Interactions : אינטראקציות

4.5     Interaction with other medicinal products and other forms of interaction
Concomitant use of medicinal products known to inhibit lipase should be given with caution as glycerol phenylbutyrate is hydrolysed by digestive lipase into phenylbutyrate acid and glycerol. This may be associated with increased risk of medicinal product interactions with lipase inhibitors and with lipase contained in pancreatic enzyme replacement therapies.

A potential effect on CYP2D6 isoenzyme cannot be excluded and caution is advised for patients who receive medicinal products that are CYP2D6 substrates.

Glycerol phenylbutyrate and/or its metabolites, PAA and PBA, have been shown to be weak inducers of CYP3A4 enzyme in vivo. In vivo exposure to glycerol phenylbutyrate has resulted in decreased systemic exposure to midazolam of approximately 32% and increased exposure to the 1-hydroxy metabolite of midazolam, suggesting that steady-state dosing of glycerol phenylbutyrate results in CYP3A4 induction. The potential for interaction of glycerol phenylbutyrate as a CYP3A4 inducer and Ravicti-SPC-0423-V1
those products predominantly metabolised by the CYP3A4 pathway is possible. Therefore, therapeutic effects and/or metabolite levels of medicinal products, including some oral contraceptives that are substrates for this enzyme may be reduced and their full effects cannot be guaranteed, following co- administration with glycerol phenylbutyrate.

Other medicinal products such as corticosteroids, valproic acid, haloperidol and probenecid may have the potential to affect ammonia levels, see section 4.4.

The effects of glycerol phenylbutyrate on cytochrome P450 (CYP) 2C9 isoenzyme and potential for interaction with celecoxib has been studied in humans with no evidence of an interaction observed.

Effects of glycerol phenylbutyrate on other CYP isoenzymes have not been studied in humans and cannot be excluded.

Compatibility studies have demonstrated glycerol phenylbutyrate chemical and physical in-use stability with the following foods and nutritional supplements: apple sauce, ketchup, squash puree, and five medical formulas (Cyclinex-1, Cyclinex-2, UCD-1, UCD-2, Polycose, Pro Phree and Citrulline) typically consumed by UCD patients (see section 4.2).