Clinical pharmacology of hexachlorophene in newborn infants

NMR quantification of H-bond donating ability for bioactive functional groups and isosteres

The H-bond donating ability for 127 compounds including drug fragments and isosteres have been quantified using a simple and rapid method with ³¹P NMR spectroscopy. Functional groups important to medicinal chemistry were evaluated including carboxylic acids, alcohols, phenols, thioic acids and nitrogen group H-bond donors. ³¹P NMR shifts for binding to a phosphine oxide probe have a higher correlation with equilibrium constants for H-bonding (log K^H_A) than acidity (pK_a), indicating that these binding experiments are representative of H-bonding ability and not proton transfer. Additionally, ³¹P NMR binding data for carboxylic acid isosteres correlates with physicochemical properties such as lipophilicity, membrane permeability and plasma protein binding. This method has been used to evaluate the H-bond donating ability of small molecule drug compounds such as NSAIDs and antimicrobials.

Poisoning Through Pediatric Skin: Cases from the Literature

Poisoning through pediatric skin leading to acute systemic symptoms is a relatively uncommonly reported phenomenon. Systemic toxicity through the skin typically occurs by direct contact between therapeutic or non-therapeutic topical agents and the skin. Though uncommon, poisoning through pediatric skin can have significant consequences and must be recognized so the offending agent may be discontinued and appropriate treatment initiated. We performed a literature search for all article types between 1950 and April 2016 to provide a single source of detectable cases of acute toxicity in pediatric patients due to percutaneous exposure. This literature review discusses relevant pediatric skin physiology along with reports of poisoning events that resulted in systemic signs and symptoms and even death to provide a comprehensive report on causes of pediatric poisoning through the skin.

Practical pharmacokinetics: what do you really need to know?

Having some understanding of pharmacokinetics is important for all clinicians when prescribing medications. Key elements to effective and safe prescribing include making sure that we don't underdose a medication making it ineffective, but also do not overprescribe a treatment known to cause toxic effects. In paediatrics, there are significant physiological and developmental differences that add to the challenges of safe prescribing. This article aims to provide the clinician with some basic paediatric pharmacokinetic principles with clinical examples to aid their prescribing skills.

Chlorhexidine inhibits L1 cell adhesion molecule-mediated neurite outgrowth in vitro

BACKGROUND

Chlorhexidine is a skin disinfectant that reduces skin and mucous membrane bacterial colonization and inhibits organism growth. Despite numerous studies assessing chlorhexidine safety in term infants, residual concerns have limited its use in hospitalized neonates, especially low-birth-weight preterm infants. The aim of this study was to assess the potential neurotoxicity of chlorhexidine on the developing central nervous system using a well-established in vitro model of neurite outgrowth that includes laminin and L1 cell adhesion molecule (L1) as neurite outgrowth-promoting substrates.

METHODS

Cerebellar granule neurons are plated on poly L-lysine, L1, or laminin. Chlorhexidine, hexachlorophene, or their excipients are added to the media. Neurons are grown for 24 h, fixed, and neurite length is measured.

RESULTS

Chlorhexidine significantly reduced the length of neurites grown on L1 but not on laminin. Chlorhexidine concentrations as low as 125 ng/ml statistically significantly reduced neurite length on L1. Hexachlorophene did not affect neurite length.

CONCLUSION

Chlorhexidine at concentrations detected in the blood following topical applications in preterm infants specifically inhibited L1-mediated neurite outgrowth of cerebellar granule neurons. It is now vital to determine whether the blood-brain barrier is permeable to chlorhexidine in preterm infants.

Chlorhexidine bathing in a tertiary care neonatal intensive care unit: impact on central line-associated bloodstream infections

BACKGROUND

Despite implementation of recommended best practices, our central line-associated bloodstream infection (CLABSI) rates remained high. Our objective was to describe the impact of chlorhexidine gluconate (CHG) bathing on CLABSI rates in neonates.

METHODS

Infants with a central venous catheter (CVC) admitted to the neonatal intensive care unit from April 2009 to March 2013 were included. Neonates with a birth weight of 1,000 g or less, aged less than 28 days, and those with a birth weight greater than 1,000 g were bathed with mild soap until March 31, 2012 (baseline), and with a 2% CHG-impregnated cloth starting on April 1, 2012 (intervention). Infants with a birth weight of 1,000 g or less, aged 28 days or more, were bathed with mild soap during the entire period. Neonatal intensive care unit nurses reported adverse events. Adjusted incidence rate ratios (aIRRs), using Poisson regression, were calculated to compare CLABSIs/1,000 CVC-days during the baseline and intervention periods.

RESULTS

Overall, 790 neonates with CVCs were included in the study. CLABSI rates decreased during the intervention period for CHG-bathed neonates (6.00 vs 1.92/1,000 CVC-days; aIRR, 0.33 [95% confidence interval (CI), 0.15-0.73]) but remained unchanged for neonates with a birth rate of 1,000 g or less and aged less than 28 days who were not eligible for CHG bathing (8.57 vs 8.62/1,000 CVC-days; aIRR, 0.86 [95% CI, 0.17-4.44]). Overall, 195 infants with a birth weight greater than 1,000 g and 24 infants with a birth weight of 1,000 g or less, aged 28 days or more, were bathed with CHG. There was no reported adverse event.

CONCLUSIONS

We observed a decrease in CLABSI rates in CHG-bathed neonates in the absence of observed adverse events. CHG bathing should be considered if CLABSI rates remain high, despite the implementation of other recommended measures.

Fate of organohalogens in US wastewater treatment plants and estimated chemical releases to soils nationwide from biosolids recycling

This study examined the occurrence in wastewater of 11 aromatic biocides, pesticides and degradates, and their fate during passage through US treatment plants, as well as the chemical mass contained in sewage sludge (biosolids) destined for land application. Analyte concentrations in wastewater influent, effluent and sludge from 25 facilities in 18 US states were determined by liquid chromatography electrospray (tandem) mass spectrometry. Dichlorocarbanilide, fipronil, triclocarban, and triclosan were found consistently in all sample types. Dichlorophene, hexachlorophene, and tetrachlorocarbanilide were detected infrequently only, and concentrations of the phenyl urea pesticides diflubenzuron, hexaflumuron, and linuron were below the limit of detection in all matrixes. Median concentrations (+/-95% confidence interval) of quantifiable compounds in influent ranged from 4.2 +/- 0.8 microg L(-1) for triclocarban to 0.03 +/- 0.01 microg L(-1) for fipronil. Median concentrations in effluent were highest for triclocarban and triclosan (0.23 +/- 0.08 and 0.07 +/- 0.04 microg L(-1), respectively). Median aqueous-phase removal efficiencies (+/-95% CI) of activated sludge treatment plants decreased in the order of: triclosan (96 +/- 2%) > triclocarban (87 +/- 7%) > dichlorocarbanilide (55 +/- 20%) > fipronil (18 +/- 22%). Median concentrations of organohalogens were typically higher in anaerobically than in aerobically digested sludges, and peaked at 27 600 +/- 9600 and 15 800 +/- 8200 microg kg(-1) for triclocarban and triclosan, respectively. Mass balances obtained for three primary pesticides in six activated sludge treatment plants employing anaerobic digestion suggested a decreasing overall persistence from fipronil (97 +/- 70%) to triclocarban (87 +/- 29%) to triclosan (28 +/- 30%). Nationwide release of the investigated organohalogens to agricultural land via municipal sludge recycling and into surface waters is estimated to total 258 000 +/- 110 00 kg year(-1) (mean +/- 95% confidence interval), with most of this mass derived from antimicrobial consumer products of daily use. This study addresses some of the data gaps identified by the National Research Council in its 2002 study on standards and practices of biosolids application on land.

Managing drugs safely

There is hard data to show that newborn infants are more likely than adults to experience adverse reactions to drugs. Paradoxically, drug-related legislation to ensure safe and effective drug use in humans neglected neonates until 2002, when the Best Pharmaceuticals Act for Children was signed into law in the USA. The situation for neonates should now catch up with that for adults and neonates will be prescribed more licensed drugs in the near future. If we are to be able to analyze the underlying system errors to improve the safe use of drugs in the studied patient population, reporting of adverse drug events and reactions needs to happen in a blame free environment. In addition, computerized physician order entry will certainly further improve the current situation by preventing errors in ordering, transcribing, verifying, and transmitting medication orders.

Differences between children and adults: implications for risk assessment at California EPA

The California legislature enacted a law requiring the California Environmental Protection Agency (Cal/EPA) Office of Environmental Health Hazard Assessment (OEHHA) to evaluate whether our risk assessment methodologies are adequately protective of infants and children. In addition both OEHHA and the California Air Resources Board must examine whether the Ambient Air Quality Standards set for criteria air pollutants and the health values developed for air toxics are adequately protective of infants and children. We have initiated a program to look at potential differences in response to toxicants between children and adults. We are evaluating this issue from the perspective of exposure differences as well as toxicokinetic and toxicodynamic differences between children and adults. Data on specific chemicals are rather limited. As a result, we will be pooling information to determine whether there are generic differences between children and adults that may be applicable to risk assessment in general or to risk assessment of specific classes of compounds. This paper discusses the rationale for approaching the issue of determining whether our risk assessment methods are adequate for infants and children and includes a discussion of some of the available information on both qualitative and quantitative differences in response to toxicants between children and adults or immature and mature laboratory animals. We provide examples of differences between children and adults in absorption, metabolism, and excretion of toxicants as well as qualitative differences in toxic response.

Alternative routes of drug administration--advantages and disadvantages (subject review). American Academy of Pediatrics. Committee on Drugs

During the past 20 years, advances in drug formulations and innovative routes of administration have been made. Our understanding of drug transport across tissues has increased. These changes have often resulted in improved patient adherence to the therapeutic regimen and pharmacologic response. The administration of drugs by transdermal or transmucosal routes offers the advantage of being relatively painless.12 Also, the potential for greater flexibility in a variety of clinical situations exists, often precluding the need to establish intravenous access, which is a particular benefit for children.

This statement focuses on the advantages and disadvantages of alternative routes of drug administration. Issues of particular importance in the care of pediatric patients, especially factors that could lead to drug-related toxicity or adverse responses, are emphasized.

Drug administration to the pregnant or lactating woman: a reference guide for dermatologists

Dermatologists are occasionally faced with the problem of appropriate systemic drug administration to the lactating or pregnant woman. The physician's responsibility is to be aware of the potential risk of prescribing a specific therapeutic agent, to inform the mother of this risk, and to administer an alternate, less deleterious drug, if available. The purpose of this review is to provide guidelines for dermatologists who must consider the risks to the fetus or neonate of drug administration to the pregnant woman or lactating mother.

Hexachlorophene toxicosis in a litter of Doberman pinschers

A litter of 5-week-old Doberman Pinschers with pustular dermatitis was treated dermally with a hexachlorophene-containing emulsion. Shortly after a second treatment, all of the puppies developed neurologic signs consisting of muscle tremors, ataxia, and apparent muscle weakness. The clinical history and signs, histologic lesions within the central nervous system, and measurement of hexachlorophene in liver and kidney tissue confirmed a diagnosis of hexachlorophene toxicosis.

Drug Disposition in the Pediatric Patient

The pediatric patient is a unique individual who undergoes continual physiologic change from the time of conception through adolescence. The pharmacokinetics of therapeutic agents are influenced by physiologic changes that ultimately affect drug therapy. The gastric absorption of many therapeutic agents is altered by changes in gastric pH, gastric emptying, intestinal motility, biliary function, pancreatic function, and regional blood flow. Intramuscular absorption is erratic and unpredictable because of reduced skeletal muscle mass, alterations in regional blood flow, and physical activity. Percutaneous absorption is increased in the neonate due to increased water content and decreased thickness of the stratum corneum. The distribution of many therapeutic agents is increased in the neonate and infant because of an increase in extracellular fluid and total body water, alterations in tissue binding, and decreased plasma protein binding. The metabolic capacity and elimination processes of the newborn are greatly reduced compared to the adult; hepatic function is approximately one-half that of adults and renal elimination is similarly reduced. Hepatic function in the infant and young child may actually exceed that in the adult due to the increase in hepatic metabolic surface area to body weight ratio. Renal function matures relatively quickly in the neonate and approaches adult drug renal elimination rates within the first year of life. There is a lack of clinical research that defines therapeutic guidelines in the pediatric patient for specific drugs. However, an understanding of these physiologic changes that take place during growth and development in the pediatric patient will facilitate optimal drug therapy in this patient population. Following the initiation of drug therapy, the continued physiologic changes taking place in the pediatric patient necessitate continual therapeutic drug monitoring and periodic dosage adjustments. These special considerations challenge and enhance the responsibility of the pharmacist as a key member in assuming safe and effective pediatric drug therapy.

Vaginal absorption of hexachlorophene during labor

Surgical soap that contains hexachlorophene is used as an antiseptic lubricant for vaginal examinations during labor in some centers. Theoretically, hexachlorophene can be absorbed from the vaginal mucosa and be potentially toxic to the fetus and neonate. To evaluate vaginal absorption and placental transfer of hexachlorophene, we measured levels in mixed arterial/venous cord serum and postpartum maternal serum in 28 women whose vaginal examinations were lubricated with pHisoHex during labor. The serum of 12 women had detectable levels of hexachlorophene, with a high level of 942 ng/ml. Cord serum had detectable levels in nine neonates, with a high level of 617 ng/ml. The conclusion is that hexachlorophene from vaginal lubricants is variably absorbed from the vaginal mucosa, and appreciable amounts can be detected in maternal and cord serum. Because of the potential for neonatal hexachlorophene toxicity, we recommend the use of alternative lubricants for pelvic examinations during labor.

Cytokinetic and cytogenetic effect of agricultural chemicals on human lymphoid cells in vitro. II. Organochlorine pesticides

Human lymphoid cells of LAZ-007 cell line, incubated with 10(-4) to 10(-6) molar of eight different organochlorine pesticides had dose related cytotoxicity, mitotic depression and cell cycle traverse inhibition. In cultures incubated with 10(-4) M concentrations, M1 metaphases were as high as 13% (Dicofol) as compared to less than 1% in the controls. The frequency of M3 metaphases in cultures incubated with 10(-6) M concentrations ranged from 11% (Chlordane) to 15% (Endosulfan) compared to 17% in control cultures. Statistically significant increase in SCE frequency was seen in cells exposed to Chlordane, Dicofol, Endosulfan and Toxaphene. On metabolic activation with rat liver microsomal S-9 enzymes, Chlordane, Dicofol and Tetradifon induced SCE frequency was higher than that of nonactivated cultures.

Percutaneous absorption of chlorhexidine in neonatal cord care

The percutaneous absorption of chlorhexidine during its routine use in topical antiseptic preparations used in umbilical cord care was investigated by determining plasma chlorhexidine concentrations at ages 5 and 9 days. These showed that percutaneous absorption of chlorhexidine occurred in preterm neonates treated with a 1% solution of chlorhexidine in ethanol, but not in term infants similarly treated, or in preterm infants treated only with a dusting powder containing 1% chlorhexidine and 3% zinc oxide.

Pharmacology and toxicology of infant skin

Cutaneous metabolism and pharmacology have been the focus of increased scientific inquiry in the past 2 decades. However, in the past few years, attention has been focused specifically on the effects of topically applied drugs in infants as different qualitatively or quantitatively from their effects in adults. Prior to 1972, it was known that brain damage occurred in animals with prolonged blood levels of 2 microgram/ml hexachlorophene, and that washing newborn babies with a standard 3% hexachlorophene liquid soap for 3-5 days resulted in significant blood levels of the compound. However, this knowledge was not disseminated widely enough to prevent the tragic deaths of infants after the use of baby powder contaminated with 6.6% hexachlorophene [1]. This incident highlighted the need for increased understanding of drug effects not only from the viewpoint of the skin as a target organ, but also of percutaneous penetration and resultant blood levels; the affinity of other body tissues for drugs and their metabolites, metabolites which may result from the effect of the skin itself acting on the drug; and the infant's much greater ratio of surface area to body weight, allowing the infant to percutaneously absorb proportionately greater quantities of topical medication than an adult. Although tissue distribution of most drugs has not been studied in infants, it is known that such distribution often depends on age. For example, in infants and children with a given plasma level, of drugs such as barbiturates, morphine and tetracycline, the brain tissue level may exceed that of the adult. Thus, drugs and chemicals that penetrate infant skin may produce effects different than those penetrating adult skin.

Neonatal spongioform myelinopathy after restricted application of hexachlorophane skin disinfectant

At least four out of 97 low birth weight (less than 1750 g) newborn infants who had received only limited skin disinfection with 3% hexachlorophane (HCP) emulsion developed spongioform myelinopathy in association with detectable amounts of HCP in their brains. These four cases were found in a post-mortem survey of 20 out of the 27 infants who died. Another nine of these infants had detectable amounts of HCP in the brain but no myelinopathy. It is at present not possible to define a 'safe" level of exposure to 3% HCP emulsion for small preterm infants in the first 2 weeks of life.

Absorption of chlorhexidine from the intact skin of newborn infants

34 newborn infants who had been bathed in a standard manner with Hibiscrub were studied to find out whether it was absorbed percutaneously. Low levels of chlorhexidine were found in the blood of all 10 babies sampled by heel prick, and 5 of 24 from whom venous blood was taken. The detection of chlorhexidine varied greatly with the method and timing of sampling, and no correlation was found between gestational or postnatal age and chlorhexidine levels.