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Concept: Tramadol


The human ability to synchronize with other individuals is critical for the development of social behavior. Recent research has shown that physiological inter-personal synchronization may underlie behavioral synchrony. Nevertheless, the factors that modulate physiological coupling are still largely unknown. Here we suggest that social touch and empathy for pain may enhance interpersonal physiological coupling. Twenty-two romantic couples were assigned the roles of target (pain receiver) and observer (pain observer) under pain/no-pain and touch/no-touch conditions, and their ECG and respiration rates were recorded. The results indicate that the partner touch increased interpersonal respiration coupling under both pain and no-pain conditions and increased heart rate coupling under pain conditions. In addition, physiological coupling was diminished by pain in the absence of the partner’s touch. Critically, we found that high partner’s empathy and high levels of analgesia enhanced coupling during the partner’s touch. Collectively, the evidence indicates that social touch increases interpersonal physiological coupling during pain. Furthermore, the effects of touch on cardio-respiratory inter-partner coupling may contribute to the analgesic effects of touch via the autonomic nervous system.

Concepts: Psychology, Opioid, Pain, Analgesic, Human behavior, Tramadol, Synchronization, Race condition


The photodegradation and biotic transformation of the pharmaceuticals lidocaine (LDC), tramadol (TRA) and venlafaxine (VEN), and of the metabolites O-desmethyltramadol (ODT) and O-desmethylvenlafaxine (ODV) in the aquatic environmental have been investigated. Photodegradation experiments were carried out using a medium pressure Hg lamp (laboratory experiments) and natural sunlight (field experiments). Degradation of the target compounds followed a first-order kinetic model. Rates of direct photodegradation (light absorption by the compounds itself) at pH 6.9 were very low for all of the target analytes (⩽0.0059h(-1) using a Hg lamp and ⩽0.0027h(-1) using natural sunlight), while rates of indirect photodegradation (degradation of the compounds through photosensitizers) in river water at pH 7.5 were approximately 59 (LDC), 5 (TRA), 8 (VEN), 15 (ODT) and 13 times (ODV) higher than the rates obtained from the experiments in ultrapure water. The accelerated photodegradation of the target compounds in natural water is attributed mainly to the formation of hydroxyl radicals through photochemical reactions. Biotic (microbial) degradation of the target compounds in surface water has been shown to occur at very low rates (⩽0.00029h(-1)). The half-life times determined from the field experiments were 31 (LDC), 73 (TRA), 51 (VEN), 21 (ODT) and 18h (ODV) considering all possible mechanisms of degradation for the target compounds in river water (direct photodegradation, indirect photodegradation and biotic degradation).

Concepts: Water, Photochemistry, Tramadol, Venlafaxine, Prime number, Alcohols, Photochemical reaction, Surface water


We analyze the effects of a multimodal analgesic regimen on postoperative pain, function, adverse effects and satisfaction compared to patient-controlled analgesia (PCA). Thirty-six patients undergoing TKA were randomized to receive either (1) periarticular injection before wound closure (30cc 0.5% bupivacaine, 10mg MSO4, 15mg ketorolac) and multimodal analgesics (oxycodone, tramadol, ketorolac; narcotics as needed) or (2) hydromorphone PCA. Preoperative and postoperative data were collected for VAS pain scores, time to physical therapy milestones, hospital stay length, patient satisfaction, narcotic consumption and medication-related adverse effects. The multimodal group had lower VAS scores, fewer adverse effects, lower narcotic usage, higher satisfaction scores and earlier times to physical therapy milestones. Multimodal pain management protocol decreases narcotic usage, improves pain scores, increases satisfaction and enhances early recovery.

Concepts: Opioid, Pain, Morphine, Analgesic, Hydrocodone, Tramadol, Codeine, Analgesics


Objective-To determine the pharmacokinetics of tramadol hydrochloride (30 mg/kg) following twice-daily oral administration in Hispaniolan Amazon parrots (Amazona ventralis). Animals-9 healthy adult Hispaniolan Amazon parrots. Procedures-Tramadol hydrochloride was administered to each parrot at a dosage of 30 mg/kg, PO, every 12 hours for 5 days. Blood samples were collected just prior to dose 2 on the first day of administration (day 1) and 5 minutes before and 10, 20, 30, 60, 90, 180, 360, and 720 minutes after the morning dose was given on day 5. Plasma was harvested from blood samples and analyzed by high-performance liquid chromatography. Degree of sedation was evaluated in each parrot throughout the study. Results-No changes in the parrots' behavior were observed. Twelve hours after the first dose was administered, mean ± SD concentrations of tramadol and its only active metabolite M1 (O-desmethyltramadol) were 53 ± 57 ng/mL and 6 ± 6 ng/mL, respectively. At steady state following 4.5 days of twice-daily administration, the mean half-lives for plasma tramadol and M1 concentrations were 2.92 ± 0.78 hours and 2.14 ± 0.07 hours, respectively. On day 5 of tramadol administration, plasma concentrations remained in the therapeutic range for approximately 6 hours. Other tramadol metabolites (M2, M4, and M5) were also present. Conclusions and Clinical Relevance-On the basis of these results and modeling of the data, tramadol at a dosage of 30 mg/kg, PO, will likely need to be administered every 6 to 8 hours to maintain therapeutic plasma concentrations in Hispaniolan Amazon parrots. (Am J Vet Res 2013;74:957-962).

Concepts: Pharmacology, Chromatography, High performance liquid chromatography, Tramadol, Parrot, Amazon parrot, Parrots, O-Desmethyltramadol


The objective of this study was to compare the postoperative analgesic effects of dexketoprofen, tramadol, and buprenorphine in dogs undergoing ovariohysterectomy. Seventy-five adult female dogs were randomly assigned to receive an intravenous injection (IV) of 1mg/kg of dexketoprofen (D), 0.02mg/kg of buprenorphine (B) or 2mg/kg of tramadol (T). Pain assessment was performed during 48h after ovariohysterectomy using a dynamic interactive visual analogue scale (DIVAS) and Glasgow composite measure pain scale (CMPS-SF). Rescue analgesia was required in 43%, 21%, and 5% of dogs in the B, T, and D groups, respectively, with significant differences between B and D (p=0.010) groups. The DIVAS and CMPS-SF values of the B group were significantly higher than those of the T and D groups. The most common undesirable effect was dysphoria in dexketoprofen group. Tramadol and dexketoprofen provide superior postoperative analgesia compared with buprenorphine in dogs undergoing ovariohysterectomy.

Concepts: Opioid, Pain, Morphine, Analgesic, Buprenorphine, Methadone, Tramadol, Analgesics


OBJECTIVE: The purpose of this work is to study the prevalence, intensity, and treatment of pain in Portuguese palliative care teams. METHODS: Twenty-one palliative care teams were invited to participate in a cross-sectional survey. Ten of these accepted and were included in the study. Data of all patients observed on the 18th week of 2011 were collected. The data collected concerning pain were: demographic data, pain intensity, drugs prescribed, and invasive techniques. The intensity of pain was rated using a five-point verbal rating scale from none to maximum. The Pain Management Index (PMI) was used to calculate the adequacy of the analgesia. RESULTS: A total of 164 patients were included in this study. One hundred fifty-one (92 %) had cancer. The median age was 71 years (16 to 95). Eighty-four (51 %) were females. Pain was directly assessed in 136 (83 %) of the patients, whereas 27 patients could not report pain because of cognitive failure. Of those directly assessed, 77 (57 %) had pain when they were assessed: 42 (55 %) mild, 25 (32 %) moderate, 9 (12 %) severe, and 1 (1 %) maximum. Non-opioid analgesics were used: paracetamol in 61 (37 %) and NSAID in 20 (12 %). Tramadol was the only opioid for mild to moderate pain used in 25 (15 %) patients. The opioids most used for moderate to intense pain were: morphine 74 (45 %), transdermal (TD) fentanyl 32 (20 %), and buprenorphine TD 28 (17 %). The adjuvants most used were: corticosteroids 38 (23 %), gabapentin 37 (23 %), and amitriptyline 15 (9 %). Only five (4 %) patients had a negative PMI, meaning an inadequate analgesia. CONCLUSION: The general prevalence of pain is similar to that reported by other. The prevalence of moderate to severe pain is also similar to that reported in other studies, although severe pain is somewhat lower than indicated in most reports. According to the PMI, pain control was acceptable to good.

Concepts: Opioid, Pain, Morphine, Analgesic, Buprenorphine, Suffering, Fentanyl, Tramadol


Embryo transfer is a surgical technique that is widely used in reproductive biotechnology. Despite the ethical obligation to relieve animals' post-operative pain, analgesia is not routinely provided after embryo transfer surgery because it has been suggested that analgesics may be detrimental to embryo survival. Studies suggest, however, that the potential for adverse effects varies depending on the type of analgesic used and the timing of its administration. The authors carried out a study to determine whether pre-operatively administered tramadol, a synthetic analogue of codeine, influenced birth rate, litter survival or the post-operative body weights of surrogate dams. Compared with controls that were not given any analgesic, surrogate dams given tramadol had similar birth rates and similar body weights at all time points. The tramadol-treated surrogate dams showed a statistically significant increase in the number of offspring that survived to weaning. The authors conclude that pre-operatively administered tramadol does not harm the success rate of embryo transfer surgery and even may improve litter survival.

Concepts: Opioid, Paracetamol, Morphine, Analgesic, Hydrocodone, Tramadol, Codeine, Analgesics


The serotonin (5-hydroxtryptamine, 5-HT) system plays a role in analgesia and emesis. The aim of this study was to test whether opioids or ketamine inhibit the human 5-HT transporter and whether this increases free plasma 5-HT concentrations. HEK293 cells, stably transfected with the human 5-HT transporter cDNA, were incubated with morphine, hydromorphone, fentanyl, alfentanil, pethidine (meperidine), tramadol, ketamine, and the reference substance citalopram (specific 5-HT transporter inhibitor). The uptake of [(3)H]5-HT was measured by liquid scintillation counting. In a second series of experiments, study drugs were incubated with plasma of ten healthy blood donors and change of 5-HT plasma-concentrations were measured (ELISA). The end point was the inhibition of the 5-HT transporter by different analgesics either in HEK293 cells or in human platelets ex vivo. Tramadol, pethidine, and ketamine suppressed [(3)H]5-HT uptake dose-dependently with an IC50 of 1, 20.9, and 230 μM, respectively. These drugs also prevented 5-HT uptake in platelets with an increase in free plasma 5-HT. Free 5-HT concentrations in human plasma were increased by citalopram 1 μM, tramadol 20 μM, pethidine 30 μM, and ketamine 100 μM to 280 [248/312]%, 269 [188/349]%, and 149 [122/174]%, respectively, compared to controls without any co-incubation (means [95 % CI]; all p < 0.005). No change in both experimental settings was observed for the other opioids. Tramadol and pethidine inhibited the 5-HT transporter in HEK293 cells and platelets. This inhibition may contribute to serotonergic effects when these opioids are given in combination, e.g., with monoamine oxidase inhibitors or selective serotonin reuptake inhibitors.

Concepts: Opioid, Serotonin, Morphine, Analgesic, Selective serotonin reuptake inhibitor, Pethidine, Tramadol, Serotonin syndrome


Opioids may inhibit the serotonin and norepinephrine transporters (SERT and NET, respectively). NET inhibition may contribute to analgesia, and SERT inhibition or interactions with serotonin receptors may cause serotonergic toxicity. However, the effects of different opioids on the human SERT, NET, and serotonin receptors have not been sufficiently studied.

Concepts: Pharmacology, Serotonin, Inhibitor, Antidepressant, Norepinephrine, Pethidine, Tramadol, 5-HT receptor


Tramadol is a weak opioid analgesic whose use has increased rapidly, and it has been associated with adverse events of hypoglycemia.

Concepts: Opioid, Pain, Morphine, Analgesic, Buprenorphine, Hydrocodone, Tramadol