Spectrophotometric analysis of purple urine secondary to methylene blue and hydroxocobalamin co-administration

BACKGROUND

The development of purple urine after methylene blue (methylthioninium chloride) and hydroxocobalamin co-administration is a rare clinical entity that has not been fully elucidated. A 47-year-old male presented to the emergency department with hypotension, cyanosis, and depressed mental status. The patient was noted to have profound peripheral and central cyanosis, as well as chocolate-colored arterial blood. He was treated with both methylene blue and hydroxocobalamin and developed purple urine for approximately 1 week.

METHODS

Color chromatography was performed by placing the patient's urine directly onto absorbent filter paper. Urine spectrophotometry was performed utilizing the NanoDrop One/One C UV-Vis Spectrophotometer.

RESULTS

Color chromatography of the urine was demonstrated clear separation of distinct red and blue phases. Urine spectrophotometry demonstrated near perfect overlap between the methylene blue + hydroxocobalamin absorbance spectrum and the patient's purple urine absorbance spectrum.

CONCLUSION

Purple urine secondary to methylene blue and hydroxocobalamin co-administration is due to combined urinary excretion of methylene blue (blue) and hydroxocobalamin (red), and not a novel purple metabolite. We anticipate that this is going to be an increasingly common clinical entity as the roles of both hydroxocobalamin and methylene blue expand from toxicologic antidotes to adjunct therapies for vasoplegia, poor cardiac output, and sepsis.

Efficacy and expenses of succimer vs. d-penicillamine plus garlic in the treatment of lead poisoning: a retrospective cross-sectional study

PURPOSE

Lead Poisoning is a major health problem in Iran. We aimed to compare efficacy of a standard regimen (Succimer) with that of a low-priced combination of D-penicillamine and Garlic in outpatients with lead poisoning.

METHODS

In this retrospective cross-sectional study, year-long clinical files of outpatients with lead poisoning in two referral toxicology clinics in Mashhad, Iran were reviewed. A total of 79 patients (all men), received either Succimer or a combination of D-penicillamen plus garlic (DPN + Gar), for 19 and 30 days, respectively. Clinical and laboratory data, including blood lead level (BLL), were analyzed and treatment expanses were compared between the two regimens.

RESULTS

Of 79 male patients, 42 were treated by DPN + Gar and 37 received Succimer. Mean BLL of DPN + Gar group before treatment (965.73 ± 62.54 µg/L) was higher than that of the Succimer group (827.59 ± 24.41) (p < 0.001). After treatment, BLL in both groups significantly reduced to 365.52 ± 27.61 µg/L and 337.44 ± 26.34 µg/L, respectively (p < 0.001). The price of a 19-day treatment with Succimer was approximately 28.6 times higher than a one-month course of treatment with garlic plus DPN. None of the treatments caused serious side effects in the patients.

CONCLUSION

Combination therapy with DPN + Gar is as effective as Succimer in Pb poisoning, while treatment with Succimer is significantly more expensive.

Protective effect of a new generation of activated and purified bentonite in combination with yeast and phytogenic substances on mycotoxin challenge in pigs

The study aimed to investigate the efficacy of new mycotoxin adsorbents based on purified and activated bentonites combined with yeast and phytogenic compounds in fattening pigs. The experiment involved 96 pigs (31.2±2.4 kg). Control (C) group was fed a diet naturally contaminated with mycotoxins (5 mg/kg deoxynivalenol, DON) without an adsorbent. Treated groups received the feed with mycotoxin adsorbents: purified and activated bentonite (T1), purified and activated bentonite, yeast derivatives, phytogenic substances (T2), and purified, activated, and sulphurated bentonite with phytogenic substances (T3). Evaluated parameters involved growth performance, organ weight, small intestine and liver histopathology, complete blood count, serum biochemistry, antioxidant status of the organism and total and free DON content in urine. In all treated groups, an significant increase in intestinal GSH and GSH/GSSG ratio was observed when compared to C. No significant effects on liver and kidney weight, complete blood count, serum or intestinal malondialdehyde concentration, or total/free DON content in urine were observed. All adsorbents improved histopathological findings in the liver when compared to C. Moreover, T1, and T2 groups showed no presence of inflammatory reaction or necrotic changes in the livers. Although, mycotoxin adsorbents investigated in this study had no significant impact on pig growth performance, they reduced the oxidative stress, and on the tissue level they protected the jejunal tissue and liver parenchyma under deoxynivalenol challenge.

Safety and toxicology assessment of sodium nitrite administered by intramuscular injection

Intramuscular (IM) injection of nitrite (1-10 mg/kg) confers survival benefit and protects against lung injury after exposure to chlorine gas in preclinical models. Herein, we evaluated safety/toxicity parameters after single, and repeated (once daily for 7 days) IM injection of nitrite in male and female Sprague Dawley rats and Beagle dogs. The repeat dose studies were performed in compliance with the Federal Drug Administration's (FDA) Good Laboratory Practices Code of Federal Regulations (21 CFR Part 58). Parameters evaluated consisted of survival, clinical observations, body weights, clinical pathology, plasma drug levels, methemoglobin and macroscopic and microscopic pathology. In rats and dogs, single doses of ≥100 mg/kg and 60 mg/kg resulted in death and moribundity, while repeated administration of ≤30 or ≤ 10 mg/kg/day, respectively, was well tolerated. Therefore, the maximum tolerated dose following repeated administration in rats and dogs were determined to be 30 mg/kg/day and 10 mg/kg/day, respectively. Effects at doses below the maximum tolerated dose (MTD) were limited to emesis (in dogs only) and methemoglobinemia (in both species) with clinical signs (e.g. blue discoloration of lips) being dose-dependent, transient and reversible. These signs were not considered adverse, therefore the No Observed Adverse Effect Level (NOAEL) for both rats and dogs was 10 mg/kg/day in males (highest dose tested for dogs), and 3 mg/kg/day in females. Toxicokinetic assessment of plasma nitrite showed no difference between male and females, with Cmax occurring between 5 mins and 0.5 h (rats) or 0.25 h (dogs). In summary, IM nitrite was well tolerated in rats and dogs at doses previously shown to confer protection against chlorine gas toxicity.

Delayed administration of N-acetylcysteine blunts recovery after an acetaminophen overdose unlike 4-methylpyrazole

N-acetylcysteine (NAC) is the only clinically approved antidote against acetaminophen (APAP) hepatotoxicity. Despite its efficacy in patients treated early after APAP overdose, NAC has been implicated in impairing liver recovery in mice. More recently, 4-methylpyrazole (4MP, Fomepizole) emerged as a potential antidote in the mouse APAP hepatotoxicity model. The objective of this manuscript was to verify the detrimental effect of NAC and its potential mechanism and assess whether 4MP has the same liability. C57BL/6J mice were treated with 300 mg/kg APAP; 9h after APAP and every 12h after that, the animals received either 100 mg/kg NAC or 184.5 mg/kg 4MP. At 24 or 48h after APAP, parameters of liver injury, mitochondrial biogenesis and cell proliferation were evaluated. Delayed NAC treatment had no effect on APAP-induced liver injury at 24h but reduced the decline of plasma ALT activities and prevented the shrinkage of the areas of necrosis at 48h. This effect correlated with down-regulation of key activators of mitochondrial biogenesis (AMPK, PGC-1α, Nrf1/2, TFAM) and reduced expression of Tom 20 (mitochondrial mass) and PCNA (cell proliferation). In contrast, 4MP attenuated liver injury at 24h and promoted recovery at 48h, which correlated with enhanced mitochondrial biogenesis and hepatocyte proliferation. In human hepatocytes, 4MP demonstrated higher efficacy in preventing cell death compared to NAC when treated at 18h after APAP. Thus, due to the wider treatment window and lack of detrimental effects on recovery, it appears that at least in preclinical models, 4MP is superior to NAC as an antidote against APAP overdose.

A metabolomic analysis of thiol response for standard and modified N-acetyl cysteine treatment regimens in patients with acetaminophen overdose

N-acetylcysteine (NAC) is an antidote to prevent acetaminophen (paracetamol-APAP)-induced acute liver injury (ALI). The 3-bag licensed 20.25 h standard regimen, and a 12 h modified regimen, are used to treat APAP overdose. This study evaluated the redox thiol response and APAP metabolites, in patients with a single APAP overdose treated with either the 20.25 h standard or 12 h modified regimen. We used liquid chromatography tandem mass spectrometry to quantify clinically important oxidative stress biomarkers and APAP metabolites in plasma samples from 45 patients who participated in a randomized controlled trial (SNAP trial). We investigated the time course response of plasma metabolites at predose, 12 h, and 20.25 h post-start of NAC infusion. The results showed that the 12 h modified regimen resulted in a significant elevation of plasma NAC and cysteine concentrations at 12 h post-infusion. We found no significant alteration in the metabolism of APAP, mitochondrial, amino acids, and other thiol biomarkers with the two regimens. We examined APAP and purine metabolism in overdose patients who developed ALI. We showed the major APAP-metabolites and xanthine were significantly higher in patients with ALI. These biomarkers correlated well with alanine aminotransferase activity at admission. Receiver operating characteristic analysis showed that at admission, plasma APAP-metabolites and xanthine concentrations were predictive for ALI. In conclusion, a significantly higher redox thiol response with the modified NAC regimen at 12 h postdose suggests this regimen may produce greater antioxidant efficacy. At baseline, plasma APAP and purine metabolites may be useful biomarkers for early prediction of APAP-induced ALI.

The effect of ranitidine administration in graded dosage to the degree of liver damage: A study on Wistar rats with acute methanol intoxication

The high incidence of alcoholic poisoning in Indonesia is caused by the use of methanol as a surrogate ingredient of nonconforming alcohol. The product of methanol metabolism is toxic to the liver. Ranitidine has been studied as an antidote to reduce the effect of methanol toxicity. The present study aimed to assess the effect of ranitidine administration on the liver damage of Wistar rats with acute methanol intoxication. This research was an experimental study with randomized and posttest-only control group design. A total of 24 male Wistar rats divided into four groups, each consisting of six Rats. The control group (K0) served as a reference normal value. The control group (K1) was intoxicated with methanol 7 g/kg body weight (b.w.) through rat gavage tube. Treatment groups were intoxicated with methanol and 15 minutes after that, Ranitidine (30 mg/kg b.w. (P1) or 60 mg/kg b.w. (P2)) was given intraperitoneally. Ranitidine administration was proven to protect the liver tissue from damage due to methanol intoxication as was indicated from the histopathological examination. Ranitidine with dose 60 mg/kg b.w. is better in reducing the degree of liver tissue damage in acute methanol intoxication rats.

What is the role of andexanet alfa in the reversal of anticoagulant effects?

ABSTRACT

Although using direct oral anticoagulants increases patient risk for hemorrhagic events, FDA-approved options for reversing anticoagulant effects are limited. This article discusses one of the more recent FDA-approved antidotes, andexanet alfa, and provides guidelines for its safe and effective use.

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.

Modulation of Paraoxonase-1 and Apoptotic Gene Expression Involves in the Cardioprotective Role of Flaxseed Following Gestational Exposure to Diesel Exhaust Particles and/or Fenitrothion Insecticide

The developmental exposure to a single chemical may elicit apoptosis in the different fetal organs, while the combined effects are restricted. We have examined the protective role of flaxseed (FS) against diesel exhaust particles (DEPs)- and/or fenitrothion (FNT)-induced fetal cardiac oxidative stress and apoptosis. A total of 48 timed pregnant rats were divided into eight groups (n = 6). The first group was saved as the control and the second fed on 20% FS diet. Animals in the third, fourth, and fifth groups were administered with DEPs (2.0 mg/kg), FNT (3.76 mg/kg), and their combination, respectively, while the sixth, seventh, and eighth groups were supplemented with 20% FS through intoxication with DEPs, FNT, and their combination, respectively. Our results revealed that DEPs and/or FNT significantly elevated the level of protein carbonyl and superoxide dismutase activity in the fetal cardiac tissues. However, the catalase activity and total thiol level were decreased; besides the histopathological alterations were remarked. Moreover, DEPs and/or FNT exhibited significant down-regulation in the anti-apoptotic (Bcl-2) and paraoxonase-1 gene expression, and up-regulation in the apoptotic (Bax and caspase-3) gene expression along with DNA fragmentation. Remarkably, FS supplementation significantly ameliorated the fetal cardiac oxidative injury, down-regulated the expression of the apoptotic genes, up-regulated the anti-apoptotic and paraoxonase-1 gene expression, reduced DNA fragmentation, and alleviated the myocardial cell architectures. These findings revealed that FS attenuates DEPs- and/or FNT-induced apoptotic cell death by repairing the disturbance in the anti-apoptotic/pro-apoptotic gene balance toward cell survival in the fetal myocardial cells.

Reversal of Apixaban and Rivaroxaban Using Activated Prothrombin Complex Concentrates in Patients with Major Bleeding

BACKGROUND

Clinical experience with using activated prothrombin complex concentrates (aPCCs) to reverse the effects of factor Xa inhibitors is limited.

OBJECTIVES

Our objective was to assess the achievement of effective clinical hemostasis using aPCC in patients on chronic apixaban or rivaroxaban therapy presenting with major bleeding in whom a reversal agent is warranted. We also assessed the safety of the drug.

METHODS

A retrospective medical records review was conducted at a tertiary referral medical center in the USA. Patients presenting with major bleeding while receiving apixaban or rivaroxaban and treated with aPCC were included. Clinical hemostasis was assessed using International Society of Thrombosis and Hemostasis Scientific and Standardization Subcommittee criteria.

RESULTS

A total of 35 patients were included in the study. The most common site of bleeding was intracerebral hemorrhage (ICH) (n = 18 [51.4%]), followed by gastrointestinal bleed (n = 10 [28.6%]). Clinical hemostasis was achieved in 24 (68.6%) patients; 11 patients (31.4%) did not achieve clinical hemostasis; nine of these patients had ICH. Seven of the patients who did not achieve hemostasis died during hospitalization. Three (8.6%) patients experienced thromboembolic events during hospitalization. In total, 21 (60%) patients were receiving concomitant medications that interact with anti-factor Xa inhibitors and can increase the risk of bleeding.

CONCLUSIONS

Our study suggests that aPCC could be an option in patients with major bleeding associated with apixaban or rivaroxaban. It may be an alternative for patients who need anticoagulation reversal if the specific antidote, andexanet alfa, is unavailable.

Improvement of therapeutic potential N-acetylcysteine in acetaminophen hepatotoxicity by encapsulation in PEGylated nano-niosomes

AIMS

N-Acetylcysteine (NAC) is an effective antidote for the treatment of acetaminophen (APAP) poisoning; however, due to its low stability and bioavailability, repeated dosing of NAC is needed. This study investigated the therapeutic efficacy of NAC by niosomal carriers.

MATERIALS AND METHODS

Niosomes were synthesized using surface active agents film hydration method and their physicochemical properties were characterized. In the in vivo study, in addition to control group, male rats were divided in different groups and challenged with an oral dose of APAP (2000 mg/kg); 4 h later, rats were administered normal saline, empty niosome (NIO), NAC (25 mg/kg) and NAC-loaded niosome (NAC-NIO) respectively, and sacrificed 48 h post-APAP overdose.

KEY FINDINGS

The particle size and zeta potential of NAC-NIO were 242.3 ± 18.5 nm and -23.9 ± 1.6 mV. The loading and encapsulation efficiency of niosomes were 1.22% ± 0.02% and 26.76% ± 6.02%. APAP administration leads to hepatic damage as evidenced by increases in serum hepatic enzyme levels and tissue levels of nitric oxide and lipid peroxidation as well as decreases in hepatic levels of reduced glutathione, catalase, superoxide dismutase, and glutathione peroxidase. Treatment of rats with NIO-NAC was remarkably more effective than NAC in improving biochemical changes such as serum hepatic aminotransferases. These findings were correlated well to the histopathological experiments.

SIGNIFICANCE

Our results suggest that NAC when delivered as a niosomal structure, is potentially more effective than NAC standard, in improving APAP-induced hepatotoxicity.

[Sea bathing dangers: marine envenoming, trauma, and infections]

Sea bathing is often a priority activity for travelers, with widely recognized health benefits. The dangers, in contrast, are underestimated, especially in tropical seas. We describe the scope of marine envenoming, trauma, and infections, representing 1-3 % of tropical and travel medicine consultations in the literature. Our review includes the eco-epidemiology, clinical approach, and prevention of envenoming by invertebrates (jellyfish, anemone, sea-urchin, starfish, octopus, sea cone) and some vertebrates (stingrays, stone fish, snakes). We include penetrating trauma (by stingray, stonefish, sea urchin, coral) and infections (mycobacteria, marine bacteria). Eating-related dangers (ciguatera, fugu, parasites) are not described here. We also present antidotes, antivenoms, and first-aid.

A Humanized Monoclonal Antibody Cocktail to Prevent Pulmonary Ricin Intoxication

PB10 IgG₁, a monoclonal antibody (MAb) directed against an immunodominant epitope on the enzymatic subunit (RTA) of ricin toxin (RT), has been shown to passively protect mice and non-human primates from an aerosolized lethal-dose RT challenge. However, it was recently demonstrated that the therapeutic efficacy of PB10 IgG1 is significantly improved when co-administered with a second MAb, SylH3, targeting RT's binding subunit (RTB). Here we report that the PB10/SylH3 cocktail is also superior to PB10 alone when used as a pre-exposure prophylactic (PrEP) in a mouse model of intranasal RT challenge. The benefit of the PB10/SylH3 cocktail prompted us to engineer a humanized IgG1 version of SylH3 (huSylH3). The huPB10/huSylH3 cocktail proved highly efficacious in the mouse model, thereby opening the door to future testing in non-human primates.

[Simplified N-acetylcystein treatment after paracetamol overdose - new recommendations from Swedish Poisons Information Centre]

Since the late 1970s N-acetylcystein has been used as an antidote after paracetamol intoxication. The treatment is traditionally given as three consecutive infusions for 20 hours and 15 minutes. The total dose given is 300 mg/kg. Half of this amount is given as a bolus during the first 15 minutes of treatment.  This regime has proven very efficient in avoiding liver injury. However, side effects, caused by histamine release, are common (10-15%). Symptoms as flush, urticaria and, in rare cases, bronchospasm, angioedema and circulatory shock typically appear during the bolus dose and may lead to interrupted and inadequate treatment. In addition, the regime is complicated leading to a risk of administration errors. During the last years several publications have described the use of a model with two infusions instead of three. The first and the second infusions are merged and given over four hours. The third infusion and the total dose are left unchanged. This modified regime has been shown to reduce side effects and seems not to increase the risk of liver injury. As of November 1, 2019, the Swedish Poisons Information Centre will change its recommendations to the new two-infusion protocol.

Use of Rodent Sedation Tests to Evaluate Midazolam and Flumazenil in Green Iguanas (Iguana iguana)

This study aimed to evaluate the applicability of rodent behavioral tests to assess the effects of midazolam and flumazenil in green iguanas. Four tests commonly used to assess sedation in rodents-the open field test, forced swim test, behavioral scale, and traction test-were conducted in 10 juveniles iguanas. The animals received midazolam (2 mg/kg IM) or 0.9% NaCl (0.4 mL/kg IM), and the tests were conducted between 0 and 300 min thereafter. To verify the effects of midazolam and flumazenil, the most informative tests from the evaluation stage and the limb withdrawal latency time (LWLT) were used. All 10 iguanas were tested under 4 conditions, as follows: MS, midazolam (2 mg/kg IM), followed 30 min later by 0.9% NaCl (0.4 mL/kg IM); FS, flumazenil (0.05 mg/kg IM), followed by 0.9% NaCl (0.4 mL/kg IM) 30 min later; MF, midazolam (2 mg/ kg IM), followed by flumazenil (0.05 mg/kg IM) 30 min later; and CON, 0.9% NaCl (0.4 mL/kg IM). The behavioral scale and the forced swim test showed the best detection of the onset, peak effect, and the differences between the sedated and control iguanas, with testing done between 15 and 240 min after drug administration. The sedative effect of midazolam began at 15 min and persisted through 180 min when assessed on the behavioral scale and 240 min when assessed by the forced swim test; flumazenil administration reversed the sedative effect. An increase in the LWLT was observed in the midazolam treatment groups between 15 and 30 min after drug administration. Flumazenil decreased LWLT between 15 and 180 min in the FS and at 60 min in the MF. In conclusion, the best methods to assess sedation in iguanas were the behavioral scale and the forced swim test. A dose of 2 mg/kg of midazolam was effective at inducing sedation in these juvenile iguanas, and this effect could be reversed by flumazenil.

EDTA-modified mesoporous silica as supra adsorbent of copper ions with novel approach as an antidote agent in copper toxicity

PURPOSE

Mesoporous silica (MS) have been considered as a biocompatible compound and found to have various pharmaceutical applications. Recently, novel approaches in applications of MS as antidote agents were introduced. In this study, the capacity of ethylenediaminetetraacetic acid modified mesoporous silica (MS-EDTA) was evaluated in in vitro and in vivo adsorption of copper (Cu).

METHODS

The MS-EDTA was characterized by fourier transform infrared (FT-IR) and X-ray diffraction, while surface area was determined by N2 adsorption-desorption technique. Morphological studies were observed by high resolution-transmission electron microscopy and field emission-scanning electron microscopy and the sizes were determined by dynamic light scattering. The capacity of these particles for copper adsorption was investigated in vitro in both 1.2 and 7.2 pH. In in vivo animal study, the Cu adsorption efficiency of MS-EDTA in Cu-overdosed mice was evaluated. In this case, an animal model of acute copper poisoning was prepared.

RESULTS

The MS-EDTA with surface area of 352.35 was synthesized. Scanning electron microscope showed spherical particle formation with less than 500 nm in size. Transmission electron microscope images showed porous and honeycomb structure. FT-IR spectroscopy showed an appropriate formation of functional groups. Particle efficiency was investigated for Cu adsorption. MS-EDTA in both media showed a high adsorption capability for Cu (II) adsorption in pH=1.2 and pH=7.2. In addition, the study of Langmuir, Freundlich, and Redlich-Peterson adsorption models showed that copper adsorption by MS-EDTA followed the Freundlich model with multi-layer adsorption. In vivo evaluation showed that MS-EDTA could alleviate the symptoms of acute copper poisoning by lowering Cu plasma levels.

CONCLUSION

Structural evaluation showed successful formation of MS-EDTA. In vitro analysis demonstrated that supreme Cu adsorption occurs in both pH conditions (7.2 and 1.2), and was especially more favorable in simulated intestinal pH (7.2). The in vivo studies in animal models with acute Cu poisoning showed that MS-EDTA could be a potent antidote agent.

[Improved and harmonised laboratory analysis of paracetamol provides safer assessment of poisoning cases]

Toxicological analysis is an important part of the acute treatment of various intoxications. Rapid laboratory responses are important for the patient to be assessed and treated correctly, and also to exclude poisoning and thus avoid unjustified and costly overtreatment. In Sweden, paracetamol (acetaminophen) is one of the most common pharmaceuticals in drug poisoning. Paracetamol overdose can cause severe liver damage unless treated early with the antidote acetylcysteine. A nation-wide initiative for improved laboratory measurement of paracetamol in plasma/serum samples has resulted in a marked reduction in the inter-laboratory coefficient of variation to generally below 10%. The introduction of a harmonized national reporting range for plasma/serum paracetamol covering at least 50-5 000 µmol/l was also recommended. This initiative will hopefully contribute to better healthcare from both a patient and health resource perspective in cases of paracetamol poisoning.

Simple minimally-invasive automatic antidote delivery device (A2D2) towards closed-loop reversal of opioid overdose

With approximately 48,000 attributed deaths in 2017, the opioid overdose is now the leading cause of death amongst Americans under the age of 50. The overdose process can be interrupted by the administration of naloxone, a safe and effective opiate antagonist that can reverse the effects of overdose and minimizing the delay in administering the antidote is critical in preventing permanent damage to patients. A closed-loop implantable drug delivery system is an ideal solution to minimize the response time, however, they often feature complex designs that are expensive to fabricate and require a more invasive surgical implantation. Here we propose a simple, low-cost, minimally-invasive automatic antidote delivery device (A2D2) that can administer a large dose of naloxone upon detection of overdose-induced respiratory failure. The subcutaneously placed device can be activated using an externally applied time varying magnetic field from a wearable device. Using a custom magnetic field generator, we were able to release the drug within 10 s. Our bench-top evaluation showed that A2D2 can release 1.9 mg of powdered drug within 60 s and up to 8.8 mg in 600 s. We also performed in vivo evaluation to demonstrate rapid drug releasing capability in the subcutaneous space of mice. However, we saw a small amount of leakage (1.75% of payload) over the course of 1000 h of simulated implantation. Thus, additional research is needed to verify the long term stability of our device and to demonstrate the closed-loop release mechanism to revive overdosed animals. Nevertheless, our preliminary results show the potential of using a simple, low-cost, subcutaneous device for emergency drug delivery application.

Treatment of adult lead poisoning with D-penicillamine

Background The aim of the current study was to evaluate the efficacy of D-penicillamine in the treatment of lead poisoning mainly in the outpatient setting. Methods In a case series study performed during the recent epidemic of lead poisoning in Iran, lead-poisoned patients referring to our outpatient clinic were treated with 250-mg D-penicillamine capsules administered every 6 h for 5 or 10 days based on availability of the medication. They were recommended to re-check blood lead level (BLL) 4 weeks after cessation of the treatment and refer to our clinic again. Results In 63 patients with lead poisoning but without signs and symptoms of lead encephalopathy, median BLL was 106 [84, 131] μg/dL on presentation, which declined to a mean of 52.6 ± 28.8 μg/dL after a median treatment period of 7 [5, 10] days (p < 0.001). There was no statistically significant difference between the 5- and 10-day treatment protocols regarding complications and recovery. Treatment had resulted in a median decrease of 54 μg/dL [33, 90] (range: -20 to 231 μg/dL) in the patients' BLLs (33.9% declined in BLL measurements; range: -29.69% to 99.06%). Conclusions D-penicillamine may be an acceptable substitute treatment in adult lead poisoning. Although our sample size was limited, we could not detect any serious adverse effects in our cases showing that D-penicillamine resulted in acceptable recovery rates. This may be helpful especially in epidemics with limitations in antidote access.

Natural antidotes and management of metal toxicity

The global burden of heavy metal especially mercury, arsenic, lead, and cadmium toxicities remains a significant public health challenge. Developing nations are particularly at high risk and carry the highest burden of this hazard. Chelation therapy has been the mainstay for treatment of heavy metal poisoning where the chelating agent binds metal ions to form complex ring-like structures called "chelates" to enhance their elimination from the body. Metal chelators have some drawbacks such as redistribution of some heavy metals from other tissues to the brain thereby increasing its neurotoxicity, causing loss of essential metals such as copper and zinc as well as some serious adverse effects, e.g., hepatotoxicity. The use of natural antidotes, which are easily available, affordable, and with little or no side effects compared to the classic metal chelators, is the focus of this review and suggested as cheaper options for developing nations in the treatment of heavy metal poisoning.

Supramolecular therapeutics to treat the side effects induced by a depolarizing neuromuscular blocking agent

Succinylcholine (Sch) is the only depolarizing neuromuscular blocking agent widely used for rapid sequence induction in emergency rooms. Unfortunately, a variety of (sometimes lethal) adverse effects, such as hyperkalemia and cardiac arrest, are associated with its use, and currently there are no specific antidotes to reverse Sch or to treat these side-effects. Methods: The binding behaviors of Sch and several synthetic receptors, including cucurbit[7]uril, sulfo-calix[4]arene and water-soluble carboxylatopillar[6]arene (WP[6]), were first investigated. With a mouse model, a leathal dose of Sch was selected for evaluation of the antidotal effects of these synthetic receptors on Sch induced mortality. The antidotal effects of a selected synthetic receptor, WP[6], on Sch induced cardiac arrhythmias, hyperkalemia, rhabdomyolysis and paralysis were subsequently evaluated with rat and mouse models. The reversal mechanism was also investigated at a cellular level. Results: All of these macrocyclic molecules exhibited relatively high binding affinities with Sch in vitro. In a Sch-overdosed mouse model, immediate injection of these synthetic receptors right after Sch administration increased the overall survival rate, with WP[6] standing out with the most effective antidotal effects. In addition, administration of WP[6] also reversed the paralysis induced by Sch in a mouse model. Moreover, infusion of WP[6] to Sch-overdosed rats reduced the incidence of cardiac arrhythmia, inhibited the otherwise abnormally high serum potassium levels, and relieved the muscular damage. At the cellular level, WP[6] reversed the Sch induced depolarization and reduced the efflux of intracellular potassium. Conclusion: Synthetic receptors, particularly WP[6], exhibited high binding affinities towards Sch, and presented a significant potential as supramolecular therapeutics to treat the various side effects of Sch by specifically sequestering Sch in vivo.

Organophosphorus Compounds Poisoning in a Neonate: A Case Report

Organophosphorus compounds (OPC) are widely used insecticides. Such poisoning is very rare in neonate. A 23 days old infant was admitted with severe respiratory distress, excessive secretion from nose and mouth, bluish discoloration of extremities and poor feeding for 4 hours. He was pale, cyanosed and lethargic with gasping respiration. Frothing was coming through mouth and nose. There was watering of eyes, pupils were pin pointed and light reflex was sluggish. The baby was hypothermic, hypotonic with altered sensorium. Capillary refill time was <3 sec. The neonate was gasping; there was crepitation over lung fields. Precordium and abdomen was normal. An odor of OPC was smelt on clothing and secretions of the infant. The baby was wrapped with a cloth that was ware during pesticide spraying in the field. In addition to general measures, decontamination of skin and clothing and gastric lavage was done. Empirical antibiotic, injection atropine and pralidoxime were given. Patient showed clinical improvement with disappearance of cholinergic signs. The baby was discharged on 7th day of admission after full recovery.

Methylene Blue Administration During and After Life-Threatening Intoxication by Hydrogen Sulfide: Efficacy Studies in Adult Sheep and Mechanisms of Action

Exposure to toxic levels of hydrogen sulfide (H2S) produces an acute cardiac depression that can be rapidly fatal. We sought to characterize the time course of the cardiac effects produced by the toxicity of H2S in sheep, a human sized mammal, and to describe the in vivo and in vitro antidotal properties of methylene blue (MB), which has shown efficacy in sulfide intoxicated rats. Infusing NaHS (720 mg) in anesthetized adult sheep produced a rapid dilation of the left ventricular with a decrease in contractility, which was lethal within about 10 min by pulseless electrical activity. MB (7 mg/kg), administered during sulfide exposure, maintained cardiac contractility and allowed all of the treated animals to recover. At a dose of 350 mg NaHS, we were able to produce an intoxication, which led to a persistent decrease in ventricular function for at least 1 h in nontreated animals. Administration of MB, 3 or 30 min after the end of exposure, whereas all free H2S had already vanished, restored cardiac contractility and the pyruvate/lactate (P/L) ratio. We found that MB exerts its antidotal effects through at least 4 different mechanisms: (1) a direct oxidation of free sulfide; (2) an increase in the pool of "trapped" H2S in red cells; (3) a restoration of the mitochondrial substrate-level phosphorylation; and (4) a rescue of the mitochondrial electron chain. In conclusion, H2S intoxication produces acute and long persisting alteration in cardiac function in large mammals even after all free H2S has vanished. MB exerts its antidotal effects against life-threatening sulfide intoxication via multifarious properties, some of them unrelated to any direct interaction with free H2S.

Aminophylline shortage and current recommendations for reversal of vasodilator stress: an ASNC information statement endorsed by SCMR

Pharmacologic reversal of serious or intolerable side effects (SISE) from vasodilator stress is an important safety and comfort measure for patients experiencing such effects. While typically performed using intravenous aminophylline, recurrent shortages of this agent have led to a greater need to limit its use and consider alternative agents. This information statement provides background and recommendations addressing indications for vasodilator reversal, timing of a reversal agent, incidence of observed SISE with vasodilator stress, clinical and logistical considerations for aminophylline-based reversal, and alternative non-aminophylline based reversal protocols.

Effects of Modified Palygorskite Supplementation on Egg Quality and Mineral Element Content, and Intestinal Integrity and Barrier Function of Laying Hens

This study was conducted to investigate effects of modified palygorskite (MPal) supplementation on the laying performance, egg quality and mineral element content, immunity, oxidative status, and intestinal integrity and barrier function of laying hens. A total of 360 52-week-old Hyline Brown hens were randomly assigned into four dietary treatments for a 7-week feeding trial. The birds were fed a basal diet supplemented with 0 (control group), 0.25, 0.5, and 1 g/kg MPal, respectively. The supplementation of MPal did not alter laying performance and egg quality among groups. Compared with the control group, MPal inclusion decreased lead (Pb) content in yolks at 49 days, and either 0.5- or 1-g/kg MPal supplementation decreased Pb accumulation in yolks at 25 days and manganese (Mn) accumulation in yolks at 25 and 49 days. The contents of jejunal secretory immunoglobulin A (SIgA), ileal SIgA, and immunoglobulin G were decreased by the dietary 0.5-g/kg MPal supplementation. The supplementation of MPal also decreased malondialdehyde content in jejunum and ileum, and decreased serum diamine oxidase activity of the laying hens at 25 and 49 days. The inclusion of 0.5 and 1 g/kg MPal enhanced villus height in jejunum and ileum, and also increased the ratio of villus height to crypt depth in ileum. In conclusion, MPal supplementation decreased Pb and Mn contents in yolks, and exhibited beneficial effects on the intestinal immunity, oxidative status, and intestinal integrity and barrier function of laying hens and its optimal dosage was 0.5 g/kg.

Monitoring Dose Response of Cyanide Antidote Dimethyl Trisulfide in Rabbits Using Diffuse Optical Spectroscopy

INTRODUCTION

Cyanide (CN) poisoning is a serious chemical threat from accidental or intentional exposures. Current CN exposure treatments, including direct binding agents, methemoglobin donors, and sulfur donors, have several limitations. Dimethyl trisulfide (DMTS) is capable of reacting with CN to form the less toxic thiocyanate with high efficiency, even without the sulfurtransferase rhodanese. We investigated a soluble DMTS formulation with the potential to provide a continuous supply of substrate for CN detoxification which could be delivered via intramuscular (IM) injection in a mass casualty situation. We also used non-invasive technology, diffuse optical spectroscopy (DOS), to monitor physiologic changes associated with CN exposure and reversal.

METHODS

Thirty-six New Zealand white rabbits were infused with a lethal dose of sodium cyanide solution (20 mg/60 ml normal saline). Animals were divided into three groups and treated with saline, low dose (20 mg), or high dose (150 mg) of DMTS intramuscularly. DOS continuously assessed changes in tissue hemoglobin concentrations and cytochrome c oxidase redox state status throughout the experiment.

RESULTS

IM injection of DMTS increased the survival in lethal CN poisoning. DOS demonstrated that high-dose DMTS (150 mg) reversed the effects of CN exposure on cytochrome c oxidase, while low dose (20 mg) did not fully reverse effects, even in surviving animals.

CONCLUSIONS

This study demonstrated potential efficacy for the novel approach of supplying substrate for non-rhodanese mediated sulfur transferase pathways for CN detoxification via intramuscular injection in a moderate size animal model and showed that DOS was useful for optimizing the DMTS treatment.

[Promethazine - an old pharmaceutical that has got a renaissance. An avalanche-like increase in the number of overdose cases in Sweden]

Promethazine is a phenothiazine derivative antihistamine first introduced in the 1940s that is used in multiple medical conditions as a sedative/hypnotic agent. The drug is not addictive, which probably explains why it is increasingly used in the care of drug addicts. During the recent decade the sales of promethazine in Sweden have increased threefold while the yearly number of overdose cases with this drug at the Swedish Poisons Centre has increased from 100 to nearly 700. The anticholinergic delirium that may be provoked by this poisoning carries a symptomatology which may resemble the symptoms seen after an intracranial catastrophe, wherefore some cases are exposed to unnecessary diagnostic measures and invasive ventilator treatment. The case report and literature review presented in this paper conclude that physostigmine is the drug of choice in delirium provoked by overdose of promethazine, and that its use in this setting carries a minimal risk of serious side effects.

Flumazenil reduces respiratory complications during anesthesia emergence in children with preoperative upper respiratory tract infections

Despite its benignity, upper respiratory infections (URIs) 1 increase the risk of postoperative respiratory complications during the perioperative and postoperative periods. Flumazenil could improve the symptoms of respiratory obstruction.To evaluate the effect of flumazenil on the occurrence of respiratory complications during anesthesia emergence of children with preoperative URI.This was a prospective study of 164 consecutive pediatric patients who underwent strabismus surgery under general anesthesia at the Tianjin Eye Hospital between August 2016 and April 2017. The patients were grouped as: normal airway (N), recent mild URI (I), normal airway and flumazenil (NF), and recent mild URI and flumazenil (group IF) (n = 41/group). An initial dose of flumazenil (0.1 mg) was administrated intravenously to groups IF and NF. The intraoperative and postoperative respiratory complications were recorded by one anesthesiologist unaware of the grouping.All patients underwent surgery uneventfully. The incidence of postoperative respiratory complications in post-anesthesia care unit (PACU) was higher in group I compared with the other 3 groups (IF: 17%; I: 41%; NF: 5%; N: 10%; P = .0147). During the PACU period, significant differences among groups were seen for cough (IF: 15%; I: 20%; NF: 2%; N: 0%; P = .004), secretion (IF: 17%; I: 29%; NF: 5%; N: 7%; P = .007), low oxygen saturation (IF: 12%; I: 32%; NF: 2%; N: 7%; P = .001), and glossocoma (IF: 15%; I: 34%; NF: 10%; N: 32%; P = .015).Respiratory complications during anesthesia emergence were higher in patients with recent preoperative URI compared to patients with healthy airways. Postoperative flumazenil could reduce the incidence of glossocoma.

Rivaroxaban reversal with prothrombin complex concentrate or tranexamic acid in healthy volunteers

Essentials Specific reversal agents for managing severe factor Xa inhibitor-associated bleeding are lacking. We assessed 4-factor-prothrombin complex concentrate (4F-PCC) and tranexamic acid (TXA). 4F-PCC, but not TXA, reduced the prothrombin time and increased endogenous thrombin potential. These agents may be viable options for reversal of therapeutic doses of rivaroxaban.

SUMMARY

Background Oral activated factor X inhibitors such as rivaroxaban are widely used, but specific reversal agents are lacking. Although four-factor prothrombin complex concentrate (4F-PCC) and tranexamic acid (TXA) are sometimes used to manage serious bleeding, their efficacy is unknown. Prior studies in healthy subjects taking rivaroxaban revealed that 4F-PCC partially reverses the prolonged prothrombin time (PT), and fully restores the endogenous thrombin potential (ETP). The effect of TXA has not been evaluated. Methods In this double-blind, parallel-group study, 147 healthy volunteers given rivaroxaban 20 mg twice daily for 3 days were randomized after their morning dose on day 4 to receive intravenous 4F-PCC (50 IU kg-1 ), TXA (1.0 g), or saline. Standardized punch biopsies were performed at baseline and after 4F-PCC, TXA or saline administration. Reversal was assessed by measuring bleeding duration and bleeding volume at biopsy sites, and by determining the PT and ETP. Results As compared with saline, 4F-PCC partially reversed the PT and completely reversed the ETP, whereas TXA had no effect. Neither 4F-PCC nor TXA reduced bleeding duration or volume. All treatments were well tolerated, with no recorded adverse events. Conclusions Although 4F-PCC reduced the PT and increased the ETP in volunteers given supratherapeutic doses of rivaroxaban, neither 4F-PCC nor TXA influenced punch biopsy bleeding.

[Goal-directed administration of antidote for reversal of dabigatran anticoagulation]

Goal-directed administration of antidote for reversal of dabigatran anticoagulation Idarucizumab is a monoclonal antibody fragment that acts as an antidote to dabigatran. Idarucizumab is indicated in dabigatran-associated serious bleeds and to reverse dabigatran anticoagulation before acute surgical interventions or invasive medical procedures. The recommended dose of 5 g idarucizumab is sufficient to achieve a lasting restoration of coagulation in most patients. In a number of cases however, notably in deliberate overdoses and in accumulation of dabigatran in renal failure, repeated doses of idarucizumab may be necessary to avoid persisting or rebound anticoagulation. This article gives a brief explanation of the mechanisms responsible for this phenomenon and argues that it should be anticipated. Serial monitoring of APTT or dTT in patients treated with idarucizumab should enable the early detection of treatment failure or rebound anticoagulation and, if clinically indicated, prompt administration of additional doses of antidote.

Safety and efficacy of an oxycodone vaccine: Addressing some of the unique considerations posed by opioid abuse

Among vaccines aimed at treating substance use disorders, those targeting opioids present several unique medication development challenges. 1) Opioid overdose is a common complication of abuse, so it is desirable for an opioid vaccine to block the toxic as well as the addictive effects of opioids. 2) It is important that an opioid vaccine not interfere with the action of opioid antagonists used to reverse opioid overdose or treat addiction. 3) Some opioids are immunosuppressive and chronic ongoing opioid use could interfere with vaccine immunogenicity. 4) Although antibody-bound oxycodone is unable to enter the brain because of its size, it might still be able to activate peripheral opioid receptors. To assess vaccine impact on opioid toxicity, rats vaccinated with oxycodone conjugated to keyhole limpet hemocyanin subunit dimer (OXY-dKLH) adsorbed to alum or controls vaccinated with dKLH were compared with regard to oxycodone-induced hotplate analgesia and oxycodone-induced respiratory depression and bradycardia. Vaccination shifted the dose-response curves to the right, representing protection, for each of these endpoints. Naloxone was equally effective in both OXY-dKLH and control groups, providing complete and rapid reversal of respiratory depression. The administration of a long-acting naltrexone formulation during vaccination did not impair vaccine immunogenicity in mice. Similarly, serum anti-oxycodone antibody titers were not altered by continuous morphine infusion during vaccination compared to opioid-naïve controls. Competitive ELISA assay showed negligible or low affinity of immune antiserum for endogenous opioids or opioid antagonists. In vitro receptor binding assays showed that antibody-bound oxycodone does not activate mu opioid receptors. These data support further study of OXY-dKLH as a potential treatment for oxycodone abuse and suggest that vaccination might also reduce the severity of oxycodone overdose.

Effect of repeated administration of 4-methylpyrazole on renal function and lipid peroxidation products in rat kidney after ethylene glycol poisoning

Toxic effects of ethylene glycol (EG) and its metabolites are mainly related to metabolic acidosis and kidney damage. EG biotransformation involving CYP2E1 affects the oxidant-antioxidant balance. The study assessed the effect of repeated administration of 4-methylpyrazole (4MP, 15mg/kg b.w. after 2h, followed by 10mg/kg b.w. every 12h) on renal function (creatinine, urea and urinary protein levels) as well as products of kidney's lipid peroxidation (MDA and TBARS levels) in rats poisoned with EG (5745mg/kg b.w.). Serum EG and glycolic acid (GA) concentrations were measured throughout the experiment. Repeated administration of 4MP reduced the rate of EG elimination, extended the period of EG persistence in serum and significantly limited formation of GA. The study showed the temporary intensification of kidney oxidative processes that correlated with changes in kidney function. It was found that the use of 4MP in EG poisoning inhibited its biotransformation to toxic metabolites, but simultaneously intensified oxidative damages in kidneys.

Rational designing of an antidote nanoparticle decorated with abiotic polymer ligands for capturing and neutralizing target toxins

Many of macromolecular toxins induce cell death by directly interacting with cells or induction of inflammatory cytokines. Abiotic polymer ligands (PLs) composed of functional monomers are able to bind and neutralize toxins in vivo and are of great interest for efficient antidotes. However, little has been reported about recognition and neutralization of target molecules in the bloodstream because of readily elimination from the bloodstream. Here, we report a rational design of PLs-decorated lipid nanoparticles (PL-NPs) for neutralizing a target toxin in vivo. PL that decorated on the NPs would cooperatively interacts with target biomacromolecules since the lipid molecules in NPs have a high degree of freedom. In the present study, N-isopropylacrylamide based PLs interacting with histones, major mediators of sepsis, were synthesized. Affinity between PL-NPs and histones depends on monomer composition and polymer length. The optimized PL-NP showed little affinity for plasma proteins. The PL-NPs inhibited the toxicity of histones both in vitro and in vivo, suggesting that PLs on the NPs cooperatively bound to histones and neutralized their toxicity. In addition, circulation time of optimized PL was significantly prolonged by the modification onto NPs. These results provide a platform for designing antidote nanoparticles neutralizing toxic biomacromolecules.

Treatment of severe fluoroacetamide poisoning in patient with combined multiple organ dysfunction syndrome by evidence-based integrated Chinese and Western medicines: A case report

RATIONALE

Fluoroacetamide poisoning is the acute and severe disease of human, which leads to nervous, digestive, and cardiovascular system damage or even death in a short period of time.

PATIENT CONCERNS

We report a case of a 65-year-old woman with loss of consciousness, nausea, and vomiting who was sent to the hospital by passers-by.

DIAGNOSIS

She was diagnosed with severe fluoroacetamide poisoning with combined multiple organ dysfunction syndrome.

INTERVENTIONS

When the diagnosis was unclear, we gave gastric lavage, support and symptomatic treatment, and closely with the vital sign. When the diagnosis was clear, based on the evidence of retrieved, muscle injection of acetamide, calcium gluconate, and vitamin C. Traditional Chinese medicine aspect, oral administration of mung bean soup of glycyrrhizae and Da-Cheng-Qi decoction enema.

OUTCOMES

By setting reasonable treatment for patients, she had no special discomfort and complications after treatment. Besides, through 1-month follow-up, it was confirmed that the treatments were effective.

LESSONS

Evidence-based integrated Chinese and Western medicines can effectively improve the therapeutic effects in severe fluoroacetamide-poisoned patients with combined MODS.

Prolonged methylprednisolone therapy after the pulse treatment for patients with moderate-to-severe paraquat poisoning: A retrospective analysis

This retrospective study aims to evaluate the effect of prolonged methylprednisolone (MP) therapy on the mortality of patients with moderate-to-severe paraquat (PQ) poisoning after the pulse treatment.We performed a retrospective analysis of patients with acute moderate-to-severe PQ poisoning that were admitted to the emergency department from May 2012 to August 2016. Out of 138 patients, 60 were treated with pulse treatment (15 mg kg day MP for 3 days) and 78 were treated with prolonged MP therapy after pulse treatment (15 mg kg day MP for 3 days; afterward, the dosage was reduced in half every 2 days, and the MP therapy was terminated until 0.47 mg kg day). Kaplan-Meier method was used to compare the mortality between the 2 groups. Cox proportional hazard models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI).The mortality of the prolonged MP therapy after pulse treatment group was lower than that of the pulse group (47.4% vs 63.3%; log-rank tests, P  =  .003). According to the multivariate Cox analysis, the prolonged MP therapy after pulse treatment was significantly associated with a lower mortality risk (HR: 0.31, 95% CI: 0.19-0.52, P < .001) compared with the pulse group. In addition, the prolonged MP therapy after pulse treatment caused more incidences of leucopenia than the pulse treatment alone (25.6% vs 11.7%, P  =  .04).The prolonged MP therapy after pulse treatment can reduce the mortality of moderate-to-severe PQ poisoning patients.

Hemostatic effects of the ticagrelor antidote MEDI2452 in pigs treated with ticagrelor on a background of aspirin

Essentials MEDI2452 is a specific antidote of the platelet P2Y12 receptor antagonist ticagrelor. Hemostatic effects of MEDI2452 were evaluated in pigs treated with ticagrelor and aspirin. MEDI2452 eliminated free ticagrelor within 5 min and gradually normalized platelet aggregation. Improvements in blood pressure (significant) and in blood-loss and survival (non-significant) were observed.

SUMMARY

Background Ticagrelor, a P2Y12 antagonist, is approved for the prevention of thromboembolic events. However, antiplatelet therapies carry a risk of bleeding. Objective To explore the hemostatic effects of MEDI2452, an antidote for ticagrelor. Methods Pigs, pre-treated with aspirin, were given an intravenous infusion of ticagrelor or vehicle. At the end of the infusion, a piece of a liver lobe was cut off and a bolus of MEDI2452 or vehicle was administered intravenously. Blood was collected to monitor blood loss, mean arterial blood pressure (MAP) was recorded and survival time was observed over 4 h. Blood samples for drug plasma exposures and platelet aggregation were collected. Results MEDI2452 eliminated the free concentrations of ticagrelor and its active metabolite AR-C124910XX within 5 min. ADP-induced platelet aggregation was close to normal at 60 min, which was not significantly different from aspirin alone. MEDI2452 numerically reduced ticagrelor-mediated effects: body-weight-adjusted blood loss in the 15- to 90-min interval, 12 (confidence interval [CI] 95% 7-28] vs. 17 (CI 95% 5-31) (ticagrelor and aspirin) vs. 5 (CI 95% 3-9) mL kg-1 (aspirin alone), survival 70% (CI 95% 47-100) vs. 45% (CI 95% 21-92) (ticagrelor and aspirin) vs. 100% (CI 95% 100-100) (aspirin alone), and median survival time, 240 (CI 95% 180-240) vs. 169 (CI 95% 64-240) (ticagrelor and aspirin) vs. 240 (CI 95% 240-240) min (aspirin alone). Finally, MEDI2452 significantly attenuated the decline in MAP, 0.08 (CI 95% 0.07-0.09) vs. 0.141 (CI 95% 0.135-0.148) (ticagrelor and aspirin) vs. 0.04 (CI 95% 0.03-0.05) mmHg per min (aspirin alone) and maintained MAP at a significantly higher level, 73 (CI 95% 51-95) vs. 48 (CI 95% 25-70) (ticagrelor and aspirin) vs. 115 (CI 95% 94-136) mmHg (aspirin alone). Conclusion MEDI2452 eliminated free ticagrelor and AR-C124910XX within 5 min. This translated into a gradual normalization of ADP-induced platelet aggregation and significant improvement in blood pressure and numerical but non-significant improvements in blood-loss and survival.

Neurotoxicity after high-dose methotrexate (MTX) is adequately explained by insufficient folinic acid rescue

PURPOSE

To challenge the view that the dose of folinic acid rescue after high-dose methotrexate (MTX) has no significance in the prevention of neurotoxicity and to present the minority view that neurotoxicity can be prevented by an adequate dose of folinic acid, without compromising treatment results. Several fallacies that led to the misunderstanding of post MTX neurotoxicity are presented.

METHODS

Data mining using search engines was used to find relevant publications, and an e-mail survey of more than 60 authors of articles in this field was performed. All relevant articles identified were read in their entirety.

RESULTS

Examples of clinical studies with neurotoxicity following inadequate rescue are given. Some studies demonstrated no neurotoxicity when adequate doses of folinic acid rescue were started 24-36 h after the start of HDMTX rescue even after mega doses of MTX. Rescue started after 42 h was associated with neurotoxicity except in patients with low serum MTX levels after 24 and 36 h. ALL protocols with neurotoxicity, especially BFM-like protocols, are presented. Protocol is reported in which single protocol changes prevented neurotoxicity.

CONCLUSIONS

From the published data, when folinic acid rescue is given in a sufficiently high enough dose and is started 24-36 h after the beginning of the methotrexate exposure, and virtually all forms of post MTX neurotoxicity can be prevented without compromising therapeutic results.

Management of Acute Hepatotoxicity Including Medical Agents and Liver Support Systems

Drug-induced liver injury (DILI) can be predictable or idiosyncratic and has an estimated incidence of approximately 20 cases per 100,000 persons per year. DILI is a common cause of acute liver failure in the United States. No accurate tests for diagnosing DILI exist, and its diagnosis is based on exclusion of other conditions. Managing DILI includes discontinuing the suspected causative agent and in selected cases administering an antidote. Liver support systems are used for long-term support or as a bridge to transplantation and are effective for improving encephalopathy, hyperbilirubinemia, and other liver-related conditions, but whether they improve survival remains uncertain.

Atropine Eye Drops: A Proposed Field Expedient Substitute in the Absence of Atropine Autoinjectors

Nerve agents are a threat to military and civilian health. The antidote, atropine sulfate, is delivered by autoinjector, which is a limited resource. We propose the use of 1% atropine ophthalmic solution (supplied commercially in 5mL or 15 mL bottles) via oral, ocular, and intranasal administration as an expedient substitute in austere environments.

Impact of 30-Day Oral Dosing with N-acetyl-l-cysteine on Sprague-Dawley Rat Physiology

A number of studies have demonstrated a protective effect associated with N-acetyl-l-cysteine (NAC) against toxic chemical exposure. However, the impact of long-term oral dosing on tissue pathology has not been determined. In this study, the authors assessed the impact of long-term oral NAC administration on organ histopathology and tissue glutathione (GSH) and total glutathione- S-transferase (GST) activity levels in Sprague-Dawley (SD) rats. Groups of 20 SD rats (10 males, 10 females), 8 weeks of age, were dosed daily by oral gavage with deionized H2O (negative controls) or NAC solution at a rate of 600 or 1200 mg/kg/day for 30 days. Animals were euthanized 6 h after treatment on study day 30. There were no significant differences in final body weights or weekly average weight gain between treatment groups. Serum alanine amino-transferase (ALT) activities were significantly elevated ( p ≤.05) in NAC-treated animals compared to controls when measured on study day 30. Histopathologic evaluation of the stomach, small intestine, liver, kidneys, spleen, thymus, and lungs revealed no lesions associated with NAC administration. When measured on study day 30, total GST activity for kidney and skin from NAC-treated animals were increased 39% to 131% as compared to controls. Tissue GSH concentrations from NAC-treated animals were increased 24% to 81% as compared with negative controls. Further studies are needed to determine if the observed increase in tissue GSH concentration and GST activity provide a degree of chemoprotection against dermal and systemic chemical toxicants.

[Overdose of modified-release paracetamol calls for changed treatment routines. New guidelines from the Swedish Poisons Information Centre]

Overdose of modified-release paracetamol calls for changed treatment routines. New guidelines from the Swedish Poisons Information Centre  The sales of modified-release paracetamol tablets are steadily increasing in Sweden as are the number of overdose cases with this formulation. The Swedish Poisons Information Centre has noted that the standard treatment protocol with N-acetylcysteine (NAC), which is based on overdoses with immediate-release paracetamol formulations, is often inadequate in this setting. In this paper, an adult who overdosed on 66.5 grams of modified-release paracetamol tablets and developed severe liver impairment (max ALT 6,660 U/l) despite timely and rigorous NAC treatment is presented. The patient's peak S-paracetamol of 2,800 µmol/l was delayed to 19 hours post-ingestion. Moreover, a pharmacokinetic and clinical study of similar cases showed that seven (21%) of the 34 patients who received NAC treatment within 8 hours after ingestion developed liver impairment. Finally, new Swedish guidelines for management of these cases are presented. The guidelines are also available on www.giftinfo.se.

Efficacy of an adenosine A1 receptor agonist compared with atropine and pralidoxime in a rat model of organophosphate poisoning

The objective of this study was to evaluate the effects of an adenosine A1 agonist, phenylisopropyl adenosine (PIA), on metamidophos poisoning compared to specific antidotes. Rats were poisoned with metamidophos (30 mg/kg, oral) and observed for 24 hours. One group received sodium chloride (1 mL/kg) and four experimental groups received atropine (5 mg/kg), pralidoxime (PAM, 20 mg/kg), atropine/PAM (5/20 mg/kg) or PIA (1 mg/kg) intraperitoneally. Atropine reduced salivation and prevented respiratory distress when compared to sodium chloride-treated rats. Treatment with PAM did not cause any suppression of cholinergic signs. Atropine and PAM combination prevented salivation, convulsion and respiratory distress. PIA delayed initial time of the salivation, convulsion and time to death. However, PIA was found ineffective against the metamidophos-induced cholinergic symptoms and mortality. All treatments, except PIA, lead to survival of these animals. Acetylcholinesterase (AChE) activity was not normalized by PIA or PAM. PIA prevented metamidophos-induced diaphragmatic muscle necrosis as much as PAM. In conclusion, a single dose of PIA was unable to protect the rats from metamidophos toxicity. Further studies are needed involving a combination of PAM and/or atropine with repeated doses of PIA to clarify the efficacy of adenosine agonists in OP poisoning.

Calcium gluconate and sodium succinate for therapy of sodium fluoroacetate experimental intoxication in cats: clinical and electrocardiographic evaluation

Sodium fluoroacetate (SFAC) or Compound 1080 is a potent rodenticide, largely used after 1946 for rodent and home pest control. The toxic effects of SFAC are caused by fluorocitrate action, a toxic metabolite, which has a competitive action with aconitase enzyme, leading to citrate accumulation and resulting in interference in energy production by Krebs cycle blockade. In the present study, domestic cats were intoxicated with oral doses of fluoroacetate (0.45 mg/kg). The intoxicated animals presented emesis, diarrhea with abdominal pain posture and an abdominal palpation, tachypnea, bilateral midriasis, hypothermia, hyperexcitability and convulsions. Blood gas analysis indicated decreased pH and bicarbonate levels. Serum ionized calcium was also decreased. ECG showed non–specific changes in ventricular repolarization and ventricular arrhythmias. The survival rate was 75% in the treated group with calcium gluconate and sodium succinate and 37.5% in the nontreated group.

Arsenic trioxide poisoning: a description of two acute overdoses

Arsenic is a traditional poison that has a history extending back into ancient times, as a medicinal agent, a homicidal poison and more recently in deliberate and unintentional self-poisoning. We report two cases of acute poisoning with an unwettable formulation of arsenic trioxide. Both patients had early gastrointestinal toxicity and were treated with early whole bowel irrigation (WBI). Chelation therapy with dimercaptosuccinic acid (dimercaptosuccinate, DMSA) was commenced within 24 hours and serial blood and urine arsenic concentrations were measured. Neither patient suffered any adverse outcome in spite of very high blood and urine concentrations of arsenic. Arsenic quantification in blood, urine and faeces suggested that enhanced gastrointestinal decontamination was minimally effective for decontamination and that DMSA for at least two weeks was required.

Histological Effect of Methotrexate and Folinic Acid on Oral Epithelium of Albino Rats

OBJECTIVE

To determine the extent of damage to oral epithelium caused by high dose methotrexate (HDMTX) and the ameliorating role of folinic acid (FA) on damaging effect of methotrexate.

STUDY DESIGN

Experimental study.

PLACE AND DURATION OF STUDY

Anatomy Department of Post Graduate Medical Institute (PGMI), Lahore, from March to September 2013.

METHODOLOGY

Forty-two albino rats were randomly allocated to 3 groups: Exp group-I was given HDMTX intramuscularly (I/M) on alternate days, Exp group-II was given both MTX and FA(I/M) on alternate days, and the control group received no intervention. After 16 days, buccal mucosa was excised for histological analysis under light microscope using H & E stains to see the effect of intervention.

RESULTS

Exp group-I showed marked reduction in epithelial thickness compared to Exp group-II, and the control (F = 46.44, p < 0.001) had significantly depleted basal layer (F = 6.32, p < 0.004), as well as inflammatory infiltrate with evidence of erosion and ulceration. Exp group-II showed less atrophic changes, a few inflammatory cells, no erosion and ulceration compared to the Exp group-I. Assuming epithelial thickness of control group 100% intact, the Exp group-II was found to have 78% intact and Exp group-I had only 38% thickness intact. Thus FArescued epithelial thickness by 40%.

CONCLUSION

Folinic acid considerably saved oral mucosa from the damaging effect of HDMTX, improving quality of life of patients.