Commentary: the peripheral mechanisms of abnormal temporal summation

Effect of apatinib on the pharmacokinetics of tramadol and O-desmethyltramadol in rats

Since the combination of anticancer drugs and opioids is very common, apatinib and tramadol are likely to be used in combination clinically. This study evaluated the effects of apatinib on the pharmacokinetics of tramadol and its main metabolite O-desmethyltramadol in Sprague-Dawley (SD) rats and the inhibitory effects of apatinib on tramadol in rat liver microsomes (RLMs), human liver microsomes (HLMs) and recombinant human CYP2D6.1. The samples were determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The in vivo results showed that compared with the control group, apatinib increased the AUC(0-t), AUC(0-∞) and Cmax values of tramadol and O-desmethyltramadol, and decreased the values of VZ/F and CLz/F. In addition, the MRT(0-t), MRT(0-∞) values of O-desmethyltramadol were increased. In vitro, apatinib inhibited the metabolism of tramadol by a mixed way with IC50 of 1.927 µM in RLMs, 2.039 µM in HLMs and 15.32 µM in CYP2D6.1. In summary, according to our findings, apatinib has a strong in vitro inhibitory effect on tramadol, and apatinib can increase the analgesic effect of tramadol and O-desmethyltramadol in rats.

Comprehensive management of adults with chronic migraine: Clinical practice guidelines in Mexico

Introduction:

Migraine is a polygenic multifactorial disorder with a neuronal initiation of a cascade of neurochemical processes leading to incapacitating headaches. Headaches are generally unilateral, throbbing, 4–72 h in duration, and associated with nausea, vomiting, photophobia, and sonophobia. Chronic migraine (CM) is the presence of a headache at least 15 days per month for ≥3 months and has a high global impact on health and economy, and therapeutic guidelines are lacking.

Methods:

Using the Grading of Recommendations, Assessment, Development, and Evaluations system, we conducted a search in MEDLINE and Cochrane to investigate the current evidence and generate recommendations of clinical practice on the identification of risk factors and treatment of CM in adults.

Results:

We recommend avoiding overmedication of non-steroidal anti-inflammatory drugs (NSAIDs); ergotamine; caffeine; opioids; barbiturates; and initiating individualized prophylactic treatment with topiramate eptinezumab, galcanezumab, erenumab, fremanezumab, or botulinum toxin. We highlight the necessity of managing comorbidities initially. In the acute management, we recommend NSAIDs, triptans, lasmiditan, and gepants alone or with metoclopramide if nausea or vomiting. Non-pharmacological measures include neurostimulation.

Conclusions:

We have identified the risk factors and treatments available for the management of CM based on a grading system, which facilitates selection for individualized management.

Who are Prone to Develop Adverse Effects with Oral Tramadol? a Retrospective Cohort Study

Objective

Oral tramadol is a commonly prescribed analgesic in Hong Kong. Significant adverse effects are frequently observed in our locality. Our study aims to describe the rate of significant adverse effect that warrant discontinuation of oral tramadol and identify the risk factors for development of adverse effect.

Design

Retrospective cohort study.

Methods

Adult patients aged greater than 18 years old admitted to the emergency medicine ward of a large-scale local hospital in Hong Kong being prescribed with oral tramadol during in-hospital stay were recruited. Significant adverse effects during the hospital stay were observed as the outcome of interest.

Results

A total of 575 subjects were recruited. 29.9% experienced significant adverse effects likely related to tramadol. Age (p=0.006; odds ratio [OR] = 1.017, 95% confidence interval [CI] = 1.005-1.029) and sex (p=0.006; OR=1.696, 95% CI= 1.166-2.465) were statistically significant predictors of adverse effects after oral tramadol.

Conclusion

Our study suggests that female and increasing age patients are significant predictors for the development of adverse effect after taking oral tramadol. Possible adverse effects should be explained to the patients careful especially the higher risk groups. (Hong Kong j. emerg.med. 2014;21:3-9)

Tramadol abuse in a binge pattern in a young depressed woman

BACKGROUND

Tramadol is a central analgesic with a unique pharmacological profile in that it is an opioid agonist and an inhibitor of serotonin and norepinephrine reuptake. We describe a case of abuse of tramadol in a binge pattern in a young woman who had initially received the prescription of tramadol as an analgesic as needed.

CASE DESCRIPTION

The patient had no history of drug or alcohol abuse, but suffered from depression. Over time, she had increased the doses up to 30 ml of tramadol 100 mg/ml oral solution a week. She took the drug in consecutive 'pinches', from afternoon to evening. Tramadol improved her mood, gave her euphoria, but also caused constipation and urinary retention. Detoxification was carried out by partial replacement with tramadol 100 mg extended release and gradual reduction of the number of pinches. The patient found it hard to follow the program because of withdrawal symptoms of an opioid type and especially because of the worsening of depression.

CONCLUSION

The action of tramadol on the monoaminergic system is believed to be a factor that limits abuse liability and gives advantageous antidepressant-like properties, but it also involves the risk of inducing abuse of the analgesic to improve mood as if it were a stimulant.

Multivariate optimization of surfactant-assisted directly suspended droplet microextraction combined with GC for the preconcentration and determination of tramadol in biological samples

In this work, a novel procedure based on surfactant-assisted directly suspended droplet microextraction for the determination of tramadol prior to GC with flame ionization detection is proposed. In this technique, a free microdroplet of solvent is transferred to the surface of an immiscible aqueous sample containing Triton X-100 and tramadol while being agitated by a stirring bar placed on the bottom of the sample vial. After the predetermined time, the microdroplet of solvent is withdrawn by a syringe and analyzed. The effective parameters such as the type of organic solvent, extraction time, microdroplet volume, salt content of the donor phase, stirring speed, the source phase pH, concentration of Triton X-100, and extraction temperature were optimized. For this purpose, a multivariate strategy was applied based on an experimental design in order to screen and optimize the significant factors. This method requires minimal sample preparation, analysis time, solvent consumption, and represents significant advantages over customary analytical methods. The linearity ranged from 10 to 2000 μg/L with RSDs (n = 5) of 7.3-10. Preconcentration factors and the LODs were 391-466 and 2.5-6.5 μg/L, respectively. Finally, this method was applied to the analysis of biological samples and satisfactory results were obtained.

Analgesics in patients with hepatic impairment: pharmacology and clinical implications

The physiological changes that accompany hepatic impairment alter drug disposition. Porto-systemic shunting might decrease the first-pass metabolism of a drug and lead to increased oral bioavailability of highly extracted drugs. Distribution can also be altered as a result of impaired production of drug-binding proteins or changes in body composition. Furthermore, the activity and capacity of hepatic drug metabolizing enzymes might be affected to various degrees in patients with chronic liver disease. These changes would result in increased concentrations and reduced plasma clearance of drugs, which is often difficult to predict. The pharmacology of analgesics is also altered in liver disease. Pain management in hepatically impaired patients is challenging owing to a lack of evidence-based guidelines for the use of analgesics in this population. Complications such as bleeding due to antiplatelet activity, gastrointestinal irritation, and renal failure are more likely to occur with nonsteroidal anti-inflammatory drugs in patients with severe hepatic impairment. Thus, this analgesic class should be avoided in this population. The pharmacokinetic parameters of paracetamol (acetaminophen) are altered in patients with severe liver disease, but the short-term use of this drug at reduced doses (2 grams daily) appears to be safe in patients with non-alcoholic liver disease. The disposition of a large number of opioid drugs is affected in the presence of hepatic impairment. Certain opioids such as codeine or tramadol, for instance, rely on hepatic biotransformation to active metabolites. A possible reduction of their analgesic effect would be the expected pharmacodynamic consequence of hepatic impairment. Some opioids, such as pethidine (meperidine), have toxic metabolites. The slower elimination of these metabolites can result in an increased risk of toxicity in patients with liver disease, and these drugs should be avoided in this population. The drug clearance of a number of opioids, such as morphine, oxycodone, tramadol and alfentanil, might be decreased in moderate or severe hepatic impairment. For the highly excreted morphine, hydromorphone and oxycodone, an important increase in bioavailability occurs after oral administration in patients with hepatic impairment. Lower doses and/or longer administration intervals should be used when these opioids are administered to patients with liver disease to avoid the risk of accumulation and the potential increase of adverse effects. Finally, the pharmacokinetics of phenylpiperidine opioids such as fentanyl, sufentanil and remifentanil appear to be unaffected in hepatic disease. All opioid drugs can precipitate or aggravate hepatic encephalopathy in patients with severe liver disease, thus requiring cautious use and careful monitoring.

Strategies of pain reduction during the bone marrow biopsy

Examination of the bone marrow biopsy and aspirate allows diagnosis and assessment of various conditions such as primary hematologic and metastatic neoplasms, as well as nonmalignant disorders. Despite being performed for many years, according to many different protocols, the procedure still remains painful for the majority of patients. This paper summarizes the current knowledge of pain reduction measures in the bone marrow biopsy and aspiration.

Severe Tramadol Addiction in a 61 Year-Old Woman without a History of Substance Abuse

We describe here the first case of Tramadol addiction and withdrawal in an elderly female patient in apparently good physical health. We report successful treatment with mirtazapine and clonidine. We believe that patients must be advised to take Tramadol regularly and to stop gradually especially after long treatment periods; moreover physicians must consider the potential physical dependence when they prescribe Tramadol for pain. Hence, we are observing some patients who continue to take Tramadol in order “to achieve a feeling of well-being,” even though their pain is controlled after disease regression. Finally, the establishing of an evidence-based Tramadol detoxification protocol would be highly desirable

Individualizing analgesic prescription Part I: pharmacogenetics of opioid analgesics

The current use of analgesics is based on the empiric administration of a given drug with clinical monitoring for efficacy and toxicity. However, individual responses to drugs are influenced by a combination of pharmacokinetic and pharmacodynamic processes, and each of these components, in addition to pain perception and processing, seem to be regulated by genetic factors. Whereas polymorphic drug-metabolizing enzymes and drug transporters may affect the pharmacokinetics of drugs, polymorphic drug targets and disease-related pathways may influence the pharmacodynamic action of drugs. After usual dose, drug toxicity, as well as inefficacy, can be observed depending on the polymorphism, the analgesic considered and the presence or absence of active metabolites. Thus, cytochrome P450 (CYP)2D6 polymorphism influences codeine and tramadol analgesic effects, CYP2C9 has an impact on the disposition of some nonsteroidal anti-inflammatory drugs, and opioid receptor polymorphism (118A>G) may reduce morphine potency. Moreover, drug interaction mimics genetic deficiency and contributes to the variability in response to analgesics. This two-part review summarizes the available data on the pharmacokinetic-pharmacodynamic consequences of known polymorphisms of drug-metabolizing enzymes (CYP and uridine diphosphate glucuronosyltransferase), drug transporters (multidrug resistance proteins, multidrug resistance-associated proteins, organic anion-transporting polypeptides, and serotonin transporters), relevant drug targets (such as µ-opioid receptor, serotonin receptor and cyclooxygenases) and other nonopioid biological systems, on currently prescribed central and peripheral analgesics.

[A case of a second cancer of metachronous multiple primary non-small cell lung cancer successfully treated with TS-1 and CDDP chemotherapy]

The patient was a 66-year-old man who had undergone right upper lobectomy and ND 2a systematic lymph node dissection for lung cancer (M/D adenocarcinoma, p-stage IB) in March of 1999 . On November 2003, postoperative routine chest computed tomography(CT) demonstrated a mass in left S6, and pathological diagnosis revealed P/D squamous cell carcinoma (cT1N2M0, stage IIIA) by CT-guided needle biopsy and mediastinoscopy. At first, we tried two courses of a combination chemotherapy consisting of carboplatin (CBDCA) and paclitaxel every 3 weeks. After 2 courses, the regimen was stopped because of grade 3 arthritis. Then, two courses of CBDCA and gemcitabine were performed. The evaluation of the response was SD by the guidelines of Response Evaluation Criteria in Solid Tumor Groups. Next, gefitinib was orally administered for 6 months but the tumor and mediastinal lymph nodes were growing. In January 2005, oral administration of TS-1 (60 mg/1, 2 courses, 75 mg/3-6 courses) was begun twice a day for 21 consecutive days while cisplatin (60 mg/m(2)) was administered intravenously on day 8. The response was PR (the tumor decreased by 46%), no serious adverse effect was observed, and the patient maintained good quality of life throughout the chemotherapy. This case suggests that TS-1+CDDP chemotherapy may be an effective treatment in patients with advanced lung cancer even after many protocols of chemotherapy.

Seizures associated with intoxication and abuse of tramadol

PURPOSE

To assess the frequency of seizures and patient characteristics associated with tramadol intoxication and abuse in young addicts.

METHODS

Patients with history of tramadol abuse and intoxication were prospectively studied during a 3-year period. The characterstics of patients with seizures and those without seizures were compared.

RESULTS

Fifty-seven patients (mean age 22.3 years [range 16-43 years], 47 males) were included. Tonic/clonic seizures occurred in 31 (54.4%) patients, (26 males and 5 females): single in 14 (45%), multiple in 17 (55%) patients after a tramadol dose ranging from 250-2500 mg. Seizures occurred within 24 h after tramadol intoxication in 26 (84%) patients, and later in 5 (16%) patients. Compared to addicts without seizures, the abusers with seizures were younger (p < 0.05). Both epileptiform and nonepileptiform electroencephalographic patterns were more common in patients with seizures than in patients without seizures, but the differences did not reach statistical significance.

CONCLUSION

The neurotoxicity of tramadol commonly manifests as generalized tonic-clonic seizures occurring most frequently within 24 h after tramadol intake. Seizures were more common in younger abusers with a longer duration of exposure to tramadol and with the combined use of tramadol with alcohol.

Polymorphisme génétique et interactions médicamenteuses : leur importance dans le traitement de la douleur

OBJECTIVES

To evaluate the impact of certain genetic polymorphisms on variable responses to analgesics

SOURCES

Systematic review, by means of a structured computerized search in the Medline database (1966-2004). Articles in English and French were selected. References in relevant articles were also retrieved.

MAIN FINDINGS

Most analgesics are metabolized by CYP isoenzymes subject to genetic polymorphism. NSAIDs are metabolized by CYP2C9; opioids described as "weak" (codeine, tramadol), anti-depressants and dextromethorphan are metabolized by CYP2D6 and some "potent" opioids (buprenorphine, methadone or fentanyl) by CYP3A4/5. After the usual doses have been administered, drug toxicity or, on the contrary, therapeutic ineffectiveness may occur, depending on polymorphism and the substance. Drug interactions mimicking genetic defects because of the existence of CYP inhibitors and inducers, also contribute to the variable response to analgesics. Some opioids are substrates of P-gp, a transmembrane transporter also subject to genetic polymorphism. However, P-gp could only play a minor modulating role in man on the central effects of morphine, methadone and fentanyl.

CONCLUSION

In the near future, pharmacogenetics should enable us to optimize therapeutics by individualizing our approach to analgesic drugs and making numerous analgesics safer and more effective. The clinical usefulness of these individualized approaches will have to be demonstrated by appropriate pharmacoeconomic studies and analyses.

Tramadol: does it have a role in emergency medicine?

Tramadol is a synthetic analgesic new to the Australasian market where its use is rapidly increasing. It is used extensively overseas, particularly in Europe where it has been popular since its introduction in Germany in the late 1970s. Tramadol has a dual mechanism of action: weak mu opioid receptor agonist and a reuptake inhibitor of serotonin and noradrenaline. Thus, it has distinct advantages and disadvantages compared to other available analgesics. Its use is advocated in a variety of acute and chronic pain states as well as some non-analgesic applications. The use of tramadol in an emergency setting is not well studied, with most published trials assessing its efficacy and tolerability in postoperative or dental models. This literature review concludes that tramadol does not offer any particular benefits over existing analgesics for the majority of emergency pain relief situations.