Potential DDIs far outnumber actual drug interactions. The potential for an adverse interaction to occur is often theoretical, and clinically important adverse effects occur only in the presence of specific risk factors. Several studies have shown the efficacy of computers in early detection of DDIs. However, a correct risk-benefit evaluation by the prescribing physician, together with a careful clinical, physiological and biochemical monitoring of patients, is essential. Future directions of drug interaction research include the increasing importance of pharmacogenetics in preventing DDIs and the evaluation of interactions with biological drugs.

Aims Cutaneous manifestations are frequently reported in association with drug use. The aim of this study was to analyse the skin reactions reported to the spontaneous surveillance systems of four Italian regions (Friuli Venezia Giulia, Lombardy, Sicily and the Veneto), and correlate the reports with estimated drug consumption during the same period, paying particular attention to the reactions to antimicrobial agents and nonsteroidal anti-inflammatory drugs (NSAIDs). Methods All of the adverse drug reactions (ADRs) reported spontaneously between January 1996 and December 1997 to the surveillance systems of four Italian regions (a total population of about 20 million people) were analysed by a panel of experts including dermatologists. On the basis of the Critical Term List of the World Health Organization (WHO), the reactions were classified as either serious or nonserious events. Drug consumption was expressed as a daily defined dose (DDD)/1000 inhabitants/day. Results A total of 2224 adverse skin reaction reports (44.7% of all of the reported ADRs) were identified, making a reporting rate of about 5.5 per 100 000 inhabitants/year. The female/male ratio was 1.58, and the reporting rate progressively increased with age. The drug categories with the highest number of cutaneous reactions were antimicrobials, followed by NSAIDs, analgesics and radiology contrast media. There was a total of 372 (16.9%) serious reaction reports, the most frequent being angioedema (171 cases), erythema multiforme (68 cases) and photosensitivity (37 cases). Co-trimoxazole, followed by the cephalosporins and fluoroquinolones, were associated with the highest consumption-related reporting rate among the antimicrobials, and aspirin and dipyrone among the NSAIDs and analgesics. Conclusions Spontaneous reports from four Italian regions revealed that the skin was the organ most frequently affected by ADRs. The paper shows the validity of a regional decentralized system in Italy. health service use and costs [4, 6]. Keywords

Large spontaneous reporting databases represent an important source for signal detection of rare adverse drug reactions (ADR), such as TdP. The number of reports associated to donepezil, famotidine and mitoxantrone could be considered unexpected on the basis of current evidence and needs further investigations on their true TdP-liability.

No abstract