Acute tramadol enhances brain activity associated with reward anticipation in the nucleus accumbens

Patterns and social factors associated with non-prescription use of Tramadol: a cross-sectional study among youth in urban informal settlements in Ghana

BACKGROUND

Non-prescription use of Tramadol is increasingly becoming common among vulnerable populations. This study examines the factors associated with non-prescription use of Tramadol among youth in urban informal settlements in the Asokore Mampong Municipality, Ghana.

METHODS

Cross-sectional data from Tramadol users aged 15 to 35 years living in urban informal settlements were analyzed. Non-prescription use of Tramadol was assessed using the item "Have you ever used Tramadol for any reason without a prescription from a healthcare professional?". The responses were dichotomized as yes = 1, otherwise = 0. Multivariable logistic regression models evaluated the factors associated with non-prescription use of Tramadol.

RESULTS

Data on 200 Tramadol users were obtained. Family/friends (52.3%), were the main source of knowledge on Tramadol. Energy boost (43%) was the most cited reason for Tramadol use. Approximately 52% indicated a continuing non-prescription use of Tramadol for energy boost. Multivariable logistic regressions showed that those who lived alone (OR = 6.34: 95% CI = 2.03-19.82), migrants (OR = 3.97, 95% CI = 1.31-12.05) and the unemployed (OR = 3.57, 95% CI = 1.02-12.58) were significantly more likely to report non-prescription use of Tramadol.

CONCLUSIONS

Non-prescription use of Tramadol is a threat to the youth in urban informal settlements in the Asokore Mampong Municipality. Interventions such as strict drug monitoring and regulation, drug use education, strict parental supervision, and sustainable jobs may contribute to controlling non-prescription use of Tramadol.

Exploring the potential use of melatonin as a modulator of tramadol-induced rewarding effects in rats

Background

Melatonin is responsible for regulating the sleep-wake cycle and circadian rhythms in mammals. Tramadol, a synthetic opioid analgesic, is used to manage moderate to severe pain but has a high potential for abuse and dependence. Studies have shown that melatonin could be a potential modulator to reduce tramadol addiction.

Methods

Male Wistar rats were used to investigate the effect of melatonin on tramadol-induced place preference. The rats were divided into four groups: control, tramadol, tramadol + melatonin (single dose), and tramadol + melatonin (repeated doses). Tramadol was administered intraperitoneally at 40 mg/kg, while melatonin was administered at 50 mg/kg for both the single dose and repeated-dose groups. The study consisted of two phases: habituation and acquisition.

Results

Tramadol administration produced conditioned place preference (CPP) in rats, indicating rewarding effects. However, melatonin administration blocked tramadol-induced CPP. Surprisingly, repeated doses of melatonin were ineffective and did not reduce the expression of CPP compared to that of the single dose administration.

Conclusion

The study suggests that melatonin may be a potential therapeutic option for treating tramadol addiction. The results indicate that melatonin attenuates the expression of tramadol-induced CPP, supporting its uses as an adjunct therapy for managing tramadol addiction. However, further studies are needed to investigate its effectiveness in humans.

Caffeine modulates apoptosis, oxidative stress, and inflammation damage induced by tramadol in cerebellum of male rats

Tramadol, an opioid used as analgesic, can induce neurotoxic effects associated to cognitive dysfunction. Moreover, caffeine has been reported to have neuroprotective effects. In this regard, we hypothesized that administration of caffeine can modulate tramadol-induced damages in cerebellum. For this study, forty male Wistar rats were divided into four groups: the control group, the tramadol group (50mg/kg), the caffeine group (37.5mg/kg), and the tramadol+caffeine group (50mg/kg tramadol+37.5mg/kg caffeine). At the end of study (day 21), after performing rotarod behavioral test, cerebellum tissue samples were removed and prepared for further evaluations including biochemical profile markers (MDA, GPx, and SOD), immunohistochemistry for Caspase-3, as well as the expression of genes involved in cellular processes such as inflammation markers (IL-1β, HMGB1, IL-6, and TNF), apoptosis markers (Caspase-3, Caspase-8, Bax, and P21), and autophagy markers (LAMP2, ATG5, BECN1, and ATG12). Stereological evaluations were performed to determine the total volume of granular and molecular layers and white matter of cerebellum tissue and numerical density of the Purkinje cells. Our results showed that the stereological parameters, biochemical profiles (except MDA) and behavioral function were significantly higher in the tramadol+caffeine group compared to the tramadol group. Autophagy-related genes were significantly upregulated in tramadol+caffeine group compared to the tramadol group. While the expression of inflammatory and apoptosis genes, MDA level, as well as density of apoptosis cells were significantly lower in the tramadol+caffeine group compared to the tramadol group. Briefly, it can be concluded that administration of caffeine has neuroprotective effects in cerebellar damages induced by tramadol.

The effect of orexin-2 and endocannabinoid-1 antagonists on neuronal activity of hippocampal CA1 pyramidal neurons in response to tramadol in rats

Background:

CA1, as a major structure involved in learning and memory, has been shown to be affected by tramadol addiction. Both orexin and endocannabinoid receptors express in CA1 and play an important role in drug dependency. The aim of this study was to evaluate the modulatory effects of orexin-2 (OX2R) and endocannabinoid-1 (CB1R) receptors on neuronal activity in CA1, in response to tramadol in rats.

Materials and Methods:

Male Wistar rats were divided into 8 groups (n = 6–7); saline-dimethyl sulfoxide (DMSO), tramadol-DMSO, saline-TCS-OX2-29, saline-AM251, tramadol-TCS-OX2-29, tramadol-AM251, saline-TCS-OX2-29-AM251, tramadol-TCS-OX2-29-AM251. Tramadol was injected intraperitoneally, and then, AM251 (1 nmol/0.3 μL), CB1R antagonist and TCS-OX2-29 (1 nmol/0.3 μL), OX2R antagonist, were microinjected individually or concurrently into the CA1. Using in vivo extracellular single-unit recording, the firing of CA1 pyramidal neurons was investigated.

Results:

Tramadol decreased neuronal activity in CA1 (P < 0.01) but increased it after micro-injection of DMSO. TCS-OX2-29 increased neuronal activity in saline group (P < 0.05) but decreased it in tramadol group. AM251 had no effect on saline group but decreased neuronal activity in tramadol group (P < 0.05). Concurrent micro-injection of TCS-OX2-29 and AM251 had no effect on saline group but decreased neuronal activity in tramadol group (P < 0.05).

Conclusions:

Our findings suggest that neural activity in CA1 is rapidly affected by acute use of tramadol, and some of these effects may be induced through the endocannabinoid and orexin systems. Thus, the function of endocannabinoid and orexin systems in CA1 may play a role in tramadol addiction.

The acute effects of different doses of tramadol on neuronal activity of medial prefrontal cortex in rats

Background:

Tramadol is an opioid analgesic with monoamine reuptake inhibitory effects. Although tramadol has been widely used to control pain, there is controversy about the risk of abuse. Therefore, in the present study, the acute effects of tramadol on neuronal activity in the medial prefrontal cortex (mPFC), which is one of the important centers of the reward system, were investigated electrophysiologically.

Materials and Methods:

Tramadol was injected interperitoneally (12.5 and 25 mk/kg) or subcutaneously (40 mg/kg) and its effect on the firing of mPFC neurons was investigated, using in vivo extracellular single unit recording.

Results:

Tramadol could not significantly affect neural activity in mPFC, suggesting no acute and rapid effect on mPFC.

Conclusions:

The present results showed that neural activity in mPFC was not rapidly affected by acute application of tramadol. Since the role of mPFC in tramadol addiction has been elucidated, it can be concluded that these effects may be due to delayed responses or chronic use of tramadol.

Incidence and risk factors for prolonged postoperative opioid use following lumbar spine surgery: a cohort study

OBJECTIVE

Sustained postoperative opioid use after elective surgery is a matter of growing concern. Herein, the authors investigated incidence and predictors of long-term opioid use among patients undergoing elective lumbar spine surgery, especially as a function of opioid prescribing practices at postoperative discharge (dose in morphine milligram equivalents [MMEs] and type of opioid).

METHODS

The OptumLabs Data Warehouse (OLDW) was queried for postdischarge opioid prescriptions for patients undergoing elective lumbar decompression and discectomy (LDD) or posterior lumbar fusion (PLF) for degenerative spine disease. Only patients who received an opioid prescription at postoperative discharge and those who had a minimum of 180 days of insurance coverage prior to surgery and 180 days after surgery were included. Opioid-naive patients were defined as those who had no opioid fills in 180 days prior to surgery. The following patterns of long-term postoperative use were investigated: additional fills (at least one opioid fill 90-180 days after surgery), persistent fills (any span of opioid use starting in the 180 days after surgery and lasting at least 90 days), and Consortium to Study Opioid Risks and Trends (CONSORT) criteria for persistent use (episodes of opioid prescribing lasting longer than 90 days and 120 or more total days' supply or 10 or more prescriptions in 180 days after the index fill). Multivariable logistic regression was performed to identify predictors of long-term use.

RESULTS

A total of 25,587 patients were included, of whom 52.7% underwent PLF (n = 13,486) and 32.5% (n = 8312) were opioid-naive prior to surgery. The rates of additional fills, persistent fills, and CONSORT use were 47%, 30%, and 23%, respectively, after PLF and 35.4%, 19%, and 14.2%, respectively, after LDD. The rates among opioid-naive patients were 18.9%, 5.6%, and 2.5% respectively, after PLF and 13.3%, 2.0%, and 0.8%, respectively, after LDD. Using multivariable logistic regression, the following were identified to be significantly associated with higher risk of long-term opioid use following PLF: discharge opioid prescription ≥ 500 MMEs, prescription of a long-acting opioid, female sex, multilevel surgery, and comorbidities such as depression and drug abuse (all p < 0.05). Elderly (age ≥ 65 years) and opioid-naive patients were found to be at lower risk (all p < 0.05). Similar results were obtained on analysis for LDD with the following significant additional risk factors identified: discharge opioid prescription ≥ 400 MMEs, prescription of tramadol alone at discharge, and inpatient surgery (all p < 0.05).

CONCLUSIONS

In an analysis of pharmacy claims from a national insurance database, the authors identified incidence and predictors of long-term opioid use after elective lumbar spine surgery.

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.

Central Nervous System Targets: Supraspinal Mechanisms of Analgesia

While the acute sensation of pain is protective, signaling the presence of actual or potential bodily harm, its persistence is unpleasant. When pain becomes chronic, it has limited evolutionarily advantage. Despite the differing nature of acute and chronic pain, a common theme is that sufferers seek pain relief. The possibility to medicate pain types as varied as a toothache or postsurgical pain reflects the diverse range of mechanism(s) by which pain-relieving "analgesic" therapies may reduce, eliminate, or prevent pain. Systemic application of an analgesic able to cross the blood-brain barrier can result in pain modulation via interaction with targets at different sites in the central nervous system. A so-called supraspinal mechanism of action indicates manipulation of a brain-defined circuitry. Pre-clinical studies demonstrate that, according to the brain circuitry targeted, varying therapeutic pain-relieving effects may be observed that relate to an impact on, for example, sensory and/or affective qualities of pain. In many cases, this translates to the clinic. Regardless of the brain circuitry manipulated, modulation of brain processing often directly impacts multiple aspects of nociceptive transmission, including spinal neuronal signaling. Consideration of supraspinal mechanisms of analgesia and ensuing pain relief must take into account nonbrain-mediated effects; therefore, in this review, the supraspinally mediated analgesic actions of opioidergic, anti-convulsant, and anti-depressant drugs are discussed. The persistence of poor treatment outcomes and/or side effect profiles of currently used analgesics highlight the need for the development of novel therapeutics or more precise use of available agents. Fully uncovering the complex biology of nociception, as well as currently used analgesic mechanism(s) and site(s) of action, will expedite this process.

Bupropion increases activation in nucleus accumbens during anticipation of monetary reward

RATIONALE

Bupropion is used for major depressive disorder, smoking cessation aid, and obesity. It blocks reuptake of dopamine and noradrenaline and antagonizes nicotinic acetylcholine receptor. Animal studies showed that bupropion enhanced rewarding effects. In addition, bupropion has the potential to treat patients with reward processing dysfunction. However, neural substrates underlying the bupropion effects on reward function in human subjects are not fully understood.

OBJECTIVES

We investigated single-dose administration of bupropion on neural response of reward anticipation in healthy subjects using a monetary incentive delay (MID) task by functional magnetic resonance imaging (fMRI), especially focusing on nucleus accumbens (NAc) activity to non-drug reward stimuli under bupropion treatment.

METHODS

We used a randomized placebo-controlled within-subject crossover design. Fifteen healthy adults participated in two series of an fMRI study, taking either placebo or bupropion. The participants performed the MID task during the fMRI scanning. The effects of bupropion on behavioral performance and blood oxygenation level-dependent (BOLD) signal in NAc during anticipation of monetary gain were analyzed.

RESULTS

We found that bupropion significantly increased BOLD responses in NAc during monetary reward anticipation. The increased BOLD responses in NAc were observed with both low and high reward incentive cues. There was no significant difference between placebo and bupropion in behavioral performance.

CONCLUSIONS

Our findings provide support for the notion that bupropion enhances non-drug rewarding effects, suggesting a possible mechanism underlying therapeutic effects for patients with motivational deficit.

Chronic use of tramadol after acute pain episode: cohort study

OBJECTIVE

To determine the risk of prolonged opioid use in patients receiving tramadol compared with other short acting opioids.

DESIGN

Observational study of administrative claims data.

SETTING

United States commercial and Medicare Advantage insurance claims (OptumLabs Data Warehouse) January 1, 2009 through June 30, 2018.

PARTICIPANTS

Opioid-naive patients undergoing elective surgery.

MAIN OUTCOME MEASURE

Risk of persistent opioid use after discharge for patients treated with tramadol alone compared with other short acting opioids, using three commonly used definitions of prolonged opioid use from the literature: additional opioid use (defined as at least one opioid fill 90-180 days after surgery); persistent opioid use (any span of opioid use starting in the 180 days after surgery and lasting ≥90 days); and CONSORT definition (an opioid use episode starting in the 180 days after surgery that spans ≥90 days and includes either ≥10 opioid fills or ≥120 days' supply of opioids).

RESULTS

Of 444 764 patients who met the inclusion criteria, 357 884 filled a discharge prescription for one or more opioids associated with one of 20 included operations. The most commonly prescribed post-surgery opioid was hydrocodone (53.0% of those filling a single opioid), followed by short acting oxycodone (37.5%) and tramadol (4.0%). The unadjusted risk of prolonged opioid use after surgery was 7.1% (n=31 431) with additional opioid use, 1.0% (n=4457) with persistent opioid use, and 0.5% (n=2027) meeting the CONSORT definition. Receipt of tramadol alone was associated with a 6% increase in the risk of additional opioid use relative to people receiving other short acting opioids (incidence rate ratio 95% confidence interval 1.00 to 1.13; risk difference 0.5 percentage points; P=0.049), 47% increase in the adjusted risk of persistent opioid use (1.25 to 1.69; 0.5 percentage points; P<0.001), and 41% increase in the adjusted risk of a CONSORT chronic opioid use episode (1.08 to 1.75; 0.2 percentage points; P=0.013).

CONCLUSIONS

People receiving tramadol alone after surgery had similar to somewhat higher risks of prolonged opioid use compared with those receiving other short acting opioids. Federal governing bodies should consider reclassifying tramadol, and providers should use as much caution when prescribing tramadol in the setting of acute pain as for other short acting opioids.

Delta-opioid receptor antagonist naltrindole reduces oxycodone addiction and constipation in mice

Oxycodone, a widely prescribed and very potent oral opioid analgesic agent, is highly addictive and has many side effects, including troublesome constipation. Our studies in mice indicated that pretreatment of naltrindole did not significantly affect the analgesic efficacy of oxycodone but attenuated the tolerance and withdrawal induced by chronic oxycodone administration. Naltrindole also attenuated the oxycodone-induced rewarding and re-instatement behaviors, as shown by the conditioned place preference test. Further, oxycodone-induced decrease in intestinal transit (i.e., constipation) was reduced by naltrindole. However, naltrindole did not block the respiratory depression produced by oxycodone. Taken together, these data suggest that naltrindole can attenuate some major side effects while retaining the analgesic efficacy of oxycodone in mice. Naltrindole and oxycodone may have the potential to be a potent analgesic combination with much lower levels of oxycodone's side effects of addictive liability and constipation.