Tramadol--present and future

Comparison of patient-controlled analgesia versus continuous infusion of tramadol in post-cesarean section pain management

AIM

To evaluate and compare analgesic efficacy, drug consumption and patient satisfaction with the i.v. patient-controlled and continuous infusion modes of administration of tramadol.

METHODS

A total of 40 pregnant women in American Society of Anesthesiologists physical status classification system risk classes I-II scheduled for cesarean section were randomized into two groups to receive treatment in single-blind fashion. Patients in both groups received tramadol as an i.v. infusion 15 min before the end of surgery under general anesthesia for cesarean section. In the post-anesthesia care unit, the 20 patients allocated to group I were given i.v. tramadol in patient-controlled anesthesia (PCA), while the 20 other patients assigned to group II received it as a continuous infusion. Pain visual analog scores (VAS), mean arterial pressure (MAP), heart rate, total tramadol consumption, sedation scores, side-effects (nausea/vomiting) and patient satisfaction were evaluated seven times in the course of the first postoperative 24 h. The Mann-Whitney U-test and Friedman's anova were used for the statistical treatment of data.

RESULTS

VAS, sedation scores and nausea/vomiting scores were similar in both groups (P > 0.05). The 24-h tramadol consumption was significantly lower in group I (420.15 ± 66.58 mg) than in group II (494.00 ± 29.45 mg), while patient satisfaction was significantly higher in group I (P < 0.05).

CONCLUSION

While tramadol administration by either of the methods used may ensure efficient early postoperative anesthesia in cesarean section patients, i.v. PCA may be preferred because of the lower drug consumption and higher patient satisfaction associated with it.

Comparison of local anesthetic efficacy of tramadol hydrochloride (with adrenaline) versus plain tramadol hydrochloride in the extraction of upper molar teeth

PURPOSE

To evaluate the efficacy of local anesthesia using tramadol hydrochloride (HCl) with versus without adrenaline in the extraction of upper molar teeth.

PATIENTS AND METHODS

This was a double-blinded study that included 100 patients who required extraction of 1 upper molar by the conventional method and were allocated randomly into 1 of 2 groups: in group A (n = 50), each patient received an initial dose of drug A (tramadol HCl 50 mg and adrenalin 0.0225 mg diluted to 1.8 mL by distilled water); in group B (n = 50), each patient received an initial dose of drug B (tramadol HCl 50 mg diluted to 1.8 mL by distilled water). Degree of pain during tooth extraction, duration of surgery, and total number of cartridges used were recorded intraoperatively. Postoperatively, patients were instructed to record any adverse effects, such as nausea or vomiting, on the first day of the operation.

RESULTS

There were significant differences in the number of cartridges used and the degree of intraoperative pain. However, there was no significant difference in duration of surgery or side effects.

CONCLUSIONS

The results of this study suggest that tramadol HCl in combination with adrenaline can be used as an alternative local anesthetic in oral and maxillofacial surgery when, for some unusual reason, a patient cannot receive a conventional local anesthetic.

Tramadol Extended-Release for the Management of Pain due to Osteoarthritis

Current knowledge on pathogenesis of osteoarticular pain, as well as the consequent several, especially on the gastrointestinal, renal, and cardiovascular systems, side effects of NSAIDs, makes it difficult to perform an optimal management of this mixed typology of pain. This is especially observable in elderly patients, the most frequently affected by osteoarthritis (OA). Tramadol is an analgesic drug, the action of which has a twofold action. It has a weak affinity to mu opioid receptors and, at the same time, can result in inhibition of the reuptake of noradrenaline and serotonin in nociceptorial descending inhibitory control system. These two mechanisms, "opioidergic" and "nonopioidergic," are the grounds for contrasting certain types of pain that are generally less responsive to opioids, such as neuropathic pain or mixed OA pain. The extended-release formulation of tramadol has good efficacy and tolerability and acts through a dosing schedule that allows a high level of patients compliance to therapies with a good recovery outcome for the patients' functional status.

Preemptive subcutaneous tramadol for post-operative pain in lower abdomen surgeries: A randomized double blinded placebo-control study

Background:

Recently, the preemptive analgesic effects of subcutaneous infiltration of tramadol (T) in the site of incision have not been extensively studied. In this study, we investigated the effect of subcutaneous T infiltration before the incision of surgery on post-operative pain, in lower abdomen surgeries.

Materials and Methods:

This double-blind study was carried out on 90 patients (18-65 years) of American Society Anesthesiologists physical status I and II who were candidates for a lower abdomen surgery during 2011. They were randomly assigned to receive preemptive subcutaneous T or normal saline (NS). The visual analogue scale for pain (VAS) in rest and cough position and opium total dose consumption were compared between two groups in times 0, 15, 30, 60 min and 2, 4, 6, 12, 24 h after the surgery.

Results:

The VAS in cough and rest position in the first 24 h following the surgery was lower in group T (P < 0.05). Opium consumption was lower in group T (P < 0.05).

Conclusion:

Subcutaneous preemptive infiltration of T before surgical incision reduces post-operative opioid consumption.

Tramadol/Paracetamol fixed-dose combination for chronic pain management in family practice: a clinical review

The family practitioner plays an important role in the prevention, diagnosis, and early management of chronic pain. He/she is generally the first to be consulted, the one most familiar with the patients and their medical history, and is likely the first to be alerted in case of inadequate pain control or safety and tolerability issues. The family practitioner should therefore be at the center of the multidisciplinary team involved in a patient's pain management. The most frequent indications associated with chronic pain in family practice are of musculoskeletal origin, and the pain is often multimechanistic. Fixed-dose combination analgesics combine compounds with different mechanisms of action; their broader analgesic spectrum and potentially synergistic analgesic efficacy and improved benefit/risk ratio might thus be useful. A pain specialist meeting held in November 2010 agreed that the fixed-dose combination tramadol/paracetamol might be a useful pharmacological option for chronic pain management in family practice. The combination is effective in a variety of pain conditions with generally good tolerability. Particularly in elderly patients, it might be considered as an alternative to conventional analgesics such as NSAIDs, which should be used rarely with caution in this population.

Comparison of peritonsillar infiltration of tramadol and lidocaine for the relief of post-tonsillectomy pain

BACKGROUND

Several studies have reported the use of peritonsillar infiltrations of local anaesthetics and/or locally active analgesic drugs for the relief of post-tonsillectomy pain, with variable results in terms of quality and duration of analgesia. We aimed to compare the effects of peritonsillar infiltration of lidocaine versus tramadol versus placebo on post-tonsillectomy pain.

METHODS

Sixty patients over the age of 10 years undergoing bilateral elective tonsillectomy under general anaesthesia were randomised into three groups. The first group received peritonsillar infiltration of tramadol, the second 2 per cent lidocaine and the third normal saline. In all groups, peritonsillar infiltration was carried out after tonsillectomy but prior to tracheal extubation. Post-operative comparisons were made to assess the quality of pain control and the patients' analgesic requirements.

RESULTS

Peritonsillar infiltration of tramadol provided an analgesic effect comparable to that of lidocaine in the first 6 hours post-operation, as reflected by visual analogue scale pain scores and opioid requirements, which were lower compared with the placebo group.

CONCLUSION

Peritonsillar infiltration of tramadol provided pain control in the first 6 hours post-tonsillectomy which was comparable to that of lidocaine.

The comparison of intraincisional injection tramadol, pethidine and bupivacaine on postcesarean section pain relief under spinal anesthesia

Background:

Bupivacaine, tramadol, and pethidine has local anesthetic effect. The aim of this study was to compare effect of subcutaneous (SC) infiltration of tramadol, pethidine, and bupivacaine on postoperative pain relief after cesarean delivery.

Materials and Methods:

120 patient, scheduled for elective cesarean section under spinal anesthesia, were randomly allocated to 1 of the 4 groups according to the drugs used for postoperative analgesia: Group P (Pethidine) 50 mg ,Group T (Tramadol) 40 mg, Group B (Bupivacaine 0.25%) 0.7 mg/kg, and Group C (control) 20CC normal saline injection in incision site of surgery. Pain intensity (VAS = visual analogous scale) at rest and on coughing and opioid consumption were assessed on arrival in the recovery room, and then 15, 30, 60 minutes and 2, 6, 12, 24 hours after that.

Results:

VAS scores were significantly lower in groups T and P compared with groups B and C except for 24 hours (VAS rest) and 6 hours (VAS on coughing) postoperatively (P < 0.05). The number of patients requiring morphine were significantly different between the groups (105 doses vs. 87, 56, 46, doses for group C, B, T and P, respectively, P < 0.05) in all the times, except for 2 and 6 hours postoperatively.

Conclusions:

The administration of subcutaneous pethidine or tramadol after cesarean section improves analgesia and has a significant morphine-sparing effect compared with bupivacaine and control groups.

Recurrent seizures in tramadol intoxication: implications for therapy based on 100 patients

Tramadol is an atypical opioid analgesic used in the treatment of mild to moderate pain. Despite being a GABA(A) agonist, seizures are a prominent complication with its therapeutic use, abuse or overdose. For patients who have had a tramadol-induced seizure, the likelihood of recurrent seizures and the need for emergent anticonvulsant prophylaxis is unknown. However, treatment of patients with anticonvulsants prophylactically may cause adverse effects and increased morbidity in tramadol poisoning. We studied the outcome and frequency of recurrent seizures in tramadol-intoxicated patients in an attempt to determine the need for prophylactic anticonvulsant therapy. This was a retrospective cohort study of tramadol-intoxicated patients who had at least one seizure. Patients' age, sex, cause(s) of intoxication, route of poisoning, dose or number of capsules or tablets taken, vital signs, other signs or symptoms, numbers of seizures, length of stay, co-ingestions and past medical history were ascertained. Exactly 100 patients met the inclusion criteria. Eighty-two per cent were men, and 50% were between 21 and 30 years old. By our standard clinical protocol, none were treated with seizure prophylaxis after their first seizure. Only 7% had recurrent seizures and all patients recovered without sequelae. Because of the low risk of multiple seizures in tramadol poisoning and the lack of morbidity in patients who do seize, it appears to be unnecessary to administer prophylactic anticonvulsant therapy in patients with tramadol poisoning, even if they have an initial seizure.

Striking differences in proconvulsant-induced alterations of seizure threshold in two rat models

During drug development, seizure threshold tests are widely used to identify potential proconvulsant activity of investigational drugs. The most commonly used tests in this respect are the timed intravenous pentylenetetrazole (PTZ) infusion seizure test and the maximal electroshock seizure threshold (MEST) test in mice or rats. To our knowledge, no study is available in which proconvulsant drug activities in these models are directly compared, which prompted us to perform such experiments in male Wistar rats. Five drugs with reported proconvulsant activity were tested in the two models: d-amphetamine, chlorpromazine, caffeine, theophylline, and tramadol. Furthermore, the anticonvulsant drug phenobarbital was included in the experiments. While phenobarbital exerted anticonvulsant activity in both models, the five proconvulsant drugs markedly differed in their effects. In the dose range tested, d-amphetamine significantly lowered the PTZ seizure threshold but increased the MEST, caffeine and theophylline did not alter the PTZ seizure threshold but decreased the MEST, and tramadol reduced the PTZ threshold but increased the MEST. These marked differences between seizure threshold tests are most likely a consequence of the mechanisms underlying seizure induction in these tests. Our data indicate that using only one seizure threshold model during preclinical drug development may pose the risk that potential proconvulsant activity of an investigational drug is overseen. However, the label "proconvulsant" may be misleading if such activity only occurs at doses high above the therapeutic range, but the drug is not proconvulsant or even exerts anticonvulsant effects at lower, therapeutically relevant doses.

Epileptic seizure following IV tramadol in a patient with mental retardation and cerebellar ataxia

OBJECTIVE

To present a case of an epileptic seizure related to intravenous (IV) tramadol for pain control following a total abdominal hysterectomy operation on a patient with mental retardation and cerebellar ataxia.

BACKGROUND

Tramadol is an analgesic with a dual mechanism of action and has several side effects, one of which is epileptic seizure.

CASE REPORT

A 42-year-old female with mental retardation and cerebellar ataxia presented with an epileptic seizure after administration of IV tramadol for postoperative pain. Magnetic resonance imaging scans were normal, but laboratory tests showed hypocalcemia. Next, calcium replacement was administered. Postoperative pain treatment with tramadol was discontinued because tramadol was felt to be a possible cause of the seizure observed in this patient. In order to treat the epileptic seizure, IV phenytoin sodium infusion was started. On the second postoperative day, calcium levels were found to be normal, and the IV antiepileptic medication was changed to an oral form. The patient had no subsequent seizures during the clinical follow-up. She was discharged on the fourth postoperative day without any other complications.

CONCLUSION

Even in recommended doses, IV tramadol may cause epileptic seizures on predisposed patients.

Serotonin syndrome induced by tramadol intoxication in an 8-month-old infant

Severe cases of pediatric tramadol intoxication are rarely reported. We report on serotonin syndrome after tramadol intoxication. An 8-month-old girl developed extreme agitation after accidentally ingesting a tablet of her father's medication (Monocrixo LP (Thérabel Lucien Pharma, Levallois Perret, France), 200 mg tramadol). Unable to sleep, she was admitted the next morning to our Pediatric Emergency Department after an episode of epistaxis. Vital signs were significant for sinus tachycardia and a neurologic examination revealed intermediately reactive pupils, agitation alternating with drowsiness with a Glasgow Coma Scale of 10, and increased lower-limb reflexes. Within 24 hours, she developed hyperthermia and high blood pressure. She did not experience seizures. Neurologic and cardiovascular effects resolved on day 2. Tramadol serum plasma levels confirmed the intoxication (680 μg/L). She was discharged on day 5 with no sequelae. Serotonin syndrome was described in adults when tramadol was associated with selective serotonin-reuptake inhibitors in contexts of therapy or intoxication. Our patient developed moderate serotonin syndrome. The clinical presentation was unusual compared with previous pediatric cases of tramadol intoxication, in which opioid effects and seizures were usually predominant. This case illustrates that serotonin syndrome can occur in children intoxicated with tramadol.

Review: Pharmacogenetic aspects of the effect of cytochrome P450 polymorphisms on serotonergic drug metabolism, response, interactions, and adverse effects

The field of pharmacogenetics contains a wealth of potential for the enhancement of clinical practice by providing a more effective match between patient and drug, consequently reducing the probability of an adverse drug reaction. Although a relatively novel concept in the forensic context, pharmacogenetics has the capability to assist in the interpretation of drug related deaths, particularly in unintentional drug poisonings where the cause of death remains unclear. However, the complex pharmacology of the drugs when subjected to genetic variations in metabolism makes interpretation of the expected response and adverse events difficult. Many possess multiple metabolic pathways, narrow therapeutic indices and active metabolites or enantiomers which may be eliminated via different pathways to the parent drug. A number of these drugs, which are metabolised primarily by the CYP450 system, are also associated with serotonin syndrome, or serotonin toxicity, especially when used concomitantly with other serotonin active drugs which rely on the same metabolic pathways for drug elimination. A comprehensive understanding of polymorphic drug metabolism and its expected outcomes is therefore essential when interpreting the involvement of drugs in adverse reactions. This review examines the genetically variable CYP450-mediated metabolism of a number of serotonin-active drugs that are often implicated in cases of serotonin toxicity, to assess the impact of pharmacogenetics on drug metabolism, response, interactions and adverse effects.

Compatibility and stability of ternary admixtures of tramadol, haloperidol, and hyoscine N-butyl bromide: retrospective clinical evaluation

BACKGROUND

Combination of drugs for subcutaneous infusion is common practice in palliative medicine, however, there is no information pertaining to the compatibility and stability of tramadol combined in ternary admixtures and no information exists regarding its clinical performance.

METHODS

Tramadol hydrochloride, haloperidol lactate, and hyoscine N-butyl bromide have been examined for compatibility and stability when combined in solution under conditions mimicking their potential use via subcutaneous infusion in terminal oncology patients. Concentration ranges were 8.8-33.3 mg/mL, 0.208-0.624 mg/mL, and 3.33-6.67 mg/mL for tramadol hydrochloride, haloperidol lactate, and hyoscine N-butyl bromide. With these, 27 different admixtures were prepared and stored at 25 degrees C using 0.9% saline as diluent. Quantification was performed by high-performance liquid chromatography (HPLC). The clinical performance of the admixture was retrospectively assessed in 28 terminal oncology patients exhibiting Karnofsky's indexes of 10%-20%.

RESULTS

All three drugs were very stable (>92%) at 25 degrees C for 15 days. Pain was completely controlled in all patients. Fifty percent of the patients suffered from 3-5 vomiting episodes per day and of these, 75% experienced complete control of the episodes. None of the patients showed local reactions after subcutaneous administration of the admixture.

RESULTS

Our results confirm the compatibility and stability of the ternary admixture and its utility in highly vulnerable patients exhibiting moderate symptoms.

Preoperative tramadol combined with postoperative small-dose tramadol infusion after total abdominal hysterectomy: a double-blind, randomized, controlled trial

This double blind, randomized, controlled trial investigated whether a single preoperative intravenous (iv) dose of tramadol (100 mg) given 30 min before abdominal hysterectomy resulted in improved analgesic efficacy, reduced postoperative morphine patient-controlled analgesia (PCA) use and reduced side effects when combined with a postoperative small-dose tramadol infusion. Two-hundred twenty-four patients undergoing elective abdominal hysterectomy were randomly allocated to one of two groups: the tramadol group (n = 113) received iv tramadol (100 mg) 30 min before surgery, and the control group (n = 111) received an equivalent volume of normal saline. Upon awakening from general anesthesia, all patients received a loading dose of 0.5 mg/kg of tramadol and a small-dose infusion of tramadol (0.1 mg/kg/h) for 48 h. In addition, all patients were connected to morphine PCA delivering a morphine bolus of 0.02 mg/kg with a 6-min lock-out. Data on pain intensity at rest and during movement, morphine consumption, side-effects and overall patient satisfaction were recorded. A total of 189 patients completed the study. Preemptive tramadol was associated with superior analgesia at rest and with movement in the first 24 h after surgery (p < 0.01), a longer interval to first morphine PCA request (p = 0.019), and reduced morphine PCA use (p = 0.017). The tramadol group had reduced nausea (p = 0.015), dizziness (p = 0.001) and drowsiness (p = 0.0001), while other side-effects were similar. In conclusion, a single dose of iv tramadol (100 mg) 30 min prior to abdominal hysterectomy improves analgesia, and reduces morphine PCA requirements, nausea, dizziness and drowsiness when combined with a postoperative small-dose tramadol infusion and morphine PCA when compared to the same analgesic regimen that omitted the preemptive tramadol.

Tramadol dependence: a survey of spontaneously reported cases in Sweden

BACKGROUND

Tramadol is a weak opioid analgesic, which is generally considered to be safe. However, conflicting data exist on the dependence potential of tramadol.

OBJECTIVE

The aim of this study was to investigate occurrence of tramadol dependence and associated risk factors using spontaneously reported adverse drug reactions.

METHODS

The Swedish database for spontaneously reported adverse drug reactions, Swedish Drug Information System (SweDIS), was searched for reports on tramadol dependence from 1 January 1995 until 31 December 2006. Selection was conducted based on the DSM-IV definition of dependence. Available information was scrutinised and registered and then presented descriptively.

RESULTS

A total of 104 reports of tramadol dependence were identified, of which 60 (58%) concerned women. The median age (range) was 45 (15-84) years. Information on a history of substance abuse was present in 31 patients (30%) and 41 patients (39%) had a documented past or current use of a drug of abuse. Prescribed doses of tramadol ranged between 50-800 mg/day, and ingested doses between 50-4000 mg/day. Time of onset ranged from some weeks up to 4 years. In 72 (69%) cases the reaction was classified as serious, mainly due to hospitalisations for detoxification or discontinuation of tramadol.

CONCLUSIONS

There is an occurrence of tramadol dependence in association with analgesic treatment within the recommended dose range. In susceptible patients a severe and serious dependence syndrome may develop. A history of abuse or use of a drug of abuse seems to be an important risk factor.

Spectral characteristics of tramadol in different solvents and beta-cyclodextrin

Effect of solvents and beta-cyclodextrin on the absorption and fluorescence spectra of tramadol drug has been investigated and compared with anisole. The solid inclusion complex of tramadol with beta-CD is investigated by FT-IR, (1)H NMR, scanning electron microscope (SEM), DSC and semiempirical methods. The thermodynamic parameter (DeltaG) of inclusion process is determined. A solvent study shows (i) the spectral behaviour of both tramadol and anisole molecules is similar to each other and (ii) the cyclohexanol group in tramadol is not effectively conjugated with anisole group. However, in beta-CD, due to space restriction of the CD cavity, a weak interaction is present between the above groups in tramadol. beta-Cyclodextrin studies show that tramadol forms 1:2 inclusion complex with beta-CD. A mechanism is proposed for the inclusion process.

Dose-independent occurrence of seizure with tramadol

INTRODUCTION

Tramadol, as a centrally-acting, opioid-like analgesic with serotonin reuptake inhibition property, is one of the most prescribed analgesics in the world. We assessed the incidence of seizure, as it is one of the most important adverse effects.

METHODS

In a cross-sectional study, 215 cases of tramadol users or abusers who were admitted to Loghman-Hakim Hospital Poisoning Center (LHHPC) in Tehran during a 5-month period, from April 2007 to September 2007, were assessed to evaluate the occurrence of seizure. Patients with positive history of co-ingestion of other drugs, addiction, convulsive disorders, renal diseases, or head trauma with abnormal electroencephalography (EEG) or computerized tomography (CT) scan of the brain were excluded, thus 132 patients were included in the study. For patients who had seizure, CT scan of the brain and EEG were performed, and frequency and type of seizure were identified. Mean tramadol dose was compared between patients with and without seizure.

RESULTS

Among the patients, 97 (73.5%) were male. Seizure occurred in 61 patients (46.2%) within 24 hours after tramadol ingestion. The majority of patients who had seizure were male (male, 83.6% vs. female, 16.4%). Mean tramadol dose was lower among females than males (males, 2413 mg vs. females, 1706 mg), but the difference was not statistically significant. Of 35 patients with documented seizure type, all showed generalized tonic-clonic seizure and 12 patients had abnormal EEG (35.3%). No statistically significant difference was observed in mean tramadol intake between patients with or without seizure. Analysis of patients with seizure, according to tramadol intake, indicated that most patients used tramadol in the dose range of 500-1000 mg followed in occurrence by 1500-2000 mg, then 100-500 mg, 2500-3000 mg, and 3500-4000 mg.

CONCLUSIONS

Mean tramadol intake does not differ between patients with and without seizure, and the most common dose range in those with seizure is 500-1000 mg. We thus conclude that the incidence of seizure with tramadol is not dose dependent.

Subcutaneous Tramadol Infiltration at the Wound Site Versus Intravenous Administration after Pyelolithotomy

Background:

Recently, the peripheral anesthetic effect of tramadol has been the theme of many studies. The postoperative analgesic effects of subcutaneous wound infiltration with tramadol have not been extensively studied and compared with those of intravenous administration.

Objective:

To compare the therapeutic effects and complications of intravenous versus local wound infiltration of using tramadol following pyelolithotomy.

Methods:

This double-blind study was carried out on 60 patients (age 18–60 y) of American Society of Anesthesiologists physical status I–II who were awaiting pyelolithotomy in Sina Hospital, Tehran, Iran, during 2006 and 2007. They were randomly assigned to receive intravenous or subcutaneous wound infiltration with tramadol. Vital signs, the intensity of pain (visual analog scale), and the level of consciousness (Ramsey Sedation Scale [RSS]), as well as the frequency of nausea and vomiting were recorded during 30 minutes to 1 hour after the patient entered the recovery room. Vital signs were also recorded every hour until 6 hours postoperatively and then on the day after the patient was transferred to the ward.

Results:

The RSS was lower in patients who had received subcutaneous infiltration of tramadol (p < 0.001). A significant difference was noted in the severity of pain between the groups; it was higher in the group that received intravenous tramadol. The average time for the first meperidine requirement was 45.2 ±8.4 min (mean ± SD) in the subcutaneous group and 21.6 ± 12.4 min in the intravenous group. Total meperidine consumption was lower in patients who had received subcutaneous wound infiltration with tramadol compared with those who had received intravenous tramadol (p < 0.001). Nausea and vomiting were more frequent during the first hour of recovery; the complication, however, was less frequent in the subcutaneous group.

Conclusions:

Subcutaneous wound infiltration with tramadol reduces postoperative opioid consumption and produces less nausea and vomiting than does intravenous administration.

Tramadol intoxication: a review of 114 cases

Tramadol as a centrally acting analgesic is extensively used in the management of moderate to severe pain. It slightly affects opioid receptors and inhibits the reuptake of norepinephrin and serotonin in the CNS. There are reports about toxicity and abuse of tramadol. The objective of the present study was to evaluate epidemiology of intentional tramadol intoxications. All poisoning cases that admitted to Loghman-Hakim Hospital Poison Center from April to May 2007 were studied. A total of 114 cases (82 men and 32 women) of intentional tramadol intoxications with the median age of 23.66 +/- 6.87 years (range 16-54 years) were identified. Other illicit drugs were found to be used in combination with tramadol in some of the cases, which among them benzodiazepines were the most common. Tramadol overdose has been one of the most frequent causes of drug poisoning in the country in the recent years, especially in male young adults with history of substance abuse and mental disorders. Nausea, vomiting, Central Nervous System (CNS) depression, tachycardia, and seizure are the most common findings in this kind of poisoning. Cardiopulmonary arrest was found as the cause of death in cases who had ingested more than 5000 mg tramadol.

Cancer pain and analgesia

Pain ranges in prevalence from 14-100% among cancer patients and occurs in 50-70% of those in active treatment. Cancer pain may result from direct invasion of tumor into nerves, bones, soft tissue, ligaments, and fascia, and may induce visceral pain through distension and obstruction. Cancer pain is multifaceted. Clinicians may describe cancer pain as acute, chronic, nociceptive (somatic), visceral, or neuropathic. Despite implementation of the WHO guidelines, reports of undertreatment of cancer pain persist in various clinical settings and in spite of decades of work to reduce unnecessary discomfort. Substantial obstacles to adequate pain relief with opioids include specific concerns of patients themselves, their family members, physicians, nurses, and the healthcare system. The WHO analgesic ladder serves as the mainstay of treatment for the relief of cancer pain in concert with tumoricidal, surgical, interventional, radiotherapeutic, psychological, and rehabilitative modalities. This multidimensional approach offers the greatest potential for maximizing analgesia and minimizing adverse effects. Primary therapies are directed at the source of the cancer pain and may enhance a patient's function, longevity, and comfort. Adjuvant therapies include nonopioids that confer analgesic effects in certain medical conditions but primarily treat conditions that do not involve pain. Nonopioid medications (over-the-counter agents) are useful in the management of mild to moderate pain, and their continuation through step 3 of the WHO ladder is an option after weighing a drug's risks and benefits in individual patients. Symptomatic treatment of severe cancer pain should begin with an opioid, regardless of the mechanism of the pain. They are very effective analgesics, titrate easily, and offer a favorable risk/benefit ratio. Cancer pain remains inadequately controlled despite the diagnostic and therapeutic means of ensuring that patients feel comfortable during their illness. Therefore, all practitioners need to make control of cancer pain a professional duty, even if they can only use the most basic and least expensive analgesic medications, such as morphine, codeine, and acetaminophen, to reduce human suffering.

Respiratory depression with tramadol in a patient with renal impairment and CYP2D6 gene duplication

We observed opioid-related respiratory depression in a patient receiving tramadol via patient-controlled analgesia. Predisposing factors were the patient's genetic background and renal impairment. Complete recovery occurred after naloxone administration, thus confirming opioid intoxication. Analysis of the patient's genotype revealed a CYP2D6 gene duplication resulting in ultra-rapid metabolism of tramadol to its active metabolite (+)O-desmethyltramadol. Concomitant renal impairment resulting in decreased metabolite clearance enhanced opioid toxicity. This genetic CYP2D6 variant is particularly common in specific ethnic populations and should be a future diagnostic target whenever administration of tramadol or codeine is anticipated, as both drugs are subject to a comparable CYP2D6-dependent metabolism.

Analgesia best practice after cardiac surgery

Sources of pain after cardiac surgery include sternotomy, rib retraction, conduit harvest, and drain tubes sites. An analgesic regimen should consider individual patient characteristics, including age, preoperative history of pain and response to analgesics, comorbidities, and psychologic state. Intraoperative and postoperatively administered opioids remain the mainstay of therapy, but adjunctive analgesics such as paracetamol, nonsteroidal anti-inflammatory drugs and tramadol, and regional techniques, can reduce opioid consumption and opioid-induced respiratory depression. This may facilitate earlier tracheal extubation, mobilization, and recovery.

Intraarticular tramadol-bupivacaine combination prolongs the duration of postoperative analgesia after outpatient arthroscopic knee surgery

BACKGROUND

Intraarticular (IA) local anesthetics are often used for the management and prevention of pain after arthroscopic knee surgery. Recently, IA tramadol was also used for the management of these patients. However, the IA combination of local anesthetic and tramadol has not been evaluated in arthroscopic outpatients. Our primary aim in this study was to evaluate the analgesic effect of an IA combination of bupivacaine and tramadol when compared with each drug alone using visual analog scale (VAS) pain scores in patients undergoing day-care arthroscopic knee surgery. Additionally, we assessed analgesic demand.

METHODS

Ninety ASA I/II patients undergoing arthroscopic partial meniscectomy, performed by a single surgeon under general anesthesia, were assigned in a randomized, double-blind manner into three groups: group B (n = 30) received 0.25% bupivacaine, group T (n = 30) received 100 mg tramadol, and group BT (n = 30) received 0.25% bupivacaine and 100 mg tramadol to a total volume of 20 mL by the IA route after surgery. Postoperative pain scores were measured on a VAS, at rest and on mobilization at 0.5, 1, 2, 4, 6, 8, 12, and 24 h. Duration of analgesia, the subsequent 24 h consumption of rescue analgesia, time to ambulation, and time to discharge were evaluated. In addition, the systemic side effects of the IA injected drugs were also assessed.

RESULTS

The results showed significantly lower VAS pain scores in group BT (P << 0.1) when compared with groups T and B. Group BT had a later onset of postsurgical pain and longer time to first rescue analgesic than groups B and T. The 24 h consumption of analgesic was significantly less in group BT when compared with the other two groups (26.7% of the patients required rescue analgesia in group BT, whereas this number was 90% in group B and 86.7% in group T). In addition, time in hours to discharge and time to unassisted ambulation were significantly shorter in group BT when compared with groups T and B, and this was not associated with any detectable systemic effects.

CONCLUSION

The IA admixture of tramadol 100 mg with bupivacaine 0.25% provides a pronounced prolongation of analgesia compared with either drug alone in patients undergoing day care arthroscopic knee surgery.

Post-herniorrhapy infiltration of tramadol versus bupivacaine for postoperative pain relief: a randomized study

BACKGROUND AND OBJECTIVES

Inguinal hernia repair is frequently associated with persistent postoperative discomfort and pain and late discharge from the hospital. We evaluated the postoperative analgesic effect of local wound infiltration with tramadol following herniorrhaphy among adult patients.

PATIENTS AND METHODS

Forty-three adult male patients were randomly assigned to two groups; group T (n=23) received tramadol 1 mg/kg in 10 mL 0.9% normal saline and group B (n=20) received 10 mL of 0.25% bupivacaine, both as a local wound infiltration prior to skin closure. Postoperatively, pain severity, time to first analgesic requirement, analgesic consumption, and incidence of side effects were recorded.

RESULTS

During the first postoperative day, there was a significant difference between the two groups in the recorded visual analog scale rating higher in group B (P<.05) and the time to first analgesic requirement (6.6A+/-0.99 hours in group B vs 3.7+/-0.74 hours in group T; P<.05). There was no difference in the incidence of side effects among the two groups. Postoperative consumption of fentanyl and diclofenac was higher in group B than group T (65% vs 18% and 80% vs 21.7%, respectively, P

CONCLUSIONS

Locally infiltrated tramadol prior to herniorrhaphy wound closure provides better pain relief compared to bupivacaine in adult patients.

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MESH Headings

• Adolescent
• Adult
• Analgesics, Opioid/administration & dosage
• Analgesics, Opioid/therapeutic use
• Anesthetics, Local/administration & dosage
• Anesthetics, Local/therapeutic use
• Anti-Inflammatory Agents, Non-Steroidal/administration & dosage
• Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
• Bupivacaine/administration & dosage
• Bupivacaine/therapeutic use
• Diclofenac/administration & dosage
• Diclofenac/therapeutic use
• Fentanyl/administration & dosage
• Fentanyl/therapeutic use
• Hernia, Inguinal/surgery
• Humans
• Incidence
• Male
• Middle Aged
• Pain Measurement
• Pain, Postoperative/drug therapy
• Risk Factors
• Severity of Illness Index
• Time Factors
• Tramadol/administration & dosage
• Tramadol/therapeutic use
• Treatment Outcome

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Affiliation(s)

Abdullah M Kaki Department of Anaesthesia, Faculty of Medicine, King Abdalaziz University Hospital, Jeddah, Saudi Arabia
Waleed Al Marakbi

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Use of a sparse sampling study design to assess transfer of tramadol and its O-desmethyl metabolite into transitional breast milk

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

There are presently no published data on tramadol transfer into breast milk or on its effects in the breastfed infant.

WHAT THIS STUDY ADDS

We have provided quantitative data on the absolute and relative infant doses of rac-tramadol and it rac-O-desmethyl metabolite for the breastfed infant. We have also demonstrated a novel sparse sampling data collection method for investigating infant exposure via milk.

AIMS

To investigate the transfer of rac-tramadol and its rac-O-desmethyl metabolite into transitional milk, and assess unwanted effects in the breastfed infant.

METHODS

Tramadol HCl (100 mg six hourly) was administered to 75 breastfeeding mothers for postoperative analgesia on days 2-4 after Caesarian section. Milk and plasma samples were collected after administration of four or more doses. Rac-tramadol and rac-O-desmethyltramadol were measured by high performance liquid chromatography. Milk : plasma ratio (M : P) and infant doses were calculated by standard methods. The behavioural characteristics of the exposed breastfed infants and a matched control group of infants not exposed to tramadol were also studied. RESULTS At steady-state, mean (95% CI) M : P was 2.2 (2.0, 2.4) for rac-tramadol and 2.8 (2.5, 3.1) for rac-O-desmethyltramadol. The estimated absolute and relative infant doses were 112 (102, 122) microg kg(-1) day(-1) and 30 (28, 32) microg kg(-1) day(-1), and 2.24% (2.04, 2.44)% and 0.64% (0.59, 0.69)% for rac-tramadol and rac-O-desmethyltramadol, respectively. The exposed infants and control breastfed infants had similar characteristics, including Apgar scores at birth and Neurologic and Adaptive Capacity Scores.

CONCLUSIONS

The combined relative infant dose of 2.88% at steady-state was low. The similarity of NACS in exposed infants and controls suggests that there were no significant behavioural adverse effects. We conclude that short-term maternal use of tramadol during establishment of lactation is compatible with breastfeeding.

Fatal unintentional intoxications with tramadol during 1995–2005

Tramadol is an extensively used centrally acting analgesic and is considered a safe drug devoid of many serious adverse effects of traditional opioids. However, recently, toxicity and an abuse potential of tramadol have been reported. This study examined fatal unintentional tramadol intoxications among Swedish forensic autopsy cases between 1995 and 2005. All fatal intoxications were selected, in which toxic concentrations of tramadol (>1 microg/g femoral blood) had been detected, and where the forensic pathologist considered the intoxication unintentional and the fatal outcome at least partly explained by tramadol. Toxicology analyses, police reports, autopsy protocols and medical records were scrutinized. A total of 17 cases (eleven men and six women) of fatal unintentional tramadol intoxications were identified. For these cases the median age was 44 years (range 18-78 years) and the median tramadol concentration was 2.0 microg/g (range 1.1-12.0 microg/g). Other pharmaceutical substances, illicit drugs or ethanol were detected in addition to tramadol in all of these cases. In fact, intoxication with multiple drugs was considered the cause of death in 10 (59%) cases. However, in seven cases tramadol was the only substance present in toxic concentrations. A history of substance abuse was identified in 14 (82%) subjects and a present tramadol abuse in 8 (47%). These results suggest that fatal intoxications with tramadol may occur unintentionally and that subjects with a history of substance abuse may be at certain risk. Precaution is therefore warranted when prescribing tramadol in such patients.

Post-herpetic neuralgia in older adults: evidence-based approaches to clinical management

Many individuals across the globe have been exposed to the varicella-zoster virus (VZV) that causes chickenpox. After chickenpox has resolved, the virus remains latent in the dorsal root ganglia where it can re-emerge later in life as herpes zoster, otherwise known as shingles. Herpes zoster is a transient disease characterised by a dermatomal rash that is usually associated with significant pain. Post-herpetic neuralgia (PHN) is the term used for the condition that exists if the pain persists after the rash has resolved. Advanced age and compromised cell-mediated immunity are significant risk factors for reactivation of herpes zoster and the subsequent development of PHN. Though the pathophysiology of PHN is unclear, studies suggest peripheral and central demyelination as well as neuronal destruction are involved. Both the vaccine against VZV (Varivax) and the newly released vaccine against herpes zoster (Zostavax) may lead to substantial reductions in morbidity from herpes zoster and PHN. In addition, current evidence suggests that multiple medications are effective in reducing the pain associated with PHN. These include tricyclic antidepressants, antiepileptics, opioids, NMDA receptor antagonists as well as topical lidocaine (lignocaine) and capsaicin. Reasonable evidence supports the use of intrathecal corticosteroids, but the potential for neurological sequelae should prompt caution with their application. Epidural corticosteroids have not been shown to provide effective analgesia for PHN. Sympathetic blockade may assist in treating the pain of herpes zoster or PHN. For intractable PHN pain, practitioners have performed delicate surgeries and attempted novel therapies. Although such therapies may help reduce pain, they have been associated with disappointing results, with up to 50% of patients failing to receive acceptable pain relief. Hence, it is likely that the most effective future treatment for this disease will focus on prevention of VZV infection and immunisation against herpes zoster infection with a novel vaccine.

Pharmacokinetics and dose proportionality of three Tramadol Contramid® OAD tablet strengths

A three-way crossover study in 27 human volunteers was conducted to characterize the pharmacokinetics and to assess the dose proportionality of 100 mg, 200 mg and 300 mg strengths of a novel once-a-day tramadol controlled-release tablet (Tramadol Contramid OAD) following single-dose administration. Serial blood samples were collected at predefined timepoints over a 48 h period and racemic tramadol and O-desmethyltramadol concentrations in plasma were determined using a validated LC-MS/MS method. Pharmacokinetic parameters were derived using noncompartmental methods. Following dose normalization and logarithmic transformation of concentration-dependent parameters, the results were compared using analysis of variance (ANOVA). The residual variability thereby obtained was used to construct 90% classical confidence intervals. The two one-sided tests procedure was used for all pairwise comparisons. Dose proportionality was concluded since the 90% CI for the ratio of geometric means was included in the acceptance range of 0.80-1.25 for all comparisons.

Does tramadol wound infiltration offer an advantage over bupivacaine for postoperative analgesia in children following herniotomy?

BACKGROUND

It has been demonstrated that tramadol is an effective analgesic. We aimed to compare postoperative analgesic effects of wound infiltration with tramadol (T) or bupivacaine (B) and intramuscular tramadol (I) after herniotomy in children.

METHODS

In this study, 75 children were randomly assigned to group T, group B and group I. Wound infiltration was performed to the patients in group T (2 mg.kg-1 tramadol in 0.2 ml.kg-1 saline) and group B (0.2 ml.kg-1 0.25% bupivacaine) into the surgical incision. Twenty minutes before the end of the surgery 2 mg.kg-1 tramadol was injected i.m. in group I. Faces pain scale was used for assessing pain severity. Patients with pain score>2 were treated with paracetamol. The frequency of side effects and analgesic use were recorded. Patients were discharged on the next day.

RESULTS

No side effects were recorded in any group. The pain scores of the patients at the first, fourth and eighth hours were significantly higher in group B and group I than group T (P<0.05). The pain scores of the patients at the first hour were significantly higher in group I compared with group B (P<0.05). Average time to first analgesic requirement was significantly longer in group T (6.72+/-4.09 h after herniotomy than both group I (4.49+/-3.9 h) and group B (6.04+/-3.7 h) (P<0.05).

CONCLUSIONS

Wound infiltration with tramadol may be a good choice for postoperative analgesia in children having inguinal herniotomy.

Enantioselective pharmacokinetics of tramadol in CYP2D6 extensive and poor metabolizers

OBJECTIVE

To describe in detail the intravenous, single oral and multiple oral dose enantioselective pharmacokinetics of tramadol in CYP2D6 extensive metabolizers (EMs) and poor metabolizers (PMs).

METHODS

Eight EMs and eight PMs conducted three phases as an open-label cross-over trial with different formulations; 150 mg single oral tramadol hydrochloride, 50 mg single oral tramadol hydrochloride every 8 h for 48 h (steady state), 100 mg intravenous tramadol hydrochloride. Urine and plasma concentrations of (+/-)-tramadol and (+/-)-M1 were determined for 48 h after administration.

RESULTS

In all three phases, there were significant differences between EMs and PMs in AUC and t(1/2) of (+)-tramadol (P< or =0.0015), (-)-tramadol (P< or =0.0062), (+)-M1 (P< or =0.0198) and (-)-M1 (P< or =0.0370), and significant differences in C(max) of (+)-M1 (P<0.0001) and (-)-M1 (P< or =0.0010). In Phase A and C, significant differences in t(max) were seen for (+)-M1 (P< or =0.0200). There were no statistical differences between the absolute bioavailability of tramadol in EMs and PMs. The urinary recoveries of (+)-tramadol, (-)-tramadol, (+)-M1 and (-)-M1 were statistically significantly different in EMs and PMs (P<0.05). Median antimodes of the urinary metabolic ratios of (+)-tramadol / (+)-M1 and (-)-M1 were 5.0 and 1.5, respectively, hereby clearly separating EMs and PMs in all three phases.

CONCLUSION

The impact of CYP2D6 phenotype on tramadol pharmacokinetics was similar after single oral, multiple oral and intravenous administration displaying significant pharmacokinetic differences between EMs and PMs of (+)-tramadol, (-)-tramadol, -(+)-M1 and (-)-M1. The O-demethylation of tramadol was catalysed stereospecific by CYP2D6 in the way that very little (+)-M1 was produced in PMs.