Peritoneal Absorption of Vancomycin during and after Resolution of Peritonitis in Continuous Ambulatory Peritoneal Dialysis (CAPO) Patients

We studied the absorption of i.p. loading dose of vancomycin (30 mg/kg of body weight) in five continuous ambulatory peritoneal dialysis (CAPD) patients, both at the time of peritonitis and after its resolution. Mean vancomycin absorption after 6 h of i.p. dwell was 74% from inflamed and 51% from noninflamed peritoneum. Mean peritoneal absorption half-life of vancomycin was 3.2 and 7.2 h in the inflamed vs. non inflamed peritoneum, respectively.

Comparison of US population and live birth rates with poison exposures reported to the National Poison Data System (NPDS): children ages 0-5 years from 2000 to 2012

BACKGROUND

Monitoring of poison control center data has provided an important public health surveillance tool. Previous work has identified the population with the greatest risk of poisoning as children of < 6 years. It follows that the size of the population at highest risk should be an important driver/factor of poison center volume. Therefore, one would expect population changes to be reflected in corresponding National Poison Data system (NPDS) call volume changes. We examined this relationship.

METHOD

This was a retrospective comparison of young children's poison exposures reported to NPDS with changes in US population as reported by the US Census Bureau and by live birth counts in the United States. We examined the relation of population and live birth counts to NPDS exposures in children of 0-5 years and for the total (children of 0-5 years).

RESULTS

There was a statistically significant relation between exposures and population for the three of the seven age groups (1-3 years old) and between exposures and live birth counts for the five of the seven age groups (1-4 years old and total (0-5)). The highest correlation was seen with the age groups of 2-year olds (r = 0.815; slope, 4.7373; 95% CI, 2.36-7.11) and 1-year olds (r = 0.785; slope, 4.878; 95% CI, 2.163-7.592). Live birth count was more closely related than population for all but the 1-year-old age groups.

DISCUSSION

Our study reports a number of interesting findings including 1) live birth counts and population are closely associated with each other, 2) poison exposures in NPDS were more strongly associated with live birth counts than with population, 3) the population at greatest risk is the 1- and 2-year-old age groups and the strongest associations between exposures and population and exposures and live birth counts occurred in these two age groups, and 4) changes occurring in the live birth counts, both positive and negative, were reflected in annual changes reported in NPDS human exposures in children < 6 years. These results mean that population changes underlie 37%-66% of the changes in poison exposures and suggests that the population at risk should be considered in monitoring poisoning injuries in the future.

CONCLUSION

These results provide a quantitative assessment of the age-based risk rates and changes over time for NPDS exposure in children who are 0-5 years old. With the decrease in live births noted over the last 4 years (2008, 2009, 2010, and estimated 2011), US poison centers may expect a similar decline in human exposures in children of 0-5 years. Our analysis adds additional support to the validity of this data set as a public health surveillance tool.

The pharmacokinetics and bioavailability of prochlorperazine delivered as a thermally generated aerosol in a single breath to volunteers

A thermally generated aerosol (TGA) system can effect reliable delivery of excipient-free drug to alveoli, resulting in rapid systemic drug absorption. We developed a pharmacokinetic model of prochlorperazine, administered by inhalation and as a rapid intravenous infusion, and we determined absolute TGA bioavailability in eight healthy volunteers in this institutional review board-approved, two-period crossover study. After the drug was administered as either a 5-s intravenous infusion or a TGA single-breath inhalation, blood was collected at various times for up to 24 h. Plasma prochlorperazine concentrations were measured using liquid chromatography-tandem mass spectrometry. Inhalation and rapid intravenous administration produced similar plasma prochlorperazine concentration profiles. Intravenous and inhalation pharmacokinetics were well characterized by a simultaneous two-compartment model with multiple absorption delays. Prochlorperazine pharmacokinetic parameters were similar to those reported for single intravenous doses. The geometric mean bioavailability after TGA delivery was 1.10. The administration of prochlorperazine by inhalation resulted in pharmacokinetics similar to that seen after intravenous administration, in terms of speed, extent, and consistency of absorption.

Multiple chemical sensitivities--syndrome and solution

After describing two patients seen by the author, we define multiple chemical sensitivities and discuss the scope of the problem and the epidemiology. Although the incidence of multiple chemical sensitivities is not known, the demographics are similar to that of agoraphobia. The classical conditioning model is proposed as a useful description of multiple chemical sensitivities. The desensitization approach to the diagnosis and treatment is proposed. Results with three patients were encouraging and the approach seems worthy of further evaluation and refinement.

Behavioral treatment of phobic avoidance in multiple chemical sensitivity

The clinical ecology model of environmental illness, or multiple chemical sensitivity (MCS), and particularly the theoretical assumptions, diagnostic procedures, and therapeutic recommendations promulgated by clinical ecologists are reviewed. No scientific evidence is found for their claims. MCS is conceptualized, instead, as a phobic disorder explicable in terms of the two-factor model of avoidance. Three cases of MCS are discussed in light of this model, and a comprehensive behavioral treatment package that includes biofeedback-assisted in vivo desensitization and cognitive restructuring is proposed.

Screening for disulfiram-induced liver test dysfunction in an inpatient alcoholism program

The objective of this study was to report the frequency of disulfiram-related elevations of four commonly used hepatic screening chemistries using a retrospective record review design. An inpatient alcoholism program was selected for the setting. Patients who had initial laboratory values within the normal range started daily supervised doses of disulfiram, then underwent follow-up testing after 2 and 4 weeks on the drug. The study population consisted of 108 patients receiving disulfiram and 27 patients who did not receive disulfiram (controls). The four screening serum chemistries performed were aspartate aminotransferase (SGOT), alanine aminotransferase (SGPT), alkaline phosphatase, and gamma-glutamyl transferase. Twenty-seven (25%) of the 108 patients who were taking 250 mg of disulfiram a day for 2 to 4 weeks had disulfiram-related elevations in alanine aminotransferase above the upper limit of normal, as opposed to one elevation in 27 patients (4%) for whom disulfiram was not prescribed. In the 108 patients (with initially normal serum chemistries) who were prescribed disulfiram, 32 were discontinued from the drug at 2 weeks and an additional 11 were discontinued from the drug at 4 weeks because of one or more abnormal serum chemistries. Alanine aminotransferase was the most specific and sensitive indicator of the four screening chemistries performed.

Massive strychnine intoxication: serial blood levels in a fatal case

A fatal case of strychnine intoxication is reported. The patient expired despite early aggressive management and prevention of metabolic complications. Serial blood levels are reported. In contrast to a previous report describing first order elimination kinetics, our data suggest that strychnine follows Michaelis-Menton elimination kinetics. The case illustrates the rapid, dramatic course of severe strychnine ingestions. A review of the toxicokinetics, mechanism of action and treatment of strychnine intoxication follows.

Massive overdoses with sustained-release lithium carbonate preparations: pharmacokinetic model based on two case studies

Clinically significant delayed absorption after lithium overdose has been reported previously without adequate explanation. We have studied two patients after they took massive intentional lithium overdoses. The first patient presented shortly after ingesting 74 g of lithium carbonate. Pharmacokinetic analysis with a multicompartmental model of 29 serum lithium concentrations during 300 h (including hemodialysis) established absorption and elimination kinetics. Lithium absorption was both slow (peak concentration 33 h after the initial overdose) and delayed (a second peak occurred at 148 h, 30 h after initiation of oral tube feedings). The delayed absorption of a large fraction of lithium implicated a gastrointestinal drug reservoir. Study of the pharmacokinetics in a second patient, who ingested 98 g of lithium carbonate, provided additional evidence of an endogenous reservoir. This patient's medical management was guided by experience gained from the initial case. Appropriate management for a predicted endogenous drug reservoir may have shortened intensive care and hospitalization. In treating overdoses of sustained-release drug preparations, clinically significant delayed absorption triggered by enteral fluids must be considered as a contributor to delayed absorption.

Enhanced clearance of vancomycin by hemodialysis in a child

Clearance of vancomycin by hemodialysis has previously been reported to be negligible. We describe a child undergoing chronic hemodialysis using a hollow fiber dialyzer with cellulose acetate membrane. When the patient was treated with intravenous vancomycin for staphylococcal bacteremia, the serum vancomycin half-life was found to decrease by more than 90% during each course of hemodialysis. We conclude that, contrary to prevailing opinion, vancomycin can be rapidly cleared by hemodialysis in the small pediatric patient, and that the dosage should be adjusted accordingly.

Fatal transcutaneous iron intoxication

Accidental iron intoxication is one of the most serious and potentially fatal intoxications in young children. Occurrence in the adult population is rare and is usually associated with a suicide or homicide attempt. Heretofore, all reported cases have involved oral ingestion of ferrous and ferric salts of iron. In a case of fatal iron intoxication reported by Doolin and Drueck, in addition to swallowing a liquid form of ferrous chloride, the patient aspirated it and absorbed it through chemically burned and denuded areas of skin when he fell into a vat of saturated ferrous chloride at work. It is the purpose of this report to describe the first case of fatal iron intoxication in which the sole route of iron absorption was the burned skin. Clinical course of this patient paralleled that of acute oral iron intoxication with development of refractory acidosis, disseminated intravascular coagulation, respiratory and renal failure, and sepsis.

Toxicodynamic approach to management of the poisoned patient

We recommend a toxicodynamic approach to the management of the poisoned patient. We define the period between ingestion and onset of toxic manifestations (clinical or laboratory) as the preclinical phase, during which the management of the patient necessarily depends solely on the history of ingestion and the predicted toxicity. In the toxic phase during which the patient shows clinical or laboratory evidence of toxicity, the history, clinical status (signs, symptoms, drug levels, laboratory parameters), and toxicodynamics should guide the therapy. In the resolution phase, when the patient shows clinical improvement and declining drug levels, treatment should be based on clinical status. Gastrointestinal decontamination is critical in the first two phases and may be of value during the resolution phase until the body drug burden declines to safe levels. We recommend an aggressive approach to gastrointestinal decontamination, especially in the preclinical phase. With a history of a potentially toxic ingestion of an absorbable drug, an observation period until passage of a charcoal-laden stool should be achieved before discharge of the patient.

Comparison of equal-weight oral dosages of verapamil hydrochloride and diltiazem hydrochloride in patients with mild to moderate hypertension

The clinical efficacy, safety, and tolerability of oral verapamil and diltiazem, at total daily dosages of equal weight, were evaluated in a placebo-controlled, double-blind crossover study. Thirty-six ambulatory patients with chronic, stable, mild to moderate hypertension (supine diastolic blood pressure of 94-116 mm Hg) received a dosage of either verapamil or diltiazem 80 mg t.i.d. as the hydrochloride salt for one week after an antihypertensive-drug washout period. Each then received 120 mg of the same drug t.i.d. for one week. After another two-week washout period, the patients were crossed over to the other drug. Each patient had a 12-lead electrocardiogram and measurement of supine and standing blood pressure weekly. In the 32 patients completing the study, low-dose verapamil reduced supine diastolic blood pressure (DBP) from a mean of 101.5 +/- 5.2 to 95.3 +/- 9.5 mm Hg; high dose verapamil reduced DBP to 90.9 +/- 7.4 mm Hg. Standing DBP was reduced to a similar degree. Diltiazem showed an almost identical effect: Supine DBP was reduced from a mean of 101.7 +/- 5.3 to 94.0 +/- 10.1 mm Hg with the low dose and to 91.0 +/- 8.6 mm Hg with the high dose, with similar effects on standing DBP. The high dose of both drugs significantly increased the QTc interval, and both doses of diltiazem significantly increased the PR interval compared with baseline. Both drugs exhibited consistent efficacy with minimal adverse effects. The electrophysiologic safety profile of verapamil was superior to that of diltiazem.

Capsicum and capsaicin--a review: case report of the use of hot peppers in child abuse

Capsaicin, the active principle of hot peppers of the genus Capsicum, exhibits broad bioactivity. It targets neuronal structures which contain substance P, clinically seen as gastrointestinal and dermatologic irritation, bronchospasm and fibrinolysis. As a research tool, capsaicin profoundly alters neurologic anatomy and function. We review the toxicity of capsaicin and comment briefly on the use of hot peppers in child abuse.

Acute overdose with sustained release drug formulations. Perspectives in treatment

Acute overdose with sustained release formulations presents special problems for the health care system. Proper management requires a basic understanding of the pharmacokinetic and pharmacodynamic characteristics of the drugs taken in overdose because different techniques employed by the manufacturers to produce sustained release formulations lead to differences in these characteristics in comparison with conventional formulations. In general, with sustained-release formulations, there is a prolongation of the time for the patient to manifest toxicity ('preclinical phase'), as well as the period of high drug concentrations and clinical toxicity ('toxic phase') and the resolution phase (clinical improvement with declining drug concentrations). Continued drug absorption over a prolonged period alters the normal drug concentration-time profile. The prolonged absorption half-life may appear as an increase in elimination half-life, even though the clearance of the drug stays the same. Gastrointestinal decontamination is extremely important in the management of overdose with sustained release formulations. We advocate an aggressive decontamination approach to management, especially in the preclinical phase. With a history of potentially toxic ingestion of an adsorbable drug, a charcoal stool following administration of oral activated charcoal should be a minimum requirement for discharge of the patient. Gastrointestinal decontamination is critical in the preclinical and the toxic phases and may be of value during the resolution phase until the drug concentrations decline to the therapeutic range.

Modulation of ethanol-induced central nervous system depression by ibuprofen

We investigated the effect of pretreatment with a prostaglandin synthetase inhibitor, ibuprofen, on the pharmacokinetics and pharmacodynamics of ethanol in six fasting subjects. Ibuprofen caused a 10% decrease in the maximum rate of elimination of ethanol. Visual memory, which is a function primarily mediated by the right cerebral hemisphere, was measured by the Benton Visual Retention test and was more impaired during combined ibuprofen and ethanol dosing than during ethanol dosing alone (P = 0.05). The auditory-verbal memory of the subjects, which is primarily a function of the left cerebral hemisphere, was assessed by the Selective Reminding Test and showed decreased impairment during combined ibuprofen and ethanol dosing as compared with ethanol dosing alone (P = 0.04). The opposite effect of ibuprofen on ethanol-induced cognitive impairment as measured by two lateralized functions is consistent with the reports in tissue and animal models that central nervous system effects of ethanol may be mediated at least in part by prostaglandins.

Neurobehavioral sequelae of subcutaneous injection with metallic mercury

A 19 year old, white male, with nine years of education, attempted suicide by injection of metallic mercury (Hg) into the left forearm. CT scan findings suggesting mercury infiltration of the brain and results from urinalysis indicated clinically high levels of Hg excretion. Premorbid cognitive history was essentially normal, yet comprehensive neuropsychological assessment revealed significant impairment of higher cortical functioning beyond those expected of a moderately to severely disturbed psychiatric patient. Neuropsychological test results appear to offer a more sensitive, quantitative assessment of heavy metal toxicity.

Serum osmolal gap and ethanol concentration: a simple and accurate formula

The estimation of serum ethanol concentration by measurement of serum osmolality has been re-evaluated. A formula for calculation of serum osmolality was first validated in 193 patients who had not ingested ethanol. The mean difference between measured and calculated osmolality ("osmolal gap") was 1.5 mOsm/Kg +/- 5.3 mOsm/Kg (1 S.D.). In 37 sera from 35 patients who had ingested ethanol, the osmolal gap was highly correlated with measured serum ethanol (r = 0.994). The serum ethanol (mmol/L) was related to osmolal gap (mOsm/Kg) by the formula: Ethanol = 0.83 X osmolal gap. The factor 0.83 indicated that the behavior of ethanol in serum did not conform to that expected from ideal solutions. This equation accurately predicted serum ethanol in 32 additional samples (r = 0.988). We propose that the formula above be used in place of those that have been previously proposed. The previous formulas involved unwarranted assumptions of ideality and had not been experimentally derived from studies of ethanol in serum.

Acute amoxicillin nephrotoxicity following an overdose

A 3 year old boy developed acute renal failure following an ingestion of 574 mg/kg of amoxicillin. Accidental ingestions of oral penicillins occur commonly, and are usually considered completely nontoxic. Based on this case, however, the possibility of adverse effects following large oral doses of penicillin-type antibiotics, mediated by allergic hypersensitivity or direct toxicity, should be considered.

Carbamazepine toxicity: comparison of measurement of drug levels by HPLC and EMIT and model of carbamazepine kinetics

A 23-month-old boy accidently ingested 2000 mg (148 mg/kg) of carbamazepine. The delayed onset of convulsions coincided with the peak serum level of total parent drug and an active metabolite (carbamazepine 10,11-epoxide). Comparisons of homogeneous enzyme multiplied immunoassay technique (EMIT) and high pressure liquid chromatography (HPLC) revealed that the EMIT slightly over-estimated plasma carbamazepine levels due to immunochemical cross reactivity with the epoxide metabolite. The peak plasma levels of the parent drug plus the active metabolite were more accurately determined by HPLC. These results emphasize the need to understand both the presence of active metabolites and characteristics of the assay being used in managing clinical intoxication with carbamazepine.

Dosage recommendations for activated charcoal-sorbitol treatment

Activated charcoal-sorbitol mixture is used for the treatment of acute poisoning. Based on our experience with healthy adults, overdosed patients and published reports, we have devised a protocol for use of this mixture in different concentrations of sorbitol. The dose is based on the size of the patient, type of poison, and the clinical status. In seriously ill adult patients, we recommend the use of 1 g/kg of activated charcoal in 4.3 ml/kg body weight of 70% sorbitol every 4 hours until the first stool containing charcoal appears. In children and ambulatory adults, the same dose of activated charcoal may be administered in 4.3 ml/kg body weight of 35% sorbitol. Patients requiring multiple doses may be administered activated charcoal as aqueous and sorbitol suspensions alternately every 2-6 hours after the first charcoal stool has appeared. The patients on multiple dose regimen, especially children, should be closely monitored for any fluid or electrolyte imbalance or depletion of essential vitamins.

Activated charcoal in oral ethanol absorption: lack of effect in humans

Activated charcoal has been recommended for use in poisonings by ethanol, other toxic alcohols and glycols, but it has been avoided with therapeutic use of oral ethanol. Six healthy young adults drank a dose of ethanol designed to give a peak concentration of 125 mg/dl on two different days after overnight fasting. Each individual drank the same dose on both occasions; but on one of these days, the subjects drank an aqueous slurry of 60 g of superactive charcoal prior to ethanol ingestion. We compared the pharmacokinetic profile of ethanol with and without activated charcoal treatment. The fraction of ethanol absorbed was similar on both protocols. The mean peak ethanol concentration after pretreatment with activated charcoal was 8% greater than ethanol alone (p = 0.08). Thus oral activated charcoal does not significantly impair ethanol absorption and can be used in patients requiring oral ethanol. Our results do not support the use of activated charcoal in overdose of ethanol alone. Extending our results to poisonings by other toxic alcohols and glycols, the use of activated charcoal to reduce their absorption deserves evaluation.

Impairment of cognitive and psychomotor function by ethanol in social drinkers

Ethanol is known to impair cognitive and psychomotor function in high doses. We studied the impairment of cognitive, psychomotor and behavioral responses in controlled environment in a group of healthy young social drinkers at below and above legal limit for presumption of intoxication (100 mg/dl). Attention, concentration, auditory-verbal memory and memory for visuospatial information were significantly impaired at both levels. Motor speed was impaired only at higher levels though fine coordination was impaired at both doses. Females showed more impairment on visual as well as auditory-verbal memory functions. With low doses, choice reaction time improved with the nonpreferred hand.

Comparative single-dose pharmacokinetics of amantadine hydrochloride and rimantadine hydrochloride in young and elderly adults

The single-dose pharmacokinetics of amantadine hydrochloride and rimantadine hydrochloride were compared in a randomized, two-period, crossover study involving six young (less than or equal to 35 years) and six elderly (less than or equal to 60 years) adults. Subjects ingested single 200-mg oral doses after an overnight fast, and serial plasma (0 to 96 h), nasal mucus (0 to 8 h), and urine (0 to 24 h) samples were collected for assay of drug concentration by electron capture gas chromatography. For both groups combined, rimantadine differed significantly from amantadine in peak plasma concentration (mean +/- standard deviation, 0.25 +/- 0.06 versus 0.65 +/- 0.22 micrograms/ml), plasma elimination half-life (36.5 +/- 15 versus 16.7 +/- 7.7 h), and percentage of administered dose excreted unchanged in urine (0.6 +/- 0.8 versus 45.7 +/- 15.7%). No significant age-related differences were noted for rimantadine. Urinary excretion (0 to 24 h) of rimantadine and its hydroxylated metabolites averaged 19% of the administered dose. The maximum nasal mucus drug concentration was similar for both drugs (0.42 +/- 0.25 versus 0.45 +/- 0.32 micrograms/g), and the ratio of maximum nasal mucus to plasma concentration was over twofold higher after rimantadine than after amantadine. These findings may in part explain the clinical effectiveness of rimantadine in influenza A virus infections at dosages that have lower toxicity than those of amantadine.

Poisonings

While the three demonstration programs failed to document a major impact on prevention of poisoning, they do provide a rationale for selected strategies that may have wide application. Future efforts and successes in poison prevention will involve both the primary care physician and the poison center, using primary and passive interventions. The primary physician can be a source of information and counseling, while the poison center, having succeeded in secondary prevention, can expand its role into primary prevention.

Submersion injury. Epidemiology, prevention, and management

The epidemiology of injuries resulting from submersion in water and their prevention are reviewed and the management of submersion injury is detailed.

Sulindac hepatotoxicity: a case report and review

A 44 year old female, previously on propranolol, phenytoin and phenobarbital, developed hepatotoxicity while on sulindac and acetaminophen containing analgesic. A limited review of hepatotoxicity and drug interactions of sulindac is presented. The possible mechanism of hepatotoxicity and its treatment is suggested.

Pharmacokinetics of multiple-dose cefoperazone in hemodialysis patients

We studied the pharmacokinetics of cefoperazone 2 g i.v. every 12 h for 7 days in 12 patients on hemodialysis with normal hepatic function. The half-life of indocyanine green was determined in each patient via ear oximetry. Serum levels of cefoperazone during dialysis were well described by a two-compartment multidose infusion model. From this model we determined the steady state volume of distribution (Vdss), elimination phase half-life during dialysis T1/2D) and off hemodialysis (T1/2), and the corresponding elimination rate constants (KeD and Ke). Multiple correlations between pharmacokinetic parameters, liver function, and physical characteristics of the patients were evaluated. The T1/2 of cefoperazone was 2.9 h off compared to 2.3 h during hemodialysis. The corresponding elimination rate constants were Ke = 0.45/h versus KeD = 0.80/h. Cefoperazone clearances were 78 ml/min off dialysis compared to 140 ml/min during hemodialysis. Vdss was 0.20 liters/kg. The indocyanine green half-life ranged from 1.8 to 4.6 min with a mean of 2.7 min. The ages of the patients correlated with the beta phase half-life (r = 0.68, p = 0.015). We found no significant correlations among the other parameters including hepatic enzymes and indocyanine green half-life. Thus, hemodialysis approximately doubles the elimination rate constant (clearance), but, assuming drug redistribution kinetics remain unchanged, only shortens half-life by about 20%. Scheduling of a 12-hour dosing regimen to coincide with the end of hemodialysis should obviate any need for alteration of dose. Cefoperazone is thus unique among cephalosporins, since the half-life does not change appreciably with end-stage renal disease or dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

The deterrent effect of poison-warning stickers

We examined the effect of poison-warning stickers on toddler behavior before and after an education program. Twenty children aged 12 to 30 months were randomly assigned to an experimental or control group. We observed the children for two five-minute sessions in a room containing ten pairs of containers, half of which were labeled with Mr Yuk stickers. Each child was allowed to play freely on the floor, and we recorded the manipulations of the labeled and unlabeled containers. During session 1, neither group showed a statistical preference for labeled or unlabeled containers. During session 2, control subjects again did not show a preference for labeled or unlabeled containers. We found that children in the experimental group preferred to touch labeled containers after undergoing education. Our findings suggest that toddlers may not be deterred from manipulating containers that are labeled with poison-warning stickers.

A user-oriented information system for emergency medicine

A user-oriented Emergency Medical Services Information System ( EMSIS ) has been developed in our medical center that can readily be established by any interested medical center. This minicomputer based system provides online registration of poison center calls, access to the Poisindex (C) data base, concise patient information sheets, access to EMS treatment protocols, assistance in the differential diagnosis of acute poisoning, dosage recommendations for drugs with a narrow therapeutic margin, and kinetic analysis of drug overdoses. Video terminals access EMSIS in the Emergency Department, pharmacy, outpatient medicine clinic, pediatric clinic, medicine wards, poison control center, and biomedical engineering. A PDP 11/70 with 256 Kb core and 48 ports running under RSTS /E V7 .0 supports an average of 20 simultaneous users.

Generalized convulsions as the presenting sign of amoxapine intoxication

Two infants presented for medical evaluation with sudden onset of seizures or coma, without obvious cause. Suspicious circumstances led to toxicological screening analysis. Amoxapine, a recently released antidepressant, was found in the gastric contents of both children an undetermined time after the putative ingestion, but elevated serum concentrations were noted only in one. The pharmacokinetics are described. There were no obvious cardiotoxic or anticholinergic effects in these infants. Thus, they, like older children and adults, manifest mainly central nervous system toxicity rather than the cardiotoxicity and anticholinergic effects of overdose seen with tricyclic antidepressants.

Effect of activated charcoal in 70% sorbitol in healthy individuals

Activated charcoal in 70% sorbitol enjoys wide use in the management of acute poisonings but the effects of the activated charcoal-sorbitol mixture in healthy individuals have not been characterized. We were concerned about the possibility of sorbitol causing changes in the routinely monitored serum chemistry and hematological parameters, either directly due to the absorbed polyol or due to the diarrhea induced by it, thus complicating the diagnosis and management in an overdose setting. We assessed the action of a single dose of 30g of activated charcoal in 150 ml of 70% sorbitol and its effects on serum osmolality, electrolytes, metabolic profile (SMAC), magnesium, hepatic enzymes, and complete blood count in healthy adult individuals. The only significant change in the laboratory parameters tested was the consistent rise in serum sodium and phosphorus concentrations four hours after drinking the charcoal-sorbitol mixture. However, a similarly consistent rise in the concentrations at the same hours on another day without ingestion of the charcoal-sorbitol mixture suggested the rise was due to circadian rhythm or other factors unrelated to the cathartic. The lack of effect on routinely monitored laboratory parameters, relative palatability and the rapid onset (40-225 minutes), and long duration (7 to 127 hours) of purgation, make charcoal-sorbitol an attractive combination for use as a gastrointestinal decontaminant. Possible effects of multiple dose regimens and the effects in pediatric and geriatric populations need further study.

Yellow rain: chemical warfare in Southeast Asia and Afghanistan

Circumstantial and laboratory evidence has accumulated supporting the use in Southeast Asia and Afghanistan of Russian-made lethal chemical agents. In this paper we will attempt to answer the question, "What is Yellow Rain?", summarize some of the massive data on microtoxins and mycotoxicoses, discuss the toxicology of the trichothecenes, give a brief historical perspective on chemical warfare, and touch on some of the political implications of these developments. The ubiquitous and insidious mycotoxins have been more or less causally linked to several human diseases, from ergotism to Reye's syndrome, as well as enormous livestock morbidity and mortality. We raise the concern that the Yellow Rain "experiments" pose the threat of massive use of chemical/biological warfare. The importance of an informed, vocal medical constituency cannot be overestimated.

Pharmacokinetics of aztreonam in patients with various degrees of renal dysfunction

We have studied the pharmacokinetics of 1-g intravenous doses of aztreonam in four groups of six volunteers each, distinguished by their creatinine clearances (greater than 80, 30 to 80, 10 to 29, and less than 10 ml/min). Subjects received 1 g of aztreonam intravenously without any complications. Aztreonam serum and urine levels were measured by microbiological methods and by high-pressure liquid chromatography, and unbound serum aztreonam was determined by ultrafiltration. Serum levels were well described by a two-compartment infusion model. From this model we determined steady-state volume of distribution, alpha distribution phase half-life, beta elimination phase half-life, and total clearance of aztreonam. The mean of beta elimination phase half-life ranged from 2 h in normal subjects to 6 h in anephric patients. The total clearance of aztreonam correlated closely with corrected creatinine clearance calculated from serum creatinine, age, and sex (r = 0.97, P less than 0.001) and ranged from a mean value of 107 ml/min in normal subjects to 29 ml/min in functionally anephric patients. Some 75% of aztreonam excretion was renal. Urinary recovery of aztreonam ranged from 58% of the administered dose in normal subjects to 1.4% in uremic patients. Free aztreonam in serum correlated inversely with creatinine clearance (P less than 0.001). A nomogram was developed as a guide for adjustment of aztreonam dosage according to renal function.

Differences in side effects of amantadine hydrochloride and rimantadine hydrochloride relate to differences in pharmacokinetics

In a double-blind, placebo-controlled study, the comparative toxicities and blood concentrations of amantadine hydrochloride and rimantadine hydrochloride were determined. Healthy, working adults ingested either 200 (n = 52) or 300 mg (n = 196) per day in divided doses for 4.5 days. Mean plasma drug concentrations at 4 h after the first dose were lower in rimantadine recipients given 100- (140 versus 300 ng/ml for rimantadine and amantadine, respectively; P less than 10(-5)) or 200-mg doses (310 versus 633 ng/ml; P less than 10(-5)). The plasma drug concentrations after the first dose correlated significantly with total symptom sources for both amantadine and rimantadine, but the plasma levels of toxic and nontoxic subjects overlapped extensively. At 300-mg/day dosage amantadine was associated more often with adverse central nervous system symptoms (33% of amantadine versus 9% of rimantadine recipients; P less than 0.001) and sleep disturbance (39 versus 13%; P less than 0.001), but not gastrointestinal symptoms (19.5 versus 16.0%). However, no differences between the drugs were noted in symptom frequency or scores in volunteers with similar plasma concentrations. Amantadine and rimantadine differ in their pharmacokinetics but not in their potential for side effects at comparable plasma concentrations.

Strychnine poisoning. Recovery from profound lactic acidosis, hyperthermia, and rhabdomyolysis

Strychnine poisoning results in a predictable and treatable sequence of events involving blockade of the inhibitory neurotransmitter, extensor muscle spasms, seizures, and respiratory paralysis. These spasms may lead to hyperthermia, profound lactic acidosis, and rhabdomyolysis. Acidosis is primarily attributable to lactate, as indicated by the correlation between arterial pH and log of lactic acid concentration (r = -0.878). Interruption of the strychnine blockade is the primary therapy for strychnine poisoning. Phenobarbital in moderate doses should be the first intervention and anesthetic doses should be used if necessary. Suppression of convulsions will permit successful management of the complications of strychnine poisoning. Our patient survived, even though at one point he had a pH of 6.55, a lactate level of 32 mM/liter, a temperature of 43 degrees C, and rhabdomyolysis with an increased creatine phosphokinase level of 359,000 mU/ml (5,983 mumol/s/liter).

Comparison of alphabetic and phonetic retrieval of online drug information

Alphabetic, phonetic, and combined alphabetic and phonetic methods of retrieving online drug information were compared. Twenty-four volunteers participated in the study representing four user groups: physicians, nurses, pharmacists, and nonhealth-care hospital staff. Each subject performed 150 searches, 50 by each retrieval method. Using the alphabetic method, drug information was retrievable only if the drug name was spelled correctly. Using the phonetic method, searches were conducted based on the phonetic spelling of requests (e.g., "symetadine" for cimetidine). The combined method used a phonetic search only after an initial alphabetic search was unsuccessful. The elapsed time between the first entry and an indication that the information had been found or could not be found was determined, and the number of drug names not found and the number of excess tries were counted. There were no significant differences in elapsed time among the three methods. Pharmacists had the shortest mean elapsed time and physicians the longest. The average number of excess tries using the phonetic system was a third of the number required using the alphabetic method. The number of drugs not found showed only slight differences among the three methods. The subjects found the desired information on the first try 67% of the time with the alphabetic method, 66% with the combined method, and 90% with the phonetic method. The phonetic method had an average of 75 matches versus 20 for the alphabetic and combined methods. These results support use of a combined alphabetic and phonetic system for retrieving drug information.

Reduction in caffeine toxicity by acetaminophen

A patient who allegedly consumed 100 tablets of an over-the-counter analgesic containing sodium acetylsalicylate, caffeine, and acetaminophen displayed no significant CNS stimulation despite the presence of 175 micrograms of caffeine per mL of serum. Because salicylates have been reported to augment the stimulatory effects of caffeine on the CNS, attention was focused on the possibility that the presence of acetaminophen (52 micrograms/mL) reduced the CNS toxicity of caffeine. Studies in DBA/2J mice showed that: 1) pretreatment with acetaminophen (100 mg/kg) increased the interval between the administration of caffeine (300 to 450 mg/kg IP) and the onset of fatal convulsions by a factor of about two; and 2) pretreatment with acetaminophen (75 mg/kg) reduced the incidence of audiogenic seizures produced in the presence of caffeine (12.5 to 75 mg/kg IP). The frequency of sound-induced seizures after 12.5 or 25 mg/kg caffeine was reduced from 50 to 5% by acetaminophen. In the absence of caffeine, acetaminophen (up to 300 mg/kg) did not modify the seizures induced by maximal electroshock and did not alter the convulsant dose of pentylenetetrezol in mice (tests performed by the Anticonvulsant Screening Project of NINCDS). Acetaminophen (up to 150 micrograms/mL) did not retard the incorporation of radioactive adenosine into ATP in slices of rat cerebral cortex. Thus the mechanism by which acetaminophen antagonizes the actions of caffeine in the CNS remains unknown.

Computer-aided emergency telecommunications for the deaf

Computer-aided telecommunications provide deaf teletypewriter users with 24-hour toll-free access to emergency services. An interface and software link the deaf caller's teletypewriter (TDD) with a microprocessor by reducing and inverting voltage levels between the two devices. This system facilitates rapid transmission of linguistically controlled triage questions to meet the communication needs of deaf patients.