International journal of clinical pharmacology, therapy, and toxicology最新文献

Loxapine is a drug which is used in the treatment of psychotic disorders. The drug is extensively biotransformed in humans to produce a variety of metabolites, some of which have pharmacological activity. Seven-hydroxyloxapine is 4-5 times more active than the parent drug, although its concentrations in plasma are relatively low. Eight-hydroxyloxapine, on the other hand, is inactive, but is present in higher concentrations in plasma than the parent drug. In the present randomized crossover study to evaluate the bioequivalence of two dosage forms containing loxapine, the parent drug and its 7-hydroxy and 8-hydroxy metabolites were monitored for up to 96 hours after the administration of the test or reference formulations. Estimates of average bioavailability (AUC- infinity, AUC0t and Cmax) were obtained by the difference of the least squares means of log test and log reference. A 90% confidence interval for the log difference was derived from the within-subject error. The test of bioequivalence requires the 90% confidence band so calculated to fall entirely within an imposed regulatory interval of 80-125%. The results showed the two formulations to be bioequivalent in terms of the log mean differences and 90% confidence bands calculated for all three analytes. In fact, the within-subject variabilities of the metabolites were relatively low, so that the 90% confidence intervals for ln AUC0 infinity, ln AUC0t and ln Cmax calculated for the metabolites, were narrower that those for the parent drug.(ABSTRACT TRUNCATED AT 250 WORDS)

We examined the effect of foscarnet (Foscavir) in 15 AIDS patients with cytomegalovirus infection. Cytomegalovirus infection was presented as retinits (n = 8), colitis (n = 3), oral (n = 1) and perianal ulcers (n = 3) and pneumonitis (n = 1). Induction therapy with foscarnet showed a complete response in 9 and a partial response in 6 patients after a medium therapy of 3.5 weeks. Three patients showed progressive disease under ganciclovir and were treated subsequently with foscarnet. Main side effects were ulcers of the glans penis (n = 6) and a rise of creatinine (> 1.5 mg/dl; n = 4). Therapy was changed to ganciclovir because of renal toxicity in 1 patient receiving induction therapy with foscarnet. Within a period of foscarnet therapy between 5 and 9 months (median: 7 months) no clinical progression occurred. Medium survival after diagnosis of cytomegalovirus infection was 7.4 months. We describe our experience with foscarnet and compare treatment results of cytomegalovirus infection at certain locations.

Prostaglandins are known to interfere with drug metabolizing processes. Nocloprost (9 beta-chloro-16,16-dimethyl PG E2) is a promising new cytoprotective prostaglandin in clinical evaluation for the treatment of ulcer disease and prophylaxis of gastric lesions caused by NSAID. Pharmacokinetic interactions of 400 micrograms nocloprost with 15 mg/kg antipyrine and 500 mg sulfamethazine (all given p.o.) were studied with a controlled, single-blind crossover trial in 16 healthy male volunteers (age 22-25 years, body weight 63-94 kg, body height 175-187 cm) in order to measure potential interferences with oxidative and conjugative drug metabolism. All individuals were extensive metabolizers of debrisoquine, 9 were slow and 7 rapid acetylators of sulfamethazine. Antipyrine and its major metabolites were measured in serum respectively, urine with the HPLC-method, sulfamethazine and its acetylated metabolite with a colorimetric technique. Nocloprost premedication (30 min prior to the test drugs) did neither interfere significantly with the oxidative processes involved in the disposition of antipyrine nor with the N-acetylation of sulfamethazine. Higher metabolic and renal clearance values of sulfamethazine in slow acetylators were most likely the result of the affected drug absorption. Nocloprost significantly reduced absorption rates of antipyrine and sulfamethazine in the group of slow but not of rapid acetylators. The extent of bioavailability remained unchanged. This phenomenon was certainly caused by the effects of the cytoprotective prostaglandin on those gastrointestinal functions which are determinants of drug absorption.

In order to enable the setting of regulatory criteria for the equivalence of absorption rates on a sound scientific basis, the variation of Cmax/AUC and Cmax was evaluated. Under most conditions, the variation of Cmax/AUC was 10-25% higher than that of AUC independently of the variability of the extent of absorption. By contrast, the variation of Cmax was 50-60% higher than that of AUC and was strongly dependent on the variability of the extent of absorption. Therefore, it is recommended that for establishing the equivalence of absorption rates, the 90% confidence limits for the percentage ratio of the Cmax/AUC values of two drug products should be (based on their logarithmic averages or medians) between 75 and 133%. Regulatory decisions based on Cmax, while not favored, should expect that the 90% confidence limits for the percentage ratio of the Cmax values of two drug products be (based on their logarithmic averages or medians) between 70 and 143%. These recommendations parallel and are contingent upon the internationally harmonized criterion for the equivalence of extents of absorption which requires that the 90% confidence limits for the percentage ratio of two AUC values (based on their logarithmic averages or medians) be between 80 and 125%.

A total of 502 children up to the age of 14 years were treated for iron deficiency or overt anemia. ITF 282 was prescribed to 256 children, and a commercially available ferrous polystyrene sulphonate preparation to 246, in a randomized double-blind, double-dummy, ten-center trial. One oral vial of ITF 282 (60 mg iron) was administered once a day to children weighing up to 40 kg; and twice a day to children with body weight equal or superior to 40 kg. In the reference group, oral vials of polystyrene sulphonate (52.5 mg iron) were administered once a day to children weighing up to 40 kg, and twice a day to children weighing 40 kg or more. Treatments lasted 60 days. The treatments' efficacy and tolerability were evaluated taking into consideration: special hematology, symptomatology, safety hematology and hematochemistry, urinalysis. At the end of treatment, the trend was detected to the normalization of the main hematologic parameters in both groups (hemoglobin, hematocrit, ferritin, blood iron, transferrin saturation, MCHC). Although in the first month the reference treatment appears to provide somewhat faster results, significantly greater values of blood iron are observed at the end of the observation in the ITF 282 group, indicating a more progressive and steady therapeutic effect. The overall clinical rating was, although not significant, in favor of ITF 282, with a failure rate of 18.0 vs 24.0%. The general tolerance, although favorable with both treatments, was significantly more favorable with ITF 282. With this medication, 13 patients complained of 13 events (1 heartburn, 6 constipation, 6 abdominal pain) vs 48 events reported by 43 patients with the reference medication (1 heartburn, 2 epigastric pain, 14 constipation, 14 abdominal pain, 3 skin rash, 14 vomiting). These observations confirm that, although the most modern preparations of ferrous ions exhibit a relatively low frequency of adverse events of limited clinical concern, it is nevertheless possible to decrease (with the use of more "physiologic" preparations in which the iron is reversibly bound to a protein carrier) the prevalence and, tendentially, duration and intensity of such events without prejudice for the clinical efficacy. Therefore, the good clinical tolerability of ITF 282 effectively removed one of the main obstacles to the correct compliance with iron treatments (necessarily to be taken long-term), as reduced the risks of undesired events in a particularly susceptible population subgroup, such as children.

In a double-blind crossover study, the pharmacokinetics and effects on night-time respiration and body movements of midazolam 7.5 mg, flunitrazepam 1 mg, and placebo were studied in 5 elderly insomniac patients with the static charge sensitive bed-method (SCSB). In a supine position, the gastrointestinal absorption rate of flunitrazepam (tmax 0.6 h) was faster than that of midazolam (tmax 0.95 h). The elimination phase half-life of midazolam was about twice as long as reported earlier in healthy adult volunteers, but ageing did not affect the elimination of flunitrazepam. The shape of the serum concentration-time curve of both benzodiazepine derivatives was quite similar. The sleep of these five insomniacs became more peaceful and the respiration more regular during midazolam and flunitrazepam, compared with placebo. Both benzodiazepines significantly decreased body movements and the cumulative movement time remained shorter throughout the night, compared with placebo. Total variability (VI) was clearly decreased with flurazepam, and a similar but not statistically significant tendency was seen with midazolam, compared with placebo. Accordingly, the proportion of quiet sleep (QS) increased (p = 0.014) and the proportion of active sleep (AS) decreased (p = 0.019) with both benzodiazepines, compared with placebo. This reflects the changed control of respiration by higher brain structures. No signs of increased respiratory resistance (i.e. ballistocardiographic respiratory amplitude variation BRV < 60%) were seen with either of the drugs or placebo. There were no differences in the subjects' own estimation of their sleep during medication with these drugs. Only the sleep onset latency was shorter with flunitrazepam compared with midazolam and placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Hydroxyzine is frequently used to tranquilize chronic obstructive pulmonary disease patients, who may be concomitantly receiving narcotic analgesics. Therefore, its effect alone and in combination with meperidine on arterial blood gases and ventilation at rest were evaluated in 44 patient volunteers, who gave informed consent. Hydroxyzine, 1.5 mg/kg i.v. caused no significant decrease in PaO2 and pH, no increase in PaCO2 at 5, 10, 20, 30 and 60 min post-infusion (n = 13, mean age = 63.4 years). Meperidine, 1.5 mg/kg i.v. caused a significant (p < 0.001) reduction in PaO2 for 20 min with concomitant increase in PaCO2 (n = 14; mean age = 49.4 years). The combination of the same doses of hydroxyzine with meperidine i.v. caused no greater decrease in PaO2 or in pH or increase in PaCO2 than did meperidine alone (n = 17; mean age = 52.6 years), indicating no greater ventilatory depression with the combination than with meperidine alone. The lack of significant pH decreases at 30 and 60 min further corroborates no potentiation of meperidine by hydroxyzine. In conclusion, hydroxyzine, even when given through the i.v. route in excess of the maximum i.m. therapeutic dose, caused no changes in PaO2, PaCO2 or pH in chronic obstructive pulmonary disease patients. Therefore, its i.m. administration resulting in lower blood levels than i.v., is not likely to cause ventilatory depression. Furthermore, hydroxyzine caused no potentiation of the ventilatory depression induced by meperidine, hence hydroxyzine may be safely employed in combination with meperidine.

The precision and accuracy of HPLC and FPIA for the measurement of flecainide plasma levels were compared below, in and above the therapeutic range (200-1,000 ng/ml). Following a calibration crossover study, five standard plasma solutions of varying flecainide concentrations (SPS) and 99 flecainide containing plasma samples of 24 in-patients (IPS) were analyzed with both methods. The results show that within the range of approximately 500-1,500 ng/ml, the two methods did not differ in either precision (expressed as coefficient of variation, CV) or accuracy (expressed as relative error, RE). Close to the lower limit and below the therapeutic range however, HPLC provided greater precision and accuracy than FPIA.

Bacteriological specimens from a total of 64 patients with six common, highly relevant clinical indications were collected for an in vitro investigation. By means of standard microbiological methods, 149 species of organism were differentiated, and their relative sensitivity to Taurolin, a broad spectrum chemotherapeutic and antitoxin, as well as 5 conventional finished pharmaceuticals were tested in agar diffusion tests. Taurolin, which was tested in 3 different galenic formulations, produced practically identical, but considerably wider zones of inhibition than all other compared products. In contrast to other substances which exhibited a failure rate of up to 24.8%, no gaps in the activity spectrum in the form of the lack of inhibition zone formation were observed.

The aim of this study was to compare the efficacy and safety of amikacin given either as single injection or as two injections within 12-h interval in the treatment of severe gram-negative infections in elderly patients. Thirty-nine non-selected consecutive patients of a general internal medicine facility were randomized to receive the same total daily dose of amikacin either as a single dose (19 patients) or divided into two doses injected at 12-h interval (20 patients). Amikacin was used alone or in combination with metronidazole, clindamycin, fosfomycin or a beta-lactam. Clinical and bacteriological responses were satisfactory and comparable in the two groups. There was no difference between the once/day and the twice-a-day groups with respect to drug dosage, duration of therapy and concomitant treatment. Only one patient (BID group) showed a rise of serum creatinine during the observation period. Amikacin alone or in combination can be regarded as an efficacious and safe antibiotic in the treatment of severe gram-negative infections in elderly patients, whether the daily dose is administered in a single infusion or in a BID interval.