Background The best polytherapy is associated with a major risk of adverse events (ADEs) and with an increase of both mortality and morbidity.

Purpose To evaluate the frequency of the appearance of ADEs in those patients undergoing polytherapy compared to the frequency of ADEs tied to monotherapy.

Materials and Methods Patients entering A.O ‘Gaetano Rummo’ of Benevento were monitored by a dedicated hospital pharmacist, over a period of twenty-four months, by collecting data concerning recorded ADEs and total value analysis (mono/polytherapy), the seriousness and the number of medications considered suspicious.

Results Out of 253 reports made, 140 (55.3%) involved patients undergoing polytherapy compared to 113 attributable to monotherapy. More precisely, 108 ADEs were considered ‘serious’ and 55.5% of these (60 cases) were due to the polytherapy. Out of 48 serious cases imputable to the use of one drug, just 1 has ended with the death of the patient (anaphylactic shock by ceftriaxone), 1 endangered the patient’s life and for 16 of them it was remedied by prolonging hospitalisation. Out of 145 cases which were considered by the detector as ‘not serious’, 80 proved to have been associated with polytherapy while 60 were relative to 1 medicine.

Conclusions The multi-drug approach represents a significant factor which can cause the appearance of ADEs. To improve health care it is desirable that competent professional figures, such as the pharmacist, would more often employed in a departmental activity of pharmacovigilance in order to develop a prior information network on the risk of medicine interactions and the proper use of the medication.

No conflict of interest.