[Is there an improvement of drug safety in Germany in recent years?]. / Hat sich die Arzneitherapiesicherheit in den letzten Jahren in Deutschland verbessert?

The goal of drug therapy to prolong life or to improve the quality of life can be accomplished by modern drug therapy to a respectable degree. However, the risks of drug therapy have increased through more specific drugs and lead to often surprisingly multi-faceted side effects as in the case of biologicals. We have performed a systematic review of meta analyses, clinical studies, and reviews of the last five years concerned with adverse drug reactions (ADR) and adverse drug events (ADE). From these data emerges a distinct lack of reliable studies for Germany on incidence, severity and preventability of ADR and ADE; however, there are indications of their increase as is also evident from other countries. There are indications also for a better incidence management culture and better documentation. The step to utilize computerized physician order entry and decision support systems is a proven method to reduce medication related problems, leading also to reduction of in-hospital time and reduced drug expenses. Taking this decisive step to improve drug safety requires an appreciation of the magnitude of the problem and the determination to change an established but inferior system of drug administration in a fundamental way.

Effects of normalization of plasma testosterone levels in hypogonadal men on plasma levels and urinary excretion of asymmetric dimethylarginine (ADMA).

Elevated plasma levels of asymmetric dimethylarginine (ADMA) inhibit nitric oxide formation and exert a proatherogenic action. Low testosterone (T) levels are associated with increased cardiovascular risks. This study analyzed the effects of normalization of plasma T levels on plasma levels and urinary excretion of ADMA in hypgonadal men (n=10) receiving transdermal T administration. Plasma T levels, starting from clearly hypogonadal T plasma concentrations with a mean level of 4.0+/-2.72 nmol/l at baseline, rose to >10 nmol/l after 2 weeks, with plasma T levels within the normal range of men (mean level of 22.5+/-11.3 nmol/l) over the last 16 weeks of the 24 weeks of T administration. Normalization of plasma T led to a small but significant fall of plasma ADMA (519+/-55 vs. 472+/-59 nmol/l, p=0.031). The outcome of this study may be viewed as a favorable effect of normalization of plasma testosterone on plasma ADMA since even small elevations of plasma ADMA significantly increase cardiovascular risk. While this effect of normalization of plasma T may impress as favorable, most available studies on effects of T administration to hypogonadal men have not shown beneficial effects on functions of the vascular wall.

Low dialysance of asymmetric dimethylarginine (ADMA)--in vivo and in vitro evidence of significant protein binding.

BACKGROUND: Increased blood levels of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) predict cardiovascular mortality in patients with end-stage renal disease. Despite its low molecular weight, available information on the impact of hemodialysis (HD) on ADMA plasma levels is controversial. METHODS: We assessed plasma concentrations, dialyzer clearance and total amount of ADMA removed in 30 patients with end-stage renal disease during regular HD. In addition, plasma ADMA levels were assessed in 10 patients with acute renal failure treated with extended HD. RESULTS: Regular HD decreased plasma creatinine (from 774 +/- 42 to 312 +/- 17 micromol/l) and urea (from 24.5 +/- 1.5 to 8.4 +/- 0.5 mmol/l) concentrations significantly (both p < 0.001), whereas plasma ADMA remained unchanged (4.35 +/- 0.19 vs. 4.76 +/- 0.24 micromol/l). ADMA clearance was 92 +/- 6 ml/min, and the total amount removed in the spent dialysate was 37 +/- 4 micromol. The clearances of creatinine (161 +/- 3 ml/min) and of urea (173 +/- 3 ml/min) were significantly higher. Furthermore, even during extended HD, plasma ADMA concentrations did not decrease significantly (1.73 +/- 0.22 vs. 1.63 +/- 0.18 micromol/l). CONCLUSION: In conclusion, dialysance of ADMA is markedly lower than expected from its molecular weight because of significant protein binding of the substance. Since markedly increased ADMA blood concentrations have been linked to cardiovascular complications due to atherosclerosis in patients with ESRD, new strategies should be evaluated to remove this putative uremic toxin.

[Incidence and prevention of lethal undesirable drug effects]. / Zur Häufigkeit und Vermeidbarkeit von tödlichen unerwünschten Arzneimittelwirkungen.

About every second decision of a medical doctor concerns drug therapy. On the basis of a representative Norwegian study, which analyzed fatal drug reactions in stationary patients of internal medicine wards by autopsy and plasma drug concentrations, in Germany 58,000 fatalities are occurring in this patient population. The treating physicians classified only 6% of drug induced fatalities as such. Therefore, the risk of drug therapy is grossly underestimated. In half of the cases medication errors were causative and therefore these could potentially all be avoided. In addition to improved pre- and postgraduate education in clinical pharmacology the use of computer-based expert systems would be a decisive step to optimize drug therapy.

Elevated nitric oxide levels in patients with chronic liver disease and cirrhosis correlate with disease stage and parameters of hyperdynamic circulation.

Chronic liver diseases are accompanied by changes in splanchnic and systemic circulation. These changes are characterised by a reduction in peripheral vascular resistance and an increased cardiac output at rest. An increased release of nitric oxide (NO) has been proposed to play a role in the pathogenesis of vasodilatation and vascular hypocontractility. This study was designed to determine the nitric oxide metabolism measured as circulating nitrate levels in serum/urine in patients with chronic liver disease and cirrhosis. The nitrate concentrations were significantly increased in advanced degrees in cirrhosis Child B and C, and normal or even reduced in patients with chronic active hepatitis and early cirrhosis. In our study the connections between the extent of portal hypertension and nitrate levels were evident. The presence of ascites as well as the the progression of oesophageal varices were associated with higher circulating nitrate levels. The connection between increased nitric oxide production and the haemodynamic sequelae of portal hypertension is also apparent in the significant correlation between plasma renin and serum nitrate levels. Circulating nitrate levels also correlated to the serum interleukin-6 levels. This study demonstrated that the increased nitric oxide metabolism is associated with the haemodynamic alterations induced by portal hypertension.

Comparison of different activity parameters in atopic dermatitis: correlation with clinical scores.

BACKGROUND: Several laboratory markers have been described to correlate positively with disease activity of atopic dermatitis (AD). These include soluble adhesion molecules and eosinophil granular proteins. Although the correlation of these parameters with the severity and extent of skin involvement has been repeatedly studied in the past, no systematic investigation has been performed over a lengthy period of time. In addition, no subjective disease parameters recorded by the patient have been included in studies dealing with disease activity. OBJECTIVES: To assess the validity of different objective and subjective parameters [soluble E-selectin (sE-selectin), soluble vascular cell adhesion molecule-1 (sVCAM-1), eosinophil cationic protein (ECP), urinary nitrate excretion (reflecting endogenous nitric oxide formation) and the patients' impressions of pruritus, sleeplessness and skin status] as markers of AD disease activity. METHODS: Twenty patients were examined for 1 year and their skin status was evaluated by an established score (SCORAD). sE-selectin, sVCAM-1 and ECP were analysed by commercial test kits. Urinary nitrate concentration was measured by gas chromatography-mass spectrometry. The subjective parameters, pruritus, sleeplessness and impression of skin status, were recorded by the patients on a visual analogue scale. RESULTS: In this long-term trial, only sE-selectin and the subjective parameters showed a statistically significant correlation with the SCORAD score. CONCLUSIONS: Our data indicate that basic clinical scoring remains a most effective and relevant method of recording skin disease activity in AD.

Knowledge on drug dosages of ward physicians.

OBJECTIVE: Dosing errors are a common source for preventable adverse drug events. This study evaluated the knowledge of German hospital physicians with respect to the daily dosage of frequently used drugs. METHODS: A questionnaire survey was carried out among 168 ward physicians from three university and four municipal hospital departments of internal medicine asking for the daily dosage of 17 frequently used drugs. RESULTS: One hundred twenty-seven of 168 physicians returned a completed questionnaire, a response rate of 75.6%. Only 50% of the dose estimates were within the therapeutic range. Even in cases of frequent prescription 7% of the stated doses were overdosed and 15% were underdosed. CONCLUSIONS: The results of this survey suggest that adverse drug events and the lack of therapeutic effect due to dosing errors could be prevented by an improved knowledge of daily dosages.

Effects of intravenous oxygen on prostacyclin and thromboxane formation in patients with peripheral occlusive arterial disease.

Oxygen infusion is used in complementary medicine for treatment of peripheral occlusive arterial disease. The mechanism of action is unknown. Thus, we determined the effects of oxygen infusion on prostacyclin, thromboxane and nitric oxide synthesis. Twelve patients with peripheral occlusive arterial disease received oxygen 40 ml/d intravenously for 3 weeks. Study parameters, analyzed by gas chromatography-mass spectrometry on day 1, 3, 10, 16, 21: 2,3-dinor-6-oxo-PGF(1alpha), colour invisible 2,3-dinor-TXB2 and nitrate in one-hour-urine before and after oxygen infusion, reflecting prostacyclin, thromboxane and nitric oxide synthesis. Urinary 8-iso-PGF2alpha, indicating oxidative stress, was assessed in one patient. Urinary 2,3-dinor-6-oxo-PGF1alpha rose from baseline more than 4-fold after oxygen infusion. In contrast, urinary 2,3-dinor-TXB2 excretion remained unchanged. Oxygen infusion had no effect on urinary nitrate excretion. Urinary 8-iso-PGF(2alpha) was not influenced by oxygen infusion with and without diclofenac pretreatment. Our data demonstrate a shift of the prostacyclin/thromboxane ratio toward prostacyclin by oxygen infusion. Thus, a mechanism of action is provided and clinical trials with intravenous oxygen find a rational basis.

Blood donors on medication. Are deferral periods necessary?

OBJECTIVES: Drugs and their metabolites in transfused blood components may cause effects in the recipient. If the treated disorder is not to be regarded as an exclusion criterion from blood donation, donors on medication should be deferred for a period consistent with the drug's pharmacokinetics. GENERAL PRINCIPLES AND METHODS: Peak plasma drug concentrations of 3% or less of the therapeutic concentration were regarded to be safe for the recipient of a blood product. For teratogenic drugs a much lower safety level of less than 0.000001% has been proposed. For the calculation of deferral periods, both the type of blood component to be prepared and the drug's pharmacokinetics for a given formulation were considered. SUGGESTED WAITING PERIODS: For drugs with known teratogenic risks, we suggest a deferral period of 28 plasma-elimination half-lives. For non-teratogenic drugs, a simple, conservative approach could be based on waiting for five plasma-elimination half-lives, thus reaching the required 3% safety level already in any donor. If, however, the type of blood component to be prepared is also considered, a more differentiated approach appears to be appropriate: for blood components containing 50 ml or less plasma from a single donor, donor medication may be disregarded because of the high dilution in the recipient's plasma volume, whereas for blood components with higher plasma contents (250 ml on average) from a single donor on medication the 3% safety level will be achieved by observing the deferral period of five plasma-elimination half-lives mentioned. A guideline for 191 drugs and drug classes has been elaborated accordingly.

Availability of medicines in the European Union: results from the EURO-Medicines project.

OBJECTIVE: There is at present no comprehensive directory of medicines available in European countries. Such a directory would be valuable to policy analysts, clinicians, regulatory agencies, pharmaceutical companies and consumer groups. The aim of this project was to compile such a directory of all medicines marketed in each of the European Union member countries. METHODS: Lists of medicines for each country, compiled from several national sources, classified by Anatomical-Chemical-Therapeutic (ATC) code. Census date was late 1998. RESULTS: A comprehensive directory was created using data from 14 of the 15 European Union countries. Numbers of trade names and of active ingredients varied widely, from Germany with 18,554 and 1,973, respectively, to Denmark with 1,915 and 1,016, respectively. In individual therapeutic areas, there were variations in the numbers of active ingredients available: the least variation between countries was in antineoplastic medicines (ATC code L, maximum number available in any country 101, minimum 60) and wider variation in alimentary (ATC code A, maximum 256. minimum 103) or cardiovascular (ATC code C, maximum 269, minimum 112). Only 7% of all the active ingredients were available in all the countries studied. The Scandinavian countries had the greatest proportion of active ingredients (60%) available in all other countries. Each country had a number of active ingredients available only in that country Italy had the largest number of these. CONCLUSIONS: The directory illustrates the wide variations in the availability of medicines across the European Union. The range of drugs available in each country represents differences in regulatory and market policies, as well as cultural and historic differences. This directory lends itself to many further analyses.

Artifactual-free analysis of S-nitrosoglutathione and S-nitroglutathione by neutral-pH, anion-pairing, high-performance liquid chromatography. Study on peroxynitrite-mediated S-nitration of glutathione to S-nitroglutathione under physiological conditions.

The endogenous potent vasodilators and inhibitors of platelet aggregation S-nitrosoglutathione (GSNO) and S-nitroglutathione (GSNO2) are frequently analyzed by high-performance liquid chromatography (HPLC) using mobile phases of acidic pH. These systems are associated with problems stemming from rapid and considerable artifactual formation of GSNO from glutathione (GSH) and ubiquitous nitrite. We describe a novel ion-pairing HPLC method with UV absorbance detection at 334 nm for the highly specific and interference-free analysis of GSNO and GSNO2 in the presence of high GSH and nitrite concentrations. Complete avoidance of artifactual formation of GSNO was accomplished by using the anion-pairing agent tetrabutylammoniumhydrogen sulphate in the mobile phase that enables analysis of GSNO at neutral pH, at which GSH and nitrite do not react to form GSNO. This HPLC system was used to study formation of GSNO2 from GSH and peroxynitrite under physiological conditions. We found by this HPLC system that peroxynitrite (0-300 microM) reacts with GSH (0-5 mM) to form GSNO2 at a mean yield of 2%. Analysis of the same samples by a cation-pairing HPLC system with acidic mobile phase (pH 2.0) revealed, however, GSNO plus GSNO2 formation of the order of 20% due to on column reaction of GSH with peroxynitrite-derived nitrite to form GSNO. Ammonium sulfamate is frequently used to remove nitrite from thiol-containing solutions under acidic conditions. By means of the anion-pairing HPLC system it is demonstrated that nitrite removal by this method is incomplete even when ammonium sulfamate is used at high concentrations. These findings underscore the absolute requirement of neutral pH conditions for the analysis of GSNO. The novel anion-pairing HPLC method should be useful to provide reliable data on formation, reaction and metabolism of GSNO and GSNO2 in biological fluids using various detectors including mass spectrometers.

Drug expenditure in hospitals: what do German ward physicians know?

AIMS: Ward physicians hold key positions in the course of efforts to reduce drug expenditures in hospitals. This study evaluated the knowledge of German hospital physicians with respect to the daily therapeutic costs of 21 frequently used drugs. METHODS: A questionnaire survey was carried out among 168 ward physicians from university and municipal hospital departments of internal medicine. RESULTS: One hundred and twenty-seven physicians returned a completed questionnaire, a response rate of 75.6%. On average the physicians successfully identified both low cost and expensive drugs. The prices of inexpensive and moderately expensive drugs were generally overestimated whereas those for the expensive and highly expensive drugs were underestimated in 35% and 68% of respondents, respectively. CONCLUSIONS: The results of this survey of German hospital physicians suggest that a more economically efficient use of drugs could be achieved by an improved knowledge of daily therapeutic costs.

S-Transnitrosylation of albumin in human plasma and blood in vitro and in vivo in the rat.

S-Nitrosoalbumin (SNOALB) is the most abundant physiological circulating nitric oxide (NO) carrier regulating NO-dependent biological actions in humans. The mechanisms of its formation and biological actions are still incompletely understood. Nitrosation by authentic NO and S-transnitrosylation of the single sulfhydryl group located at Cys-34 of human albumin by the physiological S-nitroso compounds S-nitrosocysteine (SNOC) and S-nitrosoglutathione (GSNO) are two possible mechanisms. On a quantitative basis, we investigated by gas chromatography-mass spectrometry the contribution of these two mechanisms to SNOALB formation in human plasma and blood in vitro. GSNO and SNOC (0-100 microM) rapidly and efficiently (recovery=35%) S-transnitrosylated albumin to form SNOALB. NO (100 microM) S-nitrosated albumin to SNOALB at a considerably lower extent (recovery=5%). The putative NO-donating drugs glyceryl trinitrate and sodium nitroprusside (each 100 microM) failed completely in S-nitrosating albumin. Bubbling NO into human plasma and blood resulted in formation of SNOALB that inhibited ADP-induced platelet aggregation. Infusion of GS(15)NO in the rat resulted in formation of S(15)NOALB, [(15)N]nitrate and [(15)N]nitrite. Our results suggest that S-transnitrosylation of albumin by SNOC and GSNO could be a more favored mechanism for the formation of SNOALB in the circulation in vivo than S-nitrosation of albumin by NO itself.