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| Newsletters and Reviews Anticoagulant Rodenticides Carbon Monoxide Celexa Chemical Warfare Dangers of the Sun Ethylene Glycol Fertilizers Herbals Hydrofluoric Acid Insect Repellents Methanol Poison Ivy Rabies Raves and Club Drugs Tox Update 2007 Winter Hazards Download Newsletters Order Bulk Material |
Winter Hazards Carbon Monoxide
Antidotal therapy for carbon monoxide toxicity is oxygen. Victims of mild to moderate toxicity should be treated by using 100% oxygen by face mask. This shortens the half-life of carbon monoxide from approximately 6 hours to 90 minutes. Severe toxicity requires the administration of oxygen under pressure in a hyperbaric chamber. Under three atmospheres of pressure, the half-life of carbon monoxide is further reduced to about 30 minutes. Ethylene glycol (EG) is commonly available as automobile radiator antifreeze. Because of its sweet taste, improperly stored antifreeze is a common source of EG exposures in children. The need for therapy may be based on a history of ingestion, anion gap metabolic acidosis, increased osmolar gap or oxalate crystals in the urine. The best determinant is a serum ethylene glycol concentration greater than 20 mg/dl. Unfortunately, many health care facility laboratories are unable to perform this useful measurement. Therefore, in each hospital, a protocol for obtaining immediate ethylene glycol levels should be developed if one does not currently exist.
Antizol® (fomepizole) by Orphan Medical in Minnetonka, Minnesota. is a specific antidote for the treatment of ethylene glycol toxicity. It works by inhibiting the enzyme alcohol dehydrogenase which is responsible for the conversion of ethylene glycol into its toxic metabolites that cause the renal injury and metabolic acidosis. Antizol® is recommended as first line therapy.
Antizol® and ethanol are easily dialyzable. Therefore, frequency of dosing must be increased during dialysis. Adjunctive therapy with folinic acid and folate will enhance the metabolism of formic acid to carbon dioxide and water. Long-Acting Anticoagulants As the weather turns colder, small rodents seek the warmth of homes, leading to an increased use of rodenticide baits. Consequently, rodenticide exposures sharply increases in children. The most common agents used in these products are long acting anticoagulants, such as brodifacoum, diphacinone or bromiadiolone. They are usually in the form of blue-green colored loose pellets and less commonly in solid blocks. Because the concentration of the active ingredient is usually low (0.1%-0.005%), it takes about a “mouthful” (15-20 pellets) to produce significant anticoagulation in a child.These agents are vitamin K1 antagonists which inhibit the synthesis of vitamin K dependent clotting factors. Signs of toxicity may not occur for 24-36 hours. Initial treatment may consist of emptying the stomach, and the use of activated charcoal. If toxicity can be demonstrated by a significant increase in PT/INR values at 36-48 hours post ingestion, then vitamin K1 should be considered. In patients, with active bleeding, administer fresh frozen plasma and/or factor concentrates in addition to packed red cells and vitamin K1.
Cough and cold products are found universally within most American households. Virtually thousands of products help ameliorate coughing, nasal congestion, excessive secretions and other symptoms of the common cold and “flu”. Many of the cough and cold products combine a variety of pharmacological agents. These can challenge the health care provider more than the ingestion of a single agent. Most cough and cold preparations contain various combinations of the following pharmacological agents: analgesics and antipyretics, antihistamines, decongestants, expectorants and, finally, cough suppressants. Analgesics and antipyretics Most cough and cold preparations contain acetaminophen, aspirin or ibuprofen as their analgesic and antipyretic agent. Usually, the analgesic/antipyretic component as the greatest potential to cause toxicity and the dose ingested directs the treatment. Antihistamines Antihistamines are heavily used in products to treat the common cold despite questionable efficacy. The toxicity of antihistamines is variable and unpredictable. Anticholinergic effects usually predominate.Antihistamine products include:
In adult overdoses, the antihistamine effects usually predominate over the sympathomimetic effects of the decongestants. In pediatric overdoses, either the anticholinergic or sympathomimetic effects may predominate. A general rule of thumb is that children can tolerate three times the maximum daily dose of the individual agent. Decongestants Sympathomimetic oral decongestants are used for their vasoconstrictive properties to relieve the engorgement of the vascular beds of the mucous membranes causing nasal stuffiness. Pseudoephedrine and phenyephrine are the most common ingrediants. Phenylpropanolamine was widely used until the FDA restricted its use in 2000. Be aware that products containing phenylpropanolamine are still available in many homes.Adolescents and adults may experience agitation, tachycardia, and modest hypertension with ingestion of decongestants. Paradoxically, pediatric patients may experience drowsiness as the primary symptom. As with antihistamines, gastric decontamination is indicated in patients who present promptly (<1-2 hours) after ingestion. Activated charcoal should always be used in ingestions of sustained release preparations. Usually, pediatric patients can tolerate up to 3-4 times the maximum daily dose. Expectorants Expectorants are used to facilitate the elimination of mucous and other respiratory debris. They have little efficacy and have very little toxicity. Guaifenesin is the major expectorant in this category. Terpin hydrate and ammonium chloride have been used historically, but are uncommon now.Cough Suppressants The two agents used primarily in this category are codeine and dextromethorphan. Dextromethorphan, a non-addictive opiate isomer, is not a controlled substance as is codeine. Therefore, it is found in most non-prescription cough suppressant formulations. Ethanol Liquid cough and cold preparations may contain ethanol as a solvent and a preservative. Its concentration may be as high as 20-25%. These preparations pose an ingestion risk for children. Ethanol causes central nervous system depression, as well as symptomatic hypoglycemia.
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