Nalmefene to prevent epidural narcotic side effects in pediatric patients: a pharmacokinetic and safety study

STUDY OBJECTIVE: To determine the pharmacokinetics and preliminary efficacy of nalmefene in children in preventing epidural-induced narcotic side effects. DESIGN: Double-blind, placebo-controlled study. SETTING: University-affiliated children's hospital. PATIENTS: Thirty-four children (aged 2-12 yrs) undergoing cardiothoracic surgery with epidural anesthesia. INTERVENTIONS: Patients were randomized to receive intravenous bolus nalmefene 1 microg/kg or placebo. MEASUREMENTS AND MAIN RESULTS: Six blood samples (one before nalmefene administration and five from 13 randomly designated time points) from each patient were assayed to determine plasma nalmefene concentrations. Patients were assessed for pain, nausea, vomiting, and urinary retention for 24 hours after administration. Concentration-time data were analyzed by a limited sampling strategy with adult pharmacokinetic parameters used as Bayesian priors. A two-compartment, first-order model was fitted to the data using ADAPT II. Pharmacokinetic parameter estimates in these patients were similar to values reported in adults. The initial disposition half-life (t(1/2alpha)) was 0.36+/-0.11 hour, the terminal elimination half-life (t(1/2beta)) 8.7+/-2.3 hours, clearance 0.729+/-0.172 L/kg/hr, and steady-state volume of distribution 7.21+/-2.49 L/kg. Ability to prevent epidural narcotic-induced side effects could not be documented at the 1-microg/kg dose. No statistically significant differences were noted between study and placebo groups with regard to pain, nausea, vomiting, or urinary retention. CONCLUSION: Nalmefene has similar pharmacokinetics in children as in adults. It was administered safely to these patients and did not produce unmanageable pain.     

Prospective randomized trial comparing the outcome and cost of in vitro fertilization with that of a traditional treatment algorithm as first-line therapy for couples with infertility

OBJECTIVE: To determine whether IVF or a standard infertility treatment algorithm results in better outcome and/or lower cost when used as first-line therapy for couples with infertility. DESIGN: Prospective, randomized clinical study. SETTING: University-affiliated infertility clinic. PATIENT(S): Couples with newly diagnosed infertility and no prior treatment. INTERVENTION(S): Couples were randomized to undergo either IVF (group 1, n = 46) or a standard infertility treatment algorithm (group 2, n = 50) as initial therapy for infertility. MAIN OUTCOME MEASURE(S): Pregnancy rates and costs per couple, per month of treatment, and per pregnancy. RESULT(S): Pregnancy rates were higher in group 2 than in group 1. Costs per couple were not statistically different, although a trend toward higher costs was apparent in group 1, reflected by a higher median cost per clinical pregnancy established and a higher cost per month of treatment. Whereas cost differences between the groups diminished over time, pregnancy rates remained the same. CONCLUSION(S): In vitro fertilization currently does not represent an appropriate first-line treatment option for couples with infertility. The use of a standard infertility treatment algorithm results in a higher pregnancy rate and lower cost and therefore should be the preferred treatment approach.     

Increased angiotensin-converting enzyme activity in a patient with severe ovarian hyperstimulation syndrome

OBJECTIVE: To assess plasma angiotensin-converting enzyme (ACE) activity in a patient with severe ovarian hyperstimulation syndrome (OHSS). DESIGN: Case report. SETTING: Private, university-affiliated infertility practice. PATIENT(S): A 35-year-old woman with OHSS. INTERVENTION(S): Clomiphene citrate induction of ovulation. MAIN OUTCOME MEASURE(S): Plasma ACE activity. RESULT(S): The patient had a brain stem infarction as a result of thrombosis caused by severe OHSS. Plasma ACE activity was significantly elevated and persisted long after resolution of the OHSS. CONCLUSION(S): Elevated ACE activity appears to have been associated with the development of OHSS in this patient. Further study of the ovarian renin-angiotensin system in the development of OHSS is warranted.     

Effect of constant light on DMBA mammary tumorigenesis in rats

A study of light, and mammary tumorigenesis was conducted in rats. One-hundred female Sprague-Dawley rats were divided by weight into two groups. One group was exposed to constant light (LL) from 26 days of age, and the second group was exposed to 8 h light and 16 h dark per day (LD). Both groups received an 8 mg dose of a chemical carcinogen, dimethylben-zanthracene (DMBA) at 52 days of age. At 13 weeks post-DMBA, there were significantly fewer mammary tumors in the LL group compared with the LD group. Constant light was clearly demonstrated to have a profound effect on mammary tissue development. Although virgin, the majority of the LL rats (29/50) had gross evidence of lactation at 141 days of age. None of the LD rats (0/50) showed evidence of milk production. These results suggest that constant light not only substantially accelerated mammary gland development, but pushed development of the tissue past the stage normally observed in virgin animals (to the lactation stage).     

Acute presentations of inherited metabolic disorders: investigation and initial management

Inborn errors of metabolism are individually rare, but so many have now been described that the general paediatrician will encounter one from time to time. For many, early treatment is important. Unfortunately, most that present acutely do so with non-specific symptoms and signs. It is therefore necessary to identify and investigate those at high risk. The most common problems are neurological (including coma, seizures and stroke-like episodes), hypoglycaemia, disorders of acid-base regulation, acute liver disease, rhabdomyolysis, cardiomyopathy and sudden collapse. Treatment should be started as soon as an inborn error is suspected. This review is a short, practical introduction and cannot cover all situations. If in doubt, consult your local specialist metabolic centre. Free, detailed instructions on the acute management of individual inborn errors of metabolism can be found on the British Inherited Metabolic Disease Group (BIMDG) Website: http://www.bimdg.org.uk/