[Risk of pharmacological interactions due to the co-administration of statins and cytochrome P450 isoenzyme 3A4-metabolized drugs: multicentre, crossover study].

Background And Objectives: Statins are safe but have a significant potential for pharmacological interactions. The objective of the study was to evaluate the prevalence of potential interactions throughout the cytochrome P450 isoenzyme 3A4 (CYP3A4) system in a large sample of statin-treated subjects and to determine which factors, from the patient and the physician, were associated with a higher risk of interactions.

Patients And Methods: This is an observational, cross-over, population study that included 7,880 subjects treated with statins. Both data from patients and from the1,681 participating physicians were recorded and analyzed.

Results: Fifty-nine percent of the participants were receiving a statin metabolized by the CYP3A4, and 21.5% of all participants received a drug, different from a statin, metabolized by the CYP3A4. There were no differences in the frequency of utilization of statins metabolized or not by the CYP3A4 in relation to the simultaneous prescription of drugs metabolized by the same pathway (22 vs. 21%, respectively). Globally, 12.9% of all participants were at risk of an interaction. These patients were older, received a higher number of drugs and had more comorbidity. Sixty percent of the physicians mentioned that the possibility of an interaction greatly conditioned their selection of a particular statin. Likewise, 56% of them had software that alerted of possible interactions. These aspects, however, did not influence the number of patients at risk of interactions.

Conclusion: The proportion of statin-treated patients at risk of interaction is elevated. Physicians do not usually pay attention to this possibility despite having available alert software and therapeutic alternatives.