Maintenance of mitochondrial function by sinapic acid protects against tramadol-induced toxicity in isolated mitochondria obtained from rat brain

It is reported that tramadol can induce neurotoxic effects with the production of DNA damage, mitochondrial dysfunction, and oxidative stress. The current study aimed to evaluate the potential role of mitochondrial impairment in the pathogenesis of tramadol-induced neurotoxicity, and protective effect of sinapic acid (SA) against it in isolated mitochondria from rat brain. Mitochondria were isolated and were incubated with toxic concentrations (100 μM) of tramadol and then cotreated with tramadol + SA (10, 50, and 100 μM). Biomarkers of mitochondrial toxicity including succinate dehydrogenases (SDH) activity, reactive oxygen species (ROS), lipid peroxidation (LPO), mitochondrial membrane potential (MMP), GSH depletion, and mitochondrial swelling were assessed. Our results showed a significant decrease in SDH activity, and a significant increase in ROS, LPO, GSH depletion, MMP collapse, and mitochondrial swelling was detected in tramadol group. We observed that 50 and 100 μM SA cotreatment for 1 h efficiently ameliorated tramadol-caused damage in mitochondrial dysfunction, accumulation of ROS, LPO, GSH depletion, depolarization of mitochondrial membrane potential, and mitochondrial swelling. These data suggest that mitochondrial impairment and oxidative stress are mechanisms involved in the pathogenesis of tramadol-induced neurotoxicity. Also, results indicate that SA antagonizes against tramadol-induced mitochondrial toxicity and suggest SA may be a preventive/therapeutic agent for tramadol-induced neurotoxicity complications.

Pharmacobezoar-Related Fatalities: A Case Report and a Review of the Literature

ABSTRACT

Pharmacobezoars develop after an acute overdose or during routine drug administration. Here, the authors present a case of fatal multidrug overdose involving a 62-year-old woman. Her usual treatment included tramadol extended-release, citalopram, and mirtazapine. Furthermore, she self-medicated and misused her husband's medications. The autopsy revealed the presence of a voluminous medication bezoar in the stomach. No mechanical complication was noted. Toxicologic analyses were performed using gas chromatography with flame ionization detection, liquid chromatography with diode array detection, gas chromatography with mass spectrometry detection, and liquid chromatography coupled to tandem mass spectrometry. Tramadol (34,000 mcg/L), O-desmethyltramadol (2200 mcg/L), propranolol (6000 mcg/L), bromazepam (2500 mcg/L), zopiclone (1200 mcg/L), and citalopram (700 mcg/L) were identified in femoral blood at toxic concentrations. Interestingly, the femoral blood and vitreous humor concentration ratio was approximately 0.7. Furthermore, an English exhaustive literature search was performed using several different electronic databases without any limiting period to identify published pharmacobezoar-related fatalities. Seventeen publications were identified reporting a total of 19 cases. Decedents' mean age was 47.6 years [0.8-79] and a clear female predominance emerged. Several drugs were involved in pharmacobezoar formation. Death was attributed to drug toxicity in 13 cases, and to mechanical complications and/or sepsis in 4 cases. A mixed cause of death was reported in 2 cases. Although rare, pharmacobezoars remain potentially lethal and raise challenges in therapeutic management.

Modulatory effects of Cannabis sativa co-administration with tramadol and codeine on cognitive function in male rats

Most teenagers mix up various psychoactive cocktail substances in combinations to get intoxicated. The role of the mixture combination of codeine (CDE), tramadol (TMD), and Cannabis sativa (CNB) on brain cognition, purinergic, cholinergic, and antioxidant enzyme activities remains unknown. This study sought to assess the mechanism of action of combinations of CDE+ TMD+ CNB on the function and activities of the brain of male Wistar rats. Forty-eight male Wistar rats were divided into 8 groups, n = 6. Group 1 served as a control, groups 2, 3, and 4 were exposed to CDE (2 mg/kg bw), TMD (10 mg/kg bw), and CNB (200 mg/kg bw), while groups 5, 6, 7, and 8 were co-administered with CDE+TMD, CNB+ TMD, CNB+CDE, and CNB+TMD+CDE orally for 28 days. This study revealed the effect of prolonged administration of CNB, TMD, and CDE on the suppression of cognitive function, acetyl-cholinesterase (AChE), butyl-cholinesterase (BChE), monoamine oxidase (MAO) enzyme activities, and antioxidant enzyme activities in rats' brains when compared against control rats (P < 0.05). However, the activities of ectonucleosides (NTPdase), adenosine deaminase (ADA), and malondialdehyde levels produced in the brain of rats were significantly elevated (P < 0.05). This study reported the mechanism behind the neurotoxicity of CNB, TMD, and CDE on rats' cognitive, cholinergic, purinergic, and antioxidant enzymes as a consequence of the drastic reduction in cholinesterase enzyme activities leading to neurotransmitter poisoning.

Neuroprotective potential of trimetazidine against tramadol-induced neurotoxicity: role of PI3K/Akt/mTOR signaling pathways

Tramadol (TRA) causes neurotoxicity whereas trimetazidine (TMZ) is neuroprotective. The potential involvement of the PI3K/Akt/mTOR signaling pathway in the neuroprotection of TMZ against TRA-induced neurotoxicity was evaluated. Seventy male Wistar rats were divided into groups. Groups 1 and 2 received saline or TRA (50 mg/kg). Groups 3, 4, and 5 received TRA (50 mg/kg) and TMZ (40, 80, or 160 mg/kg) for 14 days. Group 6 received TMZ (160 mg/kg). Hippocampal neurodegenerative, mitochondrial quadruple complex enzymes, phosphatidylinositol-3-kinases (PI3Ks)/protein kinase B levels, oxidative stress, inflammatory, apoptosis, autophagy, and histopathology were evaluated. TMZ decreased anxiety and depressive-like behavior induced by TRA. TMZ in tramadol-treated animals inhibited lipid peroxidation, GSSG, TNF-α, and IL-1β while increasing GSH, SOD, GPx, GR, and mitochondrial quadruple complex enzymes in the hippocampus. TRA inhibited Glial fibrillary acidic protein expression and increased pyruvate dehydrogenase levels. TMZ reduced these changes. TRA decreased the level of JNK and increased Beclin-1 and Bax. TMZ decreased phosphorylated Bcl-2 while increasing the unphosphorylated form in tramadol-treated rats. TMZ activated phosphorylated PI3Ks, Akt, and mTOR proteins. TMZ inhibited tramadol-induced neurotoxicity by modulating the PI3K/Akt/mTOR signaling pathways and its downstream inflammatory, apoptosis, and autophagy-related cascades.

Carbamazepine, venlafaxine, tramadol, and their main metabolites: Toxicological effects on zebrafish embryos and larvae

Pharmaceutical compounds and their metabolites are found in natural and wastewater. However, investigation of their toxic effects on aquatic animals has been neglected, especially for metabolites. This work investigated the effects of the main metabolites of carbamazepine, venlafaxine and tramadol. Zebrafish embryos were exposed (0.1-100 µg/L) for 168hpf exposures to each metabolite (carbamazepine-10,11-epoxide, 10,11-dihydrocarbamazepine, O-desmethylvenlafaxine, N-desmethylvenlafaxine, O-desmethyltramadol, N-desmethyltramadol) or the parental compound. A concentration-response relationship was found for the effects of some embryonic malformations. Carbamazepine-10,11-epoxide, O-desmethylvenlafaxine and tramadol elicited the highest malformation rates. All compounds significantly decreased larvae responses on a sensorimotor assay compared to controls. Altered expression was found for most of the 32 tested genes. In particular, abcc1, abcc2, abcg2a, nrf2, pparg and raraa were found to be affected by all three drug groups. For each group, the modelled expression patterns showed differences in expression between parental compounds and metabolites. Potential biomarkers of exposure were identified for the venlafaxine and carbamazepine groups. These results are worrying, indicating that such contamination in aquatic systems may put natural populations at significant risk. Furthermore, metabolites represent a real risk that needs more scrutinising by the scientific community.

The Behavioral and Neurochemical Changes Induced by Boldenone and/or Tramadol in Adult Male Rats

Boldenone and tramadol are abused among large sectors of adolescents. Therefore, the behavioral changes concerned with memory and cognitive functions and neurochemical variations were investigated in the cortex of rats treated with boldenone and/or tramadol. Rats were divided into control and rats treated with boldenone, tramadol, or both drugs. At the end of the treatment period, the memory and cognitive functions were evaluated by the Y-maze test (YMT) and elevated plus maze test (EPMT) and the motor activity was determined by the open field test (OFT). The cortex was dissected to carry out the neurochemical analyses. Rats treated with boldenone and/or tramadol showed impaired memory and cognitive functions and reduced motor activity. A significant increase in lipid peroxidation (MDA), nitric oxide (NO), and a significant decrease in reduced glutathione (GSH) were observed in the cortex of rats treated with boldenone and/or tramadol. The levels of acetylcholinesterase (AChE) and monoamine oxidase (MAO) decreased significantly. Western blot data showed a significant decrease in Bcl2 and a significant increase in caspase-3 and inducible nitric oxide synthase (iNOS) in rats treated with boldenone and/or tramadol. These changes were associated with neuronal death as indicated from the histopathological examination.

The present findings indicate that boldenone and/or tramadol induced impairment in memory and cognitive functions. These changes could be mediated by the increase in oxidative stress, neuroinflammation, reduced AChE level, and reduced number of survived neurons in the cortex as indicated from the decreased Bcl2 level and the histological examination.

The effects of quercetin on seizure, inflammation parameters and oxidative stress in acute on chronic tramadol intoxication

BACKGROUND

Tramadol is a widely used synthetic opioid for moderate to severe pain. Some studies have shown that tramadol can increase oxidative stress in different tissues of the body. Quercetin is also a substance with various biological effects, including antioxidant, anti-inflammatory, hepatoprotective, nephroprotective, and cardioprotective activities. The current investigation aimed at determining the effects of quercetin, with or without naloxone, on tramadol intoxication.

METHODS

This study was performed on 30 male Wistar rats divided into five groups: Group I) control group: intraperitoneal injections of normal saline 0.9% for 14 days; Group II) tramadol: 25 mg/kg for 14 days, and then a 50 mg/kg acute dose injection on the last day; Group III) acute quercetin (single dose): tramadol injection as with the second group plus 100 mg/kg of quercetin on the last day; Group IV) chronic quercetin: tramadol injection similar to the second group plus quercetin 100 mg/kg for 14 days; Group V) quercetin plus naloxone: tramadol injection similar to the second group plus injection of quercetin 100 mg/kg + intravenous naloxone 2 mg/kg on the last day, followed by a 4 mg/kg/h injection of naloxone for six hours. The rats were monitored for six hours on the last day, relating to the number and severity of seizures. Finally, the samples were prepared for biochemical investigation of the serum level of oxidative stress markers (MDA, SOD, NOx), inflammatory factors (IL-6, TNF-α), biochemical parameters (ALT, AST, creatinine, glucose) and hematological assay. The liver, heart, kidney, cortex, cerebellum, and adrenal tissues were collected to investigate the redox state.

RESULTS

None of the treatments had positive effects on the number and severity of seizures. Chronic administration of quercetin led to alteration of some blood parameters, including reduced hemoglobin level and elevated platelet counts. Acute on chronic tramadol administration resulted in a significant rise in AST, where different treatments failed to reduce their levels down to the control group.

CONCLUSION

chronic administration of quercetin showed decreased oxidative/nitrosative stress in the liver, kidney, adrenal, and heart tissues. Quercetin plus naloxone decreased oxidative stress in the heart and adrenal tissues, but adverse effects on the brain cortex and hepatic function. Single-dose quercetin reduced cardiac oxidative stress.

Morphometric, hematological and oxidative stress changes in Clarias gariepinus following sub-chronic exposure to tramadol

Tramadol is among the most famous analgesic drugs used for the management, treatment and relief of moderate to severe pain conditions. The present study investigated the effects of tramadol on the behavior, mortality, morphometric, hematology and oxidative stress parameters of C. gariepinus juveniles. The 96 h LC₅₀ value of tramadol determined by probit analysis was 88.76 mg/L. Based on this value, fish were exposed to sublethal concentrations of 4.44, 8.88, 17.75 mg/L tramadol and 0.0 mg/L (control) for the period of 15 days and allowed to recover for 5 days. Fish exposed to tramadol showed some abnormal behavioral responses and mortality increased with increase in the exposure duration and concentrations except for the control. There were variations in hepatosomatic index (HSI) and condition factor (CF) in fish exposed to tramadol. Exposure of C. gariepinus to tramadol elicited reduction in the values of white blood cell (WBC), red blood cell (RBC), hemoglobin (Hb), packed cell volume (PCV) and mean corpuscular volume (MCV) while the values of mean corpuscular hemoglobin (MCH) and the mean corpuscular hemoglobin concentration (MCHC) increased. The values of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), reduced glutathione (GSH) and lipid peroxidation (LPO) increased significantly in the exposed fish compared with the control. The values of glutathione peroxidase (GPx) however decreased. The results of the present study demonstrate that tramadol is toxic to fish and its use should be monitored in the aquatic environment.

Effects of naloxone and diazepam on blood glucose levels in tramadol overdose using generalized estimating equation (GEE) model; (an experimental study)

BACKGROUND

Tramadol is a synthetic opioid and poisoning is increasing around the world day by day. Various treatments are applied for tramadol poisoning. Due to the unknown effects of tramadol poisoning and some of its treatments on blood glucose levels, this study was conducted to investigate the overdose of tramadol and its common treatments (naloxone, diazepam), and their combination on blood glucose levels in male rats.

METHODS

This study was conducted in 45 male Wistar rats. The animals were randomly divided into five groups of 9. They received a 75 mg/kg dose of tramadol alone with naloxone, diazepam, and a combination of both of these two drugs. On the last day, animals' tail vein blood glucose levels (BGL) were measured using a glucometer at different times, including before the tramadol injection (baseline) and 1 hour, 3 hours, and 6 hours after wards. The rats were anesthetized and sacrificed 24 h after the last injection. Blood samples were then taken, and the serum obtained was used to verify the fasting glucose concentration. Data were analyzed using SPSS software at a significance level of 0.05 using a one-way analysis of variance (ANOVA) and a generalized estimating equation (GEE).

RESULTS

According to the GEE model results, the diazepam-tramadol and naloxone-diazepam-tramadol groups showed blood glucose levels five units higher than the tramadol group (p < 0.05). The diazepam-tramadol group had significantly higher blood glucose levels than the naloxone-tramadol group (p < 0.05). The mean blood glucose levels before the intervention, 3 hours and 6 hours after the injection of tramadol did not differ between the groups, but the blood glucose levels 1 hour after the injection of tramadol in the group of naloxone-tramadol were significantly lower than in the control group (p < 0.05). Blood glucose levels did not differ between the groups 24 h after injection of tramadol.

CONCLUSION

The results of the present study showed tramadol overdose does not affect blood glucose levels. The diazepam-tramadol combination and the diazepam-naloxone-tramadol combination caused an increase in blood glucose levels.

Traces of tramadol in water impact behaviour in a native European fish

Tramadol is a widely used analgesic with additional antidepressant and anxiolytic effects. This compound has been reported in continental waters reaching concentrations of µg/L as a consequence of its inefficient removal in sewage treatment plants and increasing use over time. In this study, European chubs (Squalius cephalus) were exposed to 1 µg/L of tramadol in water for 42 days with a subsequent 14 days of depuration. Our results revealed that chubs exposed to this analgesic underwent changes in their behaviour as compared to the control group. The behavioural outcome was also influenced by the individual concentration of tramadol in brain tissue. In particular, experimental fish presented anxiolytic-like effects, characterized by less bold and less social individuals. Exposed animals were less frequently out of the shelter and moved a shorter distance, indicating that they explored the new environment less during the boldness test. In the novel object recognition experiment, although they distinguished the new item, they examined it less and displayed a reduced activity. Shoal cohesion was disrupted as observed in an increased distance between individuals. After the depuration phase, this alteration remained whereas the boldness effect disappeared. Moreover, the degree of behavioural changes was correlated with the concentration of the substance in brain. According to our findings, chronic presence of tramadol in the environment can impact the fitness of exposed aquatic fauna by altering evolutionary crucial behaviours.

Preconditioning by ultra-low dose of tramadol reduces the severity of tramadol-induced seizure: Contribution of glutamate receptors

Tramadol, a weak agonist of mu-opioid receptors, causes seizure via several mechanisms. Preconditioning has been purposed to reduce the epileptic seizures in animal models of epilepsy. The preconditioning effect of tramadol on seizure is not studied yet. This study was designed to evaluate the preconditioning effect of ultra-low dose of tramadol on the seizures induced by tramadol at high dose. Furthermore, regarding the critical role of glutamate signaling in the pathogenesis of epilepsy, the effect of preconditioning on some glutamate signaling elements was also examined. Male Wistar rats received tramadol (2 mg/kg, i.p) or normal saline (1 mL/kg, i.p) in preconditioning and control groups, respectively. After 4 days, the challenging tramadol dose (150 mg/kg) was injected to all rats. Epileptic behaviors were recorded during 50 min. The expression of Norbin (as a regulator of metabotropic glutamate receptor 5), Calponin3 (as a regulator of excitatory synaptic markers), NR1 (NMDA receptor subunit 1) and GluR1 (AMPA receptor subunit 1) was measured in hippocampus, prefrontal cortex (PFC) and amygdala. Preconditioning decreased the number and duration of tremors and tonic-clonic seizures. Norbin, Calponin3, NR1 and GluR1 expression were decreased in hippocampus, and preconditioning had no effect on them. In contrast, it increased Norbin expression in PFC and amygdala, and attenuated NR1 and GluR1 upregulation following tramadol at high dose. These findings indicated that preconditioning by ultra-low dose of tramadol protected the animals against seizures following high dose of tramadol mediated, at least in part, by Norbin up regulation, and NR1 and GluR1 down regulation.

Poikilocytosis and tissue damage as negative impacts of tramadol on juvenile of Tilapia (Oreochromis niloticus)

Pharmaceuticals residue was detected in the water bodies as a consequence of the incomplete treatment. Recently, the side impacts of that residue on aquatic creatures have received a considerable attention. However, there is insufficient information about the effect of the most consumed narcotic drug (tramadol) on fish as an aquatic model. Thus, this study aims at investigating the poikilocytosis and tissue damage in Oreochromis niloticus after the exposure to 100 and 200 mg/L of tramadol hydrochloride. Three groups of fish were used; one as a control group, and the other two groups were exposed to 100 mg/L and 200 mg/L of tramadol hydrochloride respectively for 25 days. Exposure to tramadol caused a significant increase in the percentage of poikilocytosis compared to the control group. Poikilocytosis included tear-drop cell, spindle-shaped cell, sickle cell, schistocyte, blebbed cell, acanthocyte, eccentric nucleus, amoebocyte, dividing cell, and crenated cell. Moreover, liver tissue in fish exposed to tramadol showed degeneration and vacuolization of hepatocytes and atrophy of pancreatic acini as signs of histopathological alterations. Histopathological changes of brain showed severe gliosis, dark neurons, and vacuolization in fish exposed to tramadol compared to control fish. Gills tissue showed erosion, epithelial lifting, and secondary lamellae shrinking in fish exposed to tramadol compared to control fish. In conclusion, tramadol induced histopathological changes in liver, brain, and gills of Oreochromis niloticus as well as poikilocytosis were indicated clearly. Therefore, tramadol leakage to waters should be avoided to preserve aquatic creatures.

Effects of tramadol administration on male reproductive toxicity in Wistar rats The role of oxidative stress, mitochondrial dysfunction, apoptosis-related gene expression, and nuclear factor kappa B signalling

AIM

The present study investigated the role of redox balance, inflammation, mitochondrial dysfunction, and apoptosis in Tramadol (Tra)-induced testicular toxicity.

METHOD

Twenty-four male Wistar rats were randomly divided into either the control group or the groups receiving different doses of Tra (25, 50, and 75 mg/kg/day, i.p.) for 21 successive days. Testicular tissues were collected for oxidative stress, mitochondrial function, sperm assays and histopathological evaluation. Real-time polymerase chain reaction was performed to evaluate the markers of inflammation and apoptosis.

RESULTS

Tra caused a significant reduction in the sperm count, motility and morphology, while it caused a marked increase in oxidative stress parameters. In addition, Tra induced testicular mitochondrial dysfunction due to the collapse of mitochondrial membrane potential and mitochondrial swelling. It also led to the significant inhibition of anti-apoptotic Bcl-2 expression, besides a significant increase in pro-apoptotic Bax expression. There was a significant increase in the level of tumour necrosis factor-α, interlukin-1β and nuclear factor kappa B. Histopathological degenerative changes were observed in the testis after Tra exposure.

CONCLUSIONS

The present results suggest that Tra exposure may lead to reproductive toxicity due to the loss of the antioxidant defence system, mitochondrial dysfunction, and activation of inflammatory and apoptotic pathways (Tab. 4, Fig. 5, Ref. 63).

Brief Report: A Case of Tramadol Overdose: Extracorporeal Life Support and Hemoperfusion as Life-Saving Treatment

We describe the case of a 49-year-old woman with a Tramadol intoxication associated with multiorgan failure. Veno-arterial femoro-femoral extracorporeal life support (VA-ECLS) and hemoperfusion (HP) were used as rescue treatments. The emergency medical service found a woman at home unconscious. Once in the hospital, she was intubated and catecholamines support was immediately started for a severe shock. Brain CT was normal, whereas EEG revealed a metabolic encephalopathy pattern. Toxic levels of Tramadol and Quetiapine were detected. VA-ECLS was implanted due to persistent multiorgan failure, and HP with a charcoal cartridge was set to increase the Tramadol clearance. To quantify the charcoal cartridge's removal efficiency of Tramadol, Tramadol concentration was measured before and after the cartridge and before and after the treatment in the patient's blood. The charcoal cartridge showed good extraction ratio during the treatment and no significant rebound effect. VA-ECLS and HP allowed the patient to be weaned from vasoconstrictors and the resolution of the organ failures. These treatments might be lifesaving in the Tramadol intoxication.

Behaviour and cardiac response to stress in signal crayfish exposed to environmental concentrations of tramadol

Evidence of the ecological and biological impact of pharmaceuticals in surface waters on aquatic organisms is increasing. Tramadol is a synthetic opioid analgesic used to treat chronic and acute pain. To investigate its long-term effects at environmentally relevant levels, we evaluated heart rate (HR) and locomotion of signal crayfish Pacifastacus leniusculus during a 21-day exposure to 1 μg L-1 tramadol followed by 14 days depuration. Locomotion and HR were recorded over a period 30 min before and 30 min after exposure to physiological fluids of an injured conspecific, a natural stressor, four times during the tramadol exposure and four times during depuration. A significant increase in HR following stress induction was found in the majority of tramadol-exposed and control crayfish, as well as significant group-specific HR changes between both groups. Locomotor activity during tramadol treatment differed from that during depuration, in general showing less time spent in locomotion and lower distance moved. The tramadol exposed crayfish exhibited higher velocity during depuration than during the exposure period. Results may suggest a potential shift in prey-predator relationships.

Protecting the environment from psychoactive drugs: Problems for regulators illustrated by the possible effects of tramadol on fish behaviour

There is concern that psychoactive drugs present in the aquatic environment could affect the behaviour of fish, and other organisms, adversely. There is considerable experimental support for this concern, although the literature is not consistent. To investigate why, fish were exposed to three concentrations of the synthetic opiate tramadol for 23-24 days, and their anxiolytic behaviour in a novel tank diving test was assessed both before and after exposure. The results were difficult to interpret. The positive control drug, the anti-depressant fluoxetine, produced the expected results: exposed fish explored the novel tank more, and swam more slowly while doing so. An initial statistical analysis of the results provided relatively weak support for the conclusion that both the low and high concentrations of tramadol affected fish behaviour, but no evidence that the intermediate concentration did. To gain further insight, UK and Japanese experts in ecotoxicology were asked for their independent opinions on the data for tramadol. These were highly valuable. For example, about half the experts replied that a low concentration of a chemical can cause effects that higher concentrations do not, although a similar number did not believe this was possible. Based both on the inconclusive effects of tramadol on the behaviour of the fish and the very varied opinions of experts on the correct interpretation of those inconclusive data, it is obvious that more research on the behavioural effects of tramadol, and probably all other psychoactive drugs, on aquatic organisms is required before any meaningful risk assessments can be conducted. The relevance of these findings may apply much more widely than just the environmental risk assessment of psychoactive drugs. They suggest that much more rigorous training of research scientists and regulators is probably required if consensus decisions are to be reached that adequately protect the environment from chemicals.

Disinfection by-Products and Ecotoxic Risk Associated with Hypochlorite Treatment of Tramadol

In recent years, many studies have highlighted the consistent finding of tramadol (TRA) in the effluents from wastewater treatment plants (WTPs) and also in some rivers and lakes in both Europe and North America, suggesting that TRA is removed by no more than 36% by specific disinfection treatments. The extensive use of this drug has led to environmental pollution of both water and soil, up to its detection in growing plants. In order to expand the knowledge about TRA toxicity as well as the nature of its disinfection by-products (DBPs), a simulation of the waste treatment chlorination step has been reported herein. In particular, we found seven new by-products, that together with TRA, have been assayed on different living organisms (Aliivibrio fischeri, Raphidocelis subcapitata and Daphnia magna), to test their acute and chronic toxicity. The results reported that TRA may be classified as a harmful compound to some aquatic organisms whereas its chlorinated product mixture showed no effects on any of the organisms tested. All data suggest however that TRA chlorination treatment produces a variety of DBPs which can be more harmful than TRA and a risk for the aquatic environment and human health.

The molecular and biochemical insight view of lycopene in ameliorating tramadol-induced liver toxicity in a rat model: implication of oxidative stress, apoptosis, and MAPK signaling pathways

The influence of tramadol (TD) on hepatic tissue and the potential efficiency of lycopene to mitigate TD-induced hepatotoxic impacts were determined. Forty male albino rats were allocated into four groups: group I, untreated (placebo); group II, injected with TD (15 mg kg^-1) intraperitoneally (i.p.); group III, gastrogavaged with lycopene (10 mg kg^-1) per os (p.o.); and group IV received TD with lycopene with the same mentioned doses for 15 days. The results demonstrated that TD induced augmentation in tissue lipid peroxidation biomarker and disturbance in the antioxidant homeostasis and elevated the activity of serum liver injury biomarkers and decreased serum protein, globulin, and albumin. Hepatic glutathione S-transferase (GST), superoxide dismutase (SOD), thioredoxin-1 (Txn-1), and catalase (CAT) activities and gene expression were decreased and glutathione content was reduced in the TD-challenged rats, and these effects were alleviated by lycopene. Furthermore, TD induced apoptosis in liver tissues as shown by DNA fragmentation and upregulation of proapoptotic Bax and Casp-3 while lycopene upregulated the antiapoptotic Bcl-2. The results of Western blot showed that lycopene initiated low expression of mitogen activated protein kinase pathway (MAPK) protein expression in liver tissues of TD-challenged rats. In addition, lycopene reduced fatty degeneration and necrosis of the liver in TD-challenged group. Our data demonstrate that lycopene appears to be highly efficient in mitigating the hepatotoxic impacts of TD by preventing lipid peroxidation and initiating modifications in the expression and activity of antioxidant pathways. Surprisingly, lycopene fortified liver tissue by inhibiting DNA fragmentation and apoptosis signaling induced by TD. MAPK activation may be dependent from ROS generation; due to lycopene which possessed antioxidant potential did have a substantial effect on MAPK activity.

Environmentally relevant concentrations of tramadol and citalopram alter behaviour of an aquatic invertebrate

Environmental pollution by pharmaceutically active compounds, used in quantities similar to those of pesticides and other organic micropollutants, is increasingly recognized as a major threat to the aquatic environment. These compounds are only partly removed from wastewaters and, despite their low concentrations, directly and indirectly affect behaviour of freshwater organisms in natural habitats. The aim of this study was to behaviourally assess the effects of an opioid painkiller (tramadol) and antidepressant drug (citalopram) on behaviour patterns of a clonal model species, marbled crayfish. Animals exposed to environmentally relevant concentrations of both tested compounds (∼1 μg l^-1) exhibited significantly lower velocity and shorter distance moved than controls. Crayfish exposed to tramadol spent more time in shelters. Results were obtained by a simple and rapid method recommended as suitable for assessment of behaviour in aquatic organisms exposed to single pollutants and combinations.

Toxicity of naproxen sodium and its mixture with tramadol hydrochloride on fish early life stages

Pharmaceuticals occur in water bodies as a consequence of their incomplete removal during waste water treatment processes. The occurence of pharmaceuticals in surface waters as well as their possible impact on aquatic vertebrates have received considerable attention in recent years. However, there is still a lack of informations on the chronic effects of widely used drugs as well as their possible mixture toxicity on non-target aquatic vertebrates as well as their possible mixture toxicity. The aim of this study was to assess the effects of naproxen sodium on early life stages of fish and evaluate its mixture toxicity with tramadol hydrochloride, which was assessed in our earlier study as a single substance. Two embryo-larval toxicity tests with common carp (Cyprinus carpio) were performed according to the OECD guideline 210 (Fish, Early-life Stage Toxicity Test) in order to assess the subchronic toxicity of naproxen sodium and tramadol hydrochlorid-naproxen sodium mixture at the concentrations of 10; 50; 100 and 200 μg/L. These experiments were conducted for 32 days. The subchronic exposure to naproxen sodium and naproxen sodium and tramadol hydrochloride mixture had a strong effect on the early life stages of common carp. Hatching, developmental rate, morphology, histopathology and, in the case of the naproxen sodium and tramadol hydrochloride mixture, mortality were influenced. The bioindicators of oxidative stress were also influenced. The LOEC was determined at 10 μg/L for both naproxen sodium and naproxen sodium and tramadol hydrochloride mixture.

The effect of tramadol hydrochloride on early life stages of fish

The aim of this study was to perform the fish embryo acute toxicity test (FET) on zebrafish (Danio rerio) and the early-life stage toxicity test on common carp (Cyprinus carpio) with tramadol hydrochloride. The FET was performed using the method inspired by the OECD guideline 236. Newly fertilized zebrafish eggs were exposed to tramadol hydrochloride at concentrations of 10; 50; 100 and 200μg/l for a period of 144h. An embryo-larval toxicity test on C. carpio was performed according to OECD guideline 210 also with tramadol hydrochloride at concentrations 10; 50; 100 and 200μg/l for a period of 32 days. Hatching was significantly influenced in both acute and subchronic toxicity assays. Subchronic exposure also influenced early ontogeny, both morphometric and condition characteristics and caused changes in antioxidant enzyme activity. The LOEC value was found to be 10μg/l tramadol hydrochloride.

Photocatalytic degradation kinetics, mechanism and ecotoxicity assessment of tramadol metabolites in aqueous TiO2 suspensions

This study investigated for the first time the photocatalytic degradation of three well-known transformation products (TPs) of pharmaceutical Tramadol, N-desmethyl-(N-DES), N,N-bidesmethyl (N,N-Bi-DES) and N-oxide-tramadol (N-OX-TRA) in two different aquatic matrices, ultrapure water and secondary treated wastewater, with high (10 mg L(-1)) and low (50 μg L(-1)) initial concentrations, respectively. Total disappearance of the parent compounds was attained in all experiments. For initial concentration of 10 mg L(-1), the target compounds were degraded within 30-40 min and a mineralization degree of more than 80% was achieved after 240 min of irradiation, while the contained organic nitrogen was released mainly as NH4(+) for N-DES, N,N-Bi-DES and NO3(-) for N-OX-TRA. The degradation rates of all the studied compounds were considerably decreased in the wastewater due to the presence of inorganic and organic constituents typically found in effluents and environmental matrices which may act as scavengers of the HO(•). The effect of pH (4, 6.7, 10) in the degradation rates was studied and for N-DES-TRA and N,N-Bi-DES-TRA, the optimum pH value was 6.7. In contrast, N-OX-TRA showed an increasing trend in the photocatalytic degradation kinetic in alkaline solutions (pH 10). The major transformation products were identified by high resolution accurate mass spectrometry coupled with liquid chromatography (HR-LC-MS). Scavenging experiments indicated for all studied compounds the important role of HO(•) in the photocatalytic degradation pathways that included mainly hydroxylation and further oxidation of the parent compounds. In addition, Microtox bioassay (Vibrio fischeri) was employed for evaluating the ecotoxicity of photocatalytically treated solutions. Results clearly demonstrate the progressive decrease of the toxicity and the efficiency of the photocatalytic process in the detoxification of the irradiated solutions.

Chlorination of tramadol: Reaction kinetics, mechanism and genotoxicity evaluation

Tramadol (TRA) is one of the most detected analgesics in environmental matrices, and it is of high significance to study the reactivity of TRA during chlorination considering its potential toxicity to the environment. The chlorine/TRA reaction is first order with respect to the TRA concentration, and a combination of first-order and second-order with respect to chlorine concentration. The pH dependence of the observed rate constants (kobs) showed that the TRA oxidation reactivity increased with increasing pH. kobs can be quantitatively described by considering all active species including Cl2, Cl2O and HOCl, and the individual rate constants of HOCl/TRA(0), HOCl/TRAH(+), Cl2/TRA and Cl2O/TRA reactions were calculated to be (2.61±0.29)×10(3)M(-1)s(-1), 14.73±4.17M(-1)s(-1), (3.93±0.34)×10(5)M(-1)s(-1) and (5.66±1.83)×10(6)M(-1)s(-1), respectively. Eleven degradation products were detected with UPLC-Q-TOF-MS, and the corresponding structures of eight products found under various pH conditions were proposed. The amine group was proposed to be the initial attack site under alkaline pH conditions, where reaction of the deprotonated amine group with HOCl is favorable. Under acidic and neutral pH conditions, however, two possible reaction pathways were proposed. One is an electrophilic substitution on the aromatic ring, and another is an electrophilic substitution on the nitrogen, leading to an N-chlorinated intermediate, which can be further oxidized. Finally, the SOS/umu test showed that the genotoxicity of TRA chlorination products increased with increasing dosage of chlorine, which was mostly attributed to the formation of some chlorine substitution products.

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

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

Tramadol deaths in Northern Ireland: a review of cases from 1996 to 2012

In the UK tramadol is a frequently prescribed opioid analgesic which is becoming increasingly popular as a drug of misuse. Its use varies worldwide and in the last decade it has been upgraded to a controlled substance in several countries, due to an increased number of deaths associated with its use. A review of all deaths associated with tramadol in Northern Ireland was performed and this highlighted 127 cases from 1996 to the end of 2012. A 10% increase in deaths due to tramadol was noted. In 2001 tramadol deaths represented 9% of all drug misuse deaths rising to 40% in 2011. The majority of the deaths occurred in males (62%), with a median age of 41 years, living in the Belfast city area (36%). Tramadol fatalities were found in combination with other drugs/medicines (49%), alcohol (36%) or alone (23%). Most of those who died did not reach hospital, with only 2% presenting with multi-organ or acute liver failure. In just over half of the deaths tramadol had not been prescribed by a medical practitioner (53%). Depression, addiction and seizures were recognised risk factors. An increase in awareness of tramadol toxicity is needed amongst the public and doctors.

Tramadol safety--cholinergic system of rat brain without nociception

In the present investigation, changes in the levels of acetylcholinesterase (AChE) activity, acetylcholine (ACh) content, and the activity levels of plasma (PChE) and erythrocyte (EChE) cholinesterases as representatives of pseudocholinesterases were examined in different areas of the rat brain during the administration of the synthetic opioid analgesic drug tramadol (Ultram) without induction of pain. Male adult Wistar rats weighing 150 +/- 20 g were used. Tramadol was injected subcutaneously (s.c.) into the rats at 0, 24 and 48 h, and the changes in the above cholinergic parameters were recorded after the completion of 3, 6, 12, 24, 48 and 72 h. Following administration of single dose (for rats sacrificed at 24 h) and multiple doses (for rats sacrificed at 48 and 72 h) of tramadol, the ACh content showed an increase in all brain areas. Concurrently, the AChE activity was found to decrease in all the areas. PChE and EChE showed higher activity levels, with EChE showing a higher level of activity than PChE. The levels of all the parameters examined returned towards the control levels by about 24 h after the administration of single dose of tramadol. However, the ACh levels showed an elevation at 48 and 72 h (following double and triple doses, respectively). The AChE activity levels also showed a simultaneous increase at 48 and 72 h, presumably to balance the increase in ACh levels on longer treatment with tramadol. The observed changes in the cholinergic segment presumably do not cause any physiological lesion since they reverted to control levels after the time limit of change under tramadol influence. This observation indicates that tramadol can be administered safely both under nociceptive and non-nociceptive conditions.

Biodegradability and ecotoxicitiy of tramadol, ranitidine, and their photoderivatives in the aquatic environment

PURPOSE

This study was designed to assess the fate and the overall potential impacts of the widely prescribed drugs ranitidine and tramadol after their introduction into the aquatic environment.

METHODS

The probability to detect these two drugs in the aquatic environment was studied by analyzing their abiotic and biotic degradation properties. For this purpose, samples were irradiated with different light sources, and three widely used biodegradability tests from the OECD series, the closed bottle test (OECD 301 D), the manometric respirometry test (OECD 301 F) and the Zahn-Wellens test (OECD 302 B), were conducted. The ecotoxicity of the photolytically formed transformation products was assessed by performing the bacterial growth inhibition test (EN ISO 10712). Furthermore, quantitative structure-activity relationship analysis and a risk analysis based on the calculation of the predicted environmental concentrations have also been conducted to assess the environmental risk potential of the transformation products. The possible formation of stable products by microbial or photolytical transformation has been investigated with DOC and LC-MS analytics.

RESULTS

In the present study, neither ranitidine, nor tramadol, nor their photoderivatives were found to be readily or inherently biodegradable according to test guidelines. The photolytic transformation was faster under a UV lamp compared to the reaction under an Xe lamp with a spectrum that mimics sunlight. No chronic toxicity against bacteria was found for ranitidine or its photolytic decomposition products, but a low toxicity was detected for the resulting mixture of the photolytic transformation products of tramadol.

CONCLUSIONS

The study demonstrates that transformation products may have a higher environmental risk potential than the respective parent compounds.

Toxicity evaluation of verapamil and tramadol based on toxicity assay and expression patterns of Dhb, Vtg, Arnt, CYP4, and CYP314 in Daphnia magna

In this study, the toxicities of two pharmaceuticals, verapamil and tramadol were evaluated in Daphnia magna using the conventional toxicity tests (acute and chronic test) and the expression patterns of five stress responsive genes. In the chronic toxicity test, several parameters, such as the survival percentage, the body length of D. magna, the time of first reproduction, and the number of offspring per female, were adversely affected during the exposure to 4.2 mg L(-1) verapamil and 34 mg L(-1) tramadol. During the 24-h short-term exposure, verapamil particularly caused a downregulated expression of the CYP4 and CYP314 genes, whereas tramadol upregulated the expression of the CYP314 gene. Neither pharmaceutical affected the expression of Dhb, Arnt, and Vtg. However, during the 21-day long-term exposure, both verapamil and tramadol significantly reduced the expression level of the Vtg gene, a biomarker of the reproduction ability in an oviparous animal, whereas neither affected the other genes.

Abuse liability, behavioral pharmacology, and physical-dependence potential of opioids in humans and laboratory animals: lessons from tramadol

Assessment of abuse potential of opioid analgesics has a long history in both laboratory animals and humans. This article reviews the methods used in animals and in humans and then presents the data collected in the evaluation of tramadol, an atypical centrally acting opioid analgesic approved for marketing in the United States in 1998. Finally, data on the abuse of tramadol from postmarketing surveillance and case reports are presented. The consistency between animal and human study results and the predictive value of both are discussed. Overall, there was substantial agreement between animal and human data, with each having predictive value. Nonetheless, it is suggested that abuse-potential screening of new medications would benefit from an organized, integrated cross-species program.

Liver and kidney toxicity in chronic use of opioids: An experimental long term treatment model

In this study, histopathological and biochemical changes due to chronic usage of morphine or tramadol in liver and kidney were assessed in rats. Thirty male Wistar rats (180-220 g) were included and divided into three groups. Normal saline (1 ml) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4, 8, 10 mg/kg/day in the first, second and the third ten days of the study, respectively. Tramadol group (n = 10), received the drug intraperitoneally at doses of 20, 40 and 80 mg/kg/day in the first, second and the third ten days of the study, respectively. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatinin, blood urea nitrogen (BUN) and malondialdehyde (MDA) levels were measured in the serum. Liver and kidney specimens were evaluated by light microscopy. Serum ALT, AST, LDH, BUN and creatinin levels were significantly higher in morphine group compared to the control group. Serum LDH, BUN and creatinin levels were significantly increased in the morphine group compared to the tramadol group. The mean MDA level was significantly higher in morphine group compared to the tramadol and control groups (P < 0.05). Light microscopy revealed severe centrolobular congestion and focal necrosis in the liver of morphine and tramadol groups, but perivenular necrosis was present only in the morphine group. The main histopathologic finding was vacuolization in tubular cells in morphine and tramadol groups. Our findings pointed out the risk of increased lipid peroxidation, hepatic and renal damage due to long term use of opioids, especially morphine. Although opioids are reported to be effective in pain management, their toxic effects should be kept in mind during chronic usage.

Opioid neurotoxicity: comparison of morphine and tramadol in an experimental rat model

Histopathologic changes in rat brain due to chronic use of morphine and/or tramadol in progressively increased doses were investigated in this study. Thirty male Wistar rats (180-220 g) were included and divided into three groups. Normal saline (1 ml/kg) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4 mg/kg/day for the first 10 days, 8 mg/kg/day between 11-20 days, and 12 mg/kg/day between 21-30 days. The tramadol group (n = 10) received the drug intraperitoneally at doses of 20, 40, and 80 mg/kg/day in the first, second, and the third 10 days of the study, respectively. All rats were decapitated on the 30th day and the brain was removed intact for histology. The presence and the number of red neurons, which are a histologic marker of apoptosis, were investigated in the parietal, frontal, temporal, occipital, entorhinal, pyriform, and hippocampal CA1, CA2, CA3 regions. Red neurons were found in morphine and tramadol groups but not in the control group. The total number of red neurons was not different in morphine and tramadol groups, but the numbers of red neurons were significantly higher in the temporal and occipital regions in tramadol group as compared with the morphine group (p < .05). In conclusion, chronic use of morphine and/or tramadol in increasing doses is found to cause red neuron degeneration in the rat brain, which probably contributes to cerebral dysfunction. These findings should be taken into consideration when chrome use of opioids is indicated.

[Chronopharmacology of tramadol in mice]

AIM

To investigate the influence of dosing time on acute toxicity, action and pharmacokinetics of tramadol in mice to find the circadian rhythms of the drug.

METHODS

Tramadol was given (i.p.) to mice at 08:00, 12:00, 16:00, 20:00, 24:00, 04:00 and the variations of their acute mortality, responses to hot plate and tail-pressing stimulation and pharmacokinetics were investigated.

RESULTS

Significant circadian rhythm was found for the acute toxicity of tramadol in mice and the highest mortality was found when the drug was administered in the middle dark phase. The rhythm of drug toxicity coincided nicely with the rhythm of plasma drug level. Tramadol effect was demonstrated to vary circadianly and the highest effect occurred in the late dark phase. Dosing-time dependent kinetics of tramadol was also found in mice.

CONCLUSION

Significant circadian rhythm of the acute toxicity, action and pharmacokinetics was found in mice when tramadol was given at different times of the day.

Determination of the adsorption of tramadol hydrochloride by activated charcoal in vitro and in vivo

Although tramadol is one of the most widely used centrally acting analgesics worldwide, no literature is available regarding adsorption of tramadol HCl powder or tablets (Ultram; 50 mg tramadol HCl per tablet) by activated charcoal (AC) for use as potential adjunct treatment of overdose. The present study incorporated a novel combination of in vitro and in vivo methods to investigate this question. Based on a binding curve of tramadol UV absorbance (UV(a); 225 nm) plotted against the amount of AC, the ratio of amount of tramadol completely adsorbed by AC was 0.05 mg/mg. Also based on UV(a), no tramadol was detected in filtrate of slurries in which up to 62 tablets of Ultram were mixed with 50 g AC; 4.6% of unbound tramadol was detected when 100 tablets of Ultram were mixed with AC. The ratio of amount of tramadol completely adsorbed by AC in this test was 0.10. In vivo, co-administration of 0.1 g/ml of AC produced a 13- to 14-fold rightward shift in tramadol's antinociceptive dose-response curve and a 1.6-fold rightward shift in tramadol's lethality dose-response curve.

The experimental toxicology of tramadol: an overview

The experimental toxicological findings of tramadol are reviewed and discussed. Tramadol is a centrally acting analgesic. In acute toxicity studies, LD50 values are estimated to be around 300-350 mg/kg body weight (rat, mouse, oral administration). After intravenous administration the LD50 values ranged from 50 to 100 mg/kg body weight. In subacute and chronic toxicity studies, clinical signs of intoxication are mainly behavioural disorders and convulsions, beginning at dose levels of 25 mg/kg. Clinical pathological alterations or morphological lesions, in particular neuropathological findings were not detected. Overall, the battery of mutagenicity studies shows no evidence of a genotoxic risk to man. Reproductive and developmental toxicity investigations and carcinogenicity studies were without substance-dependent findings. Toxicological and toxicokinetical data of both enantiomers did not show biologically relevant deviations in comparison to the data on tramadol. The toxicological characteristic of this compound is demonstrated.

Ancillary approaches to toxicokinetic evaluations

The principal objective of toxicokinetic studies is to assess systemic exposure of the toxicity species to test compound during nonclinical toxicity studies by generation of pharmacokinetic data on the rate, extent, and duration of exposure. Toxicokinetics are normally integrated within the toxicity studies (concomitant); however, there are a number of circumstances when prospective, retrospective, or other ancillary types of toxicokinetic studies are performed in support of toxicity studies. The need for retrospective toxicokinetic studies arises when the original toxicity study was conducted with insufficient plasma concentration determinations, especially when pilot toxicity studies show lack of toxicity or unusual organ toxicities. Examples of ancillary toxicokinetic studies from the Drug Metabolism and Drug Safety departments at The R. W. Johnson Pharmaceutical Research Institute and from the scientific literature are provided that highlight the challenges associated with these alternate approaches. Each example includes a discussion of the rationale for the supportive toxicokinetic study, the specific experimental designs, the data interpretation, and the usefulness of the toxicokinetic data in decision-making. The ancillary toxicokinetic studies cited provided important information on establishing systemic exposure during long-term toxicity studies, allowing comparisons to human exposures, elucidating compound-related toxicities, and explaining lack of toxicity due to autoinduction and resulting low levels of parent compound.