By E. Phil. Corcoran College of Art + Design.
Chronic poisoning (1) Mercury vapor poisoning may lead to a fine tremor of the limbs that may progress to choreiform movements buy generic kamagra polo 100 mg erectile dysfunction causes smoking, and neuropsychiatric symptoms that may include insomnia buy kamagra polo 100mg overnight delivery erectile dysfunction drugs philippines, 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.
Salicylates are hydrolyzed rapidly by plasma and tissue esterases to acetic acid and the active metabolite salicylic acid discount kamagra polo 100 mg on line erectile dysfunction treatment karachi. Salicylic acid is more slowly oxidized to gentisic acid and conjugated with glycine to salicyluric acid and to ether and ester glucuronides cheap kamagra polo 100 mg on-line erectile dysfunction pumps review. Long-term administra- tion of high doses (to treat arthritis) or toxic overdose increases the t1/2 to 15–30 hours because the enzymes for glycine and glucuronide conjugation become saturated. If the urine pH increases to above 8, clearance is increased approximately fourfold as a result of decreased reabsorption of the ionized salicylate from the tubules. Salicylates are used to treat rheumatoid arthritis, juvenile arthritis, and osteoarthritis, as well as other inflammatory disorders. Salicylic acid is used topically to treat plantar warts, fungal infections, and corns; use is based on the destruction of keratinocytes and dermal epithelia by the free acid. Hypersensitivity (intolerance) (1) Hypersensitivity is relatively uncommon with the use of aspirin (0. The incidence of intolerance is highest 162 Pharmacology in patients with asthma, nasal polyps, recurrent rhinitis, or urticaria. Acetaminophen is recommended as a substitute for children with fever of unknown etiology. Miscellaneous adverse effects and contraindications (1) Salicylates occasionally decrease the glomerular filtration rate, particularly in patients with renal insufficiency. The use of salicylates is contraindicated in patients with bleeding disorders, such as hypothrombinemia, hemophilia, hepatic disease, and vitamin K deficiency, and use should be avoided in patients receiving anticoagulants such as coumarin and heparin. The action of anticoagulants may be enhanced by their displacement by aspirin from bind- ing sites on serum albumin. Aspirin also displaces tolbutamide, phenytoin, and other drugs from their plasma protein-binding sites. The hypoglycemic action of sulfonylureas may be enhanced by displacement from their binding sites on serum albumin or by inhibition of their renal tubular secretion by aspirin. Usual analgesic doses of aspirin (<2 g/day) decrease renal excretion of sodium urate and antagonize the uricosuric effect of sulfinpyrazone and probenecid; aspirin is contraindi- cated in patients with gout who are taking uricosuric agents. Aspirin competes for tubular secretion with penicillin G and prolongs its half-life. In adults, salicylism (tinnitus, hearing loss, vertigo) occurs as initial sign of toxicity after as- pirin or salicylate overdose or poisoning. In children, the common signs of toxicity include hyperventilation and acidosis, with accompanying lethargy and hyperpnea. Disturbance of acid–base balance results in metabolic acidosis in infants and young chil- dren and in compensated respiratory alkalosis in older children and adults. Salicylate tox- icity initially increases the medullary response to carbon dioxide, with resulting hyperventilation and respiratory alkalosis. In infants and young children, increases in lactic acid and ketone body production result in metabolic acidosis. With increased severity of toxicity, respiratory depression occurs, with accompanying respiratory acidosis. The uncoupling of oxidative phosphorylation by aspirin results in hyperthermia and hypo- glycemia, particularly in infants and young children. Treatment includes correction of acid–base disturbances, replacement of electrolytes and fluids, cooling, alkalinization of urine with bicarbonate to reduce salicylate reabsorption, forced diuresis, and gastric lavage or emesis. Overview Chapter 6 Autocoids, Ergots, Anti-inflammatory Agents, and Immunosuppressive Agents 163 a. Like aspirin, these agents are used for the treatment of inflammation associated with rheu- matic and nonrheumatic diseases. They cause drug interactions due to the displace- ment of other agents, particularly anticoagulants, from serum albumin; these interactions are similar to those seen with aspirin. The required frequency of administration may influence drug choice because of possible problems with compliance. Other adverse effects, such as hypersensitivity, are generally the same as for aspirin; the cautions and contraindications are also similar to those for aspirin. Ibuprofen, naproxen (Naprosyn, Aleve), fenoprofen (Nalfon), and ketoprofen (Orudis) a. Long-term use of ibuprofen is associated with an increased incidence of hypertension in women. Sulindac is a prodrug that is oxi- dized to a sulfone and then to the active sulfide, which has a relatively long t1/2 (16 h) because of enterohepatic cycling.
Examples of suitably worded forms are available from the Medical Defence Societies 100 mg kamagra polo with amex erectile dysfunction causes lower back pain. Key Points • A conference that involves both the parent and child helps to gain informed consent: -discuss the dental problems; -discuss the treatment options/alternatives; -agree the treatment plan purchase 100 mg kamagra polo erectile dysfunction surgery options. Often, the teeth are also abscessed so that it is necessary to combine antibiotic therapy with analgesia to obtain optimum pain relief. Additionally, analgesia is required postoperatively usually after dento-alveolar surgery. Small children, and some recalcitrant adolescents, refuse to take tablets so liquid preparations are needed. If other methods of administration, such as intramuscular or intravenous, are required then these injections should be administered by clinical staff experienced with these special techniques. Rectal administration is increasingly common as absorption from the rectal mucosa is rapid. If such a route of administration is to be used, specific consent must be obtained. It should be remembered that the dose for children of different ages needs to be carefully estimated to avoid the risk of an overdose (dangerous) or of an underdose (ineffective). The parents must be advised that all drugs must be stored in a safe place, in a child-proof container. Bathroom cabinets or kitchen cabinets are the safest places as they are out of reach and out of sight of small children. The dosages for children can be calculated on the basis of a percentage chart (Table 4. The potential side-effects and the dosages should be checked with the formulary before prescribing. The increase in asthma among children requires that this be considered before ibuprofen is prescribed. Narcotic analgesics such as codeine or morphine can be used on children but only after less powerful analgesics have been shown to be ineffective. There is a strong relationship between the perception of pain experienced and the degree of anxiety perceived by the patient. Good behaviour management reduces anxiety, which in turn reduces the perceived intensity of pain, which further reduces the experience of anxiety. Behaviour management have been covered in detail in Chapter 2 and local anaesthetic techniques in Chapter 5. The majority of dental procedures on children can be carried out using a combination of these two techniques. This chapter will deal with the methods of sedation and general anaesthesia that are applicable to dental treatment in children. Detailed descriptions of management of a variety of medical problems appear in a comprehensive book by Scully and Cawson (1998). The decision as to whether a patient should be treated under general anaesthesia or local anaesthesia, or local anaesthesia with sedation depends on a combination of factors, the most important of which are: (1) the age of the child; (2) the degree of surgical trauma involved; (3) the perceived anxiety and how the patient may (or has) responded to similar levels of surgical trauma; (4) the complexity of the operative procedure; (5) the medical status of the child. There are no hard and fast rules, and every procedure in every child must be assessed individually and the different elements considered in collaboration with the parent and, where appropriate, with the child. For example, the younger the child the greater the likelihood of a need for general anaesthesia. At the other end of the age range it is unlikely that a 15-year old will need general anaesthesia for simple orthodontic extractions, although this might be required for moderately complex surgery, such as exposing and bonding an impacted canine. The degree of trauma involved is also another factor; a single extraction is most likely to be carried out under local anaesthesia, removal of the four first permanent molars is most likely to be carried out under general anaesthesia. Anxiety perceived as excessive, especially after an attempt at treatment under local anaesthesia and sedation, would lead to simple treatment such as conservative dentistry being carried out under a general anaesthetic usually involving endotracheal intubation. Serious medical problems, for example, cystic fibrosis with the associated respiratory problems would justify using sedation instead of general anaesthesia even for more traumatic surgery, such as removal of impacted canines, but it would be appropriate to carry out this sedation in a hospital environment. The degree of intellectual and/or physical impairment in handicapped children would also be a factor to be considered. General anaesthesia carries with it a finite risk of serious morbidity such as psychological trauma and even death (3 to 4 per million). No child should be submitted to a general anaesthetic without consideration of this potentially devastating outcome.
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