ZAPATER HERNANDEZ, P.; HORGA DE LA PARTE, J. F.    GARCIA, A. G.. Risk of agranulocytosis associated to drugs: an approach to the analysis of risks using spontaneous reporting of agranulocytosis associated to calcium dobesilate treatment. []. , 19, 6, pp.9-18. ISSN 0212-7199.

Background: Frequently, decissions about the safety of drugs are based on isolated cases of patients that develop a disease, while they have been taken a drug. A new method to detect, using spontaneous reporting, increases in agranulocytosis risk among patients treated with calcium dobesilate is shown. Method: Using data of dobesilate sales, the maximum number of patients treated in a year was calculated. Spontaneous reports of agranulocytosis associated to dobesilate notified along the period 1985-2000 were identified. The number and the maximum number of cases explained by the agranulocytosis risk in a general population were calculated using the distribution of Poisson, assuming several reporting rates. Similarly, the influence of number of patients older than 60 and the duration of exposure to the drug were analysed. Results: The number of spontaneously reporting cases of agranulocytosis associated to dobesilate, in the period 1985 - 2000 was not greater than the maximum number of cases predicted by the agranulocytosis risk in a general population. Probably, a high number of dobesilate - treated patients had an advanced age and/or took the drug during several months. In these conditions, it is more difficult to identify an increase of risk associated to drug. Conclusions: To calculate the risk of agranulocytosis associated to a drug is required to consider the basal risk of agranulocytosis in a general population as well as its possible modifications in the population of patients treated with the drug. 

: Adverse drug reaction reporting systems; Poisson distribution; Risk assessment; Calcium dobesilate; Agranulocytosis.

        · |     · |     · ( pdf )