramadol at doses of 15 and 30 mg/kg significantly increased thermal thresholds at 0.5 hours after administration, compared with control treatment values, and up to 3 hours after administration, compared with baseline values. No significant differences in agitation-sedation scores were detected between tramadol and control treatments.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated oral administration of 5 mg of tramadol/kg significantly increased thermal nociception thresholds for kestrels for 1.5 hours, compared with a control treatment, and 9 hours, compared with baseline values; higher doses resulted in less pronounced antinociceptive effects. Additional studies with other types of stimulation, formulations, dosages, routes of administration, and testing times would be needed to fully evaluate the analgesic and adverse effects of tramadol in kestrels and other avian species.

Tramadol toxicity in a cat: case report and literature review of serotonin syndrome

OVERVIEW

Tramadol toxicity has not previously been reported in a cat.

CASE SUMMARY

This report describes the clinical signs, diagnosis and treatment of tramadol toxicity, manifesting as serotonin syndrome, in a cat in Australia.

PRACTICAL RELEVANCE

For any cat with suspicion of serotonin syndrome, in particular secondary to tramadol overdose, it is recommended that decontamination, monitoring and supportive care are instituted as soon as clinical signs develop. Prolonged hospitalisation may be required in the event of a severe overdose.

LITERATURE REVIEW

The literature relating to the pharmacology of tramadol and tramadol overdose, clinical manifestations of tramadol overdose, and serotonin syndrome in cats, humans and dogs is reviewed. Recommended treatment for tramadol overdose and serotonin syndrome is also discussed.

Peripheral synergism between tramadol and ibuprofen in the formalin test

Preclinical Research Analgesics with different mechanisms of action can be combined in order to obtain pharmacological synergism, employing lower doses of each agent, thus diminishing side effects. For instance, an atypical dual analgesic such as tramadol (TMD) and a nonsteroidal anti-inflammatory drug such as ibuprofen (IBU) are good candidates to be evaluated when combined and applied peripherally. The present study was conducted to evaluate possible local synergism between TMD and IBU when combined peripherally using the formalin test in rats. The effects of the individual analgesics and their combinations were evaluated simultaneously using a 5% formalin dilution. Dose-effect curves were determined for TMD (50-400 μg/paw) and IBU (1-100 μg/paw). Experimental effective doses were evaluated and isobolographic analyses were constructed to evaluate TMD-IBU combination synergism. Both drugs produced a dose-dependent analgesic effect when applied separately. Isobolographic analysis showed synergism during phase 1 (0-10 min) and phase 2 (15-60 min) when compared with theoretical doses (P < 0.05), with interaction indexes of 0.06 and 0.09, respectively. The present information supports the peripheral analgesic effect of TMD and IBU, especially when combined at appropriate doses.

Pharmacokinetics of tramadol after subcutaneous administration in a critically ill population and in a healthy cohort

Background

Tramadol is an atypical centrally acting analgesic agent available as both oral and parenteral preparations. For patients who are unable to take tramadol orally, the subcutaneous route of administration offers an easy alternative to intravenous or intramuscular routes. This study aimed to characterise the absorption pharmacokinetics of a single subcutaneous dose of tramadol in severely ill patients and in healthy subjects.

Methods/design

Blood samples (5 ml) taken at intervals from 2 minutes to 24 hours after a subcutaneous dose of tramadol (50 mg) in 15 patients (13 male, two female) and eight healthy male subjects were assayed using high performance liquid chromatography. Pharmacokinetic parameters were derived using a non-compartmental approach.

Results

There were no statistically significant differences between the two groups in the following parameters (mean ± SD): maximum venous concentration 0.44 ± 0.18 (patients) vs. 0.47 ± 0.13 (healthy volunteers) mcg/ml (p = 0.67); area under the plasma concentration-time curve 177 ± 109 (patients) vs. 175 ± 75 (healthy volunteers) mcg/ml*min (p = 0.96); time to maximum venous concentration 23.3 ± 2 (patients) vs. 20.6 ± 18.8 (healthy volunteers) minutes (p = 0.73) and mean residence time 463 ± 233 (patients) vs. 466 ± 224 (healthy volunteers) minutes (p = 0.97).

Conclusions

The similar time to maximum venous concentration and mean residence time suggest similar absorption rates between the two groups. These results indicate that the same dosing regimens for subcutaneous tramadol administration may therefore be used in both healthy subjects and severely ill patients.

Trial registration

ACTRN12611001018909

High-amylose sodium carboxymethyl starch matrices: development and characterization of tramadol hydrochloride sustained-release tablets for oral administration

Substituted amylose (SA) polymers were produced from high-amylose corn starch by etherification of its hydroxyl groups with chloroacetate. Amorphous high-amylose sodium carboxymethyl starch (HASCA), the resulting SA polymer, was spray-dried to obtain an excipient (SD HASCA) with optimal binding and sustained-release (SR) properties. Tablets containing different percentages of SD HASCA and tramadol hydrochloride were produced by direct compression and evaluated for dissolution. Once-daily and twice-daily SD HASCA tablets containing two common dosages of tramadol hydrochloride (100 mg and 200 mg), a freely water-soluble drug, were successfully developed. These SR formulations presented high crushing forces, which facilitate further tablet processing and handling. When exposed to both a pH gradient simulating the pH variations through the gastrointestinal tract and a 40% ethanol medium, a very rigid gel formed progressively at the surface of the tablets providing controlled drug-release properties. These properties indicated that SD HASCA was a promising and robust excipient for oral, sustained drug-release, which may possibly minimize the likelihood of dose dumping and consequent adverse effects, even in the case of coadministration with alcohol.

Lornoxicam versus tramadol for post-operative pain relief in patients undergoing ENT procedures

Background:

Pain following ear-nose and throat surgery is one of the most important complaints for which, several drugs are used. This prospective, randomized, double-blind controlled trial was designed to compare the analgesic effect of tramadol versus lornoxicam for post-operative pain relief in patients undergoing ENT surgical procedures.

Methods:

One hundred and twenty patients of ASA class I-II, who had undergone elective ENT surgical procedures under general anesthesia, were assigned in a randomized manner into three equal groups. Group L received lornoxicam8 mg IV, Group T received tramadol 1 mg/kg IV and Group C received IV saline after induction of anesthesia before the start of the surgery. Post-operative pain was assessed using the visual analogue scale (VAS) and sedation level was evaluated during stay in the post-anesthesia care unit with a four-point sedation scale. Intraoperative blood loss was estimated using the Five-Point Scale. Adverse events in the first 24 h post-operative were recorded.

Results:

The VAS pain scores were significantly higher in Group C as compared with those in Groups L and T at 30 min and 1, 2, 4and 6 h post-operatively, with no significant difference between Group L and Group T. The amount of morphine consumption post-operatively was significantly lower in Group L (5.2 ± 2.5 mg) and Group T (5.0 ± 2.0 mg) as compared with that in Group C (7.4 ± 2.3 mg) (P = 0.001). The time for the first analgesic requirement was significantly less in Group L (92.62 ± 24.23 min) and Group T (88 ± 21.43 min) as compared with that in Group C (42.82 ± 25.61 min), with no significant difference between the other two groups. Estimated intraoperative blood loss score by the surgeons showed no significant difference between the three groups. The most frequent side-effects in the three groups were nausea and vomiting, and their incidence was significantly higher in the placebo group as compared with the other two groups.

Conclusion:

Tramadol 1 mg/kg was comparable to lornoxicam 8 mg for post-operative pain relief in patients undergoing ENT surgical procedures; both drugs helped to reduce the post-operative opioid requirement and consequently minimized the related adverse effects of the opioids.

Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C NMR) investigations of O-desmethyltramadol hydrochloride an active metabolite in tramadol--an analgesic drug

O-desmethyltramadol is one of the main metabolites of tramadol widely used clinically and has analgesic activity. The FTIR and FT-Raman spectra of O-desmethyl tramadol hydrochloride are recorded in the solid phase in the regions 4000-400 cm(-1) and 4000-100 cm(-1), respectively. The observed fundamentals are assigned to different normal modes of vibration. Theoretical studies have been performed as its hydrochloride salt. The structure of the compound has been optimised with B3LYP method using 6-31G(**) and cc-pVDZ basis sets. The optimised bond length and bond angles are correlated with the X-ray data. The experimental wavenumbers were compared with the scaled vibrational frequencies determined by DFT methods. The IR and Raman intensities are determined with B3LYP method using cc-pVDZ and 6-31G(d,p) basic sets. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/cc-pVDZ method to display electrostatic potential (electron+nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of O-desmethyltramadol hydrochloride has been performed to indicate the presence of intramolecular charge transfer. The (1)H and (13)C NMR chemical shifts of the molecule have been anlysed.