Ibogaine for treating drug dependence. What is a safe dose?

The indole alkaloid ibogaine, present in the root bark of the West African rain forest shrub Tabernanthe iboga, has been adopted in the West as a treatment for drug dependence. Treatment of patients requires large doses of the alkaloid to cause hallucinations, an alleged integral part of the patient's treatment regime. However, case reports and case series continue to describe evidences of ataxia, gastrointestinal distress, ventricular arrhythmias and sudden and unexplained deaths of patients undergoing treatment for drug dependence. High doses of ibogaine act on several classes of neurological receptors and transporters to achieve pharmacological responses associated with drug aversion; limited toxicology research suggests that intraperitoneal doses used to successfully treat rodents, for example, have also been shown to cause neuronal injury (purkinje cells) in the rat cerebellum. Limited research suggests lethality in rodents by the oral route can be achieved at approximately 263mg/kg body weight. To consider an appropriate and safe initial dose for humans, necessary safety factors need to be applied to the animal data; these would include factors such as intra- and inter-species variability and for susceptible people in a population (such as drug users). A calculated initial dose to treat patients could be approximated at 0.87mg/kg body weight, substantially lower than those presently being administered to treat drug users. Morbidities and mortalities will continue to occur unless practitioners reconsider doses being administered to their susceptible patients.

Delayed seizure-like activity following analytically confirmed use of previously unreported synthetic cannabinoid analogues.

Synthetic cannabinoid use has become widespread, leading to increased burdens on health care providers. Symptoms range from agitation and psychosis to seizures and acute kidney injury. We report a case where a patient was assessed and treated twice within 12 h for seizures following synthetic cannabinoid intoxication. Blood sample determinations showed low concentrations of analogues not previously reported, some of which are legal. Clinicians should be aware that synthetic cannabinoids may cause an array of severe health consequences. Given the ever evolving structure of available analogues, clinicians must also be prepared for other unexpected adverse effects.

Riot control agents: the tear gases CN, CS and OC-a medical review.

INTRODUCTION: 2-Chloroacetophenone (CN), o-chlorobenzylidene malonitrile (CS) and oleoresin capsicum (OC) are common riot control agents. While serious systemic effects are uncommon, exposure to high concentrations may lead to severe complications and even death. The aim of this narrative review is to summarise all main aspects of the riot control agents CN, CS and OC toxicology, including mechanisms of toxicity, clinical features and management. METHODS: OVID MEDLINE and ISI Web of Science were searched for terms associated with CN, CS and OC toxicity in humans and those describing the mechanism of action, clinical features and treatment protocols. RESULTS: CN, CS and OC are effective lacrimating agents; evidence for toxicity, as measured by the threshold for irritation, is greatest for CN, followed by CS and OC. Typically, ocular and respiratory tract irritation occurs within 20-60 s of exposure. Ocular effects involve blepharospasm, photophobia, conjunctivitis and periorbital oedema. Following inhalation, effects may include a stinging or burning sensation in the nose, tight chest, sore throat, coughing, dyspnoea and difficulty breathing. Dermal outcomes are variable, more severe for CN and include dermal irritation, bulla formation and subcutaneous oedema. Removal from the contaminated area and fresh air is a priority. There is no antidote; treatment consists of thorough decontamination and symptom-directed supportive care. Ocular exposure requires thorough eye decontamination, an eye exam and appropriate pain management. Monitoring and support of respiratory function is important in patients with significant respiratory symptoms. Standard treatment protocols may be required with patients with pre-existing respiratory conditions. Dermal exposures may require systemic steroids for patients who develop delayed contact dermatitis. CONCLUSIONS: CN, CS and OC are effective riot control agents. In the majority of exposures, significant clinical effects are not anticipated. The irritant effects can be minimised both by rapid evacuation from sites of exposure, decontamination and appropriate supportive care.

Isopropanol poisoning.

INTRODUCTION: Isopropanol is a clear, colorless liquid with a fruity odor and a mild bitter taste. Most commonly found domestically as rubbing alcohol, isopropanol is also found in numerous household and commercial products including cleaners, disinfectants, antifreezes, cosmetics, solvents, inks, and pharmaceuticals. AIM: The aim of this review is to critically review the epidemiology, toxicokinetics, mechanisms of toxicity, clinical features, diagnosis, and management of isopropanol poisoning. METHODS: OVID MEDLINE and ISI Web of Science were searched to November 2013 using the words "isopropanol", "isopropyl alcohol", "2-propanol", "propan-2-ol", and "rubbing alcohol" combined with the keywords "poisoning", "poison", "toxicity", "ingestion", "adverse effects", "overdose", or "intoxication". These searches identified 232 citations, which were then screened via their abstract to identify relevant articles referring specifically to the epidemiology, toxicokinetics, mechanisms of toxicity, clinical features, diagnosis, and management of isopropanol poisoning; 102 were relevant. Further information was obtained from book chapters, relevant news reports, and internet resources. These additional searches produced eight non-duplicate relevant citations. EPIDEMIOLOGY: The majority of isopropanol exposures are unintentional and occur in children less than 6 years of age. Although isopropanol poisoning appears to be a reasonably common occurrence, deaths are rare. TOXICOKINETICS: Isopropanol is rapidly absorbed following ingestion with peak plasma concentrations occurring within 30 min. It can also be absorbed following inhalation or dermal exposure. Isopropanol is widely distributed with a volume of distribution of 0.45-0.55 L/kg. Isopropanol is metabolized by alcohol dehydrogenase to acetone, acetol and methylglyoxal, propylene glycol, acetate, and formate with conversion of these metabolites to glucose and other products of intermediary metabolism. The elimination of isopropanol is predominantly renal, though some pulmonary excretion of isopropanol and acetone occurs. In one case 20% of the absorbed dose was eliminated unchanged in urine, with the remainder excreted as acetone and metabolites of acetone. The elimination half-life of isopropanol is between 2.5 and 8.0 h, whereas elimination of acetone is slower with a half-life following isopropanol ingestion of between 7.7 and 27 h. MECHANISMS OF TOXICITY: While the exact mechanism of action of isopropanol has not been fully elucidated, brain stem depression is thought to be the predominant mechanism. While the clinical effects are thought to be mostly due to isopropanol, acetone may also contribute. CLINICAL FEATURES: The major features of severe poisoning are due to CNS and respiratory depression, shock, and circulatory collapse. The most common metabolic effects are an increased osmol (osmolal) gap, ketonemia, and ketonuria. Diagnosis. Poisoning can be diagnosed using the measurement of isopropanol serum concentrations, though these may not be readily available. Diagnosis is therefore more typically made on the basis of the patient's history and clinical presentation. An osmol gap, ketonemia, and/or ketonuria without metabolic acidosis, along with a fruity or sweet odor on the breath and CNS depression support the diagnosis. Management. Supportive care is the mainstay of management with primary emphasis on respiratory and cardiovascular support. Hemodialysis enhances elimination of isopropanol and acetone and should be considered in very severe poisoning. CONCLUSIONS: Severe isopropanol poisoning results in CNS and respiratory depression and circulatory collapse. Treatment primarily consists of symptom-directed supportive care. Although hemodialysis increases the elimination of isopropanol and acetone substantially, it should only be considered in severe life-threatening poisonings. Patients usually make a full recovery provided they receive prompt supportive care.

Heinz bodies formed in erythrocytes by fatty acid ozonides and ozone.

Ozonides of the methyl esters of oleic, linoleic, linolenic and arachidonic acids were found to produce Heinz body inclusions in human and mouse erythrocytes. No simple relationships between structure and activity were noted. Concomitant with Heinz body formation, methemoglobin and loss of cellular thiols were observed. Methyl ozonides readily oxidized glutathione and 1 mole of oxidized glutathione was formed per mole of methyl oleate ozonide. Methyl ozonides catalyzed the formation of disulfide-linked interchain polymers between hemoglobin and ovalbumin. Heinz bodies were not produced with ozone in the absence of unsaturated lipids. Heinz bodies were observed in the blood of mice exposed to ozone (0.85 ppm) for 48 hours. These observations suggest that fatty acid ozonides could serve as a toxic chemical species formed on ozone inhalation and could explain the divergent protective effects of lipid antioxidants and thiol generating systems in vivo.

Prevention of Ozonide-Induced Heinz Bodies in human Erythrocytes by Vitamin E.

Methyl oleate ozonide, a proposed intermediary in ozone intoxication, produced Heinz body inclusions in human erythrocytes at concentrations of from 10-4 to 2 x 10-3 M. Daily oral supplementation with either 100 mg or 200 mg of D-alpha-tocopheryl acetate prevented Heinz body formation by methyl oleate ozonide. These observations suggest that the protective effects of vitamin E against ozone-produced toxicants occurs in man as well as in animals.