Dulaglutide delays gastric emptying and has the potential to impact the rate of absorption of concomitantly administered oral medicinal products. In the clinical pharmacology studies described as follows, dulaglutide did not affect the absorption of the orally administered medications tested to any clinically relevant degree. However, for patients receiving oral medicinal products requiring rapid gastrointestinal absorption or prolonged release formulations the potential for altered drug exposure should be considered.
Sitagliptin: Sitagliptin exposure was unaffected when coadministered with a single dose of dulaglutide. Following coadministration with 2 consecutive doses of dulaglutide, sitagliptin AUC(0-τ) and Cmax decreased by approximately 7.4 % and 23.1 %, respectively. Sitagliptin tmax increased approximately 0.5 hours following coadministration with dulaglutide compared to sitagliptin alone.
Sitagliptin can produce up to 80 % inhibition of DPP-4 over a 24-hour period. Dulaglutide coadministration with sitagliptin increased dulaglutide exposure and Cmax by approximately 38 % and 27 %, respectively, and median tmax increased approximately 24 hours. Therefore, dulaglutide does have a high degree of protection against DPP-4 inactivation (see Pharmacology: Pharmacodynamics: Mechanism of action under Actions). The increased exposure may enhance the effects of dulaglutide on blood glucose levels.
Paracetamol: Following a first dose of 1 and 3 mg dulaglutide, paracetamol Cmax was reduced by 36 % and 50 %, respectively, and the median tmax occurred later (3 and 4 hours, respectively). After coadministration with up to 3 mg of dulaglutide at steady state, there were no statistically significant differences on AUC(0-12), Cmax or tmax of paracetamol. No dose adjustment of paracetamol is necessary when administered with dulaglutide.
Atorvastatin: Coadministration of dulaglutide with atorvastatin decreased Cmax and AUC(0-∞) up to 70 % and 21 %, respectively, for atorvastatin and its major metabolite o-hydroxyatorvastatin. The mean t1/2 of atorvastatin and o-hydroxyatorvastatin were increased by 17 % and 41 %, respectively, following dulaglutide administration. These observations are not clinically relevant. No dose adjustment of atorvastatin is necessary when administered with dulaglutide.
Digoxin: After coadministration of steady state digoxin with 2 consecutive doses of dulaglutide, overall exposure (AUCτ) and tmax of digoxin were unchanged; and Cmax decreased by up to 22 %. This change is not expected to have clinical consequences. No dose adjustment is required for digoxin when administered with dulaglutide.
Anti-hypertensives: Coadministration of multiple dulaglutide doses with steady state lisinopril caused no clinically relevant changes in the AUC or Cmax of lisinopril. Statistically significant delays in lisinopril tmax of approximately 1 hour were observed on Days 3 and 24 of the study. When a single dose of dulaglutide and metoprolol were coadministered, the AUC and Cmax of metoprolol increased by 19 % and 32 %, respectively. While metoprolol tmax was delayed by 1 hour, this change was not statistically significant. These changes were not clinically relevant; therefore no dose adjustment of lisinopril or metoprolol is necessary when administered with dulaglutide.
Warfarin: Following dulaglutide coadministration, S- and R-warfarin exposure and R-warfarin Cmax were unaffected, and S-warfarin Cmax decreased by 22 %. AUCINR increased by 2 %, which is unlikely to be clinically significant, and there was no effect on maximum international normalised ratio response (INRmax). The time of international normalised ratio response (tINRmax) was delayed by 6 hours, consistent with delays in tmax of approximately 4 and 6 hours for S- and R-warfarin, respectively. These changes are not clinically relevant. No dose adjustment for warfarin is necessary when given together with dulaglutide.
Oral contraceptives: Coadministration of dulaglutide with an oral contraceptive (norgestimate 0.18 mg/ethinyl estradiol 0.025 mg) did not affect the overall exposure to norelgestromin and ethinyl estradiol. Statistically significant reductions in Cmax of 26 % and 13 % and delays in tmax of 2 and 0.30 hours were observed for norelgestromin and ethinyl estradiol, respectively. These observations are not clinically relevant. No dose adjustment for oral contraceptives is required when given together with dulaglutide.
Metformin: Following coadministration of multiple dose dulaglutide with steady state metformin (immediate release formula [IR]), metformin AUCτ increased up to 15 % and Cmax decreased up to 12 %, respectively, with no changes in tmax. These changes are consistent with the gastric emptying delay of dulaglutide and within the pharmacokinetic variability of metformin and thus are not clinically relevant. No dose adjustment for metformin IR is recommended when given with dulaglutide.