Drug therapy: safety, effectiveness, and economics

The problems of safety, effectiveness and economics of a drug therapy are discussed. Adverse drug reactions (ADR) represent not only a humanistic problem but also an epidemiological and economic one. The incidents and costs of ADRs are described, as well as pharmacovigilance and pharmacoeconomics as a tool of rationalizing the expenditures on health care.

The bacterial flora and the changes of the N-nitrosamine concentration in the operated stomach

The studies included 170 patients (103 men and 67 women) aged 23 to 66 years, operated on because of an ulcerous disease. Depending on the method of surgical treatment patients were divided into 5 groups (those after gastric resection with Rydygier's method, after resection with the Billroth II method, after trunk vagotomy with pyloroplasty, after highly selective vagotomy, and after gastro-enterostomy). In all patients a qualitative estimation of the nitrate-reducing bacteria was carried out, as well as a chromatographic test of the selected N-nitrosamine concentration in the gastric juice. It was shown that the changes in the quantity of the nitrate-reducing bacteria and in the N-nitrosamine concentration depended on the type of surgical intervention conducted. The largest mean content of nitrate-reducing bacteria and the highest average N-nitrosamine concentration were confirmed in the gastric juice of patients after gastroenterostomy and after gastric resection with the Billroth II method, and the lowest values--in patients after highly selective vagotomy.

Validation of a LC method for the determination of 5-aminosalicylic acid and its metabolite in plasma and urine

The choice of a proper analytical method for the quantification of drugs and/or their metabolites in biological samples plays a significant role in the evaluation and interpretation of bioavailability, bioequivalence and pharmacokinetic data. The aim of this study was validation of a method for the identification and quantitative determination of 5-aminosalicylic acid (5-ASA) and its metabolite N-acetyl-5-aminosalicylic acid in human plasma and urine. According to previous studies on the disposition of 5-ASA (mesalazine) in a patient with inflammatory bowel diseases, we have developed a rapid, sensitive method for the determination of 5-ASA and its acetylated metabolite, N-acetyl-5-aminosalicylic acid (Ac-5-ASA). The advantage of this method is that it measures both compounds, and is more rapid, reproducible and credible than the previous studies [C. Fischer, K. Maier, U. Klotz, J. Chromatogr. Biomed. Appl. 225 (1981) 498-503; P.N. Shaw, A.L. Sivner, L. Aarons, J.B. Houston, J. Chromatogr. Biomed. Appl. 274 (1983) 393-397; B. Norlander, R. Gotthard, M. Strom, Aliment. Pharmacol. Ther. 3 (1989) 333-342; U. Klotz, G.L. Stracciari, Arzneim.-Forsch. Drug Res. II 43 (12) (1993) 1357-1359]. 5-ASA was quantitatively determined in human plasma and urine samples by liquid chromatography following prior derivatization to its acetylated metabolite (Ac-5-ASA). N-Acetyl-anthranilic acid was used as the internal standard. The detection was performed with a spectrofluorimetric detector, excitation at 311 nm, cut-off at 449 nm. The method was validated for the following parameters: linearity, recovery, sensitivity, precision, accuracy, selectivity and stability, limits of quantification and of detection. It showed good linearity (r2 > or = 0,996) in the range 0.1 ng/ml to 8 microg/ml using a Lichrospher 60 RP-select B column. The lower limit of detection was 20 ng/ml in plasma and urine. The within-run relative standard deviations (R.S.D.) were below 6.7% at all concentration levels and the between-run R.S.D. were below 25.4% at all concentration levels.

Chronopharmacokinetics of amitriptyline in rats

The circadian changes in absorption, tissue distribution and elimination of amitriptyline after single intravenous (i.v.) and intragastric (i.g.) administration, as well as the differences in pharmacokinetic profile after multiple i.g. administration (at 10:00 and 22:00 h) during a 12 h dosing interval, were investigated. The circadian changes of pharmacokinetic parameters of amitriptyline such as AUC (serum and tissues), clearance (i.v. and i.g.), volume of distribution, biological half-life and bioavailability were estimated. Acrophases for clearance appeared between 19:00 and 21:00 h; the bioavailability was highest during the dark phase at around 04:00 h. Higher values of AUC in serum were observed at the beginning of the light phase. A circadian rhythm of tissue distribution (AUC, K(D)) of amitriptyline with acrophase in the dark phase was observed for brain (12 h period), lung and liver (24 h), but not for heart or kidney. After single (i.v. and i.g.) amitriptyline administration, concentrations of its major metabolite, nortriptyline, were negligible; however, after ten doses, nortriptyline serum and tissue levels were similar to the concentrations of the parent drug with higher values during the day (light phase).

[Levels of N-nitrosamine in gastric juice of patients after surgery for ulcers]

The concentration of N-nitrosamines was determined in the gastric juice of 170 patients between 6 months and 33 years after operation for ulcer disease, including 38 patients after resection with the Rydygier method (BI-R), 36 after Billroth II method (BII), 35 after truncal vagotomy with pyloroplasty (VP), 41 after highly selective vagotomy (WWW) and 20 after gastroenterostomy (ZZJ). The concentration of N-nitrosamines in the gastric juice was estimated chromatographically. It was confirmed that their concentration in the stomach was the highest after ZZJ and BII resection, lowest after WWW.

[The effect of Helicobacter pylori infection and duodenogastric reflux on the histology of gastric mucosa in peptic ulcers]

In a group of 96 patients with peptic ulcer (36 patients with ulcer of the stomach, 60 patients with ulcer of the duodenum) we analysed the alterations of the mucosa of the stomach associated with the ulcer. A significantly frequent occurrence was shown of the athropic gastritis and of the dysplasia in patients with ulcer of the stomach in comparison with the group of patients with ulcer of the stomach in the comparison with the group of the patients with ulcer of the duodenum. Among the patients analysed we also appraised the alterations on the picture of the stomach mucosa of the Helicobacter pylori infection, of the duodeno-gastric reflux as well as of the concentration of the bile acids and of lysolecithin contained in the gastric juice in the ulcerous disease of the stomach and of the duodenum. The presence of the Helicobacter pylori infection was identified bacteriologically, the duodeno-gastric reflux was diagnosed with the radionucleide method and the concentration of the bile acids and lysolecithin in gastric juice was determined chromatographically. It was confirmed that the Helicobacter pylori infection as well as the bile acids and the lysolecithin the concentration of which in the gastric juice in patients with an ulcer in the stomach were significantly higher in comparison with patients with and the ulcer in the duodenum, were a decisive factor for more exacerbated histological alterations of the mucosa of the stomach in case of ulcer of the stomach.

Effect of ethanol dose on its chronopharmacokinetics in the rats

Circadian changes in the elimination of ethanol after its administration in the rats in two doses: low (1.5 g/kg) and high (4.5 g/kg) were investigated. Circadian rhythm in ethanol pharmacokinetics (AUC, CLpo, t1/2) was observed after the low dose but not after the high one. The maximum rate of elimination was in the dark (active) phase at 1 am. The maximum value of clearance was related to the minimum value of AUC. Although the maximum and the minimum values of Vmax and KM differed essentially the diurnal variation were not observed.

Inhibitory action of cimetidine on antipyrine metabolism

The influence of cimetidine on the activity of microsomal enzymes in vivo using the simple one-sample antipyrine test was investigated. The calculated antipyrine clearance unequivocally indicates the dose-dependent effect of cimetidine on the microsomal biotransformation of antipyrine. The IC50 of cimetidine inhibitory effect was 39.9 mg/kg. The duration of the effect was approximately 12 h and the lowest antipyrine clearance was observed 0.5 h following cimetidine administration. The in vivo results were confirmed by an in vitro study. Km for global metabolic processes of antipyrine in vitro was 1.3 mM. Vmax 9.1 nM/mg/min for control was decreased to 3.1 nM/mg/min after addition of cimetidine (4 mM). The inhibition constant of cimetidine determined by the method of Dixon, was 2.8 mM. Inhibition of antipyrine metabolism by cimetidine was noncompetitive.

Cross-reactivity between pollen extracts from six artemisia species

Pollen extracts of six different ARTEMISIA species, A. VULGARIS, A. SCOPARIA, A. PRINCEPS, A. TRIDENTATA, A. ANNUA, and A. CAMPESTRIS were compared using SDS-PAGE, IEF, immunoblotting, and immunoelectrophoretic methods. The band patterns obtained after SDS-PAGE and IEF showed a large degree of similarity between the extracts. Immunoblotting of these gels using a pool of sera from patients allergic to A. VULGARIS gave essentially the same IgE-binding band pattern with all the extracts, demonstrating an extensive degree of cross-reactivity between A. VULGARIS and the other ARTEMISIA species. FRIE using a polyspecific antiserum against A. VULGARIS showed that all the extracts contained several antigens that were immunologically identical to antigens in A. VULGARIS extract. Antigens showing immunological identity to the important A. VULGARIS allergens Ag 12 and ART V II were present in all the extracts. The cross-reactivity between A. VULGARIS and A. PRINCEPS was further verified by screening of ten Korean and nine Norwegian individual patient sera against extracts of both species in SDS-PAGE or IEF immunoblotting. Both groups of patients had essentially the same pattern of reactivity towards both pollen extracts.

Circadian changes in the elimination of amitriptyline in rats

The circadian changes in elimination and absorption of amitriptyline after its intravenous and intragastric administration in rats were investigated. The values of such parameters as: AUC, MRT, t1/2, Cl, Vd, k(a) for amitriptyline change in the circadian rhythm. The fastest elimination of amitriptyline was observed in the dark phase (the acrophases for clearance were ca. 11 p.m. for iv administration and ca. 10 p.m. for po administration). The maximal value of clearance corresponds to the minimal values of MRT and t1/2. The acrophase for the constant absorption rate (po) falls at 7 p.m. Cyclic changes were not observed as far as the bioavailability is concerned.

The effect of some microsomal enzyme inducers on amitriptyline distribution in rats

The influence of different types of enzyme inducers: phenobarbital, Aroclor 1254 and benzo(a)pyrene, on distribution of amitriptyline and its metabolite nortriptyline in rats was investigated. The level of amitriptyline and nortriptyline in serum, brain, heart and liver was determined by gas chromatography. The maximum concentration values of amitriptyline and nortriptyline as well as areas under concentration-time curves (AUC0-6) in serum and organs were statistically compared using Student t test and AUCCOMP computer program. The results suggest that studied xenobiotics significantly influence the distribution of amitriptyline and nortriptyline in rats. The changes of these drugs concentration in target organs may be very important from the toxicological point of view.

The influence of ethanol on the distribution of amitriptyline and nortriptyline in rats

The influence of ethanol in single and multiple doses on concentration-time profile of amitriptyline (1) and nortriptyline (2) in rat serum, brain, heart, and liver was studied. AUC0-6 values were calculated and statistically compared as well as cmax values in serum and tissues. Ethanol inhibited N-demethylation of 1 and therefore 2 has not been detected in biological material. AUC0-6 and cmax values were less than in control group. All AUC0-6 and cmax values for 1 in ethanol treated groups of rats were statistically significant compared with the control group.

Wide-bore capillary column gas chromatography in toxicological analysis of biological samples from multidrug overdoses fatalities

Fatalities from multidrug overdoses account for 25% of the total number of all poisoning fatalities and as such deserve greater attention from researchers than single drug overdoses. High resolution, good sensitivity, and repeatability provided by gas chromatography (GC) with wide-bore capillary silica and glass columns make GC particularly useful for identification and quantitative analysis of drugs in toxicological screening of autopsy specimens. Results of toxicological findings in three deaths from multidrug overdoses (methaqualone, doxepine, methotrimeprazine, pernazine-aspirin, paracetamol, codeine-morphine, diazepam) occurring in routine medical practice are reported.

The influence of Aroclor 1254 on the elimination of theophylline in rats

The commercial mixture of pollychlorinated biphenyls (Aroclor 1254) accelerates the elimination of theophylline (given iv and po) from the body of the rat. The increase in theophylline elimination rate by Aroclor 1254 depends on Aroclor 1254 dose and time of the dosing. Aroclor pretreatment reduced the amount of orally given theophylline in that reached the circulation by 17%. This was caused by the influence of Aroclor 1254 on the elimination rate and possible first-pass effect.

The effect of chrysene and some polycyclic aromatic hydrocarbons on the elimination of theophylline in rats

The investigations of the effect of some compounds belonging to the group of polycyclic aromatic hydrocarbons (PAH), e. g. benzo[a]pyrene, chrysene, fluorene and pyrene, on the elimination of theophylline injected i. v. into rats have shown that benzo[a]pyrene and chrysene accelerate the elimination of this drug (elimination rate constant in control group: 0.2504 h-1; after benzo[a]pyrene: 0.3626 h-1; after chrysene: 0.3582 h-1). The increase of theophylline elimination rate constant by chrysene depends on its dose, and this relationship is of sigmoid type in the dose range of 1-20 mg X kg-1. Besides, dependence of theophylline elimination rate constant on the time of chrysene dosing was also shown. After oral administration of theophylline the decrease of its amount reaching the circulation by 11% was also observed, which was caused by the influence of chrysene on the first-pass effect, beside its influence on the elimination rate.