Ephedrine and cocaine cause developmental neurotoxicity and abnormal behavior in zebrafish

Ephedrine (EPH) and cocaine (COC) are illegal stimulant drugs, and have been frequently detected in aquatic environments. EPH and COC have negative effects on the nervous system and cause abnormal behaviors in mammals and fish at high concentrations, but their mechanisms of neurotoxicity remain unclear in larvae fish at low concentrations. To address this issue, zebrafish embryos were exposed to EPH and COC for 14 days post-fertilization (dpf) at 10, 100, and 1000 ng L-1. The bioaccumulation, development, behavior, cell neurotransmitter levels and apoptosis were detected to investigate the developmental neurotoxicity (DNT) of EPH and COC. The results showed that EPH decreased heart rate, while COC increased heart rate. EPH caused cell apoptosis in the brain by AO staining. In addition, behavior analysis indicated that EPH and COC affected spontaneous movement, touch-response, swimming activity and anxiety-like behaviors. EPH and COC altered the levels of the neurotransmitters dopamine (DA) and γ-aminobutyric acid (GABA) with changes of the transcription of genes related to the DA and GABA pathways. These findings indicated that EPH and COC had noticeable DNT in the early stage of zebrafish at environmentally relevant concentrations.

Ephedrine alleviates bleomycin-induced pulmonary fibrosis by inhibiting epithelial-mesenchymal transition and restraining NF-κB signaling

Pulmonary fibrosis is a lethal and progressive pulmonary disorder in human beings. Ephedrine is a compound isolated from Ephedra and plays a regulatory role in inflammatory response. This study focused on the anti-pulmonary fibrosis effect of ephedrine and its potential molecular mechanism. After a mouse model of pulmonary fibrosis was established through bleomycin (BLM) induction, the survival percentage, body weight, and pulmonary index were measured. Hematoxylin-eosin staining and Masson's trichrome staining for lung tissues were performed to observe the pathological alterations. The viability of lung epithelial BEAS-2B cells, intracellular production of reactive oxygen species, and the levels of pro-inflammatory cytokines were examined by cell counting kit-8 assays, 2',7'-dichlorofluorescein diacetate (DCF-DA) staining, and enzyme-linked immunosorbent assay, respectively. Immunofluorescence staining was performed to determine E-cadherin and vimentin expression after BLM or ephedrine treatment. The mRNA and protein levels of cytokeratin-8, E-cadherin, α-SMA, and vimentin were subjected to quantitative polymerase chain reaction and immunoblotting. Experimental results revealed that ephedrine treatment rescued the repressive impact of BLM on BEAS-2B cell viability, and ephedrine inhibited BLM-induced overproduction of reactive oxygen species and inflammatory response in BEAS-2B cells. Additionally, ephedrine suppressed epithelial-mesenchymal transition (EMT) process stimulated by BLM treatment, as demonstrated by the reduced α-SMA and vimentin levels together with the increased cytokeratin-8 and E-cadherin levels in BLM + Ephedrine group. In addition, ephedrine inhibited NF-κB and activated Nrf-2 signaling in BLM-treated BEAS-2B cells. Moreover, ephedrine ameliorated pulmonary fibrosis in BLM-induced mice and improved the survival of model mice. In conclusion, ephedrine attenuates BLM-evoked pulmonary fibrosis by repressing EMT process via blocking NF-κB signaling and activating Nrf-2 signaling, suggesting that ephedrine might become a potential anti-pulmonary fibrosis agent in the future.

Long-term exposure to ephedrine leads to neurotoxicity and neurobehavioral disorders accompanied by up-regulation of CRF in prefrontal cortex and hippocampus in rhesus macaques

Drug addiction continues to threaten the health and welfare of people worldwide, and ephedrine abuse is a serious drug problem in many areas of the world. Ephedrine toxicity is thought to induce behavioral effects primarily through actions on the central nervous system. The corticotropin-releasing factor (CRF) system plays an important role in regulating behavioral effects induced by addictive drugs, but whether CRF is related to ephedrine toxicity remains unclear. This study seeks to examine whether there is a correlation between the CRF and chronic ephedrine neurotoxicity. To this end, we established a chronic ephedrine (0.4-1.6 mg/kg/d) exposure model in rhesus macaques, assessed its effects on body weight and behavior, examined neuronal changes in the prefrontal cortex and hippocampus, and measured the CRF expression in the prefrontal cortex and hippocampus. After 8-weeks of exposure to ephedrine, the toxic effects of ephedrine included significant weight loss and induction of behavioral changes in rhesus macaques. In particular, in the modeling group, the abnormal behavioral changes mainly manifested as irritability and behavioral sensitization. Meanwhile, the histological abnormalities included neuronal morphological changes, pyknosis and irregular shapes of neurons in the prefrontal cortex and hippocampus. In addition, the expression levels of CRF mRNA and protein were increased in the prefrontal cortex and hippocampus of ephedrine-treated animals. In summary, the finding of this study indicated that ephedrine neurotoxicity can cause neuronal damage in cerebral cortex, which in turn can result in certain neurobehavioral abnormalities, and that CRF expression in prefrontal cortex and hippocampus is elevated in response to ephedrine exposure. These observations suggested that long-term exposure to ephedrine might be causing neurotoxicity and leading to neurobehavioral disorders accompanied by up-regulation of CRF in prefrontal cortex and hippocampus.

Effects of Chronic Ephedrine Toxicity on Functional Connections, Cell Apoptosis, and CREB-Related Proteins in the Prefrontal Cortex of Rhesus Monkeys

Ephedrine abuse has spread in many parts of the world, severely threatening human health. The mechanism of ephedrine toxicity is still unclear. To explore the possible neural mechanisms of ephedrine toxicity, this study established a non-human primate model of ephedrine exposure, analyzed the functional connectivity changes in its prefrontal cortex through resting state BOLD-fMRI, and then inspected the pathophysiological changes as well as the expression of the cyclic adenosine monophosphate response element-binding protein (CREB), phosphorylated CREB (P-CREB), and CREB target proteins (c-fos and fosB) in the prefrontal cortex. After ephedrine toxicity, we found that the prefrontal cortex of monkeys strengthened its functional connectivity with the brain regions that perform motivation, drive, reward, and learning and memory functions and weakened its functional connectivity with the brain regions that perform cognitive control. These results suggest that ephedrine toxicity causes abnormal neural circuits that lead to the amplification and enhancement of drug-related cues and the weakening and damage of cognitive control function. Histology showed that the neurocytotoxicity of ephedrine can cause neuronal degeneration and apoptosis. Real-time PCR and Western blot showed increased expression of CREB mRNA and CREB/P-CREB/c-fos/fosB protein in the prefrontal cortex after ephedrine toxicity. Collectively, the present study indicates that the enhancement of drug-related cues and the weakening of cognitive control caused by abnormal neural circuits after drug exposure may be a major mechanism of brain function changes caused by ephedrine. These histological and molecular changes may be the pathophysiological basis of brain function changes caused by ephedrine.

Exploring the neuromechanism of chronic ephedrine addiction in rhesus monkeys: A behavioural and brain resting-state fMRI study

Ephedrine is thought to exert behavioural effects primarily through actions on the central nervous system. However, the neuromechanism underlying the effects of ephedrine addiction still remains unclear. Our study aimed to establish chronic ephedrine addiction models in rhesus monkeys and to investigate the neuromechanism of chronic ephedrine addiction using the behavioural methods combined with resting-state blood oxygenation level dependent-functional magnetic resonance imaging (BOLD-fMRI). Monkeys in the ephedrine addiction group (n = 6) received intramuscular injections of ephedrine using a dose escalation method, with a chronic model established in 8 weeks, while in the control group (n = 4), monkeys received a pure 0.9% saline injection. The weight and behaviors of the monkeys were observed throughout the treatment. All monkeys underwent the brain MR scans for two times (before treatment and after treatment had been discontinued). After molding, the weight of the ephedrine group was significantly reduced, while the weight of the control group increased significantly. Compared with the control group, the ephedrine addicted monkeys showed more abnormal behaviors related to addiction. In fMRI study, the ephedrine addicted monkeys showed more increased brain activation than that of the control group, mainly including the prefrontal cortex(PFC) and anterior cingulate cortex (ACC), the left ventral tegmental area(VTA), right insula, right amygdala, hippocampus, left thalamus, and left cerebellum.We hypothesize that the principal neuromechanism underlying chronic ephedrine addiction involves multiple abnormal brain neuron circuits, mainly in the PFC and the limbic system, and is closely related to addictive behaviors.

Stereochemistry of ephedrine and its environmental significance: Exposure and effects directed approach

Analysis of drugs and pharmaceuticals in the environment is typically performed with non-chiral chromatographic techniques. The environmental risks posed by chiral compounds analysed in this way must therefore be assumed to be independent of chirality, meaning that each enantiomer is equally potent in toxicity and long-lived in stability. This manuscript examines the degradation of each of the four isomers of ephedrine in river simulating microcosms and links this to toxicity data obtained by exposing three different organisms (D. magna, P. subcapitata and T. thermophila) to each of the isomers individually. Microcosms showed that significant degradation only occurred in biotic conditions and that only two isomers (1R,2S-(-)-ephedrine, 1S,2S-(+)-pseudoephedrine) degraded significantly over a period of fourteen days. This is concerning because at least one of the non-degraded isomers (1S,2R-(+)-ephedrine) has been observed in wastewater effluent, which discharges directly into rivers, meaning these isomers could be persistent in the environment. We also observed formation of 1S,2R-(+)-ephedrine in single isomer 1R,2S-(-)-ephedrine river simulating microcosms. Human liver microsome assays and mass spectrometry based data mining revealed that 1S,2R-(+)-ephedrine is not human derived but it could be formed as a results of microbial metabolic processes. Across all three organisms tested the persistent isomers (1S,2R-(+)-ephedrine and 1R,2R-(-)-pseudoephedrine) were more toxic than those that undergo degradation; meaning that if these isomers are entering or formed in the environment they might represent a potentially hazardous contaminant.

The dietary supplement ephedrine induces b-adrenergic mediated exacerbation of systemic lupus erythematosus in NZM391 mice

The dietary supplement and adrenergic receptor agonist ephedrine has been a controversial topic as its safety has been questioned. b-adrenergic receptor (b-AR) activation causes immunomodulation, which may contribute to promotion of autoimmune pathology. This report investigated the ability of ephedrine to exacerbate processes associated with autoimmune disease in a lupus-prone mouse model. To mimic human supplementation, ephedrine was administered to NZM391 (lupus-prone) and BALB/c (nonlupus prone) mice orally twice a day for three months at a dose of 50 and 100 mg/day. Some ephedrine-treated NZM391 mice also were preadministered the b-AR antagonist propranolol to investigate b-AR involvement. Mice were bled monthly, and sera were assayed for a variety of lupus manifestations and immunological measurements. In NZM391 males and females, both doses of ephedrine significantly increased lupus manifestations, including IgG production and organ-directed autoantibody titers, and significantly lowered the ratio of IgG2a/IgG1 compared to controls. Ephedrine significantly decreased female lifespan and significantly increased circulating populations of plasma cells (CD38hi CD19lo cytoplasmic IgG+) and CD40+ B1a cells, while preventing an age-related decrease in the B1a cell population expressing a high level of CD5. While ephedrine induced gender-specific immunomodulation in BALB/c mice, increases in the lupus manifestations of anti-dsDNA titers and serum urea nitrogen were not detected. Preadministration of propranolol decreased lupus manifestations and serum levels of IgG and IgE in ephedrine-treated mice, but did not block the shift towards IgG1 production. These findings indicate that ephedrine via b-AR can exacerbate lupus symptoms in NZM391 mice and that blockade of the b-ARs on B cells, and not T cells, apparently was of greater importance as the inhibition of lupus symptoms corresponded to an inhibition of immunoglobulin levels, not a change of Th1/Th2 balance.

Intoxication with over-the-counter antitussive medication containing dihydrocodeine and chlorpheniramine causes generalized convulsion and mixed acidosis

We report a 35-year-old man who was referred to our hospital with generalized convulsion and mixed acidosis presumably caused by abuse of SS-BRON tablets, an over-the-counter (OTC) antitussive medication sold in Japan. These tablets contain dihydrocodeine phosphate, methylephedrine, chlorpheniramine, and caffeine. Although it is difficult to discern which component caused these symptoms, it seems that dihydrocodeine phosphate or methylephedrine was involved in the addiction to SS-BRON and chlorpheniramine may have caused the generalized convulsion. It should be recognized that an OTC antitussive, which is quite easy to obtain, can be abused and subsequently induce serious intoxication.

Cardiotoxicity of Ma Huang/caffeine or ephedrine/caffeine in a rodent model system

Ma Huang (equivalent to 0, 12.5, 25, or 50 mg/kg ephedrine) or ephedrine (0, 6.25, 12.5, 25 mg/kg) were administered as one bolus oral dose to male F344 rats with and without caffeine. The herbal medicine Ma Huang (ephedra) in combination with caffeine caused rapid clinical signs of toxicity including salivation, hyperactivity, ataxia, and eventually lethargy, and failure to respond to stimuli. When this syndrome of clinical signs emerged, animals were moribund sacrificed, and a histological analysis for heart lesions performed. Cardiotoxicity included hemorrhage, necrosis, and degeneration in the ventricles or interventricular septum within 2-4 hours after treatment with Ma Huang (ephedra)/caffeine or ephedrine (the principal active component in Ma Huang)/caffeine. There was a steep dose response curve for cardiotoxicity with minimal toxicity seen at levels of Ma Huang (equivalent to 12.5 mg/kg ephedrine) with caffeine. However, cardiotoxic lesions occurred in 28% of animals with Ma Huang dosages equivalent to 25 mg/kg ephedrine with 15 or 30 mg/kg caffeine, and in 90% of animals at Ma Huang exposures equivalent to 50 mg/kg ephedrine with 15 or 30 mg/kg caffeine. Cardiotoxic lesions occurred in 47% of animals in the 25 mg/kg ephedrine groups with caffeine at 7.25, 15, or 30 mg/kg. There was no statistical difference in the occurrence of cardiotoxic lesions when 15 or 30 mg/kg caffeine was combined with Ma Huang equivalent to 25 or 50 mg/kg ephedrine; likewise there was no statistical difference in the occurrence of cardiotoxic lesions when 7.25, 15, or 30 mg/kg caffeine was combined with 25 mg/kg ephedrine. These results show that the cardiotoxic effects of the herbal medicine, Ma Huang, are similar to that of ephedrine, the principal active ingredient in the herbal medicine. The combination of Ma Huang or ephedrine with caffeine enhanced the cardiotoxicity over that with the herbal medicine or the active ingredient alone.

A randomized controlled trial of cetirizine plus pseudoephedrine versus loratadine plus pseudoephedrine for perennial allergic rhinitis

The purpose of this study was to compare the safety and efficacy of cetirizine plus pseudoephedrine (C+P) with loratadine plus pseudoephedrine (L+P) in the treatment of perennial allergic rhinitis. This was a double blind, randomized, parallel trial with an active control. Subjects aged 12 to 70 years with perennial allergic rhinitis for at least 2 years were enrolled and randomized to receive either of the active study medications plus a placebo resembling the other, twice daily for 4 weeks. Nasal total symptom scale (NTSS) including sneezing, rhinorrhea, nasal itching and nasal stuffiness is evaluated by subjects daily and at baseline, 2 weeks, and 4 weeks by the investigator as efficacy measurement. A total of 51 eligible patients were enrolled and 45 patients completed the treatment course. Both groups had significant reductions in NTSS after 4 weeks of treatment as assessed by the subjects, but there was no significant difference between the two groups (mean +/- SD) reduction of 4.25 +/- 2.45 with C+P vs. 3.52 +/- 2.41 with L+P, p = 0.215. As assessed by the investigator, sneezing was significantly better at 2 weeks (-1.13 vs. -0.52, p = 0.028) and nasal congestion at 4 weeks (-1.71 vs. -1.19, p = 0.031) in subjects treated with C+P compared to those treated with L+P. There were 37 treatment-related adverse events (5 in 4 subjects in the C+P group and 32 in 16 subjects in the L+P group). It was concluded that both cetirizine plus pseudoephedrine and loratadine plus pseudoephedrine are efficacious for perennial allergic rhinitis in Taiwanese subjects. Relief of sneezing and nasal congestion may be marginally better with the cetirizine preparation, which also seemed to be slightly better tolerated, although the incidence of side effects did not differ significantly.

Mecamylamine attenuates ephedrine-induced hyperactivity in rats

Ephedrine is a central nervous system stimulant that has a pharmacological profile similar to amphetamines. Ephedrine induces hyperactivity after acute administration to rats and locomotor sensitization develops to ephedrine with repeated administration. Recent research suggests that nicotinic receptors (nAChRs) play a role in the development of locomotor sensitization to d-amphetamine and the goal of the present study was to determine if nAChRs similarly mediate the effects of ephedrine after acute and repeated drug injection. On 12 consecutive days, rats were pretreated with the nAChR antagonist mecamylamine (0.3-3.0 mg/kg) or saline followed by (-)-ephedrine (10-30 mg/kg) or saline injection and locomotor activity was measured. Ephedrine produced a dose-dependent increase in locomotor activity, and sensitization to ephedrine developed with repeated injection. Mecamylamine pretreatment attenuated the hyperactivity and sensitization produced by repeated, but not acute, ephedrine (10 mg/kg) injection. The inhibitory effect of mecamylamine was overcome at the higher ephedrine dose (30 mg/kg). The present results indicate that nAChRs play a mediating role in the development of locomotor sensitization to ephedrine.

Pseudoephedrine and guaifenesin urolithiasis: widening the differential diagnosis of radiolucent calculi on abdominal radiograph

Unenhanced helical computed tomography has played an increasingly important role in the management of urinary tract stones, guiding diagnosis and control of calculus disease. We report computed tomographic and radiographic appearances of a renal calculus composed of pseudoephedrine and guaifenesin in a patient who abused over-the-counter allergy medication.

Ephedrine plus caffeine causes age-dependent cardiovascular responses in Fischer 344 rats

Human consumption of ephedrine and caffeine in dietary supplements has been associated with a number of adverse effects including changes in the ECG, myocardial infarction, hyperthermia, and, in rare instances, death. The purpose of this study was to investigate the potential mechanisms associated with the cardiotoxicity of combined ephedrine and caffeine ingestion. Seven- and fourteen-week-old Fischer 344 rats treated with ephedrine in combination with caffeine exhibited increases in heart rate (HR), temperature, and corrected QT interval. Of the 14-wk-old rats treated with 25 mg/kg ephedrine plus 30 mg/kg caffeine, 57% died within 3-5 h of treatment, whereas none of the similarly treated 7-wk-old rats nor any of the rats treated with vehicle died. One hour after treatment with this dose of ephedrine plus caffeine, 14-wk-old rats exhibited a larger increase in HR (as % increase over baseline) than 7-wk-old rats. Furthermore, the 14-wk-old rats that died had a higher HR and temperature than the 14-wk-old rats that lived. Histopathological studies suggested interstitial hemorrhage and myofiber necrosis in the 14-wk-old rats treated with the highest concentration of ephedrine and caffeine. This study showed enhanced susceptibility to ephedrine plus caffeine in 14-wk-old rats compared with 7-wk-old rats. The greater mortality in the 14-wk-old rats was associated with increases in body temperature, HR, and myocardial necrosis.

Ephedrine increases ventricular arrhythmias in conscious dogs after myocardial infarction

OBJECTIVES

This study examined the hypothesis that the sympathomimetic activity of ephedrine increases the risk of lethal arrhythmias.

BACKGROUND

The sympathomimetic amine, ephedrine, is used to augment physical performance and as a weight loss aid, but little is known about the cardiovascular consequences in individuals with ischemic heart disease.

METHODS

Fifteen dogs at low risk for ventricular fibrillation (VF) during exercise and transient myocardial ischemia 30 days after a small anterior myocardial infarction were retested after five days of ephedrine use (Xenadrine, 0.4 mg/kg/day orally). To assess the effects of ephedrine on cardiac autonomic control, baroreceptor reflex sensitivity (BRS), heart rate (HR) variability, HR response to acute myocardial ischemia, and resting catecholamines were measured before and after ephedrine. Dogs were used as their own control when possible.

RESULTS

Nine of 15 animals had increased ventricular arrhythmias during ephedrine treatment (p = 0.01) and four had VF. Three dogs that had VF could not be resuscitated. Five animals with increased arrhythmias during ephedrine treatment had none during a third exercise and ischemia test after drug washout. Heart rates were higher after 30 s of myocardial ischemia during ephedrine treatment (204 +/- 25 beats/min no drug vs. 218 +/- 26 beats/min with ephedrine, p = 0.03). All plasma catecholamines increased after ephedrine administration. No changes in BRS, HR variability, or exercise HR were noted.

CONCLUSIONS

Ephedrine increases ischemia-dependent arrhythmias at doses recommended in over-the-counter preparations. Increased arrhythmia risk was associated with augmented ischemia-dependent sympathetic reflex activation.

Acute hemorrhagic myocardial necrosis and sudden death of rats exposed to a combination of ephedrine and caffeine

Because of possible side effects of herbal medicines containing ephedrine and guarana-derived caffeine, including increased risk of stroke, myocardial infarction, and sudden death, the Food and Drug Administration recently banned the sale of ephedra-containing products, specifically over-the-counter dietary supplements. We report cardiac in 7- and 14-week-old male F344 rats exposed by gavage to ephedrine(25 mg/kg) and caffeine (30 mg/kg) administered in combination for one or two days. The ephedrine-caffeine dosage was approximately 12- and 1.4-fold, respectively, above average human exposure, based on a mg/m2 body surface-area comparison. Several (5/7) of the exposed 14-week-old rats died or were sacrificed in extremis 4-5 h after the first dosing. In these hearts, changes were observed chiefly in the interventricular septum but also left and right ventricular walls. Massive interstitial hemorrhage, with degeneration of myofibers, occurred at the subendocardial myocardium of the left ventricle and interventricular septum. Immunostaining for cleaved caspase-3 and hyperphosphorylated H2A.X, a histone variant that becomes hyperphosphorylated during apoptosis, indicated multifocal generalized positive staining of degenerating myofibers and fragmenting nuclei, respectively. The Barbeito-Lopez trichrome stain revealed generalized patchy yellow myofibers consistent with degeneration and/or coagulative necrosis. In ephedrine-caffeine-treated animals terminated after the second dosing, foci of myocardial degeneration and necrosis were already infiltrated by mixed inflammatory cells. The myocardial necrosis may occur secondarily to intense diffuse vasoconstriction of the coronary arterial system with decreased myocardial perfusion. Our work shows the direct relationship between combined ephedrine and caffeine exposure and cardiac pathology.

Ephedrine‐Induced Cardiac Ischemia: Exposure Confirmed with a Serum Level

The temporal association of symptoms consistent with ephedrine toxicity after ingestion of ephedrine-containing dietary supplements is heavily relied upon to confirm exposure. Few reports in the literature attempt to associate toxicity with serum levels of these drugs. We report a case of ephedrine-induced cardiac ischemia confirmed by a plasma level. A 22-year-old woman ingesting an ephedrine- and caffeine-containing product for 2 days presented with multiple symptoms, including palpitations, nausea, tremulousness, abdominal pain, and vomiting. The initial electrocardiogram (ECG) revealed a normal sinus rhythm with 1 mm of ST segment depression in leads V3 and V4, along with inverted T waves in leads V1-V4. Her symptoms and ST segment depression resolved over several hours with medical management. The amplitude of her T wave inversions notably diminished with therapy; however, they did not completely resolve. Troponins at presentation and the following morning were negative, and an echocardiogram showed only trace tricuspid regurgitation. A serum ephedrine level, drawn approximately 6 to 7 hr after ingestion, was 150 ng/mL. She was discharged from the hospital after being instructed to avoid ephedrine-containing products.

L-ephedrine-induced neurodegeneration in the parietal cortex and thalamus of the rat is dependent on hyperthermia and can be altered by the process of in vivo brain microdialysis

Multiple doses of the dietary supplement L-ephedrine can cause severe hyperthermia and modest dopamine depletions in the rat brain. Since D-amphetamine treatment can result in neurodegeneration, the potential of L-ephedrine to produce similar types of degeneration was investigated. Adult male rats, some implanted in the caudate/putamen (CPu) for microdialysis, were given four doses of 25 mg/kg L-ephedrine or 5 mg/kg D-amphetamine (2 h between doses) at an ambient temperature of 23 degrees C. L-ephedrine-induced degeneration in the forebrain was dependent on the degree of hyperthermia. Layer IV of the parietal cortex was the most sensitive to L-ephedrine treatment with peak body temperatures of at most 40.0 degrees C necessary to produce degeneration. Extensive neurodegeneration in the parietal cortex after L-ephedrine treatment was as pronounced as that previously described for D-amphetamine treatment and also occurred in the intralaminar, ventromedial and ventrolateral thalamic nuclei in rats with severe hyperthermia (peak body temperatures>41.0 degrees C). The neurodegeneration induced by L-ephedrine may have resulted in part from excitotoxic mechanisms involving the indirect pathways of the basal ganglia and related areas. No differences were observed between microdialysis and non-implanted rats with respect to degree of tyrosine hydroxylase (TH) loss in the CPu after either D-amphetamine or L-ephedrine treatment. However, neurodegeneration resulting from D-amphetamine and L-ephedrine was reduced in the microdialysis animals in the hemisphere ipsilateral to the probe, which raises concerns when using the technique of in vivo microdialysis to evaluate neurodegeneration. The results of this study, in conjunction with human clinical evaluation of ephedrine neurotoxicity, indicate that regionally specific damage may occur in the cortex of some humans exposed to ephedrine in the absence of stroke or hemorrhage.

Cytotoxicity assessment of Ma-huang (Ephedra) under different conditions of preparation

Ma-huang is a traditional Chinese medicinal herb derived from EPHEDRA: sinica Stapf and other EPHEDRA: species, used to treat asthma, nose and lung congestion, and fever with anhidrosis. It contains 0.5-2.5% by weight of total alkaloids, of which ephedrine accounts for 30 to 90%. Recently, large amounts of ma-huang were used as a source of ephedrine in many dietary supplements formulated for weight reduction, because ephedrine has been found effective in inducing weight loss in diet-restricted obese patients. However, indiscriminate consumption of ma-huang-containing products has resulted in many cases of poisoning, some of which were fatal. The objective of this study is to investigate the relative toxicity of ma-huang extracted under different conditions. The toxicities of various extracts were assayed using MTT colorimetry on a battery of cell lines, while ephedrine alkaloids were analyzed with HPLC. The results are summarized as follows. (1) The cytotoxicity of all ma-huang extracts could not be totally accounted for by their ephedrine contents, suggesting the presence of other toxins in the extracts. (2) Grinding was a significant condition enhancing the toxicity of the extracts. (3) The relatively high sensitivity of the Neuro-2a cell line to the toxicity of ma-huang extracts suggests that the toxic principles were acting on neuronal cells. (4) One condition to produce a ma-huang extract with high ephedrine-to-toxins ratio would be to boil the whole herb for two h.

An evaluation of l-ephedrine neurotoxicity with respect to hyperthermia and caudate/putamen microdialysate levels of ephedrine, dopamine, serotonin, and glutamate

l-Ephedrine is an active ingredient in several herbal formulations with a mechanism of action similar to amphetamine and methamphetamine. However, its potential to damage dopaminergic terminals in the caudate/putamen (CPu) has yet to be fully evaluated. The studies here used in vivo brain microdialysis experiments to determine the systemic doses and extracellular brain levels of l-ephedrine necessary to produce similar increases in CPu extracellular dopamine and marked hyperthermia that were previously shown necessary for amphetamine-induced neurotoxicity in male Sprague-Dawley rats. At an environmental temperature of 23 degrees C, a single 40 mg/kg intraperitoneal (ip) dose of l-ephedrine produced marked hyperthermia (>/= 40 degrees C), peak microdialysate ephedrine levels of 7.3 +/- 1.2 microM, and a 20-fold increase in microdialysate dopamine levels. Twenty-five mg/kg produced a lesser degree of hyperthermia, peak microdialysate ephedrine levels of 2.6 +/- 0.4 microM, and a 10-fold increase in dopamine levels. Three doses of 40 mg/kg given at 3-h intervals or 4 doses of 25 mg/kg l-ephedrine given at 2-h intervals were compared with 4 doses of 5 mg/kg d-amphetamine given at 2-h intervals. Multiple doses of either ephedrine or amphetamine caused severe hyperthermia (>/= 41.3 degrees C) but striatal tissue levels of dopamine 7 days after dosing were reduced only 25% or less by ephedrine compared to the 75% reductions produced by amphetamine. The increases in CPu microdialysate levels of serotonin produced by either 4 x 25 mg/kg l-ephedrine or 4 x 5 mg/kg d-amphetamine did not significantly differ, but elevation of dopamine levels by d-amphetamine were over 2-fold times the level caused by l-ephedrine. Microdialysate glutamate levels were elevated to the same extent by either 25 mg/kg l-ephedrine or 4 x 5 mg/kg d-amphetamine. l-Ephedrine may not be as neurotoxic to dopaminergic terminals as d-amphetamine, because non-lethal doses of l-ephedrine do not sufficiently increase the CPu dopamine levels within nerve terminals or the extracellular space to those necessary for a more pronounced long-term dopamine depletion.

Methylephedrine concentrations in blood and urine specimens

Methylephedrine is a sympathomimetic amine that appears in many over-the-counter cough and cold medications throughout the world. The abuse of methylephedrine-containing medications has been reported in Japan. Although methylephedrine is not available in the United States, it was identified in 15 cases received by the Forensic Toxicology Laboratory, Division of Forensic Toxicology, Office of the Armed Forces Medical Examiner, Armed Forces Institute of Pathology over a two-year period; 12 of the 15 cases were collected from patients or decedents located within the confines of the continental United States. Methylephedrine was identified in each case by gas chromatography-nitrogen-phosphorus detection following an alkaline extraction and subsequently confirmed using full scan electron impact mass spectrometry. Quantitation of underivatized methylephedrine was performed using the same technique. Blood methylephedrine concentrations ranged from less than 0.05 to 0.28 mg/L (n = 14), and the mean methylephedrine concentration in urine was 1.6 mg/L (range, 0.15-6.8, n = 11 [excluding case 6]). A literature search revealed little information pertaining to the interpretation of methylephedrine concentrations in the blood. Six of the 15 cases presented here were positive for methylephedrine in the blood. Three of these cases were postmortem cases, and the other three cases were nonfatal aircraft mishaps. There is no evidence in any of these cases that methylephedrine was present at toxic concentrations; therefore, it appears from the cases reviewed in this study that blood methylephedrine concentrations less than 0.3 mg/L are not associated with significant toxicity.

National Association of Medical Examiners Pediatric Toxicology (PedTox) Registry Report 3. Case submission summary and data for acetaminophen, benzene, carboxyhemoglobin, dextromethorphan, ethanol, phenobarbital, and pseudoephedrine

Data are presented from the National Association of Medical Examiners' (St. Louis, MO, U.S.A.) Pediatric Toxicology (PedTox) Registry. A total of 839 case reports have been submitted to the registry. Reported here are the concentrations of several drugs and potentially toxic substances observed in children who have died of various causes, often non-drug-related. Except for carbon monoxide, for each of the substances addressed in this report, there is insufficient information in the literature to distinguish "lethal" from "non- or sublethal" concentrations in children, and the data are presented only to provide a working frame of reference. For 30 infants whose deaths were attributed to causes other than phenobarbital, the median blood phenobarbital concentration was 7.8 mg/L, with a range of 0.1-22.4 mg/L. For eight infants whose deaths were not attributed to ethanol, the mean blood ethanol concentration was 0.029 gm/dl and ranged from 0.011 gm/dl to 0.050 gm/dl. Blood dextromethorphan concentrations in seven infants showed a mean of 0.38 mg/L and ranged from 0.10 mg/L to 0.95 mg/L. In 15 infants, blood pseudoephedrine concentrations ranged between 0.07 mg/L and 13.0 mg/L, with a mean concentration of 3.55 mg/L. Blood carboxyhemoglobin saturations for 38 children aged < or = 5 years, who died in fires and were dead on the scene and not resuscitated, ranged between 29% and 94%, with a mean saturation of 64%. Blood benzene concentrations in eight children aged < or = 6 years who died in fires and were dead on the scene showed a mean concentration of 2.3 mg/L and a range of 0.2-4.9 mg/L. For 33 children aged < or = 5 years whose deaths were attributed to nondrug causes, the mean blood acetaminophen concentration was 9.9 mg/L, and the range was 1.0-34.5 mg/L. These data are not well controlled in terms of testing methodology or cause of death determinations and should not be used as the sole source of information when assessing whether or not a death is caused by one of these substances. Further data and controlled studies are needed to work toward establishing lethal concentrations of certain drugs and toxic substances in children, and the reporting of cases to the PedTox Registry is encouraged.

An update of recent moclobemide interaction data

The classical monoamine oxidase inhibitors (MAOIs) are believed to have serious risks because of interactions with other drugs and foodstuffs, although not with a sound scientific basis in all cases. However, moclobemide, a selective reversible inhibitor of MAO-A, has a low propensity for producing drug interactions. Interaction studies have been carried out in healthy volunteers in an attempt to answer some relevant practical questions related to therapy with moclobemide. In combination with therapeutic doses of either fluvoxamine or fluoxetine, moclobemide did not provide any indication of a serotoninergic syndrome, so that no wash-out period is needed when switching from a selective serotonin re-uptake inhibitor to moclobemide or vice versa. Since concomitant treatment with moclobemide and selegiline had a supra-additive effect on the sensitivity to intravenously administered tyramine, that combination therapy should only be considered when accompanied by dietary restrictions. Concomitant treatment with moclobemide and levodopa/benserazide, however, was well tolerated. When oral ephedrine was added to steady-state moclobemide treatment, the cardiovascular effects of the former were increased to about the same extent as for oral tyramine, i.e. a potentiation of 2-4.

Potentiating effects of forskolin on the cardiovascular teratogenicity of ephedrine in chick embryos

The effects of forskolin on the teratogenicity of ephedrine in the developing chick heart were studied. Forskolin was administered to 4-day chick embryos (Hamburger-Hamilton stage 24) together with ephedrine at doses at which each agent alone caused minimal embryotoxicity. The embryos were examined for malformations on day 14 of incubation. The frequency of malformed embryos exposed to ephedrine (0.5 or 5 mumol) alone was 8 and 26%, respectively, and significantly increased to 47-72% in the presence of 1 nmol forskolin. Forskolin (1 nmol) alone did not induce a significant number of cardiac malformations. These results suggest that the increase in cAMP through stimulation of adenylate cyclase by forskolin is associated with the potentiation of ephedrine-induced cardiovascular malformations in the chick.

Further validation of FETAX: evaluation of the developmental toxicity of five known mammalian teratogens and non-teratogens

The developmental toxicity of five compounds was evaluated with the Frog Embryo Teratogenesis Assay: Xenopus (FETAX). Late Xenopus laevis blastulae were exposed to 5-azacytidine, methotrexate, pseudoephedrine, aspartame, and amaranth for 96 h. Three separate static-renewal assays were conducted for each compound. Based on Teratogenic Index [LC50/EC50 (malformation)] values, types and severity of induced malformations, and embryo growth, 5-azacytidine and methotrexate tested as having strong teratogenic potential. Pseudoephedrine scored as having moderate teratogenic potential, but amaranth and aspartame had little or no teratogenic potential. Results support the use of FETAX for the screening of developmental toxicants.

Cardiovascular teratogenicity of ephedrine in chick embryos

The cardiovascular teratogenicity and embryotoxicity of ephedrine was studied in chick embryos treated after 2.5-6 days of incubation (Hamburger-Hamilton developmental stages 17-28). The embryos were examined on day 14. Cardiovascular malformations were observed in 29% (29/101) of treated embryos. Complicated anomalies, such as double-outlet right ventricle (DORV), truncus arteriosus communis (TAC) or overriding aorta with ventricular septal defect (VSD) were seen frequently in embryos exposed to the agent on day 3 of incubation. Malformations were induced by ephedrine at a dose as low as 1 mumol/egg.

Potentiating effects of caffeine on the cardiovascular teratogenicity of ephedrine in chick embryos

Ephedrine was administered to 3-day chick embryos (Hamburger-Hamilton developmental stage 19) together with caffeine at doses where each agent alone caused minimal embryotoxicity. Embryos were examined for malformations on day 14 of incubation. The teratogenicity of ephedrine in the chick cardiovascular system was significantly potentiated by caffeine at a dose as low as 0.5 mumol (0.1 mg/egg; 2 mg/kg egg).

[Interaction of d-pseudoephedrine with water soluble extracts of Platycodi Radix on acute toxicity (author's transl)]

Effect of various combinations of Platycodi Radix water soluble extracts (Pla), 1-ephedrine (1-eph), d-pseudoephedrine (d-pseudo) and Ipecacuanhae Radix water soluble extracts (Ipe) on acute toxicity were examined in mice. Oral LD50 of Ipe, d-pseudo and 1-eph was 490 (415--578) mg/kg, 1550 (1360--1767) mg/kg and 1400 (1102--1778) mg/kg, respectively, while that of Pla was over 10 g. LD50 of Pla Ipe, d-pseudo and 1-eph given intraperitoneally was 1400 (1228--1596) mg/kg 235 (210--263) mg/kg, 245 (229--262) mg/kg and 300 (259--348) mg/kg, respectively. The ratio of the predicted LD50 value, which was calculated on the assumption that each component drug would be additively toxic when combined, to the observed LD50 value was used for comparison. The combination of d-pseudo with Pla gave a significantly greater LD50 value than the predicted LD50 value, while the combination of 1-eph with Pla showed a LD50 value which was not significantly different from Finney's additive model. A combination of d-pseudo with 1-eph and Ipe, and of 1-eph with Ipe showed a LD50 value which was not significantly different from that of the additive model.

Carcinogenicity of N-nitrosoephedrine in rats

N-nitrosoephedrine was administered orally to 32 male Srague--Dawley rats at doses of 120 mg/kg body wt. twice weekly. Of the treated animals, 50% died with preneoplastic and malignant lesions mainly in the liver, lung and forestomach. The median time of death of tumor bearing animals was 522 days after the beginning of the experiment. The observation of hyperkeratosis, papillomas, and 1 squamous cell carcinoma of the forestomach suggests that the compound not only exhibits systemic effects but is probably also a weak local carcinogen.

The effect of various environmental factors on cocaine and eph edrine toxicity

The effect of environmental factors on the toxicity of ephedrine and cocaine has been examined and the results compared with those obtained with amphetamine. Ambient temperatures were identified at which these drugs have an “aggregation effect”, and isolated mice treated with ephedrine or cocaine were then forcibly exercised and the effect of increased motor activity on body temperature and mortality compared with the results obtained by grouping the animals together. In general, the toxicity of either drug is increased by a rise in ambient temperature. Both drugs produce an aggregation effect and forced exercise increases the toxicity of each drug as much as does grouping. In all parameters tested the effects of ephedrine and cocaine resemble qualitatively those of amphetamine, but are less potent. In mice given certain central nervous system stimulants the aggregation effect may be due to hyperpyrexia associated with increased spontaneous motor activity resulting from a greater response to external stimuli.