Interactions : אינטראקציות

4.5      Interaction with other medicinal products and other forms of interaction
Potential for other medicines to affect pharmacokinetics of abrocitinib 
Abrocitinib is metabolised predominantly by CYP2C19 and CYP2C9 enzymes, and to a lesser extent by CYP3A4 and CYP2B6 enzymes, and its active metabolites are renally excreted and are substrates of the organic anion transporter 3 

(OAT3). Therefore, exposures of abrocitinib and/or its active metabolites may be affected by medicinal products that inhibit or induce these enzymes and transporter. Dose adjustments, as appropriate, are outlined in section 4.2.

Co-administration with CYP2C19/CYP2C9 inhibitors

When 100 mg abrocitinib was administered concomitantly with fluvoxamine (a strong CYP2C19 and moderate CYP3A inhibitor) or fluconazole (a strong CYP2C19, moderate CYP2C9 and CYP3A inhibitor), the extent of exposure of abrocitinib active moiety (see section 5.2) increased by 91% and 155%, respectively, compared with administration alone (see section 4.2).

Co-administration with CYP2C19/CYP2C9 inducers

Administration of 200 mg abrocitinib after multiple doses with rifampicin, a strong inducer of CYP enzymes, resulted in reduction of abrocitinib active moiety exposures by approximately 56% (see section 4.2).

Co-administration with OAT3 inhibitors

When abrocitinib 200 mg was administered concomitantly with probenecid, an OAT3 inhibitor, abrocitinib active moiety exposures increased by approximately 66%. This is not clinically significant, and a dose adjustment is not needed.

Co-administration with products which increase gastric pH

When abrocitinib 200 mg was administered concomitantly with famotidine 40 mg, an H2-receptor antagonist, abrocitinib active moiety exposures decreased by approximately 35%. The effect of elevating gastric pH with antacids, or proton pump inhibitors (omeprazole) on the pharmacokinetics of abrocitinib has not been studied and may be similar to that seen with famotidine. The higher 200 mg daily dose should be considered for patients treated concomitantly with products which increase gastric pH, as they may reduce the efficacy of abrocitinib.

Potential for abrocitinib to affect pharmacokinetics of other medicinal products 
No clinically significant effects of abrocitinib were observed in interaction studies with oral contraceptives (e.g.
ethinyl oestradiol/levonorgestrel).

In vitro, abrocitinib is an inhibitor of P glycoprotein (P-gp). Co-administration of dabigatran etexilate (a P-gp substrate), with a single dose of abrocitinib 200 mg increased dabigatran AUCinf and Cmax by approximately 53% and 40%, respectively, compared with administration alone. Caution should be exercised for concomitant use of abrocitinib with dabigatran. The effect of abrocitinib on the pharmacokinetics of other P-gp substrates has not been evaluated. Caution should be exercised as the levels of P-gp substrates with a narrow therapeutic index, such as digoxin, may increase.

In vitro, abrocitinib is an inhibitor of CYP2C19 enzyme. Co-administration of abrocitinib 200 mg once daily with omeprazole 10 mg single dose increased the AUCinf and Cmax of omeprazole by approximately 189% and 134%, respectively, indicating that abrocitinib is a moderate inhibitor of CYP2C19 enzyme. Caution should be exercised when using abrocitinib concomitantly with narrow therapeutic index medicines that are primarily metabolised by CYP2C19 enzyme (e.g. S-mephenytoin and clopidogrel). Dose adjustment may be required for other medicines primarily metabolised by CYP2C19 enzyme in accordance with their product information (e.g. citalopram, clobazam, escitalopram and selumetinib).

Co-administration of abrocitinib 200 mg once daily with caffeine 100 mg single dose increased the AUCinf of caffeine by 40% with lack of effect on Cmax, suggesting that abrocitinib is a mild inhibitor of CYP1A2 enzyme. No general dose adjustment can be recommended.