Fatal unintentional intoxications with tramadol during 1995–2005

"You get stuck in it": Young people's accounts of attempting to quit non-medical tramadol use

Aim: Non-medical use of tramadol and other prescription opioid use has become a great concern in many countries, including Sweden. This study examines key components in young people's accounts of attempting to quit drugs, focusing on non-medical use of tramadol. Methods: Repeated qualitative interviews were conducted with 12 individuals aged 19-24 years with experiences of problems related to non-medical tramadol use. The analysis used the concepts of autonomy, competence, and relatedness from self-determination theory. Results: Three themes emerged from the young people's accounts: (1) quitting initiated by parents and professionals; (2) being willing, but unable; and (3) between ambivalence and determination. These themes demonstrate conflicting emotions towards drug use along with a significant external pressure to quit, but also difficulties in quitting due to experiences of dependence, withdrawal symptoms, and mental health issues. For most participants, however, an increasing autonomous will and ability to abstain from drugs gradually developed, with the support from trusted relationships with professionals, family, and friends playing a crucial role. Conclusion: The process of trying to quit non-medical tramadol use can be challenging and involve a complex interaction between willingness and capability, where external influence can be either facilitating or hindering. This study highlights the importance of taking into account young people's own perspectives in treatment efforts, where trust is a key component.

A comparative study of postmortem distribution and postmortem diffusion of tramadol in rabbits

In recent years, the cases of tramadol intoxication have become more frequent in many countries. However, most of the previous studies have been based on cases of tramadol intoxication, and the detailed information on the differences between postmortem distribution and diffusion of tramadol remains unclear. To investigate this issue systematically, we established a postmortem distribution model and two postmortem diffusion models. Then, gas chromatography-mass spectrometry (GC/MS) was used to measure the concentrations of tramadol in various biological specimens of fluids and tissues. In postmortem distribution, the results showed an uneven distribution of tramadol in various biological specimens, and the concentrations of tramadol in urine were significantly higher than those in other fluids. In postmortem diffusion, the results showed a dosage-dependent increase of tramadol concentration in most specimens; at all time points from 0.25 to 6 h after postmortem administration, the concentrations of tramadol in fluids were not significantly different from those in tissues, and the concentrations of tramadol in urine were lower than those in both tissues and other fluids in most time points. We recommend a quantitative examination of the specimens of both fluids and tissues to provide more evidence for the forensic identification, and the realization that there is a correlation between the concentrations of fluids and tissues is important for determining antemortem and postmortem administration of tramadol. This information can serve as ancillary data in inferring the contribution of a drug to death in cases of suspected tramadol poisoning.

Tramadol and Tapentadol Induce Conditioned Place Preference with a Differential Impact on Rewarding Memory and Incubation of Craving

Tramadol and tapentadol, synthetic opioids commonly prescribed for moderate-to-severe pain, have a unique pharmacology that optimizes their analgesia and safety. However, they are not devoid of risks, presenting addictive, abuse, and dependence potential. While tramadol-reinforcing properties have been documented by various studies with human and animal models, including conditioned place preference (CPP) assays, no similar studies have been performed with tapentadol. In the present study, we performed CPP assays by intraperitoneally administering Wistar rats with a tramadol/tapentadol therapeutic dose. Animal permanence and the number of entries in the CPP compartments were recorded in the preconditioning phase and then 1 (T1), 7 (T7), and 14 (T14) days after conditioning. Both opioids induced a change in place preference (T1), suggesting that they have short-term reinforcing properties. However, only tramadol was associated with place preference retention (T7 and T14), with an increase in the number of entries in the opioid-paired compartment (T1 and T7), showing that it causes rewarding memory and incubation of craving. The results indicate that at therapeutic doses: (1) both drugs cause short-term rewarding effects and (2) as opposed to tramadol, tapentadol does not cause CPP retention, despite its higher central nervous system activity and stricter scheduling.

Short-term mortality following tramadol poisonings in Denmark

Tramadol is a commonly used opioid with a potential of addiction and abuse. Using Danish nationwide registers, we aimed to (1) characterise opioid poisonings; (2) assess the 30-day mortality following morphine, oxycodone, and mixed poisonings compared to tramadol poisonings; and (3) assess the development in tramadol poisonings during a 12-year period. Poisonings were identified from 2006 to 2017. A Cox proportional hazards regression model was used to estimate adjusted hazard ratios (aHRs) along with 95% confidence intervals (CIs) for 30-day mortality following morphine, oxycodone or mixed poisonings compared to tramadol poisonings. We identified 7718 opioid poisonings among 6365 patients. The patients with a tramadol poisoning were younger and had less comorbidities than the patients with a morphine, oxycodone or mixed poisoning. Within 30 days, a total of 205 patients died. The 30-day mortality risk was higher following morphine (aHR 3.2, 95% CI 2.0-5.1), oxycodone (aHR 2.1, 95% CI 1.2-3.6) and mixed poisonings (aHR 1.6, 95% CI 1.0-2.7) compared to tramadol poisonings. The annual number of tramadol poisonings increased from 233 in 2006 to 501 in 2013 and declined to 348 in 2017. In conclusion, despite a lower mortality risk compared to other opioid poisonings, physicians should consider the poisoning and abuse risks when prescribing tramadol.

Survival Impact of Long-Term Tramadol Use on Breast Cancer for Patients with Chronic Pain: A Propensity Score-Matched Population-Based Cohort Study

Purpose: The impact of tramadol analgesic use before breast cancer diagnosis on survival in patients with chronic pain is unclear. Therefore, we designed a propensity score-matched population-based cohort study to compare the breast cancer-related survival of patients with chronic pain who received long-term tramadol analgesic treatment with that of those who did not receive such treatment. Patients and Methods: We included patients with chronic pain and categorized them into two groups according to their analgesic use, comparing their breast cancer-related survival; patients with breast cancer and chronic pain who were prescribed ≥180 defined daily doses (DDDs) of tramadol analgesics per year >3 months before breast cancer diagnosis comprised the case group, and those who were prescribed non-tramadol analgesics before breast cancer diagnosis comprised the control group. Patients in both groups were matched at a ratio of 1:5. Results: The matching process yielded a final cohort of 624 patients (104 and 520 in the case and control groups, respectively) who were eligible for further analysis. According to both univariate and multivariate Cox regression analyses, the adjusted hazard ratio for all-cause death in the case group compared with in the control group was 3.45 (95% confidence interval = 2.36−5.04; p < 0.001). Conclusion: Long-term tramadol analgesic use prior to breast cancer diagnosis might be associated with poor overall survival in patients with chronic pain compared with such patients that did not receive long-term tramadol analgesic treatment.

A review on tramadol toxicity: mechanism of action, clinical presentation, and treatment

Aims

As an analgesic that acts upon the central nervous system (CNS), tramadol has gained popularity in treating moderate to severe pain. Recently, it has been increasingly reported as a drug of misuse with intentional overdoses or intoxications. This review focuses on tramadol intoxication in humans and its effects on different systems.

Subject and method

This narrative review provides a comprehensive view of the pharmacokinetics, mechanism of action, and incidence of tramadol toxicity with an in-depth look at its side effects. In addition, the main approaches to the management of tramadol poisoning are described.

Results

Tramadol poisoning can affect multiple organ systems: gastrointestinal, central nervous system (seizure, CNS depression, low-grade coma, anxiety, and over time anoxic brain damage), cardiovascular system (palpitation, mild hypertension to life-threatening complications such as cardiopulmonary arrest), respiratory system, renal system (renal failure with higher doses of tramadol intoxication), musculoskeletal system (rhabdomyolysis), endocrine system (hypoglycemia), as well as, cause serotonin syndrome. Seizure, a serious nervous disturbance, is more common in tramadol intoxication than with other opioids. Fatal tramadol intoxications are uncommon, except in ingestion cases concurrent with other medications, particularly CNS depressants, most commonly benzodiazepines, and ethanol.

Conclusion

With the increasing popularity of tramadol, physicians must be aware of its adverse effects, substantial abuse potential, and drug interactions, to weigh its risk–benefit ratio for pain management. Alternative therapies might be considered in patients with a previous overdose history to reduce risks for adverse outcomes.

Dynamic Distribution and Postmortem Redistribution of Tramadol in Poisoned Rats

In the past dozen years, the cases of tramadol intoxication have become frequent in many countries. Most previous studies focused on tramadol's pharmacology, such as pharmacokinetics, pharmacodynamics and pharmacogenetics. However, the dynamic distribution and postmortem redistribution (PMR) of tramadol remain unclear. Our study aimed to investigate these two issues systematically in various specimens of 216 poisoned male rats. A validated gas chromatography-mass spectrometry method was used in this study to measure the concentrations of tramadol. In the first part, 66 tramadol poisoned rats were sacrificed at 11 different time points and their organs were collected separately for the study of tramadol's dynamic distribution, which made it feasible to investigate its PMR later on. The results of this part showed that tramadol's concentrations varied according to the organ and time, and peaked 2 h after intragastric administration in the specimens of liver, kidney, spleen, lung, brain and heart-blood (except stomach and heart). Based on the results of the first part, the concentration of tramadol peaked 2 h in most tissues. Therefore, this time point was used for the study of tramadol's PMR. In the second part, the remaining 150 rats were sacrificed 2 h after intragastric administration of tramadol, and the carcasses were stored under three different conditions (-20, 4 and 20°C). The autopsy was carried out at eight different time points and their organs were collected separately. The results of this part showed that under storage temperatures of -20 and 4°C, the concentrations of tramadol in individual organs showed no significant changes at different time points whereas under a storage temperature of 20°C, the concentrations in certain organs (liver, kidney, spleen, lung, brain and heart-blood) increased significantly at the last few time points. PMR of tramadol was therefore confirmed. The process of PMR of tramadol could be slowed or stopped at lower storage temperatures (-20 or 4°C), which is significant in cases of suspected tramadol poisoning.

Repeated Administration of Clinically Relevant Doses of the Prescription Opioids Tramadol and Tapentadol Causes Lung, Cardiac, and Brain Toxicity in Wistar Rats

Tramadol and tapentadol, two structurally related synthetic opioid analgesics, are widely prescribed due to the enhanced therapeutic profiles resulting from the synergistic combination between μ-opioid receptor (MOR) activation and monoamine reuptake inhibition. However, the number of adverse reactions has been growing along with their increasing use and misuse. The potential toxicological mechanisms for these drugs are not completely understood, especially for tapentadol, owing to its shorter market history. Therefore, in the present study, we aimed to comparatively assess the putative lung, cardiac, and brain cortex toxicological damage elicited by the repeated exposure to therapeutic doses of both prescription opioids. To this purpose, male Wistar rats were intraperitoneally injected with single daily doses of 10, 25, and 50 mg/kg tramadol or tapentadol, corresponding to a standard analgesic dose, an intermediate dose, and the maximum recommended daily dose, respectively, for 14 consecutive days. Such treatment was found to lead mainly to lipid peroxidation and inflammation in lung and brain cortex tissues, as shown through augmented thiobarbituric acid reactive substances (TBARS), as well as to increased serum inflammation biomarkers, such as C reactive protein (CRP) and tumor necrosis factor-α (TNF-α). Cardiomyocyte integrity was also shown to be affected, since both opioids incremented serum lactate dehydrogenase (LDH) and α-hydroxybutyrate dehydrogenase (α-HBDH) activities, while tapentadol was associated with increased serum creatine kinase muscle brain (CK-MB) isoform activity. In turn, the analysis of metabolic parameters in brain cortex tissue revealed increased lactate concentration upon exposure to both drugs, as well as augmented LDH and creatine kinase (CK) activities following tapentadol treatment. In addition, pneumo- and cardiotoxicity biomarkers were quantified at the gene level, while neurotoxicity biomarkers were quantified both at the gene and protein levels; changes in their expression correlate with the oxidative stress, inflammatory, metabolic, and histopathological changes that were detected. Hematoxylin and eosin (H & E) staining revealed several histopathological alterations, including alveolar collapse and destruction in lung sections, inflammatory infiltrates, altered cardiomyocytes and loss of striation in heart sections, degenerated neurons, and accumulation of glial and microglial cells in brain cortex sections. In turn, Masson's trichrome staining confirmed fibrous tissue deposition in cardiac tissue. Taken as a whole, these results show that the repeated administration of both prescription opioids extends the dose range for which toxicological injury is observed to lower therapeutic doses. They also reinforce previous assumptions that tramadol and tapentadol are not devoid of toxicological risk even at clinical doses.

The plausible mechanisms of tramadol for treatment of COVID-19

Currently, no single medication has been approved for the management of coronavirus disease-2019 (COVID-19) caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, drug repositioningby investigating the use of existing drugs for management of COVID-19 patients is considered a desperate need. Tramadol is a commonly prescribed analgesic drug for treatment of moderate to severe pain with less potential for dependence and respiratory depression. Multiple evidence support that tramadol is a promising drug for treatment of COVID-19 patients. Herein, we discuss the possible beneficial effects of using tramadol against SARS-CoV-2 infection and their underlying mechanism of action. The anti-inflammatory effect of tramadol may help to suppress the COVID-19 related cytokine storm through decreasing interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP). Besides, tramadol activates natural killer (NK) and T-cells and enhances IL-2 secretion, which produce immune-enhancing effect against SARS-CoV-2. Recent studies confirmed that COVID-19 patients with acute respiratory failure showed increased fibrin formation and polymerization that may lead to thrombosis. Tramadol owing to its hypocoagulable effect may protect against venous thromboembolism in these patients. Moreover, tramadol can exert a cardioprotective effect via decreasing lactate dehydrogenase (LDH) level which is elevated in most of patients with COVID-19. Furthermore, the severity and mortality of COVID-19 have been correlated with old age patients, which may be due to the lack of antioxidant mechanisms and increased oxidative damage. Tramadol could protect COVID-19 patient from disease complications by increases the antioxidant enzymes superoxide dismutase and glutathione peroxidase while diminished malondialdehyde. More interestingly, tramadol as an effective analgesic and antitussive may have a beneficial effect on COVID-19 patients suffering from cough, headache, ache, and pain. The tramadol anti-psychotic effect may also protect against psychiatric disorders associated with SARS-CoV-2 infection. Moreover, tramadol has bactericidal activity against a wide range of pathogens including Pseudomonas aeruginosa which is common in severe COVID-19 patients leading to pneumonia with worse clinical outcomes. Therefore, we hypothesize that tramadol might be a promising adjuvant therapeutic option against SARS-CoV-2 infection. Based on that, tramadol should be considered as adjuvant therapy for COVID-19 clinical trials.

Tramadol use and public health consequences in Iran: a systematic review and meta-analysis

BACKGROUND AND AIMS

Misuse of tramadol, an opioid prescription analgesic, is known as a public health challenge globally. We aimed to systematically review studies on the prevalence of non-prescribed use, regular tramadol use and dependence, tramadol-induced poisoning and mortality in Iran.

METHODS

Consistent with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, international (Medline, Scopus, Web of Science) and Persian (SID) databases were systematically searched up to June 2019. Other relevant data were collected through personal contacts and review of reference lists. Pooled estimates of prevalence of tramadol use in subgroups of males and females, percentage of tramadol poisoning among admitted poisoning cases, tramadol-associated seizures and mortality among tramadol poisonings and percentage of tramadol as a cause of death among fatal drug-poisoning records were estimated through a random-effects model.

RESULTS

A total of 84 records were included. Pooled estimates of last 12-month use of tramadol in the Iranian general population were 4.9% [95% confidence interval (CI) = 4.1-5.9] and 0.8% (95% CI = 0.2-1.8) among males and females, respectively. The estimates for last 12-month use among Iranian male and female university students were 4.8% (95% CI = 1.9-8.9) and 0.7% (95% CI = 0.3-1.1), respectively. Six heterogeneous reports indicated the existence of regular use of tramadol and dependence in Iran. Sixty-two studies provided data on tramadol-induced poisoning, seizures and mortality. The pooled estimate of the percentage of tramadol poisoning among all drug-poisoning patients was 13.1% (95% CI = 5.7-22.9). The overall estimates of seizures and mortality among tramadol-poisoning patients were 34.6% (95% CI = 29.6-39.8) and 0.7% (95% CI = 0.0-1.9), respectively. The pooled percentage of tramadol-related fatalities among drug-poisoned cases was 5.7% (95% CI = 0.5-15.4).

CONCLUSION

Despite control policies, tramadol use is as prevalent as the use of illicit opioids in Iran. Numerous cases of tramadol abuse, dependence, poisonings, seizures and hundreds of tramadol-related deaths have been reported in recent years.

Repeated Administration of Clinical Doses of Tramadol and Tapentadol Causes Hepato- and Nephrotoxic Effects in Wistar Rats

Tramadol and tapentadol are fully synthetic and extensively used analgesic opioids, presenting enhanced therapeutic and safety profiles as compared with their peers. However, reports of adverse reactions, intoxications and fatalities have been increasing. Information regarding the molecular, biochemical, and histological alterations underlying their toxicological potential is missing, particularly for tapentadol, owing to its more recent market authorization. Considering the paramount importance of liver and kidney for the metabolism and excretion of both opioids, these organs are especially susceptible to toxicological damage. In the present study, we aimed to characterize the putative hepatic and renal deleterious effects of repeated exposure to therapeutic doses of tramadol and tapentadol, using an in vivo animal model. Male Wistar rats were randomly divided into six experimental groups, composed of six animals each, which received daily single intraperitoneal injections of 10, 25 or 50 mg/kg tramadol or tapentadol (a low, standard analgesic dose, an intermediate dose and the maximum recommended daily dose, respectively). An additional control group was injected with normal saline. Following 14 consecutive days of administration, serum, urine and liver and kidney tissue samples were processed for biochemical, metabolic and histological analysis. Repeated administration of therapeutic doses of both opioids led to: (i) increased lipid and protein oxidation in liver and kidney, as well as to decreased total liver antioxidant capacity; (ii) decreased serum albumin, urea, butyrylcholinesterase and complement C3 and C4 levels, denoting liver synthesis impairment; (iii) elevated serum activity of liver enzymes, such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and γ-glutamyl transpeptidase, as well as lipid profile alterations, also reflecting hepatobiliary commitment; (iv) derangement of iron metabolism, as shown through increases in serum iron, ferritin, haptoglobin and heme oxygenase-1 levels. In turn, elevated serum cystatin C, decreased urine creatinine output and increased urine microalbumin levels were detected upon exposure to tapentadol only, while increased serum amylase and urine N-acetyl-β-D-glucosaminidase activities were observed for both opioids. Collectively, these results are compatible with kidney injury. Changes were also found in the expression levels of liver- and kidney-specific toxicity biomarker genes, upon exposure to tramadol and tapentadol, correlating well with alterations in lipid profile, iron metabolism and glomerular and tubular function. Histopathological analysis evidenced sinusoidal dilatation, microsteatosis, mononuclear cell infiltrates, glomerular and tubular disorganization, and increased Bowman's spaces. Although some findings are more pronounced upon tapentadol exposure, our study shows that, when compared with acute exposure, prolonged administration of both opioids smooths the differences between their toxicological effects, and that these occur at lower doses within the therapeutic range.

Population Size Estimation of Tramadol Misusers in Urban Population in Iran: Synthesis of Methods and Results

Background

Estimating the population who use drugs is essential for planning, monitoring, and evaluation of substance use prevention and treatment. This study aims to estimate the population who misuse tramadol in urban population in Iran.

Methods

We used the wisdom of the experts (WOTE) and network scale-up (NSU) methods to calculate the population of tramadol misusers in 10 provincial capitals of Iran, in 2016. The WOTE was conducted among pharmacists in drugstores and the personnel of traditional medicinal herbs stores. They guessed the best estimation of tramadol misusers population in their cities. The NSU method was conducted among the general population and participants were questioned about ever and daily, non-medical use of tramadol during last 12 months in their network. The median of the methods was used to calculate the proportion of the adult population (15-49 years old).

Findings

The population size of tramadol misusers in studied cities was 83300 [95% uncertainty limits (UL): 47960-256220]. This corresponded to 6.6 per 1000 (95% UL: 3.88-20.30) of the 15-49-year-old population. The projected number of tramadol misusers for all 31 provincial capitals was 118290 (95% UL: 68100-363130840) and 212440 (95% UL: 122310-653410) for all urban areas. NSU also estimated the number of people who misuse tramadol on daily basis. These numbers were 52000 (95% UL: 19940-176570) for studied cities, 73840 (95% UL: 28320-250740) for all 31 provincial capital cities, and 132610 (95% UL: 50860-450310) for all urban areas in Iran.

Conclusion

This study presents information on high prevalence of tramadol misuse in urban population. We need national control measures and demand reduction programs to control tramadol misuse.

Risk of Seizure after Naloxone Therapy in Acute Tramadol Poisoning: A Systematic Review with Meta-Analysis

Background

Many studies have focused on the relationship between naloxone and seizure in tramadol poisoning but the results are in conflict. We performed a meta-analysis study to see whether naloxone prevents or increase the risk of seizure in tramadol poisoning.

Methods

Bibliographic literature searches were conducted in the ISI Web of Science, Excerpta Medica Database (EMBASE), PubMed, and Cochrane from January 1990 to December 2017 for relevant articles. Pooled data were analyzed by calculating odds ratios (ORs) with 95% confidence intervals (CIs). The outcome includes seizure. To investigate the publication bias, Begg's and Egger's tests were used along with funnel plot as a graphical test.

Results

Seven studies met the inclusion criteria. The meta-analysis showed I ², 27%, (P value, 0.23) indicating no significant heterogeneity. As a result, using the fixed effect, the OR was 1.14 (95% CI = 0.60-2.18, P value, 0.69) which was not significant, means naloxone did not increase the risk of seizure.

Conclusions

Naloxone therapy did not increase the risk of seizure significantly in the treatment of acute tramadol poisoning. We suggest considering the risk/benefit when administration naloxone, especially for the seizure risk factors including previous history of seizure, tramadol misuse, and co-ingestion.

Association of Tramadol With All-Cause Mortality Among Patients With Osteoarthritis

IMPORTANCE

An American Academy of Orthopaedic Surgeons guideline recommends tramadol for patients with knee osteoarthritis, and an American College of Rheumatology guideline conditionally recommends tramadol as first-line therapy for patients with knee osteoarthritis, along with nonsteroidal anti-inflammatory drugs.

OBJECTIVE

To examine the association of tramadol prescription with all-cause mortality among patients with osteoarthritis.

DESIGN, SETTING, AND PARTICIPANTS

Sequential, propensity score-matched cohort study at a general practice in the United Kingdom. Individuals aged at least 50 years with a diagnosis of osteoarthritis in the Health Improvement Network database from January 2000 to December 2015, with follow-up to December 2016.

EXPOSURES

Initial prescription of tramadol (n = 44 451), naproxen (n = 12 397), diclofenac (n = 6512), celecoxib (n = 5674), etoricoxib (n = 2946), or codeine (n = 16 922).

MAIN OUTCOMES AND MEASURES

All-cause mortality within 1 year after initial tramadol prescription, compared with 5 other pain relief medications.

RESULTS

After propensity score matching, 88 902 patients were included (mean [SD] age, 70.1 [9.5] years; 61.2% were women). During the 1-year follow-up, 278 deaths (23.5/1000 person-years) occurred in the tramadol cohort and 164 (13.8/1000 person-years) occurred in the naproxen cohort (rate difference, 9.7 deaths/1000 person-years [95% CI, 6.3-13.2]; hazard ratio [HR], 1.71 [95% CI, 1.41-2.07]), and mortality was higher for tramadol compared with diclofenac (36.2/1000 vs 19.2/1000 person-years; HR, 1.88 [95% CI, 1.51-2.35]). Tramadol was also associated with a higher all-cause mortality rate compared with celecoxib (31.2/1000 vs 18.4/1000 person-years; HR, 1.70 [95% CI, 1.33-2.17]) and etoricoxib (25.7/1000 vs 12.8/1000 person-years; HR, 2.04 [95% CI, 1.37-3.03]). No statistically significant difference in all-cause mortality was observed between tramadol and codeine (32.2/1000 vs 34.6/1000 person-years; HR, 0.94 [95% CI, 0.83-1.05]).

CONCLUSIONS AND RELEVANCE

Among patients aged 50 years and older with osteoarthritis, initial prescription of tramadol was associated with a significantly higher rate of mortality over 1 year of follow-up compared with commonly prescribed nonsteroidal anti-inflammatory drugs, but not compared with codeine. However, these findings may be susceptible to confounding by indication, and further research is needed to determine if this association is causal.

Comparative pharmacology and toxicology of tramadol and tapentadol

Moderate-to-severe pain represents a heavy burden in patients' quality of life, and ultimately in the society and in healthcare costs. The aim of this review was to summarize data on tramadol and tapentadol adverse effects, toxicity, potential advantages and limitations according to the context of clinical use. We compared data on the pharmacological and toxicological profiles of tramadol and tapentadol, after an extensive literature search in the US National Library of Medicine (PubMed). Tramadol is a prodrug that acts through noradrenaline and serotonin reuptake inhibition, with a weak opioid component added by its metabolite O-desmethyltramadol. Tapentadol does not require metabolic activation and acts mainly through noradrenaline reuptake inhibition and has a strong opioid activity. Such features confer tapentadol potential advantages, namely lower serotonergic, dependence and abuse potential, more linear pharmacokinetics, greater gastrointestinal tolerability and applicability in the treatment of chronic and neuropathic pain. Although more studies are needed to provide clear guidance on the opioid of choice, tapentadol shows some advantages, as it does not require CYP450 system activation and has minimal serotonergic effects. In addition, it leads to less side effects and lower abuse liability. However, in vivo and in vitro studies have shown that tramadol and tapentadol cause similar toxicological damage. In this context, it is important to underline that the choice of opioid should be individually balanced and a tailored decision, based on previous experience and on the patient's profile, type of pain and context of treatment.

SIGNIFICANCE

This review underlines the need for a careful prescription of tramadol and tapentadol. Although both are widely prescribed synthetic opioid analgesics, their toxic effects and potential dependence are not completely understood yet. In particular, concerning tapentadol, further research is needed to better assess its toxic effects.

High Rates of Tramadol Use among Treatment-Seeking Adolescents in Malmö, Sweden: A Study of Hair Analysis of Nonmedical Prescription Opioid Use

Background

Nonmedical prescription opioid use (NMPOU) is a growing problem and tramadol has been suggested as an emerging problem in young treatment-seeking individuals. The aim of the present study was to investigate, through hair analysis, NMPOU in this group and, specifically, tramadol use.

Methods

In a study including 73 treatment-seeking adolescents and young adults at an outpatient facility for young substance users, hair specimens could be obtained from 59 subjects. Data were extracted on sociodemographic background variables and psychiatric diagnoses through MINI interviews.

Results

In hair analysis, tramadol was by far the most prevalent opioid detected. Thirty-two percent screened positive for opioids, and of those, all but one were positive for tramadol. Ninety-eight percent reported problematic cannabis use. Significantly more opioid-positive patients also screened positive for other (noncannabis) drugs, compared to nonopioid users. Sixty-four percent fulfilled criteria of DSM-IV psychiatric disorders, other than substance use disorders according to MINI. Fifty-three percent met the symptom criteria count of ADHD above cut-off level.

Conclusion

In the present setting, tramadol, along with high rates of cannabis use, may represent a novel pattern of substance use among young treatment-seeking subjects with problematic substance use and high rates of concurrent psychiatric problems.

A 15-year overview of increasing tramadol utilisation and associated mortality and the impact of tramadol classification in the United Kingdom

PURPOSE

This study aimed to develop hypotheses to explain the increasing tramadol utilisation, evaluate the impact of tramadol classification, and explore the trend between tramadol utilisation and related deaths in the United Kingdom.

METHODS

This cross-sectional study used individual patient data, the Clinical Practice Research Datalink from 1993 to 2015, to calculate monthly defined daily dose (DDD)/1000 registrants, monthly prevalence and incidence of tramadol users, annual supply days, and mean daily dose of tramadol. Aggregated-level national statistics and reimbursement data from 2004 to 2015 were also used to quantify annual and monthly tramadol DDD/1000 inhabitants and rate of tramadol-related deaths in England and Wales. Interrupted time-series analysis was used to evaluate the impact of tramadol classification in June 2014.

RESULTS

Prevalence of tramadol users increased from 23 to 97.6/10 000 registrants from 2000 to 2015. Both annual dose and annual supply days of existing tramadol users were higher than new users. Level and trend of monthly utilisation (β₂ : -12.9, β₃ : -1.6) and prevalence of tramadol users (β₂ : -6.4, β₃ : -0.37) significantly reduced after classification. Both annual tramadol utilisation and rate of tramadol-related deaths increased before tramadol classification and decreased thereafter.

CONCLUSIONS

Increasing tramadol utilisation was influenced by the increase in prevalence and incidence of tramadol users, mean daily dose, and day of supply. Prevalence of tramadol users, tramadol utilisation, and reported deaths declined after tramadol classification. Future studies need to evaluate the influencing factors to ensure the safety of long-term tramadol use.

Acute administration of tramadol and tapentadol at effective analgesic and maximum tolerated doses causes hepato- and nephrotoxic effects in Wistar rats

Tramadol and tapentadol are two atypical synthetic opioid analgesics, with monoamine reuptake inhibition properties. Mainly aimed at the treatment of moderate to severe pain, these drugs are extensively prescribed for multiple clinical applications. Along with the increase in their use, there has been an increment in their abuse, and consequently in the reported number of adverse reactions and intoxications. However, little is known about their mechanisms of toxicity. In this study, we have analyzed the in vivo toxicological effects in liver and kidney resulting from an acute exposure of a rodent animal model to both opioids. Male Wistar rats were intraperitoneally administered with 10, 25 and 50mg/kg tramadol and tapentadol, corresponding to a low, effective analgesic dose, an intermediate dose and the maximum recommended daily dose, respectively, for 24h. Toxicological effects were assessed in terms of oxidative stress, biochemical and metabolic parameters and histopathology, using serum and urine samples, liver and kidney homogenates and tissue specimens. The acute exposure to tapentadol caused a dose-dependent increase in protein oxidation in liver and kidney. Additionally, exposure to both opioids led to hepatic commitment, as shown by increased serum lipid levels, decreased urea concentration, increased alanine aminotransferase and decreased butyrylcholinesterase activities. It also led to renal impairment, as reflected by proteinuria and decreased glomerular filtration rate. Histopathological findings included sinusoidal dilatation, microsteatosis, vacuolization, cell infiltrates and cell degeneration, indicating metabolic changes, inflammation and cell damage. In conclusion, a single effective analgesic dose or the maximum recommended daily dose of both opioids leads to hepatotoxicity and nephrotoxicity, with tapentadol inducing comparatively more toxicity. Whether these effects reflect risks during the therapeutic use or human overdoses requires focused attention by the medical community.

Mechanisms of tramadol-related neurotoxicity in the rat: Does diazepam/tramadol combination play a worsening role in overdose?

Poisoning with opioid analgesics including tramadol represents a challenge. Tramadol may induce respiratory depression, seizures and serotonin syndrome, possibly worsened when in combination to benzodiazepines. Our objectives were to investigate tramadol-related neurotoxicity, consequences of diazepam/tramadol combination, and mechanisms of drug-drug interactions in rats. Median lethal-doses were determined using Dixon-Bruce's up-and-down method. Sedation, seizures, electroencephalography and plethysmography parameters were studied. Concentrations of tramadol and its metabolites were measured using liquid-chromatography-high-resolution-mass-spectrometry. Plasma, platelet and brain monoamines were measured using liquid-chromatography coupled to fluorimetry. Median lethal-doses of tramadol and diazepam/tramadol combination did not significantly differ, although time-to-death was longer with combination (P=0.04). Tramadol induced dose-dependent sedation (P<0.05), early-onset seizures (P<0.001) and increase in inspiratory (P<0.01) and expiratory times (P<0.05). The diazepam/tramadol combination abolished seizures but significantly enhanced sedation (P<0.01) and respiratory depression (P<0.05) by reducing tidal volume (P<0.05) in addition to tramadol-related increase in respiratory times, suggesting a pharmacodynamic mechanism of interaction. Plasma M1 and M5 metabolites were mildly increased, contributing additionally to tramadol-related respiratory depression. Tramadol-induced early-onset increase in brain concentrations of serotonin and norepinephrine was not significantly altered by the diazepam/tramadol combination. Interestingly neither pretreatment with cyproheptadine (a serotonin-receptor antagonist) nor a benserazide/5-hydroxytryptophane combination (enhancing brain serotonin) reduced tramadol-induced seizures. Our study shows that diazepam/tramadol combination does not worsen tramadol-induced fatality risk but alters its toxicity pattern with enhanced respiratory depression but abolished seizures. Drug-drug interaction is mainly pharmacodynamic but increased plasma M1 and M5 metabolites may also contribute to enhancing respiratory depression. Tramadol-induced seizures are independent of brain serotonin.

Non-prescribed use of psychoactive prescription drugs among drug-impaired drivers in Sweden

AIMS

To determine the prevalence of non-prescribed drug use among subjects suspected of drug-impaired driving with a psychoactive prescription drug, and to identify associated factors.

METHODS

Subjects investigated for drug-impaired driving in Sweden during 2006-2009 with a confirmed intake of diazepam, flunitrazepam, tramadol, zolpidem or zopiclone were identified using the Swedish Forensic Toxicology Database. Information on dispensed prescription drugs was retrieved from the Swedish Prescribed Drug Register. Non-prescribed use was our outcome, defined as a psychoactive prescription drug intake confirmed by toxicological analysis in a subject by whom it was not dispensed in the 12 months preceding the sampling. Prevalence proportions were calculated for each drug and logistic regression was used to identify associated factors.

RESULTS

In total, 2225 subjects were included. The median age (range) was 34 (15-80) years and 1864 (83.8%) subjects were male. Non-prescribed use was found in 1513 subjects (58.7%); for flunitrazepam 103 (76.3%), diazepam 1098 (74.1%), tramadol 192 (40.3%), zopiclone 60 (29.7%), and zolpidem 60 (21.2%) subjects, respectively. Younger age and multiple-substance use were associated with non-prescribed use, whereas ongoing treatment with other psychoactive drugs was negatively associated with non-prescribed use.

CONCLUSIONS

Non-prescribed use of psychoactive prescription drugs was common in subjects suspected of drug-impaired driving and was more frequent for benzodiazepines and tramadol compared to zolpidem and zopiclone. The young and multi-substance users were more likely, whereas subjects with ongoing prescribed treatment with other psychoactive drugs were less likely, to use non-prescribed drugs.

Demographics and post-mortem toxicology findings in deaths among people arrested multiple times for use of illicit drugs and/or impaired driving

BACKGROUND

Multiple arrests for use of illicit drugs and/or impaired driving strongly suggests the existence of a personality disorder and/or a substance abuse problem.

METHODS

This retrospective study (1993-2010) used a national forensic toxicology database (TOXBASE), and we identified 3943 individuals with two or more arrests for use of illicit drugs and/or impaired driving. These individuals had subsequently died from a fatal drug poisoning or some other cause of death, such as trauma.

RESULTS

Of the 3943 repeat offenders 1807 (46%) died from a fatal drug overdose and 2136 (54%) died from other causes (p<0.001). The repeat offenders were predominantly male (90% vs 10%) and mean age of drug poisoning deaths was 5 y younger (mean 35 y) than other causes of death (mean 40 y). Significantly more repeat offenders (46%) died from drug overdose compared with all other forensic autopsies (14%) (p<0.001). Four or more drugs were identified in femoral blood in 44% of deaths from poisoning (drug overdose) compared with 18% of deaths by other causes (p<0.001). The manner of death was considered accidental in 54% of deaths among repeat offenders compared with 28% for other suspicious deaths (p<0.001). The psychoactive substances most commonly identified in autopsy blood from repeat offenders were ethanol, morphine (from heroin), diazepam, amphetamines, cannabis, and various opioids.

CONCLUSIONS

This study shows that people arrested multiple times for use of illicit drugs and/or impaired driving are more likely to die by accidentally overdosing with drugs. Lives might be saved if repeat offenders were sentenced to treatment and rehabilitation for their drug abuse problem instead of conventional penalties for drug-related crimes.

Case report of a fatal intoxication by Nucynta

Tapentadol (Nucynta) is a centrally acting opioid analgesic prescribed for the treatment of moderate to severe acute pain. Its efficacy is believed to be due to μ-opioid receptor agonist activity and inhibition of norepinephrine reuptake resulting in increased norepinephrine concentrations. There is only one other case in the literature relating to the toxicity of this agent or report of a fatality. This case report documents a case in which tapentadol was identified as the cause of death. The tapentadol concentration found in the heart blood submitted in this case was more than 20 times the upper limit of the therapeutic range. Possible mechanisms of death include respiratory depression, central nervous system depression, and serotonin syndrome. Based on the scene investigation and autopsy findings in this case, the medical examiner determined that the cause of death was narcotic (Nucynta) intoxication and the manner of death was undetermined.

Evaluation of abuse and dependence in addiction monitoring systems: tramadol as an example

The objective of this paper is to present an evaluation of the potential for abuse of and dependence on a drug from the data obtained from the different pharmacoepidemiological tools used by the French network for evaluation and information on pharmacodependence and addiction monitoring taking the example of tramadol. Comparison of the data from spontaneous reports with surveys in specific populations and with evaluations of indicators of diverted uses does not highlight a major problem of tramadol abuse and dependence in terms of public health, but stresses the importance of paying attention to the signal. This example of addiction monitoring of tramadol illustrates the interest of comparing results obtained from different validated sources. The implementation of repeated observational programs of abuse of and dependence on psychoactive drugs is an important aid to health authorities to define the content of the information to be delivered or regulatory decisions to reduce these problematic uses.

Tramadol--a true natural product?

We have independently investigated the source of tramadol, a synthetic analgesic largely used for treating moderate to severe pain in humans, recently found in the roots of the Cameroonian medicinal plant, Nauclea latifolia. We found tramadol and its three major mammalian metabolites (O-desmethyltramadol, N-desmethyltramadol, and 4-hydroxycyclohexyltramadol) in the roots of N. latifolia and five other plant species, and also in soil and local water bodies only in the Far North region of Cameroon. The off-label administration of tramadol to cattle in this region leads to cross-contamination of the soil and water through feces and urine containing parent tramadol as well as tramadol metabolites produced in the animals. These compounds can then be absorbed by the plant roots and also leached into the local water supplies. The presence of tramadol in roots is, thus, due to an anthropogenic contamination with the synthetic compound.

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.

A European community pharmacy-based survey to investigate patterns of prescription fraud through identification of falsified prescriptions

AIM

To identify prescription drugs involved in falsified prescriptions in community pharmacies in 6 European countries.

METHODS

A cross-sectional survey among 2,105 community pharmacies in Belgium, France, Italy, the Netherlands, Spain and Sweden was carried out to collect all suspect prescription forms. For each reported drug, the number of reported falsified prescriptions per thousand inhabitants was estimated. A falsification ratio was calculated by dividing the number of reports by the number of defined daily doses per 1,000 inhabitants per day for this drug, computed from national sale or reimbursement data.

RESULTS

On 862 prescription forms, benzodiazepines (zolpidem, bromazepam, alprazolam), buprenorphine (as an opioid maintenance drug) and tramadol were the most frequently reported. Depending on their level of use in each country, methylphenidate, morphine and flunitrazepam presented the highest falsification ratios, particularly in Spain, Belgium and France.

CONCLUSIONS

Stimulants, opioids and some benzodiazepines were the most frequently reported drugs in this survey on falsified prescriptions, but differences between countries were observed.

Postmortem redistribution of tramadol and O-desmethyltramadol

Tramadol is a widely used analgesic opioid for moderate-to-severe pain due to its efficacy and safety. Although tramadol induces less adverse effects compared with other opioids, an increased number of documented cases of dependence, abuse, intentional overdose or intoxication have been described. In fatal intoxication, the interpretation of the probable cause of death often relies on the measurement of the tramadol concentration in blood. However, postmortem redistribution (PMR) may affect the results and therefore bias the autopsy report. In the present study, the postmortem cardiac and femoral blood samples from 15 cases of fatal tramadol intoxication were obtained to assess the PMR of tramadol and its main active metabolite, O-desmethyltramadol (M1). Toxicological analysis was performed by the gas chromatography-electron impact-mass spectrometry (GC-EI-MS) method, previously developed and validated for the quantification of both analytes. The cardiac-to-femoral blood ratios of 1.40 and 1.28 were obtained for tramadol and M1, respectively. Results were compared with those in the literature and it was possible to conclude that femoral blood should be considered for quantitative interpretations in fatal cases of tramadol intoxication.

Effects of tramadol, clonazepam, and their combination on brain mitochondrial complexes

The present study is an unsubstantiated qualitative assessment of the abused drugs—tramadol and clonazepam. The aim of this study is to evaluate whether the effects of tramadol, clonazepam, and their combination on mitochondrial electron transport chain (ETC) complexes were influential at therapeutic or at progressively increasing doses. The study comprised of a total of 70 healthy male rats, aged 3 months. According to the drug intake regimen, animals were divided into seven groups: control, tramadol therapeutic, clonazepam therapeutic, combination therapeutic, tramadol abuse, clonazepam abuse, and combination abuse group. At the end of the experiment, brain mitochondrial ETC complexes (I, II, III, and IV) were evaluated. Histopathological examinations were also performed on brain tissues. The results showed that groups that received tramadol (therapeutic and abuse) suffered from weight loss. Tramadol abuse group and combination abuse group showed significant decrease in the activities of I, III, and IV complexes but not in the activity of complex II. In conclusion, tramadol but not clonazepam has been found to partially inhibit the activities of respiratory chain complexes I, III, and IV but not the activity of complex II and such inhibition occurred only at doses that exceeded the maximum recommended adult human daily therapeutic doses. This result explains the clinical and histopathological effects of tramadol, such as seizures and red neurons (marker for apoptosis), respectively.

Abuse liability and reinforcing efficacy of oral tramadol in humans

BACKGROUND

Tramadol, a monoaminergic reuptake inhibitor, is hepatically metabolized to an opioid agonist (M1). This atypical analgesic is generally considered to have limited abuse liability. Recent reports of its abuse have increased in the U.S., leading to more stringent regulation in some states, but not nationally. The purpose of this study was to examine the relative abuse liability and reinforcing efficacy of tramadol in comparison to a high (oxycodone) and low efficacy (codeine) opioid agonist.

METHODS

Nine healthy, non-dependent prescription opioid abusers (6 male and 3 female) participated in this within-subject, randomized, double blind, placebo-controlled study. Participants completed 14 paired sessions (7 sample and 7 self-administration). During each sample session, an oral dose of tramadol (200 and 400 mg), oxycodone (20 and 40 mg), codeine (100 and 200 mg) or placebo was administered, and a full array of abuse liability measures was collected. During self-administration sessions, volunteers were given the opportunity to work (via progressive ratio) for the sample dose or money.

RESULTS

All active doses were self-administered; placebo engendered no responding. The high doses of tramadol and oxycodone were readily self-administered (70%, 59% of available drug, respectively); lower doses and both codeine doses maintained intermediate levels of drug taking. All three drugs dose-dependently increased measures indicative of abuse liability, relative to placebo; however, the magnitude and time course of these and other pharmacodynamic effects varied qualitatively across drugs.

CONCLUSIONS

This study demonstrates that, like other mu opioids, higher doses of tramadol function as reinforcers in opioid abusers, providing new empirical data for regulatory evaluation.