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.