Paracetamol has been found to competitively inhibit the sulfation of EE, with pretreatment of 1 g paracetamol significantly increasing the AUC levels of EE (by 22%) and decreasing the AUC levels of EE sulfate in women [REF].
The 19-nortestosterone progestins, gestodene and, to a lesser extent, desogestrel, have been found to inhibit cytochrome P450 enzymes and to progressively inhibit the metabolism and increase the concentrations of EE [REF].