[Pharmacological interactions of statins]

To determine in primary care the frequency of pharmacological interactions of statins.

Transversal observational study.Setting. Urban health centre.Participants. 384 patients taking statins who were chosen by systematic sampling based on long-treatment cards (95% CI, accuracy 5% and expected proportion of possible interactions unknown).

Consumption of statins, the accompanying medication taken, presence of interactions according to the technical details of statins (Spanish Medication Agency, Ministry of Health and Consumption) and social and demographic variables.

In 55 patients (14.3%) (95% CI, 10.8%-17.8%) one of the statin interactions with the other drugs was checked, especially with acenocoumarol, digoxin and anti-acid drugs. In patients with some interaction, the mean number of other drugs was significantly higher (4.51.5 vs 3.31.9 SD; P<.001). 19.1% of men and 10.8% of women showed interactions, the difference being statistically significant (P=.02). By means of logistic regression, both masculine gender (OR=1.8) and taking of other medication in quantities of 5 or more (OR=2.7) appeared as variables associated with the presence of interactions.

The potential pharmacological interactions of statins reach 14.3% of patients with hypercholesterolaemia who take medication long-term. The possibility of reaching high plasma concentrations of statins and/or of modifying the therapeutic effect of various drugs enables a more appropriate use of statins to be recommended, with prescription of those statins that metabolise less through the P450 cytochrome.