Interactions : אינטראקציות

4.5    Interaction with other medicinal products and other forms of interaction

The potential for CYP450 mediated interactions involving adefovir with other medicinal products is low, based on the results of in vitro experiments in which adefovir did not influence any of the common CYP isoforms known to be involved in human drug metabolism and based on the known elimination pathway of adefovir. A clinical study in liver-transplant patients has shown that no pharmacokinetic interaction occurs when adefovir dipivoxil 10 mg once daily is administered concomitantly with tacrolimus, an immunosuppressant which is predominantly metabolised via the CYP450 system. A pharmacokinetic interaction between adefovir and the immunosuppressant, cyclosporin, is also considered unlikely as cyclosporin shares the same metabolic pathway as tacrolimus. Nevertheless, given that tacrolimus and cyclosporin can affect renal function, close monitoring is recommended when either of these agents is coadministered with adefovir dipivoxil (see section 4.4).

Concomitant administration of 10 mg adefovir dipivoxil and 100 mg lamivudine did not alter the pharmacokinetic profile of either medicinal product.

Adefovir is excreted renally, by a combination of glomerular filtration and active tubular secretion.
Co-administration of 10 mg adefovir dipivoxil with other medicinal products that are eliminated by 

tubular secretion or alter tubular function may increase serum concentrations of either adefovir or the co-administered medicinal product (see section 4.4).

Due to the high pharmacokinetic variability of pegylated interferon, no definitive conclusion can be drawn regarding the effect of adefovir and pegylated interferon co-administration on the pharmacokinetic profile of either medicinal product. Even though a pharmacokinetic interaction is unlikely given the two products are eliminated via different pathways, caution is recommended if both products are co-administered.

Paediatric population
Interaction studies have only been performed in adults.