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F Haramburu

Publications and source records attributed to F Haramburu.

At least 19 recordsLinked to original sources
PubMed1994

Adverse drug reactions: physicians' opinions versus a causality assessment method.

Since spontaneous reporting of adverse drug reactions depends on the physician's opinion of the relationship between the drug and the adverse event, we compared physicians' opinions with the scores obtained by the causality assessment method used in France. During a 2 month period, all physicians who reported adverse drug reactions (ADRs) to our pharmacovigilance centre expressed their opinions on the causal link by means of visual analogue scales. ADR reports were then assessed with the French causality assessment method by a clinical pharmacologist who was blind to physicians' opinions. The assessment by both physicians and the standardized method was performed for 75 ADR cases involving 120 drugs. Physicians used a wide range of assessments, with a preponderance of extreme scores, resulting in a U-shaped distribution, while the standardized method gave generally low scores. Scores given by physicians were very high (causality considered very likely or likely) in 60% of cases and very low (causality considered unlikely or dubious/possible) in 32% of cases. Scores obtained using the causality assessment method were low (causality dubious/possible) in 89% of cases and causality considered likely in only 11 cases, essentially in cases with positive rechallenge. Complete agreement occurred in only 6% of cases. Adding complete agreement and minor discrepancies raised the percentage to 49%.

Adverse Drug Reaction Reporting Systems↗
PubMed1994

False-positives in spontaneous reporting: should we worry about them?

Spontaneous reporting remains the most used and, undoubtedly, the most cost-effective approach for the identification of adverse drug reactions (ADRs). Most of the limitations of this method are well recognised but the possibility of receiving false-positive reports of coincidental drug-event associations has received little attention. In this paper we propose a method based on the Poisson distribution for computing the maximum number of reports of an ADR that could be expected to be reported coincidentally. Three parameters are required: (i) the background risk of the event in the reference population, (ii) the total number of patients treated with the drug considered and, (iii) the proportion of cases that have been reported to the pharmacovigilance system. For most empirical situations occurring in the post-marketing surveillance setting, the expected number remains low and only a maximum of one to three cases could be accepted as possibly coincidental. For rare adverse events such as agranulocytosis or toxic epidermal necrolysis, coincidental associations are so unlikely that a number of reports greater than three constitutes a strong warning and requires further investigation. These findings suggest that for rare events, reports of coincidental drug-event associations are too unlikely to be considered as an important limitation of spontaneous reporting.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1994

[Organization and results of drug vigilance in France].

Pharmacovigilance represents all methods of detection, assessment, information and prevention of adverse drug reactions (ADRs). It mainly involves the post-marketing phase because of the low probability of detecting all possible adverse effects of a drug during pre-marketing development. The most widely used method for pharmacovigilance is spontaneous reporting which is an excellent signal generator but precludes satisfactory calculation of incidence rates. The French Pharmacovigilance System has been set up in 1973; reporting of ADRs has been made mandatory in 1984 for prescribers. This system consists in a network of 30 regional centres under supervision of a coordinating committee at the French Drug Agency. The number of ADR cases received, assessed and recorded by the regional centres is around 10,000 per year; a similar number of cases are reported to the Drug Agency by the pharmaceutical industry. Moreover, Regional Centres work as Drug Information Centres answering more than 23,000 inquiries per year.

Adverse Drug Reaction Reporting Systems↗
PubMed1992

Power and weakness of spontaneous reporting: a probabilistic approach.

It has been clearly demonstrated that spontaneous reporting remains one of the best ways for picking up new adverse drug reactions (ADRs) once a drug is on the market. The probability of revealing a new ADR by spontaneous reporting was studied as a function of reporting rate, strength of drug-event association (relative risk), background incidence of the event and number of patients treated. The model included determination of (i) the probability of reporting at least one drug-event association case and (ii) the overall probability of concluding that the drug-event association is not coincidental. Both probabilities were generally low. The results suggest that the identification of a new risk by spontaneous reporting implies a strong association between the drug treatment and the occurrence of the event.

Adverse Drug Reaction Reporting Systems↗
PubMed1991

Spontaneous reporting: how many cases are required to trigger a warning?

A statistical method is proposed to aid decisions on the recognition of new adverse drug reactions on the basis of spontaneous reports. The maximal number of associations between drug exposure and event is calculated from an independence test between drug and event, taking into account the expected incidence of that particular event in the general population. An example is given which illustrates the method.

Chemical and Drug Induced Liver Injury↗
PubMed1990

Comparison of 500 spontaneous and 500 published reports of adverse drug reactions.

The information and case quality of 500 spontaneous and 500 published adverse drug reaction (ADR) reports were compared, including a study of the most common criteria used in different causality assessment methods. The criteria were more often of positive value in the published reports. Nevertheless, spontaneous reports play an important role in the detection of new ADRs.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1986

Computerized comparison of six adverse drug reaction assessment procedures.

Several standardized assessment procedures are currently used in the evaluation of adverse drug reactions (ADRs). Disagreement in rating ADRs can result from between-raters variability and between-methods differences in weighting the evidence. We eliminated between-raters variability by computer simulation of 1134 ADRs (including all the possible combinations of criteria currently used) and by automatic rating using different algorithms adapted from six published methods. Percentage agreement (Po) and weighted kappa test (kappa w) between pairs of methods are always better than with randomized scores, but the strength of agreement is only moderate (0.26 less than Po less than 0.59; 0.14 less than kappa w less than 0.51). The weightings of criteria are evaluated in terms of sensitivity, specificity, and predictive values. Criteria are neither sensitive (0.41 less than Se less than 0.70) nor specific (0.18 less than Sp less than 0.63) and have poor predictive values. Disagreements on weightings are considerable for three major criteria: timing of event, dechallenge, and alternative etiologic candidates. We discuss some ways of improving reliability of ADR diagnosis.

Computers↗
PubMedDate not supplied

[Computerized data processing in the Pharmacovigilance Center of Bordeaux-Aquitaine. Analysis of clientele of the Center].

Practitioners inquiries addressed to our Drug Information Centre are computerized since 1986. Their analysis allows to pinpoint special problems and needs for practitioners information, and to detect new adverse drug reactions. Time series analysis of calls (according to the practitioners specialities or geographic stay) allows to evaluate the effectiveness of the services provided by the Bordeaux Drug Information Centre.

Drug Information Services↗