Report of an Anaphylactoid and an Anaphylactic Reaction to Ketorolac in Two Pediatric Surgical Patients

Ketorolac is a potent analgesic drug that has been restricted in dosage and use because of its potential adverse effects. The diagnostic and ethical challenges of 2 children who had unpredictable adverse drug reactions to ketorolac are reported. Case 1: A 3-year-old boy received ketorolac 1 mg/kg for prevention of postoperative pain at the end of an orthopedic surgical procedure. Ten minutes later, he had bilateral palpebral edema, erythema in thorax, hypotension, and tachycardia. The adverse event was classified as a mixed reaction probably related to ketorolac. Case 2: A 7-year-old girl, who had previously received ketorolac in 2 different surgical procedures, underwent a third orthopedic surgery. She received ketorolac 1 mg/kg as pre-emptive analgesia at 1.5 hours of anesthetic time (approximately 1 hour of surgical time). The patient developed palpebral edema 5 minutes later in addition to erythema in thorax, hypotension, tachycardia, tachypnea, oxygen desaturation, and wheezing. The adverse event was classified as a systemic reaction probably related to ketorolac. The 2 patients were successfully treated with symptomatic therapy. Although rare in its frequency, ketorolac administration may be associated to anaphylactic and anaphylactoid reactions in children with or without history of previous exposure. Because ketorolac is off-licensed for pediatric patients, it should be administered only after the risks and benefits have been discussed with the child's parents in the preanesthetic consultation.

Major malformations with valproic acid

QUESTION

Increasing numbers of pregnant patients are treated with valproic acid, not just for epilepsy, but also for psychiatric conditions. Are there teratogenic risks other than the risk of spina bifida?

ANSWER

It has now become evident that valproic acid might cause more than just neural tube defects (NTDs). In a systematic review of all cohort studies intended to answer this question, higher rates of major malformations (and not just NTDs) were found in most studies. The calculated relative risk was 2.59 when compared with other antiepileptic drugs and was 3.77 when compared with risk in the general population. There is compelling evidence that the risk is dose dependent. The risks appear to begin increasing at doses of 600 mg/d and to become more prominent at doses above 1000 mg/d.

Preoperative catheterization of H-type tracheoesophageal fistula to facilitate its localization and surgical correction

PURPOSE

The aim of this study was to demonstrate that preoperative catheterization of H-type tracheoesophageal fistula facilitates its identification and surgical correction.

METHODS

This is a case series of seven patients with H-type tracheoesophageal fistula. Diagnosis was established in three patients and suspected in two more by means of an esophagogram. Confirmation of fistula was performed by endoscopy in all patients. On the day of surgery, either a rigid bronchoscope or a nasolaryngoscope was introduced into the trachea to localize and catheterize the fistula. Because of the location of the fistula, the surgical correction was performed through the neck in five patients and through the thorax in two patients. The fistulas were easily identified surgically and the corrections were successfully performed in all cases. An extensive dissection was not required in any case. Refistulization, identified by bronchoscopic examination one week after surgery, occurred in one patient. Surgical repair was performed again using same procedure described above. All patients are currently asymptomatic and without any evidence of refistulization.

CONCLUSIONS

Preoperative catheterization of H-type tracheoesophageal fistula is useful to facilitate its preoperative identification, to plan the surgical approach, and to decrease operating times and the extent of surgery.

Effect of extensively hydrolyzed milk formula on growth and resistance to bronchitis and atopic dermatitis in infants and toddlers

OBJECTIVE

This study aimed to evaluate the adverse effects of extensively hydrolyzed milk formula on growth in infants and toddlers.

METHODS

Prospectively, 45 infants and toddlers with a positive history of cow's milk allergy confirmed by positive skin prick test and high IgE levels for either alpha-lactalbumin, beta-lactoglobulin, or casein and positive single-blind food challenge received extensively hydrolyzed milk formulas for 1 year. Sex-normalized percentiles of heights and weights of infants and toddlers before their enrollment in the study were compared to those at the end of the study. The contribution of breastfeeding, early use of bottle feeding and intake of adapted or special milk formulas, and history of bronchitis and atopic dermatitis on toddlers' growth were also evaluated by multivariate analysis.

RESULTS

Similar percentiles of the children's weight and height were observed at the beginning of the study and 1 year later. According to the multivariate analysis, sex, breastfeeding, early bottle feeding, ingestion of adapted or special milk formulas, atopic dermatitis, and bronchitis were not correlated with either the children's weight or height at diagnosis of the allergy or at 1 year of follow-up (P > .10). Weights and heights were not different between toddlers who had atopic dermatitis or bronchitis during the study period and those who did not.

CONCLUSIONS

Growth of infants and toddlers with cow's milk allergy was not affected by the intake of extensively hydrolyzed milk for 1 year. Atopic dermatitis and bronchitis did not appear to have any deleterious effect on these children's growth.

A Mexican population-based study on exposure to paracetamol and the risk of wheezing, rhinitis, and eeczema in childhood

BACKGROUND

There is some evidence suggesting a link between paracetamol exposure and atopy in both adults and children.

OBJECTIVE

We aimed to investigate whether further epidemiological support for a link between paracetamol intake and allergy could be found in a population of Mexican children.

METHODS

In a cross-sectional study design, we applied the ISAAC questionnaire to 3493 children aged 6 to 7 years old. Two analyses were performed: (1) children were classified as cases if they had wheezing, rhinitis, or eczema at any time from their neonatal period up until they reached the age of 6 to 7 years, or as controls if they had never experienced these conditions, and (2) children were classified as cases if they had wheezing, rhinitis, or eczema in the 12 months prior to the study. Paracetamol intake was considered positive if it frequently occurred during the first year of life (first analysis) or in the last 12 months (second analysis).

RESULTS

Paracetamol intake in the first year of life was significantly associated with an increased risk of ev having wheezing (adjusted odds ratio [OR], 1.69; 95% confidence interval [CI], 1.23 to 2.34) and rhinitis (adjusted OR, 1.37; 95% CI, 1.20 to 1.59) but not eczema (adjusted OR, 1.45; 95% CI, 0.91 to 2.32). Frequent paracetamol intake in the last year increased the risk of wheezing (OR, 3.3; 95% CI, 1.54 to 7.18), rhinitis (OR, 1.61; 95% CI, 1.33 to 1.95), or eczema (OR, 1.82; 95% CI, 1.24 to 2.66).

CONCLUSION

Frequent paracetamol exposure was associated with a significantly increased risk of wheezing and rhinitis and probably eczema in a Mexican population of children.

META-ANALYSIS OF THE DIFFERENCES IN THE TIME TO ONSET OF ACTION BETWEEN ROCURONIUM AND VECURONIUM

1. The aim of the present study was to conduct a meta-analysis of the magnitude of differences in the onset of action (T(max)) between rocuronium and vecuronium. 2. A search was made in PubMed, EMBASE Drugs and Pharmacology, Cochrane Controlled Trials Register and Cochrane Database on Systematic Reviews. Studies comparing the T(max) at the adductor policies between rocuronium and vecuronium administered as an intravenous bolus were included in the study. Twenty-nine effect sizes obtained from 21 studies were included. 3. The result of the meta-analysis of differences was -57.9 s (95% confidence interval -71.4 to -44.3 s), favouring rocuronium over vecuronium. The smallest difference in T(max) between these neuromuscular-blocking agents was observed in children (-19.1 s). The difference in T(max) between rocuronium and vecuronium in female patients was -38.7 s. The difference in T(max) between rocuronium and vecuronium measured by electromyography was approximately 50% shorter than that determined by acceleromyography or mechanomyography. In a subanalysis between rocuronium 600 mg/kg versus vecuronium 100 mg/kg, the difference in T(max) between them was very similar to that obtained in the general meta-analysis. 4. According to subanalyses of patient age and sex, drug dose and neuromuscular monitoring systems, the T(max) of rocuronium was approximately 20-70 s faster than that of vecuronium.

Similar preoperative hemodynamic response to pancuronium and rocuronium in high-risk cardiac surgical patients

AIM

Rocuronium may be a good alternative to pancuronium in cardiac surgical patients. We evaluate the hemodynamic response to rocuronium and pancuronium administered to cardiac surgical patients.

METHODS

A single-blind, randomized clinical trial was carried out at the National Institute of Cardiology in Mexico. Twenty-two patients older than 18 years, NYHA class III-IV, and scheduled to undergo an elective cardiovascular surgical procedure were enrolled. Patients were randomly allocated to receive an i.v. bolus dose of either pancuronium 100 microg/kg or rocuronium 600 microg/kg. Peripheral arterial (radial) and venous cannulations and insertion of a multi-lumen pulmonary artery flotation catheter through the right internal jugular vein were carried out under local anesthesia. Anesthetic induction with an i.v. bolus dose of fentanyl 700 microg and diazepam 20 mg was performed and thereafter the neuromuscular blocking agent was administered. Ventilation with O2 100% was performed until a TOF < or =5% was observed and tracheal intubation was performed. After intubation, patients were maintained with O2 10 mL/kg administered by means of a pulmonary ventilator at a pressure of 20-25 cm H2O. The basal, pre-laryngoscopy, post-intubation, and pre-operative recording of a set of cardiovascular parameters were obtained.

RESULTS

No differences (P>0.05) in the hemodynamic response were observed between pancuronium and rocuronium nor during the different evaluation times in each group.

CONCLUSIONS

Rocuronium can be a safe alternative to pancuronium for patients requiring cardiac surgical procedures.

Oral misoprostol and uterine rupture in the first trimester of pregnancy: A case report

We are reporting the case of a woman with 8 weeks of amenorrhea who orally received a single dose of misoprostol 400 microg at midnight for ripening of cervix before uterine evacuation of an intrauterine gestational sac containing a single fetus (6.3 weeks of gestation) without cardiac activity. The patient had severe abdominal pain an hour later. Her blood pressure was 70/40 mmHg and her abdomen was slightly distended with direct and rebound tenderness. A transvaginal ultrasonography showed a 3-cm depth of a free fluid collection in the rectouterine pouch. Her hemoglobin and hematocrit levels were of 6.5 g/dL and 18.4%, respectively. A rupture of 1.5 cm at the left uterine horn with a protruding gestational sac was identified by laparoscopy. The gestational sac was removed and hemoperitoneal collection were successfully drained. The site of uterine rupture was primarily sutured and postoperative course was satisfactory. In summary, misoprostol administered in the first trimester of pregnancy may produce uterine rupture.

Co-administration of salbutamol and fluticasone for emergency treatment of children with moderate acute asthma

This study aimed to compare the efficacy of nebulized therapy with salbutamol alone or in combination with fluticasone. In a randomized, double-blind clinical trial, 150 children with moderate acute asthma were randomly assigned to receive by nebulizations either (i) three doses of salbutamol 30 microl/kg per dose, each dose administered every 15 min, (ii) three doses of salbutamol plus two doses of fluticasone 500 microg/dose at 15 and 30 min after first dose of salbutamol, or (iii) three doses of salbutamol/fluticasone 500 microg/dose, each combined dose administered every 15 min. Pulse oxymetry (SaO2), peak expiratory flow (PEF) and Wood et al. (Am J Dis Child, 123, 1972, 123) clinical scale were evaluated at baseline, 15, 30, 45, 60, 90 and 120 min after the first nebulization. Patients in the three groups significantly improved since 15 min after the first nebulization. We did not observe differences in the recovery of SaO2 and PEF among the three groups of treatment (p > 0.10). In group 3, children showed better clinical response at 120 min than the other two groups (p < 0.05). No significant adverse effects were observed with any treatment. To summarize, in children with acute moderate asthma, nebulized salbutamol at an accumulated dose of 90 mul/kg plus fluticasone at an accumulated dose of 1500 microg produced better clinical relief after 2 h. However, similar PEF and SaO2 responses were observed with salbutamol alone or in combination with different doses of fluticasone.

Randomized trial comparing overnight preoperative fasting period Vs oral administration of apple juice at 06:00-06:30 am in pediatric orthopedic surgical patients

BACKGROUND

We aimed to evaluate the efficacy of clear liquids orally administered at 06:00-06:30 am on the morning of surgery to reduce prolonged preoperative fasting periods.

METHODS

After obtaining informed parental consent, 100 children undergoing scheduled orthopedic surgical procedures, ASA I-II, were randomly allocated to two groups. In group 1, children underwent the typical overnight preoperative period and patients in group 2 received a commercial brand of apple juice (glucose 28 g in 250 ml) at 06:00-06:30 am on the day of surgery. Patients <3 years old received 15 ml.kg(-1) and older children 10 ml.kg(-1) to a maximum volume of 250 ml. All patients underwent overnight fasting for milk and solids.

RESULTS

Fasting time was 4.8 +/- 2.1 h (ranging from 3 to 11 h) in the group receiving apple juice at 06:00-06:30 am and 13.2 +/- 3.3 h (ranging from 5 to 19 h) in the overnight-fasting group (P < 0.05; 95% CI: -9.6 to -7.4 h). More patients were irritable (odds ratio, OR 4.5; 95% CI: 1.9-10.8) and dehydrated (OR 21.6; 95% CI: 5.9-79.0) in the overnight-fasting group. Glucose levels <2.7 mmol.l(-1) (50 mg.dl(-1)) were not reported in any case.

CONCLUSIONS

A 15 ml.kg(-1) of apple juice for patients of <3 years of age or 10 ml.kg(-1) for older children, at 06:00-06:30 am of the surgical morning is a simple procedure to prevent dehydration and to produce positive behavior in low-risk, pediatric surgical patients.

Dose minimization study of oxytocin in early labor in sows: Uterine activity and fetal outcome

Two hundred sows were randomly assigned to intramuscularly receive 0.9% NaCl (group 1) or oxytocin 0.083, 0.11 or 0.17 IU/kg (groups 2, 3 and 4, respectively) immediately after the expulsion of the first piglet. The overall duration of labor was decreased in a dose-dependent relationship. Time interval between piglets was decreased approximately 5 min in groups 3 and 4 while sows in these groups exhibited approximately 10-20 contractions x 10 births more than controls (P<0.005). Duration and intensity of uterine contractions also showed a positive dose-response relationship. As an indicative of fetal distress, approximately 2.5 times more meconium-stained piglets were born to sows receiving the higher doses of oxytocin, but in the lowest dose significantly decreased. Oxytocin 0.083 IU/kg significant decreased the mortality rate of piglets [OR 0.49 (95%CI, 0.26-0.92)]. In conclusion, we recommend the intramuscular administration of the lowest possible dose of oxytocin, which still decreases the duration of labor in sows.

Pregnancy outcome after prenatal exposure to bleomycin, etoposide and cisplatin for malignant ovarian germ cell tumors: report of 2 cases

Bleomycin plus etoposide and cisplatin seem to be a promising alternative for women with ovarian cancer. We are reporting two cases with favorable pregnancy outcome after exposure to these chemotherapeutic agents at the second and third trimesters of pregnancy. A pregnant woman with a stage Ic yolk-sac tumor underwent a right oophorectomy with omentectomy, and received five cycles of bleomycin, etoposide and cisplatin from the 22nd week of pregnancy until delivery. The second case was a pregnant woman with a stage Ia immature teratoma who underwent right salpingo-oophorectomy and received two cycles of bleomycin, etoposide and cisplatin starting at 30th week of pregnancy. The two patients did not have any evidence of recurrence of ovarian cancer for 6 and 2 years, respectively. Their babies did not have any evidence of minor or major malformations, and showed normal neurological development at 6 and 2 years of follow-up, respectively.

Randomized trial of a single, double and triple dose of 10 mg/kg of a human formulation of triclabendazole in patients with fascioliasis

1. A study performed > 10 years ago and case reports published recently suggest that triclabendazole is effective for the treatment of patients with fascioliasis. 2. To confirm the efficacy of a human formulation of triclabendazole, we enrolled 165 patients into the present study and divided the subjects into two groups: (i) those who had fascioliasis, as evidenced by the presence of ova in their stools; and (ii) patients with clinical and laboratory data suggesting fascioliasis. 3. Patients were randomly allocated to receive 10 mg/kg, p.o., triclabendazole for 1, 2 or 3 days (single-, double- and triple-dose groups, respectively). Medical history and physical and laboratory examinations were performed at baseline and at 7, 14, 30 and 60 days after treatment. Results were based on 152 patients who completed the study. 4. A sharp decrease in the proportion of clinical signs and symptoms was observed in all groups immediately after treatment. Ova disappeared from the stools of all patients in the single- and double-dose groups. Thirty days after treatment, ova were identified in the stools of two patients in the triple-dose group who received a second course of triclabendazole. 5. All cases were cured on day 60. However, the cure rate was lower when the patients with suggestive fascioliasis were included in the analysis. The cure rate was not significantly different (P > 0.05) among the three dose groups. No cases of toxic hepatitis were observed. 6. In conclusion, oral administration of 10 mg/kg of the human pharmaceutical preparation of triclabendazole for 1-3 days is safe and effective in the treatment of human fascioliasis.

Variable designs of clinical trials of neuromuscular blocking agents: an example of studies comparing rocuronium and vecuronium

BACKGROUND

Published clinical trials on neuromuscular blocking (NMB) agents are being reported with large variations in their protocols and conflictiing results may emerge from these differences. Because they have been compared in several clinical trials, the study was focused on rocuronium and vecuronium in order to evaluate whether these NMB agents were compared under homogeneous conditions. MATERIAL/ METHOD: A search was made in PubMed, Embase Drugs and Pharmacology, Cochrane Controlled Trials Register, and Cochrane Database of Systematic Reviews. Studies on the neuromuscular response at the adductor pollicis to an i.v. bolus dose of rocuronium or vecuronium in humans were included. Quality of all reports was assessed by means of the 3-item Jadad et al. scale. Twenty-five studies met our inclusion criteria and all were retrieved.

RESULTS

Randomization was performed in 21 (80.8%) studies. Blinding procedure for drug administration was mentioned in only one study without clarifying the procedure. Induction was most commonly performed with thiopental, followed by propofol. Two studies were performed in children and two in elderly patients. Withdrawals or dropouts were not mentioned in any paper. Electromyography and mechanomyography were the most common monitoring procedures. The time to maximal response, the maximum effect and the time to reach 25% recovery of neuromuscular function were the most used pharmacodynamic parameters.

CONCLUSIONS

Clinical trials on neuromuscular blocking agents, e.g. vecuronium versus rocuronium, are being performed with large variability and without following established guidelines.

Dose minimization study of single-dose epidural morphine in patients undergoing hip surgery under regional anesthesia with bupivacaine

BACKGROUND

In order to decrease the rate of adverse effects, we aimed to identify the lowest analgesic dose of epidural morphine administered to patients undergoing hip surgery.

METHODS

Forty-five ASA I-II children undergoing surgical correction of hip dysplasia under caudal or epidural anesthesia with bupivacaine were randomized to receive epidural morphine 11.2, 15 or 20 microg.kg(-1) (groups 1, 2 and 3, respectively; 15 patients per group) immediately after completion of surgery. Postoperative pain control, sedation, motor block, urinary retention, pruritus and vomiting were evaluated.

RESULTS

In the recovery room, 46.7% of patients from group 1, 33.3% from group 2, and 93.3% from group 3 were sleeping but were easy to arouse (x(2) = 12.2; P < 0.005). The rest of the patients from each respective group were completely asleep. The cardiovascular and respiratory parameters were within normal limits. The ability to move the legs returned approximately 1 h after surgery in all three groups. Seven patients (46.7%) from group 1, nine (60%) from group 2, and 13 patients (86.7%) from group 3 vomited (x(2) = 5.4; P = 0.06). One patient receiving 20 microg.kg(-1) morphine experienced urinary retention. One patient receiving 15 microg.kg(-1) morphine suffered from pruritus. The duration of analgesia was similar, 12-14 h, in all three groups.

CONCLUSIONS

In patients undergoing hip surgery under regional anesthesia with bupivacaine, epidural morphine at a dose of 11.2 microg.kg(-1) administered immediately after completion of the procedure resulted in adequate pain relief for more than 12 h. Explanation of the high rate of patients vomiting (>45%) remains to be elucidated.

Pharmacokinetics of high doses of cyanocobalamin administered by intravenous injection for 26 weeks in rats

1. High doses of vitamin B12 (cyanocobalamin) may be therapeutically effective to treat neurological alterations secondary to a wide range of disease states. The aim of the present study was to evaluate the effect of dose and repeated administration on the pharmacokinetics of cyanocobalamin in rats. 2. Forty-eight rats were randomly assigned to receive 1, 5, 25 or 100 mg/kg cyanocobalamin for 182 days (26 weeks). Cyanocobalamin plasma levels were quantified by HPLC on days 1, 85 and 182 of treatment and were analysed by means of non-compartment pharmacokinetic (PK) analysis. In addition, population PK analysis was used to fit cyanocobalamin plasma concentrations to time by means of a two-compartment model for intravascular administration. 3. The half-life of cyanocobalamin ranged from approximately 20 to 50 min, clearance ranged from 4.5 to 9 mL/min and the volume of distribution at steady state ranged from 140 to 470 mL. A statistically significant negative relationship existed between the dose of cyanocobalamin and the normalized area under the plasma concentration-time curve (AUC). This non-linearity was not exhibited in population PK analysis. No evidence of toxicity was observed. 4. At very high and prolonged doses (up to 100 mg/kg for 26 weeks), intravascular administration of cyanocobalamin in rats follows a two-compartment kinetic model and cyanocobalamin undergoes extensive extravascular distribution. The negative relationship between dose and normalized AUC is compatible with possible saturation of tubular reabsorption, thus increasing renal clearance at higher doses.

Unintended pregnancies and exposure to potential human teratogens

BACKGROUND

We aimed to investigate the risk factors associated with unintended pregnancies as well as the association between unintended pregnancies and potential teratogenic exposures.

METHODS

A cross-sectional survey was performed among women attending the Maternity School of the Samsung Cheil Hospital and Women's Health Care Center in Seoul, Korea. Demographic data, obstetric history, socioeconomic status, intention to become pregnant, and exposure to potential teratogens were obtained.

RESULTS

A total of 1354 women with median age of 29 years and median gestational age of 29 weeks were included. Of these, an educational level above high school was 74.2%, primigravida was 77.3% and unintended pregnancy was 48%. In the logistic regression analysis, women younger than 24 years of age had a relative risk (RR) of 2.5 (95% confidence interval [CI], 1.3-4.7) of having an unintended pregnancy and women with lower household monthly income level had a RR of 1.3 (95% CI, 1.0-1.6). Women with unintended pregnancies had an RR of 1.9 (95% CI, 1.5-2.5), 3.0 (95% CI, 2.0-4.5), 1.5 (95% CI, 1.0-2.3), 2.9 (95% CI, 1.1-7.2), and 2.0 (95% CI, 1.62.4) of being exposed to alcohol, medications, cigarette smoking, X-rays, or to any of these, respectively, during the first trimester of pregnancy.

CONCLUSIONS

Unintended pregnancies are more likely to occur among young women with a lower household monthly income level. Prenatal counseling should be especially recommended for women with unintended pregnancies in order to evaluate whether they have been exposed to potential teratogenic agents.

A QSAR analysis of toxicity of Aconitum alkaloids

Biological activity of Aconitum alkaloids may be related to their toxicity rather than to a specific pharmacological action. A Quantitative structure-activity relationships (QSAR) analysis was performed on the following two groups of alkaloids: compounds with an aroyl/aroyloxy group at R(14) position (yunaconitine, bulleyaconitine, aconitine, beiwutine, nagarine, 3-acetyl aconitine, and penduline), and compounds with the aroyloxy group at R(4) position (N-deacetyllappaconitine, lappaconitine, ranaconitine, N-deacetylfinaconitine, N-deacetylranaconitine). The LD(50) (micromol/kg) of the 12 alkaloids were obtained from the literature. LD(50) was significantly lower in group 1 than in group 2. The steric and core-core repulsion energies were significantly higher in group 1. The total energy and heat of formation and electronic energies were significantly lower in group 1. The reactivity index of N, C1', C4' and C6' were similar between groups. The reactivity index of C2' was significantly higher and the reactivity index of C3' and C5' were significantly lower in group 1. Log P and pKa were similar between groups. Molecular weight was significantly higher in group 1. A significant linear relationship was observed between log LD(50) and either analgesic log ED(50) or local anesthetic log ED(50). The LD(50)/analgesic ED(50) obtained from average values was 5.9 for group 1 and 5.0 for group 2. However, the LD(50)/local anesthetic ED(50) was 40.4 and 318, respectively. The study supports that the analgesic effects of these alkaloids are secondary to their toxic effects whereas alkaloids from group 2 are susceptible to be further studied as local anesthetic agents.

The local anesthetic activity of Aconitum alkaloids can be explained by their structural properties: a QSAR analysis

Alkaloids isolated from Aconitum roots exhibit anesthetic effects at peripheral nerves. We performed the present quantitative structure-activity relationship (QSAR) analysis in order to understand the mechanism of action as local anesthetics of 11 Aconitum alkaloids. The alkaloids with the highest anesthetic activity had an aroyl/aroyloxy group at R14 position while the weaker anesthetic alkaloids had the aroyloxy group at R4. The stable compounds exhibited a higher local anesthetic activity than the unstable compounds. In relation to the reactivity indexes of atoms on the aromatic ring, C2' was more reactive while C3' and C5' were less reactive in the compounds with the highest anesthetic activity. Reactivity of N, C1', C4' and C6' was similar between the two groups of alkaloids. The pKa was approximately 7.3 in both groups. The local anesthetic ED50 of alkaloids was significantly inversely related to molecular weight, core-core repulsion energy, steric energy and RI-C2', and directly related to electronic energy, total energy, RI-C5' and to the heat of formation. In conclusion, we identified a set of structural parameters that are related to the local anesthetic activity of Aconitum alkaloids. Our findings are useful to understand the mechanism of action of these alkaloids and to provide a rational for chemical manipulation of the compounds in order to obtain potent derivates with minor toxicity.

DOSE-RESPONSE OF ROPIVACAINE ADMINISTERED CAUDALLY TO CHILDREN UNDERGOING SURGICAL PROCEDURES UNDER SEDATION WITH MIDAZOLAM

1. In a double-blind randomized controlled design, 50 children were allocated to receive bupivacaine 0.25% or ropivacaine 0.25%, 0.32%, 0.40% or 0.50% by caudal block. 2. Caudal block was performed after induction of anaesthesia with 2-5% sevoflurane, atropine 10 microg/kg and midazolam 100-300 microg/kg. During the surgical procedure, patients were maintained under spontaneous ventilation and no intravenous or inhalatory anaesthetic agent was administered. For transoperative sedation, midazolam 100-300 microg/kg was administered every 0.5-1.0 h. Transoperative cardiovascular response, postoperative analgesia and local and systemic complications were evaluated. 3. Groups were similar (P > 0.05) in sex, age, weight and in the time elapsed from caudal block to the beginning of the surgical procedure. The surgical time was significantly lower in the ropivacaine 0.25% group. The duration of analgesia was 24 h with ropivacaine 0.25% and approximately 10 h in the other four groups (P < 0.001). Linear regression analysis revealed a significant relationship between the postoperative analgesic period produced by ropivacaine and the surgical time (r = -0.48, two-sided P = 0.002). Systolic and diastolic blood pressures remained in the physiologically normal range for the duration of the transoperative period. Vomiting was present in only one patient receiving ropivacaine 0.50%. 4. In children, the duration of analgesia produced by caudal block with ropivacaine may be affected by surgical time. At surgical times of 0.5-1 h, ropivacaine 0.25% produced at least 24 h postoperative analgesia. At similar surgical times, ropivacaine 0.32%, 0.40% and 0.50% produced similar analgesic times to bupivacaine 0.25%.

Elimination kinetics of ethanol in pregnant women

To evaluate the pharmacokinetics of ethanol in the early second trimester of pregnancy, ethanol concentrations simultaneously measured in the maternal blood (EtOH-MB) and in the amniotic fluid (EtOH-AF) of six pregnant women were obtained from a previous study in which a single ethanol dose of 300mgkg(-1) body weight was administered orally. For maternal blood ethanol concentration, the kinetic equation was: [Formula: see text] where k(12) and k(21) are, respectively, the rate constant of ethanol transfer from either the central compartment to the peripheral compartment or vice versa; V(max)(EtOH)is the maximal velocity for ethanol oxidation; and K(m)(EtOH) is the concentration at which half of the maximal rate of ethanol elimination is reached. The maximum concentration of EtOH in AF was 60% lower than in MB (P=0.36). However, the AUC(0-3.5h) in AF was only 16% lower than the value for MB (P=0.059). The k(12) (0.20 =/- 0.26 h(-1)) was almost twice faster than k(21) (0, h(-1)). The V(max)(EtOH) was 237.6 +/- 71.5 microgml(-1)h(-1) and K(m)(EtOH) was 3.7 +/- 4.7 microgml(-1). Our results imply that in the early second trimester, ethanol metabolism is fast. However, ethanol clearance from the AF is slower than ethanol clearance in MB. This process is widely variable, and our findings may partially explain the wide variability of ethanol's toxic effects on the fetus.