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Both agents are highly volatile and are absorbed through the skin and respiratory tract order 250mg amoxil mastercard, often from sniffing gasoline purchase amoxil 500mg otc. Properties and mechanism of action (1) Inorganic arsenic can be found in coal and metal ores amoxil 250mg mastercard, herbicides, seafood, and drinking water. Acute poisoning (1) Symptoms include severe nausea, vomiting, abdominal pain, laryngitis, and bronchitis; capillary damage with dehydration and shock may occur. The skin often appears pale and milky (‘‘milk and roses’’ com- plexion) because of anemia and vasodilation. Skin pigmentation, hyperkeratosis of the palms and soles, and white lines over the nails may be observed after prolonged exposure. Treatment is primarily supportive after acute poisoning and involves emesis, gastric lavage, rehydration, and restoration of electrolyte imbalance. Organic arsenicals are excreted more readily and are less toxic than inorganic forms; poi- soning is rare. The effects are severe hemoly- sis and subsequent renal failure; symptoms include jaundice, dark urine, and severe ab- dominal pain. Properties and mechanism of action (1) Inorganic mercury occurs as a potential hazard primarily because of occupational or indus- trial exposure. Acute poisoning and treatment (1) Mercury vapor poisoning produces chest pain, shortness of breath, nausea, vomiting, and a metallic taste. Treatment involves removal from exposure, supportive care, and chelation therapy with di- mercaprol, unithol, or succimer. Chronic poisoning (1) Mercury vapor poisoning may lead to a fine tremor of the limbs that may progress to choreiform movements, and neuropsychiatric symptoms that may include insomnia, fa- tigue, anorexia, and memory loss, as well as changes in mood and affect. Exposure of the fetus to methylmercury in utero may result in mental retardation and a syn- drome resembling cerebral palsy. Metal-chelating agents usually contain two or more electronegative groups that form stable coordinate-covalent complexes with cationic metals that can then be excreted from the body. The greater the number of metal–ligand bonds, the more stable the complex and the greater the efficiency of the chelator. Dimercaprol is an oily, foul-smelling liquid administered intramuscularly as a 10% solution in peanut oil. Dimercaprol interacts with metals, reactivating or preventing the inactivation of cellular sulfhydryl-containing enzymes. This agent is useful in arsenic, inorganic mercury, and organic mercury poisoning (and lead poisoning). The adverse effects of dimercaprol include tachycardia, hypertension, gastric irritation, and pain at the injection site. Succimer (Chemax) is a derivative of dimercaprol that can be taken orally and is approved for use in children to treat lead poisoning. The adverse effects of succimer are generally minor and include nausea, vomiting, and anorexia. Unithol (Dimaval) is another analogue of dimercaprol over which it has advantages (few adverse effects) for treatment of mercury, arsenic, and lead poisoning. This agent is used primarily to chelate excess copper in individuals with Wilson disease. Penicillamine is also used for copper and mercury poisoning and as an adjunct for the treat- ment of lead and arsenic poisoning. Allergic reactions and rare bone marrow toxicity and renal toxicity are the major adverse effects. Deferoxamine is a specific iron-chelating agent that on parenteral administration binds with ferric ions to form ferrioxamine; it also binds to ferrous ions. Deferoxamine can also Chapter 13 Toxicology 319 remove iron from ferritin and hemosiderin outside bone marrow, but it does not capture iron from hemoglobin, cytochromes, or myoglobin. Deferoxamine is metabolized by plasma enzymes and excreted by the kidney, turning urine red. Deferoxamine may cause allergic reactions and rare neurotoxicity or renal toxicity. Defer- oxamine therapy is contraindicated in patients with renal disease or renal failure. More than a million cases of acute poisoning occur each year in the United States, many in children and adolescents. The symptoms of most drug and chemical poisonings are extensions of their pharmacologic properties. Measures to support vital functions, slow drug absorption, and promote excretion are generally sufficient for treatment. Comatose patients may die as a result of airway obstruction, respiratory arrest, or aspiration of gastric contents into the tracheobronchial tube. Induction of vomiting with ipecac orally is no longer recommended for routine use at home, and is con- traindicated in children under 6 years. Urinary excretion can be enhanced by the admin- istration of agents such as sodium bicarbonate, which raises urinary pH and decreases renal reabsorption of certain organic acids such as aspirin and phenobarbital. Hemodialysis is an efficient way to remove certain low molecular weight, water-soluble tox- ins and restore electrolyte balance. Salicylate, methanol, ethanol, ethylene glycol, paraquat, and lithium poisonings are effectively treated this way; hemoperfusion may enhance the whole-body clearance of some agents (carbamazepine, phenobarbital, phenytoin). Drugs and poisons with large volumes of distribution are not effectively removed by dialysis. Antidotes (see respective agents) are available for some poisons and should be used when a specific toxin is identified. Some examples include naloxone, acetylcysteine, physostigmine, metal chelators (see above), atropine, pralidoxime, and ethanol. What treatment would be appropriate in a 3- What is the most appropriate agent to adminis- year-old boy with a dramatically elevated blood ter at this point? A 56-year-old chronic alcoholic is brought to gency room because he recently ingested the emergency room with altered mental status numerous ‘‘iron pills’’ his mother was taking for and complains of not being able to see. The child now has severe abdomi- reports running out of ‘‘whiskey’’ and ingesting nal pain, bloody diarrhea, nausea, and vomit- wood alcohol (methanol). An 18-year-old man is brought to the (A) Wristdrop emergency room by his friends because he (B) ‘‘Rice-water’’ stools ‘‘passed out. Which of the following toxic agents would (E) Carbon tetrachloride pose a problem with dermal exposure? A 23-year-old known heroin addict is (B) Organophosphate insecticides brought to the emergency room for unrespon- (C) Inorganic lead siveness. On examination he is found to have (D) Cadmium pin-point pupils and respiratory depression.

If the number in the next decimal place is less than 5 generic amoxil 500 mg with mastercard, round down: an answer of 3 purchase amoxil with visa. We add zeroes to the right of the decimal point to indicate the level of precision we are using cheap amoxil 500 mg line. Transforming Scores Many statistical procedures are nothing more than elaborate transformations. A transformation is a mathematical procedure for systematically converting a set of Review of Mathematics Used in Statistics 7 scores into a different set of scores. Adding 5 to each score is a transformation, or converting “number correct” into “percent correct” is a transformation. For example, if all of the scores contain a decimal, we might multiply every score by 10 to eliminate the decimals. For example, if you obtained 8 out of 10 on a statistics test and 75 out of 100 on an English test, it would be difficult to compare the two scores. However, if you transformed each grade to percent correct, you could then directly compare performance on the two tests. Proportions A proportion is a decimal number between 0 and 1 that indicates a fraction of the total. If 4 out of 10 people pass an exam, then the proportion of people passing the exam is 4/10, which equals. Or, if you score 6 correct on a test out of a possible 12, the proportion you have correct is 6/12, which is. We can also work in the opposite direction from a known proportion to find the num- ber out of the total it represents. Altogether, to transform the original test score of 6 out of 12 to a percent, first divide the score by the total to find the proportion and then multi- ply by 100. To transform a percent back into a proportion, divide the percent by 100 (above, 50/100 equals. Altogether, to find the test score that corresponds to a certain per- cent, transform the percent to a proportion and then multiply the proportion times the total number possible. Thus, to find the score that corresponds to 50% of 12, transform 50% to the proportion, which is. Recognize that a percent is a whole unit: Think of 50% as 50 of those things called percents. Creating Graphs One type of statistical procedure is none other than plotting graphs. In case it’s been a long time since you’ve drawn one, recall that the horizontal line across the bottom of a graph is the X axis, and the vertical line at the left-hand side is the Y axis. Notice that because the lowest height score is 63, the lowest label on the X axis is also 63. We do this with either axis when there is a large gap between 0 and the lowest score we are plotting. Jane is 63 inches tall and weighs 130 pounds, so we place a dot above the height of 63 and opposite the weight of 130. Notice that you read the graph by using the scores on one axis and the data points. For example, to find the weight of the person who has a height of 67, travel vertically from 67 to the data point and then horizontally to the Y axis: 165 is the corresponding weight. In later chapters you will learn when to connect the data points with lines and when to create other types of figures. Regardless of the final form of a graph, always label the X and Y axes to indicate what the scores measure (not just X and Y), and always give your graph a title indicating what it describes. When creating a graph, make the spacing between the labels for the scores on an axis reflect the spacing between the actual scores. For example, the labels 10, 20, and 40 would not be equally spaced because the distance between these scores is not equal. Sometimes there are so many different scores that we cannot include a label for each one. Be careful here, because the units used in labeling each axis then determine the impression the graph gives. Say that for the previous weight scores, instead of labeling the Y axis in units of 10 pounds, we labeled it in units of 100 pounds, as shown in Figure 1. Thus, always label the axes in a way that honestly presents the data, without exaggerating or minimizing the pattern formed by the data points. If you compute your grade average or if you ask your instructor to “curve” your grades, you are using statistics. When you understand from the nightly news that Senator Fluster is projected to win the election or when you learn from a television commercial that Brand X “significantly” reduces tooth decay, you are using statistics. You simply do not yet know the formal names for these statistics or the logic behind them. All empirical research is based on observation and measurement, resulting in numbers, or scores. Statistical procedures are used to make sense out of data: They are used to organize, summarize, and communicate data and to draw conclusions about what the data indicate. The goal in learning statistics is to know when to perform a particular procedure and how to interpret the answer. Unless otherwise indicated, the order of mathematical operations is to compute inside parentheses first, then square or find square roots, then multiply or divide, and then add or subtract. Round off the final answer in a calculation to two more decimal places than are in the original scores. If the digit in the next decimal place is equal to or greater than 5, round up; if the digit is less than 5, round down. A transformation is a procedure for systematically converting one set of scores into a different set of scores. Transformations make scores easier to work with and make different kinds of scores comparable. To determine the score that produces a particular proportion, multiply the proportion times the total. To transform an original score to a percent, find the proportion by dividing the score by the total and then multiplying by 100. To find the original score that corresponds to a particular percent, transform the percent to a proportion and then multiply the proportion times the total. If given no other information, what is the order in which to perform mathematical operations? For each of the following, to how many places will you round off your final answer? The intermediate answers from some calculations based on whole-number scores are X 5 4. Of the 40 students in a gym class, 13 played volleyball, 12 ran track (4 of whom did a push-up), and the remainder were absent.

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Through this opening purchase amoxil 500 mg fast delivery, the nervous colon syndrome See irritable bowel spinal cord and the meninges may herniate to cre- syndrome order amoxil with a mastercard. The nervous women consume supplements that contain folic system has two distinct parts: central and periph- acid before and during the early weeks of pregnancy eral quality 250mg amoxil. The central part is made up of the brain and in addition to getting folate in their diets. A neuralgia, facial Severe pain that usually occurs neuron consists of the nerve cell body and various in bursts along the path of the trigeminal nerve, the extensions, or processes, from the cell body. See also central nervous system; itating, and it occurs primarily in persons over age peripheral nervous system. The pain of postherpetic neuralgia can be reduced by certain medications including tricyclic nervous system, autonomic See autonomic antidepressant medications and some antiseizure nervous system. Capsaicin cream, a derivative of hot chili peppers, or lidocaine patches can be applied nervous system, central See central nervous on the area after all the blisters have healed, to system. Acupuncture and electric nerve stimu- lation through the skin can be helpful for some nervous system, parasympathetic See patients. Neuroblastoma is the most common solid tumor neurofibromatosis type 2 A genetic disorder outside the brain in infants and children. It is often that is characterized by the growth of benign tumors present at birth but may not be detected until later of both acoustic nerves (the nerves to the ears). The most common symp- These tumors, called acoustic neuromas, cause tin- toms are the result of pressure by the tumor or bone nitus (ringing in the ears), hearing loss, and prob- pain from metastases. Screening infants for neuroblastoma is not warranted because it does not decrease the neurogenic Giving rise to or arising from the morbidity (illness) or mortality rate. For example, neuro- genic pain is pain that originates in the nerves, as neurodermatitis Scaly patches of skin on the opposed to muscle pain, bone pain, etc. The nervous diagnosis and treatment of disorders of the nervous and endocrine systems often act together to regulate system. Aside istics, including multiple café au lait (coffee with from hearing and balance, these tumors can milk) spots, multiple benign tumors called neurofi- impinge on the facial nerve, causing facial paralysis, bromas on the skin, plexiform neurofibromas and press on nearby brain structures and be life- (thick and misshapen nerves due to the abnormal threatening. Acoustic neuromas may be removed by growth of cells and tissues that cover the nerve), surgery or shrunk by radiosurgery. A gliomas (benign tumors on the optic nerve), neuron receives electrical input signals from sen- epilepsy, and learning disabilities. The risk of malig- sory cells (called sensory neurons) and from other nant degeneration of neurofibromas is lower than http://www. The neuron sends electrical output signals neurotoxin Any substance that is capable of to muscle neurons (called motoneurons or motor causing damage to nerves or nerve tissue. The mature neutrophil has a segmented nucleus (it is called a seg or poly) while neuropathy Any disease or malfunction of the the immature neutrophil has a band-shape nucleus nerves. Neutropenia may be seen with viral neuropathy, accessory See accessory neu- infections and after radiotherapy and chemotherapy. A true increase in neutrophil produc- third (tertiary) and final phase of syphilis, which tion often reflects infection, particularly bacterial involve the central nervous system and can include infection. See also Creutzfeldt-Jakob disease; prion; mad cow disease Niemann-Pick disease A group of inherited biochemical disorders in which lipid (fat) accumu- newborn screening Testing of newborns to lates in the spleen, liver, lungs, bone marrow, and screen for serious treatable diseases, many of which the brain. The classical form of the disease testing for galactosemia and sickle cell disease is has its onset in very early infancy, and death usually required in most states. Other fea- other conditions, including deafness, maple syrup tures are jaundice, hepatic (liver) failure, and ascites urine disease, homocystinuria, congenital adrenal (fluid in the abdomen). Eye hallmarks include a hyperplasia, tyrosinemia, cystic fibrosis, and toxoplas- “cherry red spot” in the macula in the center of the mosis. In the classic form, accu- cystinuria; hypothyroidism, congenital; maple mulation of a substance called sphingomyelin is due syrup urine disease; phenylketonuria; sickle cell to deficiency of the enzyme sphingomyelinase. Night sweats can have many different causes, including medica- niacin deficiency See pellagra. Nicotine has powerful pharmacologic Nipah virus A member of the paramyxovirus effects (including increased heart rate, heart stroke family isolated from samples from an outbreak of volume, and oxygen consumption by the heart mus- encephalitis and respiratory illness among adult cle), as well as powerful psychodynamic effects men in Malaysia and Singapore in 1999 that causes (such as euphoria, increased alertness, and a sense a sometimes fatal form of viral encephalitis. For example, nictitating spasm nipple The pigmented projection on the surface is spasm of the eyelid with continuous winking. In the mature female, ducts that conduct milk from nidus In medicine, any structure that resembles a the mammary glands to the surface of the breast exit nest in appearance or function. This distri- technique that does not use radiation, but instead bution is very similar to the location of nipples on employs large magnetic forces to produce detailed mammals that have multiple nipples along the images of body tissues. Infection nitrogen narcosis A condition similar to intoxi- tends to strike the lungs, brain, and skin, particu- cation with alcohol characterized by euphoria, loss larly in people with an impaired immune system. The skin form of nocardio- below 30 meters (100 feet) who breathe com- sis is contracted through soil contamination of pressed air, because of the high nitrogen content of wounds. Nitrogen narcosis is reversed as the gas pressure person transmission of Nocardia. For example, rapid effect and is used to treat angina pectoris by a lymph node is a collection of lymphoid tissue. Nitrous oxide is used sometimes as a recreational drug for node, sinoatrial See sinoatrial node. Nits firmly attach to the hair shaft with a glue-like nodular hyperplasia of the prostate See substance. All nits must be removed to prevent reinfestation with nodular melanoma See melanoma, nodular. Topical preparations are available nodule A small collection of tissue that is palpable (can be felt) at any level of the skin (in the epidermis, http://www. Nodules characteristically range in size from 1 to 2 Knowing which type a patient has is important for cm in diameter. The treatment options for non-small- cell lung cancer are generally different than those for noncompliance Failure or refusal to comply. Hearing loss, for instance, can be syndromic or nonsyn- nondisjunction Failure of paired chromosomes dromic. Nondisjunction causes errors syndrome that is characterized by mildly short in chromosome number, such as trisomy 21 (Down stature, a congenital heart defect, a broad or syndrome) and monosomy X (Turner syndrome). It is relatively common, with an esti- mated incidence of 1 in 1,000–2,500 live births. The remaining Nonoxynol-9 A potent spermicide (sperm- normal results fall outside the normal range, as do killing agent) used as a contraceptive. The normal range for a particular test result, condition, symptom, or behav- nonpathogenic Incapable of causing disease. Several other names have been used for noroviruses, including Norwalk-like nonseminoma A type of testicular cancer that viruses, caliciviruses (because they belong to the arises in specialized sex cells called germ cells that virus family Caliciviridae), and small round struc- give rise to sperm. The virus is spread primarily from onal carcinoma, teratoma, choriocarcinoma, and one infected person to another by the fecal-oral yolk sac tumor. The characteristic symptoms are nausea, vomiting, diarrhea, and abdominal cramping that non-small-cell lung cancer Cancer of the lung develop 1 or 2 days after contaminated food or that is not small cell carcinoma. Symptoms typically last for 24 to chogenic carcinoma, squamous cell carcinoma, ade- 60 hours.

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In that features varying degrees of hearing loss and some cases order amoxil, allergy injection therapy is highly effec- pigmentation changes in the skin and hair buy generic amoxil on line. Some patients also take warfarin to reduce their risk of weaver’s bottom Inflammation of the bursa that clots buy genuine amoxil line, stroke, or heart attack. Warfarin works by separates the gluteus maximus muscle of the but- suppressing production of some clotting factors. Weaver’s bottom is a form of bursitis that is usually Warfarin taken by a woman during pregnancy can caused by prolonged sitting on hard surfaces that disturb the development of an embryo and a press against the bones of the bottom or midbut- fetus and lead to birth defects. Wegener granulomatosis See granulomatosis, wart A local growth on the outer layer of the skin Wegener. Papillomavirus is transmitted by contact, either with a wart on some- welt See hive. Warts that occur on the hands or feet are called Werner syndrome A premature aging disease common warts. A wart on the sole of the foot is a that begins in adolescence or early adulthood and plantar wart. Genital (venereal) warts are located results in apparent old age by 30–40 years of age. See also ture graying, early baldness, wizened face, beaked genital warts; human papillomavirus. Plantar warts are different from most other autosomal recessive manner and is due to mutation warts. It can affect any part of the body, leading to arthritis and then weight loss, Werner-His disease See trench fever. Whipple disease has mitted from birds to mosquitoes and then to people been discovered to be due to a type of bacteria by mosquito bites. Some patients relapse and virus occurs in parts of Africa and Asia and, infre- need long-term, even life-long, treatment. West Nile virus had never been seen in birds Whipple procedure A type of surgery that is or people in the Western Hemisphere prior to an used to treat pancreatic cancer and was devised by outbreak in summer 1999 in New York City. Most affected creas, the duodenum, a portion of the stomach, and people have no symptoms or minor symptoms, but other nearby tissues are removed. The whipworm is infants and small children under age 5, the aged, found worldwide, and whipworm infections are and people with impaired immune systems. Heavy infections, especially in small chil- dren, can cause gastrointestinal problems (such as Western blot A technique in molecular biology abdominal pain, diarrhea, and rectal prolapse) and that is used to separate and identify particular possibly growth retardation. It can be expressed in international units wheezing A whistling noise in the chest during as (4. Ideally, people so affected should do thought to be as follows: The victim may be first their best to relax when in the medical office. The white matter is white ments in and around the spine may be stretched or because it is the color of myelin, the insulation that torn. There may be overcompensation when the white spots on the nails See jogger’s nails. This may rock the head violently white subungual onychomycosis, proximal forward, stretching and tearing more muscles and See onychomycosis, proximal white subungual. A closed comedo may rupture and cause a low-grade skin inflamma- winter depression See seasonal affective dis- tory reaction in the area. Wilms tumor A childhood form of kidney cancer with a peak age of occurrence at 3 years of age. Symptoms can include abdominal pain, swelling, Wolff-Parkinson-White syndrome A condition and blood in the urine. Diagnosis is made by biopsy, that is caused by an abnormality in the electrical which can classify the tumors as having a favorable system of the heart, which normally tells the heart histology (microscopic appearance) or an unfavor- muscle when to contract. The outcome is also reflected by the stage of cal connection inside the heart that acts as a short the tumor (extent of spread) at the time of diagno- circuit, causing the heart to beat too rapidly and sis. Wilson disease An inherited disorder of copper metabolism that results in an abnormal accumula- Wolhynia fever See trench fever. Although the accumula- tion of copper begins at birth, symptoms of the womb See uterus. A diagnostic feature of the dis- the muscles of the hand and sometimes the forearm ease is a Kayser-Fleischer ring, a deep copper- and that occurs only during typing or use of a com- colored ring around the edge of the cornea that puter. Similar focal dystonias have also been called represents copper deposits in the eye. The main writer’s cramp, pianist’s cramp, musician’s cramp, clinical consequence of Wilson disease for most affected persons is liver disease. If treatment is begun early enough, symptomatic wormwood The plant whose essence forms the recovery is usually complete, and a life of normal basis of absinthe, a dangerous emerald-green length and quality can be expected. For example, “Wt 80 joins the long bones of the forearm (the radius, lbs” means “weight 80 pounds. Another row of carpal bones meets the hand at the five metacarpal bones that make up the palm. Xx xanthoma, planar A type of xanthoma that is characterized by flat yellow-to-orange patches or pimples that cluster together on the skin. Xanthelasma is a harmless growth of tissue caused by tiny deposits of fat in the skin, and it is xanthomatosis An accumulation of excess lipids often associated with abnormal blood fat levels in the body that is due to disturbance of lipid metab- (hyperlipidemia). Dermatologists can remove the xanthopsia A form of chromatopsia, a visual abnormal plaques. In xanthinuria A rare metabolic disorder that is xanthopsia, that color is yellow. Classic xanthinuria is inherited in an autoso- mal recessive manner and involves a defect in the xenotransplantation Transplantation from one enzyme xanthine dehydrogenase. Although xanthomas them- selves are harmless, they frequently indicate under- xeroderma Abnormally dry skin. Xeroderma lying disease, such as diabetes, lipid disorders can be caused by a deficiency of vitamin A, systemic (such as elevated blood cholesterol levels), or other illness (such as hypothyroidism or Sjogren’s syn- conditions. They are composed of lipid-laden foam drome), overexposure to sunlight, and medication. Treatment is directed toward Xeroderma can usually be addressed with the use any underlying disorder when present. Xanthoma is distinguished from xanthelasma by xeroderma pigmentosum A genetic disease that being a large nodule deep in the tissues as opposed is characterized by such extraordinary sensitivity to to a plaque on the skin surface, but both can occur sunlight that it results in the development of skin from lipid disorders. This means that X-linked traits are expressed in males and in females who are homozy- xerophagia Having a tendency to eat a dry diet. See also function of the lacrimal glands, which produce autosomal recessive trait; X-linked dominant. When xerophthalmia is due to vitamin A defi- ciency, the condition begins with night blindness X-ray High-energy radiation with waves shorter and conjunctival xerosis (dryness of the eye mem- than those of visible light. X-ray is used in low doses branes), progresses to corneal xerosis (dryness of to make images that help to diagnose diseases and the cornea), and in its late stages develops into ker- in high doses to treat cancer. The xiphoid process has no particular func- The condition is associated with increased height tion and ranges in size from miniscule to several but no malformations. Xylitol is called a affects about 1 in 1,000 males caused by the pres- nutritive sweetener because it provides calories, just ence of an extra Y chromosome.

Chronic poisoning (1) Mercury vapor poisoning may lead to a fine tremor of the limbs that may progress to choreiform movements buy amoxil in india, and neuropsychiatric symptoms that may include insomnia buy generic amoxil on line, fa- tigue cheap amoxil 250mg on-line, anorexia, and memory loss, as well as changes in mood and affect. Exposure of the fetus to methylmercury in utero may result in mental retardation and a syn- drome resembling cerebral palsy. Metal-chelating agents usually contain two or more electronegative groups that form stable coordinate-covalent complexes with cationic metals that can then be excreted from the body. The greater the number of metal–ligand bonds, the more stable the complex and the greater the efficiency of the chelator. Dimercaprol is an oily, foul-smelling liquid administered intramuscularly as a 10% solution in peanut oil. Dimercaprol interacts with metals, reactivating or preventing the inactivation of cellular sulfhydryl-containing enzymes. This agent is useful in arsenic, inorganic mercury, and organic mercury poisoning (and lead poisoning). The adverse effects of dimercaprol include tachycardia, hypertension, gastric irritation, and pain at the injection site. Succimer (Chemax) is a derivative of dimercaprol that can be taken orally and is approved for use in children to treat lead poisoning. The adverse effects of succimer are generally minor and include nausea, vomiting, and anorexia. Unithol (Dimaval) is another analogue of dimercaprol over which it has advantages (few adverse effects) for treatment of mercury, arsenic, and lead poisoning. This agent is used primarily to chelate excess copper in individuals with Wilson disease. Penicillamine is also used for copper and mercury poisoning and as an adjunct for the treat- ment of lead and arsenic poisoning. Allergic reactions and rare bone marrow toxicity and renal toxicity are the major adverse effects. Deferoxamine is a specific iron-chelating agent that on parenteral administration binds with ferric ions to form ferrioxamine; it also binds to ferrous ions. Deferoxamine can also Chapter 13 Toxicology 319 remove iron from ferritin and hemosiderin outside bone marrow, but it does not capture iron from hemoglobin, cytochromes, or myoglobin. Deferoxamine is metabolized by plasma enzymes and excreted by the kidney, turning urine red. Deferoxamine may cause allergic reactions and rare neurotoxicity or renal toxicity. Defer- oxamine therapy is contraindicated in patients with renal disease or renal failure. More than a million cases of acute poisoning occur each year in the United States, many in children and adolescents. The symptoms of most drug and chemical poisonings are extensions of their pharmacologic properties. Measures to support vital functions, slow drug absorption, and promote excretion are generally sufficient for treatment. Comatose patients may die as a result of airway obstruction, respiratory arrest, or aspiration of gastric contents into the tracheobronchial tube. Induction of vomiting with ipecac orally is no longer recommended for routine use at home, and is con- traindicated in children under 6 years. Urinary excretion can be enhanced by the admin- istration of agents such as sodium bicarbonate, which raises urinary pH and decreases renal reabsorption of certain organic acids such as aspirin and phenobarbital. Hemodialysis is an efficient way to remove certain low molecular weight, water-soluble tox- ins and restore electrolyte balance. Salicylate, methanol, ethanol, ethylene glycol, paraquat, and lithium poisonings are effectively treated this way; hemoperfusion may enhance the whole-body clearance of some agents (carbamazepine, phenobarbital, phenytoin). Drugs and poisons with large volumes of distribution are not effectively removed by dialysis. Antidotes (see respective agents) are available for some poisons and should be used when a specific toxin is identified. Some examples include naloxone, acetylcysteine, physostigmine, metal chelators (see above), atropine, pralidoxime, and ethanol. What treatment would be appropriate in a 3- What is the most appropriate agent to adminis- year-old boy with a dramatically elevated blood ter at this point? A 56-year-old chronic alcoholic is brought to gency room because he recently ingested the emergency room with altered mental status numerous ‘‘iron pills’’ his mother was taking for and complains of not being able to see. The child now has severe abdomi- reports running out of ‘‘whiskey’’ and ingesting nal pain, bloody diarrhea, nausea, and vomit- wood alcohol (methanol). An 18-year-old man is brought to the (A) Wristdrop emergency room by his friends because he (B) ‘‘Rice-water’’ stools ‘‘passed out. Which of the following toxic agents would (E) Carbon tetrachloride pose a problem with dermal exposure? A 23-year-old known heroin addict is (B) Organophosphate insecticides brought to the emergency room for unrespon- (C) Inorganic lead siveness. On examination he is found to have (D) Cadmium pin-point pupils and respiratory depression. Pyridoxine is used in a toxicology setting to reverse seizures due to isoniazid overdose. Fomepizole is an inhibitor of alcohol dehydrogenase, which might otherwise convert methanol to formic acid, which is the true toxin in such cases causing blindness and renal failure. Ethylene glycol (antifreeze) can cause similar toxicity and is also treated with fomepizole. Flumazenil is a benzodiazepine antagonist used in the management of such overdoses. Ethyl alcohol can be used to treat ingestion of both methanol and ethylene glycol; however, such use often results in ethanol intoxication, and fomepizole is preferred as it does not cause the same effects. Dextrose is an effective treatment for altered mental status due to hypogly- cemia in a diabetic patient. Strychnine is a rat poison that can cause seizures when ingested, which are managed by giving diazepam. Carbon tetrachloride is an industrial solvent that can cause fatty liver and kidney damage. Deferoxamine is an iron chelator that is given systemically to bind iron and pro- mote its excretion. Activated charcoal, good for the absorption of numerous toxic ingestions, is ineffective in this case as it does not bind iron. Phlebotomy is a treatment for iron overload in such conditions as hereditary hemochromatosis. Succimer is an orally available substance related to dimercaprol, used for lead toxicity.

By J. Jorn. Brooklyn College.

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