Evaluation of the impact of a pharmaceutical care program in children with asthma

The objective of this study was to evaluate the impact of a pharmaceutical care program on children with asthma. A comprehensive asthma education and monitoring program that includes basic asthma knowledge, symptoms and exacerbation evaluation, pharmacotherapy assessment including inhaler technique, and quality of life measurements was developed and applied in an outpatient paediatric clinic of the Catholic University of Chile. All patients with moderate asthma scheduled for outpatient visits with their internist over a 1-year period were referred for pharmacist intervention. Patients (aged 7-17) with moderate asthma attending the clinic were allocated to the intervention (group A) or control group (group B). Intervention patients were educated on their disease, pharmacotherapy, self-management, and inhalation techniques. The group B were children with their regular treatment for asthma but without pharmaceutical intervention. A paediatric asthma quality of life questionnaire (PAQLQ) was applied to both groups at 0, 2, and 9 weeks to assess the quality of life. Spirometry was done at the beginning and at the completion of the 9-week study. Beta-agonists used by each patient were also recorded. Eleven children (10.0+/-0.7 years) were included in the pharmaceutical care program, and ten children (9.9+/-0.6 years) in group B. For the individual domains of activities (A), emotions (E), and symptoms (S) there was a significant improvement in the children who received pharmaceutical care in comparison with those who did not receive it. The scores of group B did not change during the 9 weeks of follow-up. There were no significant changes in spirometric values in either group.

Hepatic kinetics of SCP-1 (N-[alpha-(1,2-benzisothiazol-3(2H)-ona-1, 1-dioxide-2-yl)-acetyl]-p-aminophenol) compared with acetaminophen in isolated rat liver

The hepatic disposition of a new analgesic, SCP-1, a derivative of acetaminophen, was studied in the isolated perfused rat liver using a recirculating system. The aim of this study was to compare the kinetic parameters of this molecule with those of acetaminophen. Sprague-Dawley rat (230-330 g) livers were perfused for 2 h with 250 ml Krebs-Henseleit bicarbonate buffer containing SCP-1 or acetaminophen, 0.07 mmol l(-1) (n=4), 0.28 mmol l(-1) (n=4), and 0.8 mmol l(-1) (n=4) (approximately one, four and ten times the therapeutic doses in man, respectively). Perfusate samples were collected from the efflux at various times. The SCP-1 and acetaminophen perfusate concentrations were assayed by a HPLC method. Pharmacokinetic analysis was carried out using a computer program. There were significant differences between the hepatic kinetics of SCP-1 and those of acetaminophen. Thus, SCP-1 elimination half-life (mean 14.8+/-10.0 min) was shorter than that of the acetaminophen (186.1+/-27.7 min) (t=11.6, P=0.0001). While the half-life of SCP-1 increases with concentration, the half-life of acetaminophen remains constant as the concentration increases. The hepatic clearance was higher for SCP-1 than acetaminophen (mean 19.01+/-14.5 ml min(-1) vs. 1.29+/-0.08 ml min(-1), respectively) (t=2.44, P<0.05), and it behaved according to dose-dependent kinetics. The SCP-1 extraction ratio was higher (mean 0.63+/-0.49) than for acetaminophen (0.04+/-0.01) (t=2.41, P<0.05) and this parameter tended to decrease as the perfusate concentrations of SCP-1 increased. It was concluded that the hepatic kinetics of SCP-1 behaved according to dose-dependent kinetics, and statistically significant differences were found between pharmacokinetics parameters of both drugs studied.

Adverse drug reactions (ADRs) in hospitalized pediatric patients. A prospective study

The aim of this study was to determine the frequency and the characteristics of ADRs in 219 hospitalized pediatric patients, using an intensive and prospective drug surveillance method. The frequency of ADRs in these patients was 13.7%. The systems most commonly affected were the gastrointestinal (32.5%), the central nervous (20.0%), and the metabolic systems (17.5%). Asparaginase, methotrexate, phenytoin, phenobarbital, erythromycin, and salbutamol were probably the drugs associated with the ADRs. According to causality, 54.2% of the ADRs were regarded as probable, and 32.2% as possible. The majority of the ADRs were moderate (51.2%), 27.9% were severe. The main treatment of the ADRs was the withdrawal of the suspected drugs. The length of the stay in the hospital and the total number of drugs given to the patients influenced significantly the frequency of ADRs. 93% of the ADRs were dose-dependent.

Pharmacokinetics of ketorolac in children after abdominal surgery

The pharmacokinetics of 2 doses of intravenous ketorolac (0.5 and 0.9 mg x kg-1) were studied in 14 children (age 2-8 years). A single dose of the drug was injected into the dorsum vein of one hand. Blood samples were collected at regular time intervals for 6 hours. Serum ketorolac concentrations were assayed using a high pressure liquid chromatography method. Pharmacokinetic values were estimated by a nonlinear computer program. The distribution volume (Vdarea), the total clearance (Cltotal), and elimination half-life (t1/2 beta) were similar in both groups of children who either received 0.5 or 0.9 mg x kg-1 of ketorolac. The estimated geometric mean Vdarea, Cltotal, and t1/2 beta ratios (95% CI in parentheses) for 0.9 mg x kg-1:0.5 mg x kg-1 were 1.24 (0.82, 1.50), 1.14 (0.88, 1.23), and 1.083 (0.40, 1.81), respectively. The pharmacokinetic parameters found in this study are different from those found by other authors in adult subjects.

Pharmacokinetics and hepatotoxicity of diclofenac using an isolated perfused rat liver

Pharmacokinetics and hepatotoxicity of diclofenac was studied in a recirculating model of isolated perfused rat liver. Ten male Sprague-Dawley rat (weighing 230-330 g) livers were perfused for 2 h with 250 mL Krebs-Henseleit bicarbonate buffer that contained 10.75 mg (group A, n = 5) and 1.075 mg (group B, n = 5) of diclofenac (approximately 100 and 10 times the therapeutic dose in man, respectively). Samples were collected from the efflux at regular time intervals for the determination of diclofenac concentrations by a high performance liquid chromatography (HPLC) method. Pharmacokinetic analyses were carried out using a computer program. To establish viability of the liver and toxicity of the drug, enzyme activity measurements of lactate dehydrogenase (LDH), aspartate aminotransferase (SGOT) and piruvate aminotransferase (SGPT) were performed by a spectrophotometric method. Oxygen consumption was also recorded during the entire perfusion period. Both groups presented bicompartmental kinetics. Concentration profiles showed that group B had a better metabolizing capacity, reflected in a 85.54 +/- 37.05 min half-life, a 0.52 +/- 0.19 mL min-1 g-1 liver clearance and a 0.517 +/- 0.188 extraction ratio, compared to group A, which presented a 123.95 +/- 88.13 min half-life, a 0.1164 +/- 0.067 mL min-1 g-1 liver clearance (P < 0.002) and a 0.116 +/- 0.680 extraction ratio (P < 0.002). LDH activity showed a significant increase in group A at 90 min in comparison with the control group, while in group B this increase was significantly higher at 10 min (P < 0.004). The aminotransferase levels did not show a significant increase. According to these results, diclofenac would not have a direct hepatotoxic effect, even at doses 100 times higher than therapeutic ones.

Pharmacokinetics of lysine clonixinate in children in postoperative care

The pharmacokinetics of 2 doses of intravenous lysine clonixinate (4 and 6 mg x kg-1) were studied in 10 children (age 4-10 years) under postoperative care. A single dose of the drug was injected in a forearm vein. Blood samples were collected at regular intervals for 3 hours. Serum clonixin concentrations (expressed as clonixin) were analyzed using a high pressure liquid chromatography method. Pharmacokinetic values were estimated by a nonlinear computer program. The distribution volume was similar in both groups of children (1.288 +/- 0.829 1 and 1. 139 +/- 0.667 1, respectively). There were no differences between the values of total plasma clearance and the administered doses (0.026 +/- 0.017 ml x min-1 and 0.017 +/- 0.008 ml x min-1, t = 1.07, p = 0.76). The elimination half-life was longer in children who received 6 mg x kg-1 (44.26 +/- 6.34 min vs 38.63 +/- 10.93 min) but this difference was not statistically significant (t = 0.99, p < 0.34). The pharmacokinetic parameters calculated in these children were different from those found by other authors in adults and experimental animals.

Disposition of nifurtimox and metabolite activity against Trypanosoma cruzi using rat isolated perfused liver

Nifurtimox disposition was investigated using the rat isolated perfused-liver method after administration of 25 micrograms mL-1 nifurtimox, and its disappearance was monitored by analysing the perfusate sample at various times. Biliary excretion was also measured. The drug concentration profile underwent a biexponential decline over the 2-h study period, with a terminal half-life of 62.76 +/- 17.56 min. Nifurtimox is a high clearance compound (15.23 +/- 5.53 mL min-1). The extraction ratio was 0.621 +/- 0.159. Biliary excretion accounted for 0.05% of the dose, the remainder consisting of highly polar metabolites. By 2 h, a minimal fraction of unchanged nifurtimox was recovered from the perfusate. Nifurtimox activity against Trypanosoma cruzi (clone CA-1) during the perfusion was also determined. Epimastigotes isolated from continuous culture were exposed to the samples of perfusate at different perfusion times in a microtitre plate. After an incubation time of 72 h at 27 degrees C, the parasite number in each well was counted under a microscope. From 0 to 75 min after the perfusion, the anti-trypanosomal activity decreased, but an increase in activity was observed at the later times. These findings show that active metabolites are formed during the perfusion.

Heparin-induced transaminase elevations: a prospective study

An intensive and prospective surveillance study of 54 patients hospitalized in the Internal Medicine Unit of Clinical Hospital of the Catholic University of Chile, who required heparin in the period between June and December of 1991 was done. The aim of the work was to characterize and study the incidence of the adverse reactions associated with heparin therapy, with special emphasis on abnormal serum transaminase elevation. Abnormal transaminase elevation was defined as a rise over 20% of the serum transaminase baseline value. For determining the serum transaminase level, a UV spectrophotometric method was used. The incidence of the adverse drug reactions (ADR) was 24.1% (13 ADR), 8 of which (14.8%) were related with heparin therapy. Three of them (5.5%) corresponded to alanine transaminase (ALAT) increase and five (9.3%) to aspartate transaminase (ASAT) elevation. By means of global introspection method, 3 cases of ALAT increases were defined as probable and 6 as possible, while 5 ASAT increases were estimated as probable and 14 as possible. All of them were of slow onset, did not require treatment and hospital stay was not prolonged. Two patients' characteristics--age and sex--were associated with the development of heparin-induced abnormal alanine transaminase concentrations. The younger male patients showed a greater frequency of heparin-induced ALAT elevation. However, this association was not observed with the heparin-induced ASAT increase. These reactions were dose-dependent. Patients with heparin-induced ALAT elevation received a dose of 154,220 IU +/- 72,970 IU in comparison to patients without that adverse reaction who received 96,210 IU +/- 40,340 IU. This difference was statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

The disposition of nifurtimox in the rat isolated perfused liver: effect of dose size

The disposition of nifurtimox was studied in the rat isolated perfused liver using a recirculating system. The drug was administered as a bolus (5.0, 15.0 or 30.0 micrograms mL-1), and its disappearance was monitored by analysing perfusate samples. In all experiments perfusate disappearance was monoexponential, and no significant difference was found between the three doses for the elimination constant (0.016, 0.011 and 0.012 min-1, respectively), half-life (46.6, 65.8 and 66.8 min, respectively), extraction rate (0.128, 0.091 and 0.099, respectively) and distribution volume (41.1, 47.3 and 30.7 mL g-1, respectively). At 30 micrograms mL-1 the hepatic clearance was lower than the other concentrations of nifurtimox (0.66, 0.51 and 0.34 mL min-1 g-1, respectively). Relatively little parent drug was recovered from the liver at the end of the perfusions. In summary, nifurtimox is cleared slowly from the rat isolated perfused liver, is poorly extracted by hepatocyte cells and is completely metabolized from 2 to 4 h after perfusion.

The pharmacokinetics of nifurtimox in chronic renal failure

The pharmacokinetics of nifurtimox, a drug used in the treatment of Trypanosoma cruzi infections, has been studied in seven patients with chronic renal failure undergoing haemodialysis, and in seven healthy subjects. Each subject took nifurtimox 15 mg.kg-1 orally and blood samples were obtained for 10 h after administration. Nifurtimox in serum was analyzed by HPLC. The patients with chronic renal failure had a higher Cmax than the control subjects due to a change in systemic availability. An alternative explanation would be that both the distribution volume and the clearance had changed. The mean half-life in the patients with chronic renal failure was similar to that in the healthy subjects.

Heparin-induced hyperkalemia: a prospective study

Heparin is frequently used for the prophylaxis and treatment of deep venous thromboembolism and it induces hypoaldosteronism leading to hyperkalemia, an uncommon adverse effect. In an intensive prospective drug monitoring study, 154 inpatients at the Internal Medicine Unit of Hospital Sotero del Río, Santiago, Chile, received heparin in the period between March and November 1990. Mean age of the patients was 65.8 +/- 12.9 years and 56.5% were female. Twenty-one (13.6%) patients developed heparin-induced adverse reactions. Thirteen events were hyperkalemia, 7 ecchymoses and 1 hematuria. The monitoring team and attending physicians have agreed to classify 9 heparin-induced hyperkalemia cases as probable and the other 4 as possible. No adverse reaction was fatal but 8 of the patients had severe hyperkalemia. Almost all reactions were dose-related. Hyperkalemia was more frequent in patients with diabetes mellitus, metabolic acidosis and long-term heparin therapy. The frequency of hyperkalemia did not correlate with age, sex, renal impairment or with previous use of anti-inflammatory drugs, heparin or aspirin.

Pharmacokinetics of gentamicin in children with nephrotic syndrome

The disposition of gentamicin was studied in five children with nephrotic syndrome and five control children to observe the effect of nephrotic syndrome on the distribution and elimination of the antibiotic. After a single intravenous dose of gentamicin (2.0 mg/kg body wt.) administered to each child, blood samples were drawn at frequent intervals during a 4-h period and then analyzed by homogeneous enzyme immunoassay (EMIT). Time-concentrations drug profiles were characterized by means of a two-compartment open model. The mean half-life of gentamicin in nephrotic children (96.4 +/- 16.8 min) was significantly longer than in the control group (62.5 +/- 7.1 min). The distribution volume of the central compartment was similar in both groups studied, but the distribution volume at steady-state was increased in children with nephrotic syndrome. Total plasma clearance was found decreased in nephrotic (2.8 +/- 0.5 ml/min/kg) in comparison with controls (3.7 +/- 0.7 ml/min/kg). From our findings, it could be concluded that serum level of children with nephrotic syndrome treated with gentamicin should be carefully monitored in order to avoid the toxic effects of the antibiotic.