Alginate-coated activated charcoal enhances fecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice, with fewer side effects than uncoated one.

Activated charcoal (AC) is a potential candidate antidote against dioxins. However, it is difficult to take AC as a supplement on a daily basis, because its long-term ingestion causes side effects such as constipation and deficiency of fat-soluble essential nutrients and hypocholesterolemia. Alginate-coated AC, termed Health Carbon (HC), was developed to decrease the side effects of AC, but its pharmacological effects, including side effects, remains unclear. Here, we show that HC enhanced fecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and decreased some side effects of unmodified AC, such as hypocholesterolemia, in male mice. Basal diet mixed with HC or unmodified AC at various concentrations was fed to mice for 16 days following a single intraperitoneal administration of [3H]TCDD. Both HC and unmodified AC at 3% or more significantly increased fecal excretion of [3H]TCDD in comparison with the control basal diet. Consistent with this, [3H]TCDD radioactivity in the liver-a major TCDD storage organ-was markedly decreased by HC at concentrations of 3% and 10%. In an examination of potential side effects, unmodified AC at 10% or more caused significant body weight reduction and at 20% caused significant hypocholesterolemia. In contrast, HC caused weight gain reduction only at a concentration of 20%, and there was no evidence of hypocholesterolemia at any dietary HC concentration. HC not only retains the ability of AC to enhance fecal excretion of TCDD but also reduces some of the side effects of AC.

Novel strategies for the treatment of acetaminophen hepatotoxicity.

INTRODUCTION: Acetaminophen (APAP) hepatotoxicity is the leading cause of acute liver failure in the western world. Despite extensive investigations into the mechanisms of cell death, only a single antidote, N-acetylcysteine, is in clinical use. However, there have recently been more efforts made to translate mechanistic insight into identification of therapeutic targets and potential new drugs for this indication. AREAS COVERED: After a short review of the key events in the pathophysiology of APAP-induced liver injury and recovery, the pros and cons of targeting individual steps in the pathophysiology as therapeutic targets are discussed. While the re-purposed drug fomepizole (4-methylpyrazole) and the new entity calmangafodipir are most advanced based on the understanding of their mechanism of action, several herbal medicine extracts and their individual components are also considered. EXPERT OPINION: Fomepizole (4-methylpyrazole) is safe and has shown efficacy in preclinical models, human hepatocytes and in volunteers against APAP overdose. The safety of calmangafodipir in APAP overdose patients was shown but it lacks solid preclinical efficacy studies. Both drugs require a controlled phase III trial to achieve regulatory approval. All studies of herbal medicine extracts and components suffer from poor experimental design, which questions their clinical utility at this point.

Arsenic intoxication: general aspects and chelating agents.

Arsenic (As) is widely used in the modern industry, especially in the production of pesticides, herbicides, wood preservatives, and semiconductors. The sources of As such as contaminated water, air, soil, but also food, can cause serious human diseases. The complex mechanism of As toxicity in the human body is associated with the generation of free radicals and the induction of oxidative damage in the cell. One effective strategy in reducing the toxic effects of As is the usage of chelating agents, which provide the formation of inert chelator-metal complexes with their further excretion from the body. This review discusses different aspects of the use of metal chelators, alone or in combination, in the treatment of As poisoning. Consideration is given to the therapeutic effect of thiol chelators such as meso-2,3-dimercaptosuccinic acid, sodium 2,3-dimercapto-1-propanesulfonate, 2,3-dimercaptopropanol, penicillamine, ethylenediaminetetraacetic acid, and other recent agents against As toxicity. The review also considers the possible role of flavonoids, trace elements, and herbal drugs as promising natural chelating and detoxifying agents.

An Appraisal of Antidotes' Effectiveness: Evidence of the Use of Phyto-Antidotes and Biotechnological Advancements.

Poisoning is the greatest source of avoidable death in the world and can result from industrial exhausts, incessant bush burning, drug overdose, accidental toxication or snake envenomation. Since the advent of Albert Calmette's cobra venom antidote, efforts have been geared towards antidotes development for various poisons to date. While there are resources and facilities to tackle poisoning in urban areas, rural areas and developing countries are challenged with poisoning management due to either the absence of or inadequate facilities and this has paved the way for phyto-antidotes, some of which have been scientifically validated. This review presents the scope of antidotes' effectiveness in different experimental models and biotechnological advancements in antidote research for future applications. While pockets of evidence of the effectiveness of antidotes exist in vitro and in vivo with ample biotechnological developments, the utilization of analytic assays on existing and newly developed antidotes that have surpassed the proof of concept stage, as well as the inclusion of antidote's short and long-term risk assessment report, will help in providing the required scientific evidence(s) prior to regulatory authorities' approval.

[NOAC: Real-life data and the role of antidotes for the treatment of bleeding]. / NOAK: Real-life-Daten und Therapie von Blutungen mit Antidots.

The non-vitamin K antagonists (NOAC) are an integral component of our antithrombotic prevention and therapy. For four of the NOAC, their non-inferiority or even superiority versus vitamin K antagonists (VKA) has been proven. Thus, the management of special patient cohorts or the management of active bleeding complications is a focus of current discussion.In addition to prospective trials, numerous retrospective analyses of health insurers or public health provider data have been analyzed and published as "real life" or "real-world evidence" data. In almost all data sets the results of the NOAC approval trials were confirmed, demonstrating their non-inferiority or even superiority versus VKA. Attempts to compare the various NOAC with each other must be viewed critically since the real-world evidence (RWE) analysis provides very divergent results depending on the cohorts analyzed. Thus, a substantial prescriber-bias must be taken into account and never be excluded.In order to improve the management of bleeding complications, NOAC antidotes were developed. While the factors Xa antidote, andexanet alpha, a modified coagulation factor deleted of an intrinsic activity, will not be available before 2018, the dabigatran antidote idarucizumab is already in clinical use. Idarucizumab, a monoclonal antibody fragment directed against dabigatran, is able to completely antagonize the effect of dabigatran within minutes. Therefore, the drug has the potential to terminate life-threatening bleeding complications earlier and make emergency surgical or interventional procedures possible without an elevated bleeding risk.

Low-Dose or High-Dose Rocuronium Reversed with Neostigmine or Sugammadex for Cesarean Delivery Anesthesia: A Randomized Controlled Noninferiority Trial of Time to Tracheal Intubation and Extubation.

BACKGROUND: Rocuronium for cesarean delivery under general anesthesia is an alternative to succinylcholine for rapid-sequence induction of anesthesia because of the availability of sugammadex for reversal of neuromuscular blockade. However, there are no large well-controlled studies in women undergoing general anesthesia for cesarean delivery. The aim of this noninferiority trial was to determine whether rocuronium and sugammadex confer benefit in time to tracheal intubation (primary outcome) and other neuromuscular blockade outcomes compared with succinylcholine, rocuronium, and neostigmine in women undergoing general anesthesia for cesarean delivery. METHODS: We aimed to enroll all women undergoing general anesthesia for cesarean delivery in the 2 participating university hospitals (Brno, Olomouc, Czech Republic) in this single-blinded, randomized, controlled study. Women were randomly assigned to the ROC group (muscle relaxation induced with rocuronium 1 mg/kg and reversed with sugammadex 2-4 mg/kg) or the SUX group (succinylcholine 1 mg/kg for induction, rocuronium 0.3 mg/kg for maintenance, and neostigmine 0.03 mg/kg for reversal of the neuromuscular blockade). The interval from the end of propofol administration to tracheal intubation was the primary end point with a noninferiority margin of 20 seconds. We recorded intubating conditions (modified Viby-Mogensen score), neonatal outcome (Apgar score <7; umbilical artery pH), anesthesia complications, and subjective patient complaints 24 hours after surgery. RESULTS: We enrolled 240 parturients. The mean time to tracheal intubation was 2.9 seconds longer in the ROC group (95% confidence interval, -5.3 to 11.2 seconds), noninferior compared with the SUX group. Absence of laryngoscopy resistance was greater in the ROC than in the SUX groups (ROC, 87.5%; SUX, 74.2%; P = 0.019), but there were no differences in vocal cord position (P = 0.45) or intubation response (P = 0.31) between groups. No statistically significant differences in incidence of anesthesia complications or in neonatal outcome were found (10-minute Apgar score <7, P = 0.07; umbilical artery pH, P = 0.43). The incidence of postpartum myalgia was greater in the SUX group (ROC 0%; SUX 6.7%; P = 0.007). The incidence of subjective complaints was lower in the ROC group (ROC, 21.4%; SUX, 37.5%; P = 0.007). CONCLUSIONS: We conclude that rocuronium for rapid-sequence induction is noninferior for time to tracheal intubation and is accompanied by more frequent absence of laryngoscopy resistance and lower incidence of myalgia in comparison with succinylcholine for cesarean delivery under general anesthesia.

Current and future directions in the treatment and prevention of drug-induced liver injury: a systematic review.

While the pace of discovery of new agents, mechanisms and risk factors involved in drug-induced liver injury (DILI) remains brisk, advances in the treatment of acute DILI seems slow by comparison. In general, the key to treating suspected DILI is to stop using the drug prior to developing irreversible liver failure. However, predicting when to stop is an inexact science, and commonly used ALT monitoring is an ineffective strategy outside of clinical trials. The only specific antidote for acute DILI remains N-acetylcysteine (NAC) for acetaminophen poisoning, although NAC is proving to be beneficial in some cases of non-acetaminophen DILI in adults. Corticosteroids can be effective for DILI associated with autoimmune or systemic hypersensitivity features. Ursodeoxycholic acid, silymarin and glycyrrhizin have been used to treat DILI for decades, but success remains anecdotal. Bile acid washout regimens using cholestyramine appear to be more evidenced based, in particular for leflunomide toxicity. For drug-induced acute liver failure, the use of liver support systems is still investigational in the United States and emergency liver transplant remains limited by its availability. Primary prevention appears to be the key to avoiding DILI and the need for acute treatment. Pharmacogenomics, including human leukocyte antigen genotyping and the discovery of specific DILI biomarkers offers significant promise for the future. This article describes and summarizes the numerous and diverse treatment and prevention modalities that are currently available to manage DILI.

A pharmacokinetic and pharmacodynamic investigation of Modufolin® compared to Isovorin® after single dose intravenous administration to patients with colon cancer: a randomized study.

PURPOSE: Leucovorin is commonly used as folate supplement in 5-fluorouracil-based chemotherapy, but needs to be converted to active 5,10-methylenetetrahydrofolate (methyleneTHF) intracellularly. This provides for interindividual differences. MethyleneTHF has recently been developed into the stable, distributable drug, Modufolin®. The aim was to compare the concentration of folate metabolites in tumor, mucosa, and plasma of patients with colon cancer after administration of Modufolin® or Isovorin® (levo-leucovorin). METHODS: Thirty-two patients scheduled for colon resection were randomized to receive Modufolin® or Isovorin® at dosage of 60 or 200 mg/m². The study drug was given as one i.v. bolus injection after anesthesia. Plasma was collected for pharmacokinetic (PK) analysis before, during, and after surgery. Tissue biopsies were collected at surgery. Folate metabolites were analyzed by LC-MS/MS. RESULTS: MethyleneTHF and THF concentrations were significantly higher in mucosa (p < 0.01, both dosages) and tumors (p < 0.01, 200 mg/m²) after Modufolin® as compared to Isovorin® administration. The results correlated with PK observations. The Modufolin® to Isovorin® C(max) ratio for methyleneTHF was 113 at 200 mg/m² and 52 at 60 mg/m²; the AUC(last) ratios were 17 and 9, respectively. The THF plasma concentrations were also higher after Modufolin® administration (C(max) ratio 23, AUC(last) ratio 13 at 200 mg/m²; C(max) ratio 15, AUC(last) ratio 11 at 60 mg/m²). CONCLUSION: Modufolin® administration resulted in significantly higher methyleneTHF levels than Isovorin® and may potentially increase the efficacy of 5-fluorouracil-based chemotherapy. The results encourage further evaluation of Modufolin® as a substitute to Isovorin® including the potential clinical benefits.

Interventions for treating phosphorus burns.

BACKGROUND: Phosphorus burns are rarely encountered in usual clinical practice and occur mostly in military and industrial settings. However, these burns can be fatal, even with minimal burn area, and are often associated with prolonged hospitalisation. OBJECTIVES: To summarise the evidence of effects (beneficial and harmful) of all interventions for treating people with phosphorus burns. SEARCH METHODS: In October 2013 for this first update we searched the Cochrane Wounds Group Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library);Ovid OLDMEDLINE; Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; EBSCO CINAHL and Conference Proceedings Citation Index - Science (CPCI-S). We did not apply any methodological filters or restrictions on the basis of study design, language, date of publication or publication status. SELECTION CRITERIA: Any comparisons of different ways of managing phosphorus burns including, but not restricted, to randomised trials. DATA COLLECTION AND ANALYSIS: We found two non-randomised comparative studies, both comparing patients treated with and without copper sulphate. MAIN RESULTS: These two comparative studies provide no evidence to support the use of copper sulphate in managing phosphorus burns. Indeed the small amount of available evidence suggests that it may be harmful. AUTHORS' CONCLUSIONS: First aid for phosphorus burns involves the common sense measures of acting promptly to remove the patient's clothes, irrigating the wound(s) with water or saline continuously, and removing phosphorus particles. There is no evidence that using copper sulphate to assist visualisation of phosphorus particles for removal is associated with better outcome, and some evidence that systemic absorption of copper sulphate may be harmful. We have so far been unable to identify any other comparisons relevant to informing other aspects of the care of patients with phosphorus burns. Future versions of this review will take account of information in articles published in languages other than English, which may contain additional evidence based on treatment comparisons.

Iron decreases biological effects of ozone exposure.

CONTEXT: Ozone (O3) exposure is associated with a disruption of iron homeostasis and increased availability of this metal which potentially contributes to an oxidative stress and biological effects. OBJECTIVE: We tested the postulate that increased concentrations of iron in cells, an animal model and human subjects would significantly impact the biological effects of O3 exposure. RESULTS: Exposure to 0.4 ppm O3 for 5 h increased mRNA for both Superoxide Dismutase-1 (SOD1) and Cyclooxygenase-2 (COX2) in normal human bronchial epithelial (NHBE) cells. Pre-treatment of NHBE cells with 200 µM ferric ammonium citrate (FAC) for 4 h diminished changes in both SOD1 and COX2 following O3 exposure. mRNA transcript levels and associated protein release of the pro-inflammatory mediators IL-6 and IL-8 were increased by O3 exposure of NHBE cells; changes in these endpoints after O3 exposure were significantly decreased by FAC pre-treatment of the cells. Exposure of CD-1 mice to 2 ppm O3 for 3 h significantly increased lavage indices of inflammation and airflow limitation. Pre-treatment of the animals with pharyngeal aspiration of FAC diminished the same endpoints. Finally, the mean loss of pulmonary function in 19 healthy volunteers exposed to 0.3 ppm O3 for 2 h demonstrated significant correlations with either their pre-exposure plasma ferritin or iron concentrations. DISCUSSION AND CONCLUSION: We conclude that greater availability of iron after O3 exposure does not augment biological effects. On the contrary, increased available iron decreases the biological effects of O3 exposure in cells, animals and humans.

Protective effect of artichoke (Cynara scolymus) leaf extract against lead toxicity in rat.

CONTEXT: Artichoke, Cynara scolymus L. (Asteraceae), has many natural antioxidants and multiple pharmacological actions. Recent studies have shown that it has antitoxic activity. OBJECTIVE: Lead (Pb) is a dangerous environmental toxicant that induces a broad range of dysfunctions in human. This study evaluated the protective effect of the hydroethanolic extract of artichoke against altered biochemical parameters in rats fed with lead-containing diet. MATERIALS AND METHODS: Thirty-two rats were randomly divided into four groups. The first (control) group received standard diet. The second, third and fourth groups received 500 mg lead/kg diet, 500 mg lead/kg diet plus 300 mg/kg b.w. artichoke extract daily, and 500 mg lead/kg diet plus 1 mg vitamin C/100 g b.w. daily for 6 weeks, respectively. Serum lead, lipoprotein profile, ALT (alanine transaminase), AST (aspartate transaminase), ALP (alkaline phosphatase), malondialdehyde (MDA) and liver histopathology assessments were conducted. RESULTS: Serum lead, triglyceride (TG), VLDL, ALT, AST, ALP and MDA levels decreased significantly (p < 0.05) in the artichoke-treated group (35.85, 38.26, 38.38, 21.90, 12.81, 26.86 and 46.91%, respectively) compared to lead-intoxicated rats without treatment. No significant change was observed in serum lead, ALP and ALT between artichoke and vitamin C-treated groups (p > 0.05). Furthermore, the liver histopathology in rats treated with artichoke showed a mild degree of lymphocyte infiltration that was relatively comparable to the control and vitamin C-treated groups. DISCUSSION AND CONCLUSION: These results clearly show that the artichoke extract in lead-poisoned rats has suitable chelating properties for the reduction of blood lead levels.

Legalon® SIL: the antidote of choice in patients with acute hepatotoxicity from amatoxin poisoning.

More than 90% of all fatal mushroom poisonings worldwide are due to amatoxin containing species that grow abundantly in Europe, South Asia, and the Indian subcontinent. Many cases have also been reported in North America. Initial symptoms of abdominal cramps, vomiting, and a severe cholera-like diarrhea generally do not manifest until at least six to eight hours following ingestion and can be followed by renal and hepatic failure. Outcomes range from complete recovery to fulminant organ failure and death which can sometimes be averted by liver transplant. There are no controlled clinical studies available due to ethical reasons, but uncontrolled trials and case reports describe successful treatment with intravenous silibinin (Legalon® SIL). In nearly 1,500 documented cases, the overall mortality in patients treated with Legalon® SIL is less than 10% in comparison to more than 20% when using penicillin or a combination of silibinin and penicillin. Silibinin, a proven antioxidative and anti-inflammatory acting flavonolignan isolated from milk thistle extracts, has been shown to interact with specific hepatic transport proteins blocking cellular amatoxin re-uptake and thus interrupting enterohepatic circulation of the toxin. The addition of intravenous silibinin to aggressive intravenous fluid management serves to arrest and allow reversal of the manifestation of fulminant hepatic failure, even in severely poisoned patients. These findings together with the available clinical experience justify the use of silibinin as Legalon® SIL in Amanita poisoning cases.

A dosing regimen for immediate N-acetylcysteine treatment for acute paracetamol overdose.

CONTEXT: Current treatment of paracetamol (acetaminophen) poisoning involves initiating a 3-phase N-acetylcysteine (NAC) infusion after comparing a plasma concentration, taken ≥ 4 h post-overdose, to a nomogram. This may result in dosing errors, a delay in treatment, or possibly more adverse effects - due to the use of a high dose rate for the first infusion when treatment is initiated. OBJECTIVE: Our aim was to investigate a novel dosing regimen for the immediate administration of NAC on admission at a lower infusion rate. METHODS: We used a published population pharmacokinetic model of NAC to simulate a scenario where a patient presents to the hospital 2 h post-overdose. The conventional regimen is commenced 6 h post-overdose when the 4-h plasma paracetamol concentration is available. We investigated an NAC infusion using a lower dosing rate initiated immediately on presentation. We determined a dosing rate that gave an area under the curve (AUC) of the concentration-time curve that was the same or greater than that from the conventional regimen on 90% of occasions. RESULTS: Lower dosing rates of NAC initiated immediately resulted in a similar exposure to NAC. An infusion of 110 mg/kg over the first 5 h (22 mg/kg/h) followed by the last two phases of the conventional regimen, or 200 mg/kg over 9 h (22.6 mg/kg/h) followed by the last phase of the conventional regimen could be used. CONCLUSION: The novel dosing regimen allowed immediate treatment of a patient using a lower dosing rate. This greatly simplifies the current dosing regimen and may reduce NAC adverse effects while ensuring the same amount of NAC is delivered.

Late extensive intravenous administration of N-acetylcysteine can reverse hepatic failure in acetaminophen overdose.

Acetaminophen is a commonly used analgesic and has been shown to be a main cause of drug-induced liver failure. N-acetylcysteine (NAC) should be employed as the antidote in case of acetaminophen poisoning within the first 8-10 hours. Oral administration of NAC is universally recommended and due to the adverse effects, the intravenous administration of the agent is reserved for patients with oral intolerance and severe complications. We here report an 18-year-old man with severe liver failure due to a huge ingestion of acetaminophen, who was taken into the Loghman Hakim Hospital Poison Center 72 hours after attempted suicide. Regarding the poor prognostic clues as his level of consciousness and impaired liver functions, an extensive intravenous regimen of NAC was started. The patient survived the condition with an additional intravenous administration of NAC past the first 72 hours of treatment. We discuss that even in late phases of intoxication; high-dose intravenous NAC can serve a substantial improvement.

A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning.

INTRODUCTION: This article reviews the experimental and clinical studies that have compared the efficacy (impact on urine lead excretion, blood and tissue lead concentrations, resolution of features and survival) of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning. It also summarizes the pharmacokinetic and pharmacodynamic aspects and the adverse effects of treatment. METHODS: Medline, Toxline, and Embase were searched for all available years to June 2009. PHARMACOKINETICS AND PHARMACODYNAMICS: The absorption of oral DMSA is more complete than sodium calcium edetate; the latter has to be administered parenterally. Both antidotes are distributed predominantly extracellularly. Sodium calcium edetate is not metabolized, whereas DMSA is extensively metabolized to mixed disulfides of cysteine. The two antidotes have elimination half-lives of less than 60 min. There is no evidence that either antidote crosses the blood-brain barrier to any major extent. Sodium calcium edetate chelates lead by displacement of the central Ca2+ ion with Pb2+. The nature of the DMSA-lead chelate is less clearly defined. There is evidence that the mixed disulfides of cysteine are the active chelating moiety in humans. If this is the case, this suggests that chelation occurs principally, if not exclusively, in the kidney. The primary source of lead mobilized by sodium calcium edetate is bone with an additional contribution from kidney and liver. EFFICACY: Comparison of the experimental studies is complicated by substantial variations in study design, particularly the antidote dose, the route and duration of treatment, the amount and duration of lead dosing, and lack of direct comparison between antidotes (comparison was usually made with control). In experimental studies that used equimolar and clinically relevant antidote doses and assessed the impact of DMSA and sodium calcium edetate on urine lead excretion and/or blood lead concentrations, similar results were found, though no direct comparison between antidotes was undertaken. DMSA was more effective than sodium calcium edetate in reducing the kidney lead concentration, sodium calcium edetate was more effective than DMSA in reducing bone lead concentrations, and there was no consistently observed effect of chelation therapy on brain lead concentrations in these experimental studies. Only two clinical studies have compared equimolar or similar antidote doses in enhancing urine lead excretion; there was no statistical difference between the antidotes, though both studies had limitations. DMSA and sodium calcium edetate had a comparable impact on lowering blood lead concentrations in a clinical study using similar molar antidote doses. ADVERSE EFFECTS: Sodium calcium edetate causes dose-related nephrotoxicity. Both agents deplete zinc and copper, the effect on zinc being significantly greater with sodium calcium edetate. A transient increase in hepatic transaminase activity has been reported with both antidotes but appears to be more common with DMSA and neither has been associated with clinically significant hepatic toxicity. Skin lesions during treatment with sodium calcium edetate are unusual and have been attributed to zinc deficiency. DMSA has occasionally been associated with a severe mucocutaneous reaction necessitating discontinuation of therapy. CONCLUSIONS: Oral DMSA and parenteral sodium calcium edetate are both effective chelators of lead. There are currently insufficient data, however, to conclude that either antidote is superior in enhancing lead excretion. Both antidotes resolve the symptoms of moderate and severe lead toxicity rapidly. Although there is greater clinical experience with sodium calcium edetate, particularly in the treatment of lead encephalopathy, oral DMSA may now be considered as an alternative in circumstances where oral therapy is preferable.

Dimercaptosuccinic acid (succimer; DMSA) in inorganic lead poisoning.

INTRODUCTION: This article reviews data on the efficacy of succimer (dimercaptosuccinic acid, DMSA) in the treatment of human inorganic lead poisoning, the adverse effects associated with its use, and summarizes current understanding of the pharmacokinetic and pharmacodynamic aspects. METHODS: Medline, Toxline, and Embase were searched and 912 papers were identified and considered. PHARMACOKINETICS AND PHARMACODYNAMICS: DMSA is absorbed rapidly but incompletely after oral administration, probably through an active transporter. There is evidence that enterohepatic circulation occurs. Most DMSA in plasma is protein (mainly albumin)-bound through a disulfide bond with cysteine; only a very small amount is present as free drug, which is filtered at the glomerulus then extensively reabsorbed into proximal tubule cells. Nonfiltered protein-bound DMSA in peritubular capillaries is also available for uptake into proximal tubule cells by active anion transport at the basolateral membrane. DMSA therefore accumulates in the kidney where it is extensively metabolized in humans to mixed disulfides of cysteine. Some 10-25% of an orally administered dose of DMSA is excreted in urine, the majority within 24 h and most (>90%) as DMSA-cysteine disulfide conjugates. It is not known whether protein-bound DMSA can chelate lead; there is evidence that the mixed disulfides of cysteine are the active chelating moiety in humans. If this is the case, this suggests that chelation occurs principally, if not exclusively, in the kidney. DOSE: DMSA 30 mg/kg/day is more effective than either 10 or 20 mg/kg/day in enhancing urine lead excretion. DURATION OF THERAPY: Initial clinical studies with DMSA involved the administration of a 5-day course of treatment. Subsequently, a 19- to 26-day regimen was introduced with the intent of preventing or at least blunting a rebound in the blood lead concentration. Studies suggest, however, that repeated courses of DMSA 30 mg/kg/day for at least 5 days are equally efficacious if a treatment-free period of at least 1 week between courses is included to allow redistribution of lead from bone to soft tissues and blood. There is also evidence that in more severely poisoned patients DMSA 30 mg/kg/day can be given for more than 5 days with benefit. EFFICACY: DMSA 30 mg/kg/day significantly increases urine lead elimination and significantly reduces blood lead concentrations in lead-poisoned patients, though there is substantial individual variation in response. Over a 5-day course, mean daily urine lead excretion exceeds baseline by between 5- and 20-fold and blood lead concentrations fall to 50% or less of the pretreatment concentration, with wide variation. Maximum enhancement of urine lead elimination typically occurs with the first dose. Most symptomatic patients report improvement after 2 days of treatment. However, DMSA did not improve cognition in children < 3 years old with mild lead poisoning, presumably because lead-induced neurological damage occurred during development in utero and/or early infancy. DMSA IN PREGNANCY AND IN THE NEONATE: DMSA is not teratogenic but did produce maternal toxicity (decreased weight gain) and fetotoxicity when given in high dose (100-1,000 mg/kg/day) in experimental studies. For this reason sodium calcium edetate is generally preferred in pregnancy. ADVERSE EFFECTS: A transient modest rise in transaminase activity during chelation occurs in up to 60% of patients but has not resulted in clinically significant sequelae. Skin reactions occur in approximately 6% of treated patients and are occasionally severe. DMSA also increases urine copper and zinc excretion but not to a clinically important extent. CONCLUSIONS: DMSA is an effective lead chelator that primarily chelates renal lead. It is generally well tolerated but may occasionally cause clinically important adverse effects. DMSA may now be considered as an alternative to sodium calcium edetate, particularly when an oral antidote is preferable.

Use of oral dimercaptosuccinic acid (succimer) in adult patients with inorganic lead poisoning.

BACKGROUND: Chelation therapy has been used as a means of reducing the body burden of lead for five decades. Intravenous sodium calcium edetate has been the preferred agent, but there is increasing evidence that dimercaptosuccinic acid (DMSA) is also a potent chelator of lead. METHODS: Oral DMSA 30 mg/kg/day was administered to adults with blood lead concentrations > or = 50 microg/dl. The impact of DMSA on urine lead excretion, on blood lead concentrations and on symptoms was observed. The incidence and severity of adverse effects was also recorded. RESULTS: Thirty-five courses were given to 17 patients. DMSA significantly (P < 0.0001) increased urine lead excretion and significantly (P < 0.0001) reduced blood lead concentrations. Mean daily urine lead excretion exceeded the pre-treatment value by a median of 12-fold with wide variation in response (IQR 8.9-14.8, 95% CI 10.1-14.6). Pre-treatment blood lead concentrations correlated well with 5-day urine lead excretion. Headache, lethargy and constipation improved or resolved in over half the patients within the first 2 days of chelation. DMSA was generally well tolerated, but one course was discontinued due to a severe mucocutaneous reaction. There was a transient increase in alanine aminotransferase (ALT) activity during 14% of chelations. DMSA caused a significant increase in urine copper (P < 0.0001) and zinc (P < 0.05) excretion. CONCLUSION: Oral DMSA 30 mg/kg/day is an effective antidote for lead poisoning, though there is a wide inter- and intra-individual variation in response.

Copper sulphate burns to the hands, a complication of traditional medicine.

An 11-year-old girl of Bedouin origin presented with infected burns on the dorsum of both her hands. The burns had an unusual configuration in the form of spirals, and child abuse was suspected. The family reported that the burns had been caused by a treatment, for head aches, dispensed by a traditional healer, which involved applying a blue fluid on the hands. Chemical analysis of the implicated substance identified it as copper sulfate. The local and systemic effects of copper sulfate are reviewed as well as traditional healing methods that may lead to burn injuries. When clinicians encounter bizarre patterns of injury they must consider besides the possibility of abuse also, more unusual etiologies.

Position paper: Ipecac syrup.

Syrup of ipecac should not be administered routinely in the management of poisoned patients. In experimental studies the amount of marker removed by ipecac was highly variable and diminished with time. There is no evidence from clinical studies that ipecac improves the outcome of poisoned patients and its routine administration in the emergency department should be abandoned. There are insufficient data to support or exclude ipecac administration soon after poison ingestion. Ipecac may delay the administration or reduce the effectiveness of activated charcoal, oral antidotes, and whole bowel irrigation. Ipecac should not be administered to a patient who has a decreased level or impending loss of consciousness or who has ingested a corrosive substance or hydrocarbon with high aspiration potential. A review of the literature since the preparation of the 1997 Ipecac Syrup Position Statement revealed no new evidence that would require a revision of the conclusions of that Statement.