Pharmacology of Methiocarb, Effects of Methiocarb on the Mammalian Body, Antidotes for Methiocarb Poisoning - Assignment Example

Case Study Name Institution Word Count Methiocarb Methiocarb is a molluscicide and insecticide for controlling spiders, insects, slugs and snails (United States Environmental Protection Agency [EPA], 1994). This toxin is a common ingredient in insecticides because it repels insects and birds in farming fields. The ingestion of this toxin by a 4-year-old boy and its effects is explained in this paper. Q1.Chemistr and Pharmacology of Methiocarb The chemical name for Methiocarb is 3.5- Dimethyl-4-(methylthio) phenol methylcarbamate (International Programme on Chemical Safety [INCHEM], 2014). Its trade name is Mesurol (56). The chemical compound is formulated using bait, Wettable powder and hopper box t2YXW1 Seed protectant-M. The physical properties of the chemical compound are a mild odour, colourless crystal powder, molecular weight of 225.3, solubility of 30 milligrams per litre of water at room temperature. The pure chemical compound has a melting point of 117 degrees Celsius and a boiling point of 311 degrees Celsius (INCHEM, 1983). In addition, Methiocarb has a density of 1.25 and a molecular formula of C11H15NO2S2 (Johnson, Rockett, Atkinson & Aldous, 2009). Methiocarb is effective in controlling molluscicidal and insecticidal activity. It is moderately soluble with reports showing that the chemical compound breaks to 80 percent when dissolved in water (Johnson et al., 2009). Methiocarb is used as a bird repellent. United States (US) farmers use this chemical compound to repel insects from cherries and blueberries. Methiocarb is also used as a bird repellent for corn, sorghum, rice and grape fields. It controls insects, which attack cherries, blueberries and grapes such as the cherry maggot, blueberry maggot and the yellow jacket (INCHEM, 1983). Methiocarb also has domestic uses such as controlling snails and slugs around the flower garden and on ornamentals (Johnson et al., 2009). Methiocarb is efficient in controlling pests such as grasshoppers, slugs, snails, plum curculio, fruit flies, mosquitoes, flies, mites, pear psylla, leafhoppers, moths and aphids (EPA, 1994). It kills these insects on contact. This compound may require more than one application to be effective. For instance, East African farmers apply Methiocarb to their unripe crops to prevent the plants or seedlings from being damaged. This is to prevent slugs and other insects from neighbouring fields from destroying the plants (INCHEM, 1983). Table 1. The Properties (Chemical and Physical) of Methiocarb (Johnson, Rockett, Atkinson & Aldous, 2009). Q32.Effects of Methiocarb on the mammalian body. What other signs/symptoms would Jimmy display? Can this chemical cause death? Why? Various studies have been conducted on the effects of Methiocarb on humans, dogs, rats and cattle. The studies showed that the mammals produce major metabolites, which were found in blood, liver, and kidneys (Toxicology Data Network, 2003). The metabolites included N-hydroxymethyl-methiocarb and Methiocarb sulphoxide. When ingested in humans, Methiocarb causes symptoms such as nausea, diarrhoea, sweating, blurred vision, salivation, vomiting and abdominal pain. In addition, the compound produces symptoms such as muscle twitching, dyspnoea, headache and tremors. Methiocarb causes temporary paralysis in extreme cases while studies suggest that respiratory depression, convulsions, anorexia, weakness and pulmonary oedema are possibilities of severe poisoning (Toxicology Data Network, 2003). Jimmy’s symptoms include laboured breathing, muscle spasms and inability to talks. His teary eyes could have caused blurred vision while laboured breathing could have symbolised respiratory depression or problem. The muscle spasms could have indicated muscle twitching or have been the response to convulsions or tremors. Respiratory depression is common symptom from the ingestion of Methiocarb. This symptom can be alleviated by administering 30ml of Ipecac Syrup and water (two glasses) which would induce vomiting (Toxicology Data Network, 2003). Other signs that would have been displayed by Jimmy include salivation, abdominal pain, sweating and diarrhoea since children have more predominant symptoms compared to adults. Methiocarb can lead to death. Regular consumption leads to death caused by acute intoxication based on studies showing a 50 percent mortality rate among rats that were administered with daily doses of Methiocarb (Toxicology Data Network, 2003). Severe toxicity from Methiocarb ingestion could lead to death due to the effect of the chemical compound on internal organs. For example, severe poisoning from the chemical compound would cause acute lung injury, respiratory depression, bronchospasm and bronchorrhea, which would lead to respiratory failure (Toxicology Data Network, 2003). The central effects of the compound would not have a fatal outcome but would cause delirium, seizures, hypertension, metabolic acidosis and hyperglycemia in patients. Death could occur if the symptomatic patient is not admitted to hospital less than 12 hours after exposure. Emergency treatment would enable physicians to decontaminate the patient (such as gastrointestinal decontamination or removing contaminated clothes) and to administer antidotes to manage the symptoms to stabilize the patient. In addition, early hospitalization would ensure that the patient is treated for seizures and admitted to the intensive care unit for toxicology monitoring (INCHEM, 1983). Q33.The medical team administers two drugs. They explain one is to counter the pellets he has ingested, and the other is to relax his muscles. What is the likely identity of these drugs, and how do they work to benefit Jimmy? The likely identities of the drugs are atropine and pralidoxime. These are the most common antidotes for Methiocarb poisoning. Atropine could have been used to counter the ingested pellets while Pralidoxime could have been used to relax the muscles. Atropine helps to manage the muscarinic effects of the ingested pellets. It helps treat salivation, bronchorrhea and urination in patients. According to Toxicology Data Network (2003), a physician should administer a dose of 0.02 mg per kilogram in children. The child would need to be monitored and double doses administered every 5 minutes to dry the pulmonary secretions. The benefit for Jimmy is that the drugs would dry the pulmonary secretions, which cause his laboured breathing. Atropine would manage the secretions although Furosemide would be more effective if Jimmy had crackle sounds in his lungs. Furosemide can only be administered after atropinisation when the effect of administering atropine is achieved (Toxicology Data Network, 2003). In Jimmy’s case, atropine could be administered intramuscularly or intravenously. It is vital that the physician monitors the effect of atropine on the patient because toxicity of the treatment can cause hyperthermia and delirium. This drug can be administered from hours or days with frequent monitoring. Pralidoxime is used to manage the cholinergic effect of Methiocarb. It is used to treat symptoms such as muscle weakness, seizures and respiratory depression. This drug would benefit Jimmy because it is a muscle relaxant. This relaxation would help Jimmy to breathe better. Pralidoxime is effective in relaxing muscles when administered within the first 48 hours. The World Health Organization recommends the administration of 30mg per kilogram then an increase of 8mg per kilogram every hour. Alternatively, dosage of 20-50mg per kilogram can be administered for 30 minutes in a 0.9% saline solution (Toxicology Data Network, 2003). Q34. How does Methiocarb work for the purpose it was intended? Is it always 100% effective? Discuss. Methiocarb is used as bait for insects, snails and slugs. These baits contain up to 4 percent of the Methiocarb and are combined with wheat bran to form pellets. The coloured pellets are then deposited in the soil. Some of these pellets are lodged in the leaves and help repel birds from fruits such as grapes, cherries, cereal grains, peaches and blueberries (INCHEM, 1983). These pellets do not disintegrate easily so that they can repel insects and birds for a long period. Methiocarb is effective because it has received EPA approval. EPA recommends that 1-1.75 lbs of Methiocarb should be used to control blueberry maggots and 2lbs for to repel birds. This application should be 7 days prior to the harvest date to ensure the insecticide is effective. In addition, the EPA recommends 1-1.3 lbs of Methiocarb per acre of cherries to control mites and cherry fruit flies. The recommendation is 14 days before the harvest day to ensure 100 percent effectiveness (INCHEM, 1983). Q35.Next to the box of snail pellets was another box containing wax blocks of a Rodenticide called Brodifacoum. How does this work and what effect would it have had on Jimmy if he had consumed sufficient? Brodifacoum is an anti-coagulant. It is an ingredient in rodent control (rodenticide) products. The usefulness of the anti-coagulant was first observed in 1970 and registered in countries such as New Zealand in the 1980s. This toxin has been successful in controlling rats and brushtail possums. This explains its wide use in rodent eradication projects. Brodifacoum works by decreasing or increasing blood clotting time (Toxicology Data Network, 2014). The increase or decrease of the clotting time causes haemorrhaging which leads to death in animals. It can be injected through the skin, respiratory system and gastrointestinal tract. The toxin is not metabolized readily in poisoned animals and the toxin may continue to reside in the liver for a number of months. This long-term persistence does not occur in arthropods such as spiders, insects and crustaceans. Brodifacoum has moderate to server health effects on humans. It irritates the skin and the eyes. Acute intoxication causes poisoning. The symptoms of the poisoning include bleeding in less severe cases to massive haemorrhage in severe cases. This haemorrhaging occurs a few days after the toxin has been ingested (Toxicology Data Network, 2014). Brodifacoum intake by Jimmy could have been the cause of the water eyes. The eye irritation could have been the symptom of the ingested toxin rather than ingestion of Methiocarb. The toxin would not have had any mutagenic or carcinogenic effect on Jimmy. However, the toxin would have impaired coagulation leading to gum bleeding, ecchymosis, hematessis, epistaxis and melena. In addition, Brodifacoum could have caused muscular hematoma on Jimmy’s knees, buttocks and elbows. An effective treatment for brodifacoum poisoning is long-term administration of Vitamin K1. References International Programme on Chemical Safety. (1983). Pesticide residues in food: Methiocarb. Retrieved from http://www.inchem.org/documents/jmpr/jmpmono/v83pr31.htm Johnson, I., Rockett, L., Atkinson, C., & Aldous, E. (20090. Proposed EQS for water framework directive annex VIII substances: Methiocarb (For consultation). Edinburg, Scotland: Water Framework Directive. Toxicology Data Network. (2003, February 13). Methiocarb. Retrieved from http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+782 Toxicology Data Network. (2014, May 15). Brodifacoum. Retrieved from http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+3916 United States Environmental Protection Agency. (1994). Methiocarb. EPA R.E.D Facts, 577, 1-8. Read More