[Something more about adverse reactions to medications]

To describe adverse drug effects (ADE) and their frequency in primary care patients.

Descriptive and longitudinal study during 1 year (1990).

Urban Health Center. Primary Care. Madrid (Spain).

15,483 persons, nine general practitioner and one pharmacist.

Doctors were invited to register any adverse drug effects they had notice in their patients. Doctors registered information and gave notice to the pharmacist about medicines, dosage and period of administration, clinical manifestations, and improving or not if drug was withdrawal.

326 adverse drugs effects were notified, 30.9 ADE per thousand attended patients. 117 principles actives were involved, and 415 clinical manifestations were registered. The more affected patients were women (2/1). The age groups with higher ADE relative frequencies were children under one year and older people.

The absolute frequency of medicines involved in ADE are different to relative frequencies when ADE per thousand prescription units are used. Some of the ADE notified were not referred before in the bibliography, so primary care is a good place to research on pharmacosurveillance.