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Drugs and pharmaceuticals: management of intoxication and antidotes
Smith, Silas W
The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases
PMID: 20358691
ISSN: 1023-294X
CID: 109056
Chiral toxicology: it's the same thing...only different
Smith, Silas W
Chiral substances possess a unique architecture such that, despite sharing identical molecular formulas, atom-to-atom linkages, and bonding distances, they cannot be superimposed. Thus, in the environment of living systems, where specific structure-activity relationships may be required for effect (e.g., enzymes, receptors, transporters, and DNA), the physiochemical and biochemical properties of racemic mixtures and individual stereoisomers can differ significantly. In drug development, enantiomeric selection to maximize clinical effects or mitigate drug toxicity has yielded both success and failure. Further complicating genetic polymorphisms in drug disposition, stereoselective metabolism of chiral compounds can additionally influence pharmacokinetics, pharmacodynamics, and toxicity. Optically pure pharmaceuticals may undergo racemization in vivo, negating single enantiomer benefits or inducing unexpected effects. Appropriate chiral antidotes must be selected for therapeutic benefit and to minimize adverse events. Enantiomers may possess different carcinogenicity and teratogenicity. Environmental toxicology provides several examples in which compound bioaccumulation, persistence, and toxicity show chiral dependence. In forensic toxicology, chiral analysis has been applied to illicit drug preparations and biological specimens, with the potential to assist in determination of cause of death and aid in the correct interpretation of substance abuse and 'doping' screens. Adrenergic agonists and antagonist, nonsteroidal anti-inflammatory agents, SSRIs, opioids, warfarin, valproate, thalidomide, retinoic acid, N-acetylcysteine, carnitine, penicillamine, leucovorin, glucarpidase, pesticides, polychlorinated biphenyls, phenylethylamines, and additional compounds will be discussed to illustrate important concepts in 'chiral toxicology.'
PMID: 19414517
ISSN: 1096-0929
CID: 100186
Inaccuracy of Electrocardiogram Interpretations Reported to the Poison Center [Meeting Abstract]
Prosser, JM; Smith, SW; Olsen, D; Nelson, LS; Hoffman, RS
ISI:000268208400213
ISSN: 1556-3650
CID: 101304
A novel approach to multihazard modeling and simulation
Smith, Silas W; Portelli, Ian; Narzisi, Giuseppe; Nelson, Lewis S; Menges, Fabian; Rekow, E Dianne; Mincer, Joshua S; Mishra, Bhubaneswar; Goldfrank, Lewis R
OBJECTIVE: To develop and apply a novel modeling approach to support medical and public health disaster planning and response using a sarin release scenario in a metropolitan environment. METHODS: An agent-based disaster simulation model was developed incorporating the principles of dose response, surge response, and psychosocial characteristics superimposed on topographically accurate geographic information system architecture. The modeling scenarios involved passive and active releases of sarin in multiple transportation hubs in a metropolitan city. Parameters evaluated included emergency medical services, hospital surge capacity (including implementation of disaster plan), and behavioral and psychosocial characteristics of the victims. RESULTS: In passive sarin release scenarios of 5 to 15 L, mortality increased nonlinearly from 0.13% to 8.69%, reaching 55.4% with active dispersion, reflecting higher initial doses. Cumulative mortality rates from releases in 1 to 3 major transportation hubs similarly increased nonlinearly as a function of dose and systemic stress. The increase in mortality rate was most pronounced in the 80% to 100% emergency department occupancy range, analogous to the previously observed queuing phenomenon. Effective implementation of hospital disaster plans decreased mortality and injury severity. Decreasing ambulance response time and increasing available responding units reduced mortality among potentially salvageable patients. Adverse psychosocial characteristics (excess worry and low compliance) increased demands on health care resources. Transfer to alternative urban sites was possible. CONCLUSIONS: An agent-based modeling approach provides a mechanism to assess complex individual and systemwide effects in rare events.
PMID: 19491602
ISSN: 1935-7893
CID: 156987
Elemental mercury neurotoxicity from self-injection [Case Report]
Schaumburg, H H; Gellido, C; Smith, S W; Nelson, L S; Hoffman, R S
PMID: 19171837
ISSN: 0028-3878
CID: 107797
Multisystem organ failure after large volume injection of castor oil [Case Report]
Smith, Silas W; Graber, Nathan M; Johnson, Rudolph C; Barr, John R; Hoffman, Robert S; Nelson, Lewis S
We report a case of multisystem organ failure after large volume subcutaneous injection of castor oil for cosmetic enhancement. An unlicensed practitioner injected 500 mL of castor oil bilaterally to the hips and buttocks of a 28-year-old male to female transsexual. Immediate local pain and erythema were followed by abdominal and chest pain, emesis, headache, hematuria, jaundice, and tinnitus. She presented to an emergency department 12 hours postinjection. Persistently hemolyzed blood samples complicated preliminary laboratory analysis. She rapidly deteriorated despite treatment and developed fever, tachycardia, hemolysis, thrombocytopenia, hepatitis, respiratory distress, and anuric renal failure. An infectious diseases evaluation was negative. After intensive supportive care, including mechanical ventilation and hemodialysis, she was discharged 11 days later, requiring dialysis for an additional 1.5 months. Castor oil absorption was inferred from recovery of the Ricinus communis biomarker, ricinine, in the patient's urine (41 ng/mL). Clinicians should anticipate multiple complications after unapproved methods of cosmetic enhancement
PMID: 19131711
ISSN: 1536-3708
CID: 96657
Solanaceous steroidal glycoalkaloids and poisoning by Solanum torvum, the normally edible susumber berry
Smith, Silas W; Giesbrecht, Esther; Thompson, Margaret; Nelson, Lewis S; Hoffman, Robert S
Ingestion of immature, environmentally stressed, or cultivar-specific Solanum species (particularly the potato) has been previously associated with gastrointestinal and neurological symptoms caused by solanaceous steroidal glycoalkaloids (SGAs). We report on two geographically, temporally disparate outbreaks of poisoning by susumber berries (Solanum torvum- Solanaceae) and on detection of alkaloids not present in non-toxic berries. Five family members in New York City participated in a traditional evening meal containing Jamaican susumber berries. All those consuming berries were symptomatic the following morning with varying degrees of gastrointestinal distress, dizziness, slurred speech, cranial nerve deficits, and ataxia. The most seriously afflicted patient developed hypertension, confusion, proximal upper extremity weakness, and hypercapnic respiratory failure requiring prolonged mechanical ventilation. A separate cohort of six patients in Toronto ate unripe Jamaican susumber berries. They presented 14h post-ingestion with varying degrees of diarrhea, weakness, facial paralysis, slurred speech, ataxia, early hypertension, and proximal weakness. Two patients had ventilatory decompensation; one required intubation. Poisonous berries appeared indistinguishable from non-toxic varieties. We isolated solasonine, larger amounts of solamargine, and other steroidal glycoalkaloids in the toxic berry strains. S. torvum poisoning can produce significant neurological and gastrointestinal effects which appear to be mediated by SGAs present in the berries
PMID: 18725244
ISSN: 0041-0101
CID: 91970
Altered Acetaminophen Pharmacokinetics and Hepatotoxicity Associated with Premature Cessation of Intravenous N-Acetylcysteine Therapy (September) [Case Report]
Smith, Silas W; Howland, Mary Ann; Hoffman, Robert S; Nelson, Lewis S
OBJECTIVE: To report a case of erratic absorption, double peak serum concentrations, and hepatotoxicity following premature cessation of intravenous Nacetylcysteine (NAC) treatment in the setting of a massive acetaminophen overdose. CASE SUMMARY: A 78-year-old man reportedly ingested approximately 96 immediate-release acetaminophen 500-mg tablets (48 g) over a one-hour period in an apparent suicide attempt. The acetaminophen concentration at 2.25 hours was 264 microg/mL. Intravenous NAC was initiated 5 hours postingestion. At 6.25 hours postingestion, the acetaminophen concentration was 281 microg/mL. Following administration of intravenous NAC for 21 hours, therapy was discontinued despite a residual acetaminophen concentration of 116 microg/mL. The patient experienced hepatotoxicity, coagulopathy, and renal injury. Pharmacokinetic analysis revealed significantly prolonged acetaminophen absorption and a second peak acetaminophen concentration of 228 microg/mL approximately 48 hours postingestion. Direct in-hospital monitoring of the patient made a second ingestion unlikely. DISCUSSION: Acetaminophen overdose is usually effectively managed with NAC. Patients with massive ingestions may have altered absorption kinetics due to acetaminophen's solubility being exceeded, physiologically or chemically altered gastrointestinal emptying or motility, or other factors. These patients may benefit from gastrointestinal decontamination and prolonged NAC therapy. CONCLUSIONS: In patients with massive acetaminophen ingestion, erratic absorption may occur, and toxic serum concentrations may persist beyond a standard 21-hour course of intravenous NAC therapy. Acetaminophen concentrations and aminotransferase levels should be evaluated at the completion of therapy intravenous NAC infusion to ensure complete elimination of acetaminophen and absence of hepatotoxicity and to exclude the need for prolonged treatment
PMID: 18628444
ISSN: 1542-6270
CID: 80581
Bedside Detection of Urine beta-Hydroxybutyrate in Diagnosing Metabolic Acidosis
Smith, Silas W; Manini, Alex F; Szekely, Tibor; Hoffman, Robert S
Objectives: While critically important, the rapid identification of the etiology of metabolic acidosis (MA) may be labor-intensive and time-consuming. Alcoholic, starvation, and severe diabetic ketoacidosis (AKA, SKA, and DKA, respectively) may produce beta-hydroxybutyrate (BOHB) in marked excess of acetone (ACET) and acetoacetate (AcAc). Unfortunately, current urine dipstick technology poorly detects ACET and cannot measure BOHB. The inability to detect BOHB might delay therapy for ketoacidoses or provoke unnecessary evaluation or empiric treatment of other causes of MA, such as toxic alcohol poisoning. The authors tested the previous assertion that commonly available hydrogen peroxide (H(2)O(2)) would improve BOHB detection. The effectiveness of alkalinization and use of a silver nitrate (AgNO(3)) catalyst was also assessed. Methods: Control and urine test specimens containing from 0.5 to 800 mmol/L ACET, AcAc, and BOHB were prepared. Urine specimens were oxidized with H(2)O(2) (3%) 1:9 (H(2)O(2):urine), alkalinized with potassium hydroxide (KOH; 10%), exposed to AgNO(3) sticks, or altered with a combination of these methods in a random fashion. Three emergency physicians (EPs) blinded to the preparation technique evaluated urine dipsticks (Multistix, Bayer Corp.) placed in the specimens for 'ketones.' Results: Multistix detected AcAc appropriately; ACET was detected only at high concentrations of >/=600 mmol/L. Multistix failed to measure BOHB at all concentrations tested. H(2)O(2) improved urinary BOHB detection, although not to clinically relevant levels (40 mmol/L). Alkalinization and AgNO(3) sticks did not improve BOHB detection beyond this threshold. Conclusions: Addition of H(2)O(2) (3%), alkalinization, or AgNO(3) sticks did not improve clinically meaningful urine BOHB detection. Clinicians should use direct methods to detect BOHB when suspected
PMID: 18637083
ISSN: 1553-2712
CID: 80582
Prolonged severe hypotension following combined amlodipine and valsartan ingestion [Case Report]
Smith, Silas W; Ferguson, Kathy L; Hoffman, Robert S; Nelson, Lewis S; Greller, Howard A
INTRODUCTION: Compared to other calcium channel blockers (CCBs), overdose with dihydropyridine CCBs are considered relatively benign due to their vascular selectivity. Although not a sustained-release preparation, amlodipine's prolonged duration of effect is concerning following overdose. In addition, angiotensin II receptor blocker blunting of vasoconstrictive and sympathetic compensatory responses could exacerbate calcium channel blocker toxicity. We describe severe toxicity associated with an overdose of amlodipine and valsartan. CASE REPORT: A 75-year-old woman presented to the ED 45 minutes after a witnessed suicidal ingestion of a 'handful' of amlodipine and valsartan tablets. Hypotension, which appeared two hours after ingestion, was refractory to crystalloids and colloids, calcium gluconate, epinephrine, norepinephrine, phenylephrine, and vasopressin infusions. High-dose insulin euglycemia (HIE) therapy, and treatment with glucagon and naloxone were successful in improving her hemodynamic status. In this combined overdose, right heart catheterization demonstrated both negative inotropic effects and decreased systemic vascular resistance. CONCLUSION: Co-ingestion of amlodipine with valsartan produced profound toxicity. Early institution of HIE therapy may be beneficial to reverse these effects
PMID: 18568804
ISSN: 1556-9519
CID: 80579