Interactions : אינטראקציות

4.5   Interaction with other medicinal products and other forms of interaction

In vitro studies showed that vinflunine had neither inducing effects on CYP1A2, CYP2B6 or CYP3A4 activity nor inhibition effects on CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4.

In vitro studies showed that vinflunine is a Pgp-substrate like other vinca alkaloids, but with a lower affinity. Therefore, risks of clinically significant interactions should be unlikely.
No pharmacokinetic interaction was observed in patients when vinflunine was combined with either cisplatin, carboplatin, capecitabine or gemcitabine.
No pharmacokinetic interaction was observed in patients when vinflunine was combined with doxorubicin. However, this combination was associated with a particularly high risk of haematological toxicity.

A phase I study evaluating the effect of ketoconazole treatment (a potent CYP3A4 inhibitor) on vinflunine pharmacokinetics indicated that co-administration of ketoconazole (400 mg orally once daily for 8 days) resulted in a 30% and 50% increase in blood exposures to vinflunine and its metabolite 4Odeacetyl-vinflunine (DVFL), respectively.

Therefore the concomitant use of vinflunine and potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, itraconazole and grapefruit juice) or inducers (such as rifampicin and Hypericum perforatum (St John’s wort)) should be avoided since they may increase or decrease vinflunine and DVFL concentrations (see section 4.4 and 5.2).

The concomitant use of vinflunine with others QT/QTc interval prolonging medical products should be avoided (see section 4.4).

A pharmacokinetic interaction between vinflunine and pegylated/liposomal doxorubicin was observed, resulting in a 15% to 30% apparent increase in vinflunine exposure and a 2 to 3-fold apparent decrease of doxorubicin AUC, whereas for doxorubicinol, the concentrations of the metabolite were not affected. According to an in vitro study, such changes could be related to adsorption of vinflunine on the liposomes and a modified blood distribution of both compounds. Therefore, caution should be excercised when this type of combination is used.

A possible interaction with paclitaxel and docetaxel (CYP3 substrates) has been suggested from an in vitro study (slight inhibition of vinflunine metabolism). No specific clinical studies of vinflunine in combination with these compounds have been carried out yet.

The concomitant use of opioids could enhance the risk of constipation.