Physicians' knowledge and attitudes regarding the spontaneous reporting system for adverse drug reactions.

The spontaneous reporting system (srs) is the most important early warning system of adverse drug reactions. As there is serious under-reporting we studied the respective knowledge and attitudes of two samples of physicians in Germany. Five hundred randomly sampled physicians and 815 physicians who had actually reported an ADR were included; the response rate to the mail questionnaire was 51.4 and 43.9%, respectively; 61.3% said to have reported at least one case in their life. As many as 75-85% of physicians said never to have sent an ADR report to the governmental or professional reporting systems. Reporting to pharmaceutical companies, on the other hand, has been substantially better. Sixty-eight and two-tenths percent indicated to have suspected an ADR without reporting it. Major reasons for not reporting were: ADR well known (75.6%), too trivial (71.1%), causality uncertain (66.3%). The ADR with the highest probability of being reported were serious unknown adverse reactions of a new drug (81.1%) or an established drug (72.9%) and serious known reactions to a new drug (65.2%). Almost 20% of the physicians admitted to not know the spontaneous reporting system and 30% to not know how to report; 54% would rather report an ADR if therapeutic advice was offered. The results indicate that the traditional ways of advertising the srs and communicating with physicians could be improved. Proactive services and professional marketing of srs are needed to reduce underreporting.

The "Phoenix" ADR database of the Drug Commission of the German Medical Profession--a clinically useful approach to optimize evidence-based medicine in Germany.

The innovative "Phoenix" database system of the Drug Commission of the German Medical Profession (AkdA) permits rapid access to data on adverse drug reactions. It enables the user to conduct searches covering a wide variety of questions within a short period of time. No one needs to be an "expert" to extract scientific knowledge from a database that currently already contains some 106,000 reports on adverse drug reactions. While our traditional apprenticeship model of physician training has served us well, an adaptation will be required for the new millennium. New tools are needed to allocate the available resources. Clinical proposals of experts or opinion leaders, guidelines, and highly graded clinical studies, like the use of clinical databases may help to improve safety and efficacy of drug administration. Evidence-based critical care medicine is therefore a potential tool for improving the effectiveness of drug therapy and for the patient's outcome. Over and above, the Phoenix database might be interpreted as an initiative instrument, which is easy to use and contributes to highlight the determinants of clinical decisions.

Analysis and occurrence of adverse events with oral anticoagulant therapy.

The antithrombotic potential of oral anticoagulants is undisputed as the frequency of recurrent thrombosis is high unless anticoagulant therapy is continued after hospital discharge. However, the relationship between potency and/or changes in anticoagulant therapy and frequency of complications remains unclear. Optimizing the clinical management of oral anticoagulation information obtained by databases may be advantageous in addition to meeting safety criteria, as described in the "Saarland Model." The Phoenix-database implicates an association between bleeding complications and the hypertensive elderly. From 1968 to 1993 most reports about cerebral/intraspinal bleedings occurred at prothrombin (PT)-values below 20% in the elder patients (>60 years of age) (12%; 367 reports). In the Saarland Model, 60 patients were followed from our department during a 3-year period. Our findings suggest neither a correlation of the range of PT values and the bleeding events nor an association with age or hypertension. It became obvious that "stable phases" of International Normalized Ratio (INR) [+/-15% change of 4 serial controls using nearly constant weekly oral anticoagulant dosages (+/-15%)] might be considered as a valid criterion of safety. At least the individual risk profile determines the patient's fate.

[Unwanted drug effects in clinical practice]. / Unerwünschte Arzneimittelwirkungen in der klinik.

BACKGROUND AND OBJECTIVE: Unwanted drug reactions (UDR) in routine clinical practice remain largely unrecorded, even though such documentation can significantly contribute to quality assurance in drug therapy. This prospective study was undertaken to ascertain within a defined time period the frequency and significance of UDR in the medical wards of a general hospital (focus on gastroenterology) and find the organisational structures needed for its documentation. PATIENTS AND METHODS: All observed UDRs among a total of 4032 in-patients were recorded on a simple registration form, filled in by doctors assigned to collect the information, which was then analysed in cooperation with the Drug Commission of the German Medical Council (AKdA). RESULTS: UDRs were recorded in 315 patients (7.8%), 135 of them (43%) already present on admission. 101 patients had been admitted because of the UDR. Gastrointestinal disorders, particularly peptic ulcer, and skin rash were the most common UDRs. Individual drugs most frequently responsible were acetylsalicylic acid, cyclophosphamide and digoxin, the most common drug groups were nonsteroid analgesics, antibiotics and cytostatic drugs. The method employed proved to be practicable and cost-effective. CONCLUSIONS: A simple and cost-effective system, integrated into the daily medical routine, can heighten awareness of UDRs among doctors and thus improve drug safety in hospitals, while concomitantly providing an important feature of further medical education.

Effects of medium amino acids on ouabain-sensitive 86Rb+ -uptake and membrane-potential dependent [3H]tetraphenylphosphonium accumulation in Friend erythroleukemia cells.

The effects of amino acids present in minimal essential medium were investigated on 86Rb+ -fluxes and on the membrane-potential dependent accumulation of the lipophilic cation [3H]tetraphenylphosphonium (TTP+) in logarithmically growing Friend erythroleukemia cells. The ouabain-sensitive 86Rb+ -uptake measured as well in complete growth medium as in Earle's balanced salt solution (EBSS) with amino acid composition present in growth medium, was 3 to 4-fold increased in comparison to the 86Rb+-uptake measured in pure EBSS only. The Na+,K+,2Cl- -cotransport measured as piretanide-sensitive 86Rb+-uptake was reduced in the presence of amino acids. Stimulation of the ouabain-sensitive 86Rb+ -uptake could be brought about by the addition of alanine alone or of the sodium ionophore monensin. In spite of the activation of the Na+,K+ -pump the membrane-potential dependent accumulation of [3H]TPP+ was about 40 per cent reduced in the presence of medium amino acids indicating a decreased membrane potential under these conditions. On the other hand, monensin which induces an electrically silent Na+ -influx via Na+/H+ -exchange was shown to hyperpolarize the membrane on the basis of [3H]TPP+-accumulation. These results suggest that the intensive uptake of neutral amino acids by Na+-cotransport in rapidly growing cells may be responsible for both stimulation of the Na+,K+ -pump and decrease in the transmembrane potential.

Influence of medium amino acids on the ouabain sensitive and insensitive 86Rb+-fluxes in HeLa cells.

Components of the 86Rb+-influx in HeLa cells were investigated in Joklik minimal essential medium, or in Earle's balanced salt solution with and without medium amino acids. The presence of amino acids led to the stimulation of the ouabain sensitive 86Rb+-uptake and inhibition of the diuretic-sensitive and residual 86Rb+-fluxes. These results show that the presence of amino acids is an important regulator of the K+/Rb+-fluxes under normal conditions in growth medium.

Erythroid differentiation and the Na+,K+-pump in ouabain-sensitive and ouabain-resistant Friend erythroleukemia cell lines.

The selection and biochemical characterization of ouabain-resistant erythroleukemia cell lines are described. Treatment of ouabain-resistant Friend erythroleukemia cell (FLC) lines with 1 mM ouabain demonstrated a reduced ouabain-sensitive 86Rb+-uptake after Na+-preloading in comparison with ouabain-sensitive cells. The ouabain- and diuretic (piretanide)-insensitive component of the 86Rb+-uptake (residual influx) was significantly enhanced in the ouabain-resistant FLC clones. Measurements of the Na+,K+-ATPase activity (E.C. 3.6.1.3) in plasma membrane preparations of the ouabain-resistant FLC clone B6/2 indicated that a ouabain-resistant Na+,K+-ATPase activity of about 20% of the total enzyme activity existed in the presence of 1 mM ouabain. Further experiments showed that the Na+,K+-ion-gradient in ouabain-resistant B6/2 cells was unaffected by ouabain exposure whereas the gradient collapsed in wild type 12 N cells. Another property of the ouabain-resistant cell lines was a decrease of the 86Rb+-uptake due to the Na+,K+, 2Cl(-)-cotransport system measured as piretanide-sensitive 86Rb+-uptake. The data on ion transport mechanisms in QuaR and QuaS FLC are discussed with respect to mutagen-induced and spontaneous cellular ouabain resistance. In addition, the role of altered ion transport mechanisms is considered for induced erythroid differentiation.

A reduction in the activity of the Na+, K+-pump in dimethylsulfoxide-treated Friend erythroleukemia cells is not due to partial inactivation of the Na+, K+-ATPase.

Treatment of Friend-erythroleukemia cells with 1.5% dimethylsulfoxide (DMSO) caused a decrease in ouabain sensitive 86Rb+-uptake beginning six to seven hours after DMSO addition indicating a reduced function of the Na+, K+-pump. However, analysis of the ouabain sensitive 86Rb+-uptake after Na+-preloading of the cells as well as measurements on the Na+, K+-ATPase activity in isolated membrane fragments revealed that no inhibition of the Na+, K+-ATPase occurred during the first 12 hours. On the contrary the Na+, K+-ATPase activity was initially enhanced and then returned to control levels during the early phase of induction by DMSO. On the other hand, 22Na+-transport into DMSO-treated cells was reduced similar to the ouabain sensitive 86Rb+ uptake in cells without Na+ preloading. The piretanide sensitive 86Rb+-uptake, due to the Na+, K+, 2Cl - cotransport system was inhibited after seven hours exposure to DMSO. Some three hours after DMSO addition the incorporation of 35S-methionine into proteins began to decrease, which was accompanied with or followed by a reduction in the methionine uptake of DMSO treated cells. Membrane-potential-dependent tetraphenylphosphonium cation uptake was not altered relative to the controls in the first 12 hours following DMSO addition. These results suggest that the reduced activity of the Na+, K+-pump in Friend cells after DMSO exposure is not due to inhibition of the Na+, K+-ATPase, but most probably due to a smaller Na+-influx, which results from inhibition of Na+-cotransport processes (amino acid uptake, Na+, K+, 2Cl - cotransport system).