Drug-drug interactions
Figure 1 shows the number of pDDIs in each category and exposed
patients. Interactions with severity scale of D and X were 17.8% of
total pDDIs (161 of 904). About 38% of the patients (86 of 227) were
exposed to at least one D or X interaction.
Drug combinations, frequency, reliability, mechanism, and applicable
recommendations for D and X interactions are shown in table 2 and 3,
respectively. Of the total pDDIs with severity scale of D and X, 23.6%
were unique drug pairs (the interaction occurred one time) (appendix 1).
The most frequent interactions were between lopinavir/ritonavir and
commonly used medications metabolized by cytochrome P450 3A4 (CYP3A4)
such as atorvastatin and alprazolam in D category and
salmeterol/fluticasone and tamsulosin in X category.